WorldWideScience

Sample records for volume histogram dvh

  1. Dose evaluation of organs at risk (OAR) cervical cancer using dose volume histogram (DVH) on brachytherapy

    Science.gov (United States)

    Arif Wibowo, R.; Haris, Bambang; Inganatul Islamiyah, dan

    2017-05-01

    Brachytherapy is one way to cure cervical cancer. It works by placing a radioactive source near the tumor. However, there are some healthy tissues or organs at risk (OAR) such as bladder and rectum which received radiation also. This study aims to evaluate the radiation dose of the bladder and rectum. There were 12 total radiation dose data of the bladder and rectum obtained from patients’ brachytherapy. The dose of cervix for all patients was 6 Gy. Two-dimensional calculation of the radiation dose was based on the International Commission on Radiation Units and Measurements (ICRU) points or called DICRU while the 3-dimensional calculation derived from Dose Volume Histogram (DVH) on a volume of 2 cc (D2cc). The radiation dose of bladder and rectum from both methods were analysed using independent t test. The mean DICRU of bladder was 4.33730 Gy and its D2cc was4.78090 Gy. DICRU and D2cc bladder did not differ significantly (p = 0.144). The mean DICRU of rectum was 3.57980 Gy and 4.58670 Gy for D2cc. The mean DICRU of rectum differed significantly from D2cc of rectum (p = 0.000). The three-dimensional method radiation dose of the bladder and rectum was higher than the two-dimensional method with ratios 1.10227 for bladder and 1.28127 for rectum. The radiation dose of the bladder and rectum was still below the tolerance dose. Two-dimensional calculation of the bladder and rectum dose was lower than three-dimension which was more accurate due to its calculation at the whole volume of the organs.

  2. SU-E-T-525: Dose Volume Histograms (DVH) Analysis and Comparison with ICRU Point Doses in MRI Guided HDR Brachytherapy for Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Badkul, R; McClinton, C; Kumar, P; Mitchell, M [University of Kansas Medical Center, Kansas City, KS (United States)

    2014-06-01

    Purpose: Brachytherapy plays a crucial role in management of cervix cancer. MRI compatible applicators have made it possible to accurately delineate gross-target-volume(GTV) and organs-at-risk(OAR) volumes, as well as directly plan, optimize and adapt dose-distribution for each insertion. We sought to compare DVH of tumor-coverage and OARs to traditional Point-A, ICRU-38 bladder and rectum point-doses for four different planning-techniques. Methods: MRI based 3D-planning was performed on Nucletron-Oncentra-TPS for 3 selected patients with varying tumor-sizes and anatomy. GTV,high-risk-clinical-target-volume(HR-CTV), intermediate-risk-clinical-target-volume(IR-CTV) and OARs: rectum, bladder, sigmoid-colon, vaginal-mucosa were delineated. Three conventionally used techniques: mg-Radium-equivalent(RaEq),equal-dwell-weights(EDW), Medical-College-of-Wisconsin proposed points-optimization (MCWO) and a manual-graphical-optimization(MGO) volume-coverage based technique were applied for each patient. Prescription was 6Gy delivered to point-A in Conventional techniques (RaEq, EDW, MCWO). For MGO, goal was to achieve 90%-coverage (D90) to HR-CTV with prescription-dose. ICRU point doses for rectum and bladder, point-A doses, DVH-doses for HR-CTV-D90,0.1cc-volume(D0.1),1ccvolume( D1),2cc-volume(D2) were collected for all plans and analyzed . Results: Mean D90 for HR-CTV normalized to MGO were 0.89,0.84,0.9,1.0 for EDW, RaEq, MCWO, MGO respectively. Mean point-A doses were 21.7% higher for MGO. Conventional techniques with Point-A prescriptions under covered HR-CTV-D90 by average of 12% as compared to MGO. Rectum, bladder and sigmoid doses were highest in MGO-plans for ICRU points as well as D0.1,D1 and D2 doses. Among conventional-techniques, rectum and bladder ICRU and DVH doses(0.1,1,2cc) were not significantly different (within 7%).Rectum D0.1 provided good estimation of ICRU-rectum-point doses (within 3.9%),rectum D0.1 were higher from 0.8 to 3.9% while bladder D0

  3. 基于DVH目标函数的VMAT计划设计研究%DVH Obejective informed Planning in volume modulated arc therapy

    Institute of Scientific and Technical Information of China (English)

    金建华; 储开岳; 商海焦; 刘海涛; 吴建亭; 赵永亮; 曹顾飞

    2015-01-01

    Objective To study the novel methods of VMAT planning based dose volume histogram ( DVH) optimization, evaluated the dosimetry and planning efficiency in VMAT planning for Esophageal Carcinoma. Methods Twelve Esophageal carcinoma patients were enrolled in this study. The conventional VMAT planning as the reference, using multi⁃criterion optimization DVH ( MCO⁃DVH ) and overlapping volume histogram prediction DVH ( OVH⁃DVH ) two different methods to get ideal objectives function for informing VMAT plans, Then evaluate the dosimetric, planning efficiency for all new VMAT plans. The difference between the paired t⁃test groups. Results The two VMAT plans based DVH objective function can meet the clinical needs. Compared with the conventional VMAT plan, Conformity index ( CI ) and Homogeneity index ( 0. 77 vs. 0. 72, P=0. 017 and 0. 10 vs. 0. 12, P=0. 047 ) is better in DVH informed plans;lung V5 and spinal cord V50 are better in MCO⁃DVH informed plan (54. 66 vs.60. 23,P=0. 013 and 0. 98 vs.0. 49,P=0. 037).Furthermore,the DVH informed plans had higher planning efficiency (8. 2 vs. 19. 5,P=0. 023) . Conclusions DVH Objective informed VMAT Planning can achieve clinical needs with much uniform dose to target,lower OAR dose and higher planning efficiency.%目的:研究基于DVH目标函数设计VMAT计划的新方法,并应用到临床食管癌患者中评估所得计划的剂量学特性和计划效率。方法对12例胸段食管癌患者以常规VMAT计划方式为参照,分别采用基于多目标优化DVH ( MCO⁃DVH)目标函数和重叠体积预测DVH ( OVH⁃DVH)目标函数设计两组VMAT计划,评估所得VMAT计划的剂量学特性、计划效率。配对t检验组间差异。结果基于DVH目标函数的两组VMAT计划均满足临床要求,与常规VMAT计划相比,靶区适形指数和均匀指数较优(0.77∶0.72,P=0.017和0.10∶0.12,P=0.047);MCO⁃VMAT计划中OAR双肺V5和脊髓V50

  4. Introducing the Jacobian-volume-histogram of deforming organs: application to parotid shrinkage evaluation.

    Science.gov (United States)

    Fiorino, Claudio; Maggiulli, Eleonora; Broggi, Sara; Liberini, Simone; Cattaneo, Giovanni Mauro; Dell'oca, Italo; Faggiano, Elena; Di Muzio, Nadia; Calandrino, Riccardo; Rizzo, Giovanna

    2011-06-07

    The Jacobian of the deformation field of elastic registration between images taken during radiotherapy is a measure of inter-fraction local deformation. The histogram of the Jacobian values (Jac) within an organ was introduced (JVH-Jacobian-volume-histogram) and first applied in quantifying parotid shrinkage. MVCTs of 32 patients previously treated with helical tomotherapy for head-neck cancers were collected. Parotid deformation was evaluated through elastic registration between MVCTs taken at the first and last fractions. Jac was calculated for each voxel of all parotids, and integral JVHs were calculated for each parotid; the correlation between the JVH and the planning dose-volume histogram (DVH) was investigated. On average, 82% (±17%) of the voxels shrinks (Jac 50% (Jac Jac Jac0.5Jac and the JVH are promising tools for scoring/modelling toxicity and for evaluating organ/contour variations with potential applications in adaptive radiotherapy.

  5. Development of a Quality Assurance Procedure for Dose Volume Histogram Analysis

    Science.gov (United States)

    Davenport, David A.

    The role of the dose-volume histogram (DVH) is rapidly expanding in radiation oncology treatment planning. DVHs are already relied upon to differentiate between two similar plans and evaluate organ-at-risk dosage. Their role will become even more important as progress continues towards implementing biologically based treatment planning systems. Therefore it is imperative that the accuracy of DVHs is evaluated and reappraised after any major software or hardware upgrades, affecting a treatment planning system (TPS). The purpose of this work is to create and implement a comprehensive quality assurance procedure evaluating dose volume histograms to insure their accuracy while satisfying American College of Radiology guidelines. Virtual phantoms of known volumes were created in Pinnacle TPS and exposed to different beam arrangements. Variables including grid size and slice thickness were varied and their effects were analyzed. The resulting DVHs were evaluated by comparison to the commissioned percent depth dose values using a custom Excel spreadsheet. After determining the uncertainty of the DVH based on these variables, multiple second check calculations were performed using MIM Maestro and Matlab software packages. The uncertainties of the DVHs were shown to be less than +/- 3%. The average uncertainty was shown to be less than +/- 1%. The second check procedures resulted in mean percent differences less than 1% which confirms the accuracy of DVH calculation in Pinnacle and the effectiveness of the quality assurance template. The importance of knowing the limits of accuracy of the DVHs, which are routinely used to assess the quality of clinical treatment plans, cannot be overestimated. The developed comprehensive QA procedure evaluating the accuracy of the DVH statistical analysis will become a part of our clinical arsenal for periodic tests of the treatment planning system. It will also be performed at the time of commissioning and after any major software

  6. Introducing the Jacobian-volume-histogram of deforming organs: application to parotid shrinkage evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Fiorino, Claudio; Maggiulli, Eleonora; Broggi, Sara; Cattaneo, Giovanni Mauro; Calandrino, Riccardo [Medical Physics, San Raffaele Scientific Institute, Milano (Italy); Liberini, Simone; Faggiano, Elena; Rizzo, Giovanna [Institute of Molecular Bioimaging and Physiology, CNR, Segrate (Italy); Dell' Oca, Italo; Di Muzio, Nadia, E-mail: fiorino.claudio@hsr.it [Radiotherapy, San Raffaele Scientific Institute, Milano (Italy)

    2011-06-07

    The Jacobian of the deformation field of elastic registration between images taken during radiotherapy is a measure of inter-fraction local deformation. The histogram of the Jacobian values (Jac) within an organ was introduced (JVH-Jacobian-volume-histogram) and first applied in quantifying parotid shrinkage. MVCTs of 32 patients previously treated with helical tomotherapy for head-neck cancers were collected. Parotid deformation was evaluated through elastic registration between MVCTs taken at the first and last fractions. Jac was calculated for each voxel of all parotids, and integral JVHs were calculated for each parotid; the correlation between the JVH and the planning dose-volume histogram (DVH) was investigated. On average, 82% ({+-}17%) of the voxels shrinks (Jac < 1) and 14% ({+-}17%) shows a local compression >50% (Jac < 0.5). The best correlation between the DVH and the JVH was found between V10 and V15, and Jac < 0.4-0.6 (p < 0.01). The best constraint predicting a higher number of largely compressing voxels (Jac0.5<7.5%, median value) was V15 {>=} 75% (OR: 7.6, p = 0.002). Jac and the JVH are promising tools for scoring/modelling toxicity and for evaluating organ/contour variations with potential applications in adaptive radiotherapy.

  7. Sensitivity of volumetric modulated arc therapy patient specific QA results to multileaf collimator errors and correlation to dose volume histogram based metrics.

    LENUS (Irish Health Repository)

    Coleman, Linda

    2013-11-01

    This study investigates the impact of systematic multileaf collimator (MLC) positional errors on gamma analysis results used for quality assurance (QA) of Rapidarc treatments. In addition, this study evaluates the relationship of these gamma analysis results and clinical dose volume histogram metrics (DVH) for Rapidarc treatment plans.

  8. Evaluation of DVH-based treatment plan verification in addition to gamma passing rates for head and neck IMRT

    NARCIS (Netherlands)

    Visser, Ruurd; Wauben, David J. L.; de Groot, Martijn; Steenbakkers, Roel J. H. M.; Bijl, Henk P.; Godart, Jeremy; van t Veld, Aart; Langendijk, Johannes A.; Korevaar, Erik W.

    Background and purpose: Treatment plan verification of intensity modulated radiotherapy (IMRT) is generally performed with the gamma index (GI) evaluation method, which is difficult to extrapolate to clinical implications. Incorporating Dose Volume Histogram (DVH) information can compensate for

  9. Outcome Modeling Using Clinical DVH Data

    CERN Document Server

    Gordon, JJ

    2015-01-01

    Purpose: To quantify the ability of correlation and regression analysis to extract the normal lung dose-response function from dose volume histogram (DVH) data. Methods: A local injury model is adopted, in which radiation-induced damage (functional loss) G is the integral of the DVH with function R(D). RP risk is H(G) where H() is the sigmoid cumulative distribution of functional reserve. RP incidence is a Bernoulli function of risk. A homogeneous patient cohort is assumed, allowing non-dose-related factors to be ignored. Clinically realistic DVHs are combined with the injury model to simulate RP data. Results: Correlation analysis is often used to identify predictor variables that are correlated with outcome, for inclusion in a predictive model. In the local injury model, all DVH metrics VD contribute to damage. Correlation analysis therefore has limited value. The subset of VD significantly correlated with incidence varies randomly from trial to trial due to random variations in the DVH set, and does not ne...

  10. Dose-volume histogram parameters and local tumor control in magnetic resonance image-guided cervical cancer brachytherapy.

    Science.gov (United States)

    Dimopoulos, Johannes C A; Lang, Stefan; Kirisits, Christian; Fidarova, Elena F; Berger, Daniel; Georg, Petra; Dörr, Wolfgang; Pötter, Richard

    2009-09-01

    To investigate the value of dose-volume histogram (DVH) parameters for predicting local control in magnetic resonance (MR) image-guided brachytherapy (IGBT) for patients with cervical cancer. Our study population consists of 141 patients with cervical cancer (Stages IB-IVA) treated with 45-50 Gy external beam radiotherapy plus four times 7 Gy IGBT with or without cisplatin. Gross tumor volume (GTV), high-risk clinical target volume (HRCTV), and intermediate-risk clinical target volume (IRCTV) were contoured, and DVH parameters (minimum dose delivered to 90% of the volume of interest [D90] and D100) were assessed. Doses were converted to the equivalent dose in 2 Gy (EQD2) by applying the linear quadratic model (alpha/beta = 10 Gy). Groups were defined for patients with or without local recurrence (LR) in the true pelvis for tumor size at diagnosis (GTV at diagnosis [GTVD] of 2-5 cm (Group 1) or greater than 5 cm (Group 2) and for tumor size response at IGBT (HRCTV) of 2-5 cm (Group 2a) or greater than 5 cm (Group 2b). Eighteen LRs were observed. The most important DVH parameters correlated with LR were the D90 and D100 for HRCTV. Mean D90 and D100 values for HRCTV were 86 +/- 16 and 65 +/- 10 Gy, respectively. The D90 for HRCTV greater than 87 Gy resulted in an LR incidence of 4% (3 of 68) compared with 20% (15 of 73) for D90 less than 87 Gy. The effect was most pronounced in the tumor group (Group 2b). We showed an increase in local control in IGBT in patients with cervical cancer with the dose delivered, which can be expressed by the D90 and D100 for HRCTV. Local control rates greater than 95% can be achieved if the D90 (EQD2) for HRCTV is 87 Gy or greater.

  11. Effect of various methods for rectum delineation on relative and absolute dose-volume histograms for prostate IMRT treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Kusumoto, Chiaki [Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan); Ohira, Shingo [Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan); Department of Medical Physics and Engineering, Osaka University Graduate School of Medicine, Suita (Japan); Miyazaki, Masayoshi [Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan); Ueda, Yoshihiro [Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan); Department of Radiation Oncology, Graduate School of Medicine, Osaka University, Suita (Japan); Isono, Masaru [Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan); Teshima, Teruki, E-mail: teshima-te@mc.pref.osaka.jp [Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka (Japan)

    2016-07-01

    Several reports have dealt with correlations of late rectal toxicity with rectal dose-volume histograms (DVHs) for high dose levels. There are 2 techniques to assess rectal volume for reception of a specific dose: relative-DVH (R-DVH, %) that indicates relative volume for a vertical axis, and absolute-DVH (A-DVH, cc) with its vertical axis showing absolute volume of the rectum. The parameters of DVH vary depending on the rectum delineation method, but the literature does not present any standardization of such methods. The aim of the present study was to evaluate the effects of different delineation methods on rectal DVHs. The enrollment for this study comprised 28 patients with high-risk localized prostate cancer, who had undergone intensity-modulated radiation therapy (IMRT) with the prescription dose of 78 Gy. The rectum was contoured with 4 different methods using 2 lengths, short (Sh) and long (Lg), and 2 cross sections, rectum (Rec) and rectal wall (Rw). Sh means the length from 1 cm above the seminal vesicles to 1 cm below the prostate and Lg the length from the rectosigmoid junction to the anus. Rec represents the entire rectal volume including the rectal contents and Rw the rectal volume of the area with a wall thickness of 4 mm. We compared dose-volume parameters by using 4 rectal contour methods for the same plan with the R-DVHs as well as the A-DVHs. For the high dose levels, the R-DVH parameters varied widely. The mean of V{sub 70} for Sh-Rw was the highest (19.4%) and nearly twice as high as that for Lg-Rec (10.4%). On the contrary, only small variations were observed in the A-DVH parameters (4.3, 4.3, 5.5, and 5.5 cc for Sh-Rw, Lg-Rw, Sh-Rec, and Lg-Rec, respectively). As for R-DVHs, the parameters of V{sub 70} varied depending on the rectal lengths (Sh-Rec vs Lg-Rec: R = 0.76; Sh-Rw vs Lg-Rw: R = 0.85) and cross sections (Sh-Rec vs Sh-Rw: R = 0.49; Lg-Rec vs Lg-Rw: R = 0.65). For A-DVHs, however, the parameters of Sh rectal A-DVHs hardly changed

  12. A moment-based approach for DVH-guided radiotherapy treatment plan optimization

    Science.gov (United States)

    Zarepisheh, M.; Shakourifar, M.; Trigila, G.; Ghomi, P. S.; Couzens, S.; Abebe, A.; Noreña, L.; Shang, W.; Jiang, Steve B.; Zinchenko, Y.

    2013-03-01

    The dose-volume histogram (DVH) is a clinically relevant criterion to evaluate the quality of a treatment plan. It is hence desirable to incorporate DVH constraints into treatment plan optimization for intensity modulated radiation therapy. Yet, the direct inclusion of the DVH constraints into a treatment plan optimization model typically leads to great computational difficulties due to the non-convex nature of these constraints. To overcome this critical limitation, we propose a new convex-moment-based optimization approach. Our main idea is to replace the non-convex DVH constraints by a set of convex moment constraints. In turn, the proposed approach is able to generate a Pareto-optimal plan whose DVHs are close to, or if possible even outperform, the desired DVHs. In particular, our experiment on a prostate cancer patient case demonstrates the effectiveness of this approach by employing two and three moment formulations to approximate the desired DVHs.

  13. Comparative study of old and new versions of treatment planning system using dose volume histogram indices of clinical plans

    Science.gov (United States)

    Krishna, Gangarapu Sri; Srinivas, Vuppu; Ayyangar, K. M.; Reddy, Palreddy Yadagiri

    2016-01-01

    Recently, Eclipse treatment planning system (TPS) version 8.8 was upgraded to the latest version 13.6. It is customary that the vendor gives training on how to upgrade the existing software to the new version. However, the customer is provided less inner details about changes in the new software version. According to manufacturer, accuracy of point dose calculations and irregular treatment planning is better in the new version (13.6) compared to the old version (8.8). Furthermore, the new version uses voxel-based calculations while the earlier version used point dose calculations. Major difference in intensity-modulated radiation therapy (IMRT) plans was observed between the two versions after re-optimization and re-calculations. However, minor difference was observed for IMRT cases after performing only re-calculations. It is recommended TPS quality assurance to be performed after any major upgrade of software. This can be done by performing dose calculation comparisons in TPS. To assess the difference between the versions, 25 clinical cases from the old version were compared keeping all the patient data intact including the monitor units and comparing the differences in dose calculations using dose volume histogram (DVH) analysis. Along with DVH analysis, uniformity index, conformity index, homogeneity index, and dose spillage index were also compared for both versions. The results of comparative study are presented in this paper. PMID:27651566

  14. Dose-volume histogram constrains for small intestine in postoperative transcutaneous radiotherapy of endometrial carcinoma: comparison between conventional and conformal techniques

    Directory of Open Access Journals (Sweden)

    Anela Ramić

    2013-09-01

    Full Text Available Introduction: The aim of this study was to determine the dose-volume histogram (DVH constrains of conventional and conformal transcutaneous radiotherapy for small intestine and perform their comparison.Methods: This retrospective-prospective study included patients who were treated for endometrial cancer using conventional transcutaneous radiotherapy at the Department of Radiotherapy Clinic of Oncology,Hematology and Radiotherapy, University Clinical Center Tuzla in the period from 2009 to 2011. The study was performed on patients of all ages suffering from this condition. The study involved 35 patients. DVHparameters which were analyzed are: minimum dose (Dmin, maximum dose (Dmax, medium dose (Daver of the small intestine, as well as the volume of the small intestine, which is included in 75%, 95% and 100%dose (V33,75Gy, V42,75Gy, V45Gy expressed in percentages and cubic centimeters of the affected organ. Working hypothesis was tested with paired t test. The difference between the variables at the level of p Results: DVH constrains of transcutaneous conformal radiotherapy showed signifi cantly smaller dose contribution on small intestine than DVH parameters of conventional transcutaneous radiotherapy (pConclusion: The dose contribution on small intestine was signifi cantly lower by planning three-dimensional conformal transcutaneous radiotherapy in comparison to the conventional planning.

  15. Dose-volume histogram constrains for small intestine in postoperative transcutaneous radiotherapy of endometrial carcinoma: comparison between conventional and conformal techniques

    Directory of Open Access Journals (Sweden)

    Anela Ramić

    2013-09-01

    Full Text Available Introduction: The aim of this study was to determine the dose-volume histogram (DVH constrains of conventional and conformal transcutaneous radiotherapy for small intestine and perform their comparison.Methods: This retrospective-prospective study included patients who were treated for endometrial cancer using conventional transcutaneous radiotherapy at the Department of Radiotherapy Clinic of Oncology,Hematology and Radiotherapy, University Clinical Center Tuzla in the period from 2009 to 2011. The study was performed on patients of all ages suffering from this condition. The study involved 35 patients. DVHparameters which were analyzed are: minimum dose (Dmin, maximum dose (Dmax, medium dose (Daver of the small intestine, as well as the volume of the small intestine, which is included in 75%, 95% and 100%dose (V33,75Gy, V42,75Gy, V45Gy expressed in percentages and cubic centimeters of the affected organ. Working hypothesis was tested with paired t test. The difference between the variables at the level of p <0.05 was considered statistically significant.Results: DVH constrains of transcutaneous conformal radiotherapy showed signifi cantly smaller dose contribution on small intestine than DVH parameters of conventional transcutaneous radiotherapy (p<0.0001.Conclusion: The dose contribution on small intestine was signifi cantly lower by planning three-dimensional conformal transcutaneous radiotherapy in comparison to the conventional planning.

  16. Quantifying the Impact of Immediate Reconstruction in Postmastectomy Radiation: A Large, Dose-Volume Histogram-Based Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ohri, Nisha [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Cordeiro, Peter G. [Department of Plastic Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Keam, Jennifer [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ballangrud, Ase [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Shi Weiji; Zhang Zhigang [Department of Biostatistics and Epidemiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Nerbun, Claire T.; Woch, Katherine M.; Stein, Nicholas F.; Zhou Ying [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); McCormick, Beryl; Powell, Simon N. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ho, Alice Y., E-mail: HoA1234@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2012-10-01

    Purpose: To assess the impact of immediate breast reconstruction on postmastectomy radiation (PMRT) using dose-volume histogram (DVH) data. Methods and Materials: Two hundred forty-seven women underwent PMRT at our center, 196 with implant reconstruction and 51 without reconstruction. Patients with reconstruction were treated with tangential photons, and patients without reconstruction were treated with en-face electron fields and customized bolus. Twenty percent of patients received internal mammary node (IMN) treatment. The DVH data were compared between groups. Ipsilateral lung parameters included V20 (% volume receiving 20 Gy), V40 (% volume receiving 40 Gy), mean dose, and maximum dose. Heart parameters included V25 (% volume receiving 25 Gy), mean dose, and maximum dose. IMN coverage was assessed when applicable. Chest wall coverage was assessed in patients with reconstruction. Propensity-matched analysis adjusted for potential confounders of laterality and IMN treatment. Results: Reconstruction was associated with lower lung V20, mean dose, and maximum dose compared with no reconstruction (all P<.0001). These associations persisted on propensity-matched analysis (all P<.0001). Heart doses were similar between groups (P=NS). Ninety percent of patients with reconstruction had excellent chest wall coverage (D95 >98%). IMN coverage was superior in patients with reconstruction (D95 >92.0 vs 75.7%, P<.001). IMN treatment significantly increased lung and heart parameters in patients with reconstruction (all P<.05) but minimally affected those without reconstruction (all P>.05). Among IMN-treated patients, only lower lung V20 in those without reconstruction persisted (P=.022), and mean and maximum heart doses were higher than in patients without reconstruction (P=.006, P=.015, respectively). Conclusions: Implant reconstruction does not compromise the technical quality of PMRT when the IMNs are untreated. Treatment technique, not reconstruction, is the primary

  17. Evaluation of dose-volume histogram parameters (V20 and mean dose) in lung cancer adaptive radiotherapy with design of composite lung volumes (ITV; Evaluacion de parametros del histograma dosis-volumen (V20 y dosis media) en radioterapia adaptada de cancer de pulmon con diseno de volumenes pulmonares compuestos (Internal Target Volume, ITV)

    Energy Technology Data Exchange (ETDEWEB)

    Monroy Anton, J. L.; Solar Tortosa, M.; Lopez Munoz, M.; Navarro Bergada, A.; Estornell gualde, M. A.; Melchor Iniguez, M.

    2013-07-01

    Physiological respiratory motion is a challenge in external radiotherapy for lung tumors. In adaptive radiotherapy, changing position of the target volume should be reflected in the simulation procedure and taken into account in the design of volumes for CTV/PTV proper coverage. This may be achieved through the design of an Internal Target Volume (ITV) as indicated in ICRU-62. However, the Dose-Volume Histogram (DVH) evaluation of the doses received by the healthy lung may vary in the case of designing a single lung volume, compared to the composite lung volume obtained with the fusion of normal breathing, inspiration and expiration (ITV{sub l}ung). (Author)

  18. SU-E-T-288: Dose Volume Population Histogram (DVPH): A New Method to Evaluate Intensity Modulated Proton Therapy Plans With Geometrical Uncertainties

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, T; Mai, N [University of Science, Ho Chi Minh City (Viet Nam); Nguyen, B [Prowess Inc, Concord, CA (United States)

    2015-06-15

    Purpose: In Proton therapy, especially intensity modulated proton therapy(IMPT), the dose distribution shape is very sensitive to errors due to sharp dose gradients at the Bragg peaks. The concept of the conventional margin is based on the assumption that dose distribution is shifted rather than deformed due to geometrical uncertainties. The goal of this study is to access the validity of the margin concept as well as propose a new approach using Dose Volume Population Histogram (DVPH) in evaluating IMPT plans. Methods: For a prostate case, an intensity modulated proton therapy is optimized based on the conventional PTV based objective function. The plan is evaluated based on the PTV DVH and CTV DVPH (dose volume population histogram) which explicitly taking into account geometric uncertainties. The DVPH is calculated based on 2197 dose distributions at different CTV possible positions for both random and systematic errors. The DVPH with a 90% confidence level is used for the comparison. Results: The minimum dose of the CTV DVPH with a 90% confidence level is only about 18% of the prescribed dose, while the minimum dose of the PTV is 95%. For bladder DVHs, the D50 and D35 is 26% and 30%, compared to 65% and 70% of the prescribed dose from the bladder DVPH with 90% confidence level. Conclusion: The results showed that the PTV concept for ensuring the prescribed dose actually delivered to the CTV is invalid in proton therapy. The good PTV DVH might Result in an underdose to the target and should not be used for IMPT optimization. For OARs, the conventional evaluation approach underestimates dose volume end points. The new concept DVPH has been proved to provide a more accurate DVH evaluation in proton therapy.

  19. Taste and Smell Disturbances after Brain Irradiation: A Dose Volume Histogram Analysis of a Prospective Observational Study

    Science.gov (United States)

    Leyrer, C. Marc; Chan, Michael D.; Peiffer, Ann M.; Horne, Elizabeth; Harmon, Michelle; Carter, Annette F.; Hinson, William H.; Mirlohi, Susan; Duncan, Susan E.; Dietrich, Andrea M.; Lesser, Glenn J.

    2014-01-01

    Purpose Radiation-induced taste and smell disturbances are prevalent in patients receiving brain radiotherapy, although the mechanisms underlying these toxicities are poorly understood. We report the results of a single institution prospective clinical trial aimed at correlating self-reported taste and smell disturbances with radiation dose delivered to defined areas within the brain and nasopharynx. Methods and Materials 22 patients with gliomas were enrolled on a prospective observational trial in which patients underwent a validated questionnaire assessing taste and smell disturbances at baseline, and at 3 and 6 weeks after commencement of brain radiotherapy. 14 patients with glioblastoma, 3 patients with grade 3 gliomas, and 5 patients with low grade gliomas participated. Median dose to tumor volume was 60 Gy (range 45–60 Gy). Dose volume histogram (DVH) analysis was performed for specific regions of interest (ROI) that were considered potential targets of radiation damage including the thalamus, temporal lobes, nasopharynx, olfactory groove, frontal pole and periventricular stem cell niche. The %v10 (percent of ROI receiving 10 Gy), %v40, and %v60 were calculated for each structure. Data from questionnaires and DVH were analyzed using stepwise regression. Results 20 of 22 patients submitted evaluable questionnaires that encompassed at least the entire radiotherapy course. 10 of 20 patients reported experiencing some degree of smell disturbance during radiotherapy, and 14 of 20 patients experienced taste disturbances. Patients reporting more severe taste toxicity also reported more severe toxicities with sense of smell (r2=0.60, pmore common in temporal lobe tumors, and may be related to the dose received by the nasopharynx. PMID:24890354

  20. Taste and smell disturbances after brain irradiation: a dose-volume histogram analysis of a prospective observational study.

    Science.gov (United States)

    Leyrer, C Marc; Chan, Michael D; Peiffer, Ann M; Horne, Elizabeth; Harmon, Michelle; Carter, Annette F; Hinson, William H; Mirlohi, Susan; Duncan, Susan E; Dietrich, Andrea M; Lesser, Glenn J

    2014-01-01

    Radiation-induced taste and smell disturbances are prevalent in patients receiving brain radiation therapy, although the mechanisms underlying these toxicities are poorly understood. We report the results of a single institution prospective clinical trial aimed at correlating self-reported taste and smell disturbances with radiation dose delivered to defined areas within the brain and nasopharynx. Twenty-two patients with gliomas were enrolled on a prospective observational trial in which patients underwent a validated questionnaire assessing taste and smell disturbances at baseline and at 3 and 6 weeks after commencement of brain radiation therapy. Fourteen patients with glioblastoma, 3 patients with grade 3 gliomas, and 5 patients with low grade gliomas participated. Median dose to tumor volume was 60 Gy (range, 45-60 Gy). Dose-volume histogram (DVH) analysis was performed for specific regions of interest that were considered potential targets of radiation damage, including the thalamus, temporal lobes, nasopharynx, olfactory groove, frontal pole, and periventricular stem cell niche. The %v10 (percent of region of interest receiving 10 Gy), %v40, and %v60 were calculated for each structure. Data from questionnaires and DVH were analyzed using stepwise regression. Twenty of 22 patients submitted evaluable questionnaires that encompassed at least the entire radiation therapy course. Ten of 20 patients reported experiencing some degree of smell disturbance during radiation therapy, and 14 of 20 patients experienced taste disturbances. Patients reporting more severe taste toxicity also reported more severe toxicities with sense of smell (r(2) = 0.60, P more common in temporal lobe tumors, and may be related to the dose received by the nasopharynx. © 2014. Published by Elsevier Inc. All rights reserved.

  1. Statistical simulations to estimate motion-inclusive dose-volume histograms for prediction of rectal morbidity following radiotherapy

    Science.gov (United States)

    THOR, MARIA; APTE, ADITYA; DEASY, JOSEPH O.; MUREN, LUDVIG PAUL

    2016-01-01

    Background and purpose Internal organ motion over a course of radiotherapy (RT) leads to uncertainties in the actual delivered dose distributions. In studies predicting RT morbidity, the single estimate of the delivered dose provided by the treatment planning computed tomography (pCT) is typically assumed to be representative of the dose distribution throughout the course of RT. In this paper, a simple model for describing organ motion is introduced, and is associated to late rectal morbidity data, with the aim of improving morbidity prediction. Material and methods Organ motion was described by normally distributed translational motion, with its magnitude characterised by the standard deviation (SD) of this distribution. Simulations of both isotropic and anisotropic (anterior-posterior only) motion patterns were performed, as were random, systematic or combined random and systematic motion. The associations between late rectal morbidity and motion-inclusive delivered dose-volume histograms (dDVHs) were quantified using Spearman's rank correlation coefficient (Rs) in a series of 232 prostate cancer patients, and were compared to the associations obtained with the static/planned DVH (pDVH). Results For both isotropic and anisotropic motion, different associations with rectal morbidity were seen with the dDVHs relative to the pDVHs. The differences were most pronounced in the mid-dose region (40–60 Gy). The associations were dependent on the applied motion patterns, with the strongest association with morbidity obtained by applying random motion with an SD in the range 0.2–0.8 cm. Conclusion In this study we have introduced a simple model for describing organ motion occurring during RT. Differing and, for some cases, stronger dose-volume dependencies were found between the motion-inclusive dose distributions and rectal morbidity as compared to the associations with the planned dose distributions. This indicates that rectal organ motion during RT influences the

  2. Dosimetric verification by using the ArcCHECK system and 3DVH software for various target sizes.

    Directory of Open Access Journals (Sweden)

    Jin Ho Song

    Full Text Available To investigate the usefulness of the 3DVH software with an ArcCHECK 3D diode array detector in newly designed plans with various target sizes.The isocenter dose was measured with an ion-chamber and was compared with the planned and 3DVH predicted doses. The 2D gamma passing rates were evaluated at the diode level by using the ArcCHECK detector. The 3D gamma passing rates for specific regions of interest (ROIs were also evaluated by using the 3DVH software. Several dose-volume histograms (DVH-based predicted metrics for all structures were also obtained by using the 3DVH software.The isocenter dose deviation was <1% in all plans except in the case of a 1 cm target. Besides the gamma passing rate at the diode level, the 3D gamma passing rate for specific ROIs tended to decrease with increasing target size; this was more noticeable when a more stringent gamma criterion was applied. No correlation was found with the gamma passing rates and the DVH-based metrics especially in the ROI with high-dose gradients.Delivery quality assurance by using 3DVH and ArcCHECK can provide substantial information through a simple and easy approach, although the accuracy of this system should be judged cautiously.

  3. Validation of 3DVH estimated DVH metrics for prostate VMAT plans

    Science.gov (United States)

    Arumugam, Sankar; Xing, Aitang; Young, Tony; Thwaites, David; Holloway, Lois

    2015-01-01

    The accuracy of 3DVH (Sun Nuclear Corporation, USA) reported DVH metrics for target volumes and Organs at Risk (OARs) for two Prostate Volumetric Modulated Arc Therapy (VMAT) plans was studied. The accuracy of 3DVH estimated DVH metrics in the presence of Multi Leaf Collimator (MLC) systematic errors was also tested with error introduced plans calculated in Pinnacle. The results of the study show that the DVH metrics estimated by 3DVH for error-free plans agree with the TPS calculation within 3%. The D95 to PTV was shown to be sensitive in detecting studied MLC errors. However the accuracy of 3DVH estimated DVH metrics for Target Volumes and OARs in the presence of MLC errors for VMAT prostate plans has limitations with this small data set. Although for most situations values matched within 3% for small MLC errors, there was up to a 9.8% difference between the TPS and 3DVH in the presence of a simulated 5mm MLC positioning error. Further study with more plans including other treatment sites is required to fully assess the performance of 3DVH in detecting potential clinical delivery errors.

  4. A Varian DynaLog file-based procedure for patient dose-volume histogram-based IMRT QA.

    Science.gov (United States)

    Calvo-Ortega, Juan F; Teke, Tony; Moragues, Sandra; Pozo, Miquel; Casals-Farran, Joan

    2014-03-06

    In the present study, we describe a method based on the analysis of the dynamic MLC log files (DynaLog) generated by the controller of a Varian linear accelerator in order to perform patient-specific IMRT QA. The DynaLog files of a Varian Millennium MLC, recorded during an IMRT treatment, can be processed using a MATLAB-based code in order to generate the actual fluence for each beam and so recalculate the actual patient dose distribution using the Eclipse treatment planning system. The accuracy of the DynaLog-based dose reconstruction procedure was assessed by introducing ten intended errors to perturb the fluence of the beams of a reference plan such that ten subsequent erroneous plans were generated. In-phantom measurements with an ionization chamber (ion chamber) and planar dose measurements using an EPID system were performed to investigate the correlation between the measured dose changes and the expected ones detected by the reconstructed plans for the ten intended erroneous cases. Moreover, the method was applied to 20 cases of clinical plans for different locations (prostate, lung, breast, and head and neck). A dose-volume histogram (DVH) metric was used to evaluate the impact of the delivery errors in terms of dose to the patient. The ionometric measurements revealed a significant positive correlation (R² = 0.9993) between the variations of the dose induced in the erroneous plans with respect to the reference plan and the corresponding changes indicated by the DynaLog-based reconstructed plans. The EPID measurements showed that the accuracy of the DynaLog-based method to reconstruct the beam fluence was comparable with the dosimetric resolution of the portal dosimetry used in this work (3%/3 mm). The DynaLog-based reconstruction method described in this study is a suitable tool to perform a patient-specific IMRT QA. This method allows us to perform patient-specific IMRT QA by evaluating the result based on the DVH metric of the planning CT image (patient

  5. Evaluation of the precision of the ArcCHECK device and software 3DVH in the estimation of the dose in the isocenter for IMRT-QA; Evaluacion de la precision del dospostivo Archeck y del Software 3DVH en la estimacion de la dosis en el isocentro para IMRT-QA

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Vicente, F.; Rodriguez Martin, G.; Bermudez Luna, R.; Roch Gonzalez, M.; Perez Gonzalez, L.; Torres Escobar, J. J.

    2013-07-01

    The aim of this paper is to analyze the accuracy of the test equipment ArcCHECK and 3DVH software in estimating the dose at isocenter for quality control of IMRT in prostate cancer. This work aims to be a first test for the comprehensive incorporation of software in the quality control of IMRT based on comparison of dose volume histograms. (Author)

  6. SU-E-T-430: Feasibility Study On Using Overlap Volume Histogram to Predict the Dose Difference by Respiratory Motion

    Energy Technology Data Exchange (ETDEWEB)

    Shin, D; Kang, S; Kim, D; Kim, T; Kim, K; Cho, M; Suh, T [The Catholic University of Korea, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: The dose difference between three-dimensional dose (3D dose) and 4D dose which considers motion due to respiratory can be varied according to geometrical relationship between planning target volume (PTV) and organ at risk (OAR). The purpose of the study is to investigate the dose difference between 3D and 4D dose using overlap volume histogram (OVH) which is an indicator that quantify geometrical relationship between a PTV and an OAR. Methods: Five liver cancer patients who previously treated stereotactic body radiotherapy (SBRT) were investigated. Four-dimensional computed tomography (4DCT) images were acquired for all patients. ITV-based treatment planning was performed. 3D dose was calculated on the end-exhale phase image as a reference phase image. 4D dose accumulation was implemented from all phase images using dose warping technique used deformable image registration (DIR) algorithm (Horn and Schunck optical flow) in DIRART. In this study OVH was used to quantify geometrical relationship between a PTV and an OAR. OVH between a PTV and a selected OAR was generated for each patient case and compared for all cases. The dose difference between 3D and 4D dose for normal organ was calculated and compared for all cases according to OVH. Results: The 3D and 4D dose difference for OAR was analyzed using dose-volume histogram (DVH). On the basis of a specific point which corresponds to 10% of OAR volume overlapped with expanded PTV, mean dose difference was 34.56% in minimum OVH distance case and 13.36% in maximum OVH distance case. As the OVH distance increased, mean dose difference between 4D and 3D dose was decreased. Conclusion: The tendency of dose difference variation was verified according to OVH. OVH is seems to be indicator that has a potential to predict the dose difference between 4D and 3D dose. This work was supported by the Radiation Technology R&D program (No. 2013M2A2A7043498) and the Mid-career Researcher Program (2014R1A2A1A10050270) through

  7. A novel method for the evaluation of uncertainty in dose volume histogram computation

    CERN Document Server

    Cutanda-Henriquez, Francisco

    2007-01-01

    Dose volume histograms are a useful tool in state-of-the-art radiotherapy planning, and it is essential to be aware of their limitations. Dose distributions computed by treatment planning systems are affected by several sources of uncertainty such as algorithm limitations, measurement uncertainty in the data used to model the beam and residual differences between measured and computed dose, once the model is optimized. In order to take into account the effect of uncertainty, a probabilistic approach is proposed and a new kind of histogram, a dose-expected volume histogram, is introduced. The expected value of the volume in the region of interest receiving an absorbed dose equal or greater than a certain value is found using the probability distribution of the dose at each point. A rectangular probability distribution is assumed for this point dose, and a relationship is given for practical computations. This method is applied to a set of dose volume histograms for different regions of interest for 6 brain pat...

  8. Methods, software and datasets to verify DVH calculations against analytical values: Twenty years late(r)

    Energy Technology Data Exchange (ETDEWEB)

    Nelms, Benjamin [Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Stambaugh, Cassandra [Department of Physics, University of South Florida, Tampa, Florida 33612 (United States); Hunt, Dylan; Tonner, Brian; Zhang, Geoffrey; Feygelman, Vladimir, E-mail: vladimir.feygelman@moffitt.org [Department of Radiation Oncology, Moffitt Cancer Center, Tampa, Florida 33612 (United States)

    2015-08-15

    Purpose: The authors designed data, methods, and metrics that can serve as a standard, independent of any software package, to evaluate dose-volume histogram (DVH) calculation accuracy and detect limitations. The authors use simple geometrical objects at different orientations combined with dose grids of varying spatial resolution with linear 1D dose gradients; when combined, ground truth DVH curves can be calculated analytically in closed form to serve as the absolute standards. Methods: DICOM RT structure sets containing a small sphere, cylinder, and cone were created programmatically with axial plane spacing varying from 0.2 to 3 mm. Cylinders and cones were modeled in two different orientations with respect to the IEC 1217 Y axis. The contours were designed to stringently but methodically test voxelation methods required for DVH. Synthetic RT dose files were generated with 1D linear dose gradient and with grid resolution varying from 0.4 to 3 mm. Two commercial DVH algorithms—PINNACLE (Philips Radiation Oncology Systems) and PlanIQ (Sun Nuclear Corp.)—were tested against analytical values using custom, noncommercial analysis software. In Test 1, axial contour spacing was constant at 0.2 mm while dose grid resolution varied. In Tests 2 and 3, the dose grid resolution was matched to varying subsampled axial contours with spacing of 1, 2, and 3 mm, and difference analysis and metrics were employed: (1) histograms of the accuracy of various DVH parameters (total volume, D{sub max}, D{sub min}, and doses to % volume: D99, D95, D5, D1, D0.03 cm{sup 3}) and (2) volume errors extracted along the DVH curves were generated and summarized in tabular and graphical forms. Results: In Test 1, PINNACLE produced 52 deviations (15%) while PlanIQ produced 5 (1.5%). In Test 2, PINNACLE and PlanIQ differed from analytical by >3% in 93 (36%) and 18 (7%) times, respectively. Excluding D{sub min} and D{sub max} as least clinically relevant would result in 32 (15%) vs 5 (2

  9. Late Toxicity After Intensity-Modulated Radiation Therapy for Localized Prostate Cancer: An Exploration of Dose-Volume Histogram Parameters to Limit Genitourinary and Gastrointestinal Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Pederson, Aaron W.; Fricano, Janine; Correa, David; Pelizzari, Charles A. [Department of Radiation and Cellular Oncology, Pritzker School of Medicine, University of Chicago, Chicago, IL (United States); Liauw, Stanley L., E-mail: sliauw@radonc.uchicago.edu [Department of Radiation and Cellular Oncology, Pritzker School of Medicine, University of Chicago, Chicago, IL (United States)

    2012-01-01

    Purpose: To characterize the late genitourinary (GU) and gastrointestinal (GI) toxicity for prostate cancer patients treated with intensity-modulated radiation therapy (IMRT) and propose dose-volume histogram (DVH) guidelines to limit late treatment-related toxicity. Methods and Materials: In this study 296 consecutive men were treated with IMRT for adenocarcinoma of the prostate. Most patients received treatment to the prostate with or without proximal seminal vesicles (90%), to a median dose of 76 Gy. Concurrent androgen deprivation therapy was given to 150 men (51%) for a median of 4 months. Late toxicity was defined by Common Toxicity Criteria version 3.0 as greater than 3 months after radiation therapy completion. Four groupings of DVH parameters were defined, based on the percentage of rectal or bladder tissue receiving 70 Gy (V{sub 70}), 65 Gy (V{sub 65}), and 40 Gy (V{sub 40}). These DVH groupings, as well as clinical and treatment characteristics, were correlated to maximal Grade 2+ GU and GI toxicity. Results: With a median follow-up of 41 months, the 4-year freedom from maximal Grade 2+ late toxicity was 81% and 91% for GU and GI systems, respectively, and by last follow-up, the rates of Grade 2+ GU and GI toxicity were 9% and 5%, respectively. On multivariate analysis, whole-pelvic IMRT was associated with Grade 2+ GU toxicity and age was associated with Grade 2+ GI toxicity. Freedom from Grade 2+ GI toxicity at 4 years was 100% for men with rectal V{sub 70} {<=}10%, V{sub 65} {<=}20%, and V{sub 40} {<=}40%; 92% for men with rectal V{sub 70} {<=}20%, V{sub 65} {<=}40%, and V{sub 40} {<=}80%; and 85% for men exceeding these criteria (p = 0.13). These criteria were more highly associated with GI toxicity in men aged {>=}70 years (p = 0.07). No bladder dose-volume relationships were associated with the risk of GU toxicity. Conclusions: IMRT is associated with low rates of severe GU or GI toxicity after treatment for prostate cancer. Rectal dose constraints

  10. SU-F-BRD-14: The Effect of Radiation-Induced Esophageal Swelling On Dose-Volume Histograms

    Energy Technology Data Exchange (ETDEWEB)

    Niedzielski, J; Martel, M; Tucker, S; Briere, T [Houston, TX (United States); UT Graduate School of Biomedical Sciences, Houston, TX (United States); Yang, J; Gomez, D [Houston, TX (United States)

    2014-06-15

    Purpose: Acute esophagitis results in esophageal swelling. Here we evaluate the effect of this response on DVH metrics calculated throughout the course of radiation therapy. Methods: Twenty-nine NSCLC patients were identified who received weekly CT imaging, and varying esophagitis grades (11 grade0 patients, 12 grade2 patients, 6 grade3 patients), using CTCAE scoring criteria. Deformable image registration was used to map the planning esophagus contour to the weekly CT images. Treatment plans were recalculated on each weekly 4DCT and DVH metrics for the esophagus were compared to the delivered treatment plan. DVH metrics were also extracted for esophagus planning-at-risk volumes (PRV) with 1–3mm uniform expansions. Results: The esophagus V50 increased as the treatment progressed by 2.3±0.7cc and 9.0±1.1cc, for the grade 0 and grade 2/3 patients, respectively. The mean esophageal dose (MED) increased by 3.5±0.9Gy, and 8.0±1.1Gy for the grade 0 and grade 2/3 patients, respectively. In some cases where the planned V50 was similar, it remained the same at the end of treatment for grade 0 cases, but increased for higher grade cases. These apparent changes in delivered dose, as expressed by the DVH, are mostly attributed to volume changes in the regions of esophagitis. In addition, portions of the esophagus of some patients moved into highdose regions. The 2mm PRV was able to account for these differences in all but 1 of the 18 G2/3 patients. The 1mm PRV produced the closest DVH metrics calculated from the average weekly plans compared to the true treatment plan. Conclusion: Esophagus radiation response affects DVH parameters throughout treatment, especially patients with high toxicity. This effect must be considered when comparing DVHs calculated using daily IGRT CT images with those from the original planning CT (e.g. for adaptive planning). Adding a margin to the esophagus can account for variation in DVH metrics.

  11. Eclipse计划系统DVH自动生成比较软件开发%Development of a Compared Software for Automatically Generated DVH in Eclipse TPS

    Institute of Scientific and Technical Information of China (English)

    谢朝; 骆科林; 邹炼; 胡金有

    2016-01-01

    目的:自动快速计算治疗计划的剂量体积直方图(DVH),并与医生处方要求相比较。方法使用AutoHotkey热键脚本语言和高级程序设计语言C#,开发了适合于Eclipse11.0计划系统的DVH自动生成比较软件ShowDVH,该软件由处方文档生成、C#中DVH操作函数、软件可视化及DVH比较报告生成模块构成。结果在临床上选取不同病种各10例,调用ShowDVH在计划系统下运行,ShowDVH不仅能生成DVH报告,还能准确判断治疗计划是否满足医生处方要求,为调强优化参数设置给予方向指导。结论该软件界面友好,功能强大,能快速计算生成比较DVH,大大节约计划设计时间,提高放射治疗物理师工作效率。%Objective This study is to automaticaly calculatethe dose volume histogram(DVH) for the treatment plan, then to compare it with requirements of doctor's prescriptions.Methods The scripting language Autohotkey and programming language C# were used to develop a compared software for automatically generated DVH in Eclipse TPS. This software is named Show Dose Volume Histogram (ShowDVH), which is composed of prescription documents generation, operation functions of DVH, software visualization and DVH compared report generation.Results Ten cases in different cancers have been separately selected, in Eclipse TPS 11.0 ShowDVH could not only automaticaly generate DVH reports but also accurately determine whether treatment plans meet the requirements of doctor’s prescriptions, then reports gave direction for setting optimization parameters of intensity modulated radiated therapy. Conclusions The ShowDVH is an user-friendly and powerful software, and can automaticaly generated compared DVH reports fast in Eclipse TPS 11.0. With the help of ShowDVH, it greatly saves plan designing time and improves working effi ciency of radiation therapy physicists.

  12. DVH Analysis of Cobalt-60 treatment plans incorporating a recently developed MLC

    Directory of Open Access Journals (Sweden)

    Gangarapu Sri Krishna

    2016-07-01

    Full Text Available Purpose: The aim of this investigation was to measure the gain in DVH indices when the recently developed MLC was used for Cobalt-60 treatments.Methods: A prototype multileaf collimator (MLC that was retrofitted to telecobalt-60 therapy machine was reported and is currently proposed for clinical trials in our institution. Ten patients’ plans that were previously planned through an ECLIPSE® treatment planning system and were treated with open beams from Cobalt-60 machine were imported into Radiation Oncology Planning System [ROPS] and the dose calculations and dose volume histogram (DVH analysis were performed. The plans were re-planned using the Cobalt-MLC, a feature available in the ROPS planning system. The DVH analysis consisted of conformity index (CI, homogeneity index (HI and conformation number (CN. The results of this study are presented in this paper. The analysis specifically aimed at measuring the gain in these indices when the MLC was compared with open beams.Results: DVH Comparison of ten sites using open and Cobalt MLC fields showed that the use of MLC results in reduced normal tissue dose, while maintaining the GTV dose. Lower value of CI for normal structures was observed demonstrating the sparing of critical organs when MLC was used. The index HI was studied to show the significance of hot spots outside the PTV. Hot spots were observed even with MLC beams for some cases due to less number of fields.Conclusion: It has been demonstrated through DVH analysis that the use of the recently developed MLC for Cobalt Teletherapy machine results in benefit for the treatment of patients.

  13. Absolute volume of the rectum and AUC from rectal DVH between 25Gy and 50Gy predict acute gastrointestinal toxicity with IG-IMRT in prostate cancer.

    Science.gov (United States)

    Mirjolet, Céline; Walker, Paul M; Gauthier, Mélanie; Dalban, Cécile; Naudy, Suzanne; Mazoyer, Frédéric; Martin, Etienne; Maingon, Philippe; Créhange, Gilles

    2016-11-04

    To determine whether dose/volume specific endpoints (DVSE) or Area under the rectal DVH curve (rAUC) better predict acute gastrointestinal (GI) toxicity in prostate cancer patients treated with IMRT in the era of daily image guidance (IG-IMRT). A set of DVSE was recorded from V25 to V75 (increments of 5Gy) (both in % and in cc) for 180 men. The rAUC was calculated for doses ranging between 25Gy and 50Gy (rAUC25-50). Univariate and multivariate logistic regressions were performed to determine the relationship between DVSE or rAUC25-50 and the appearance of any acute GI toxicity. The rates of acute grade 1 (G1), G2 and G3 GI toxicities were 53.3 %, 10.6 % and 1.1 %, respectively. No G4+ toxicity was observed. Rectal V25 to V75 expressed in % were not predictive of G ≥ 1 GI toxicity (p ≥ 0.12) whereas rectal V25 to V50 expressed in cc did correlate with GI toxicity G ≥ 1 (p ≤ 0.04). rAUC25-50 expressed in cc. Gy correlated significantly with the occurrence of any acute GI toxicity G ≥ 1 (p = 0.027). The absolute volume of the rectum between 25Gy and 50Gy and rAUC25-50 could significantly predict any acute rectal toxicity in prostate cancer patients treated with daily IG-IMRT.

  14. Improved dose-volume histogram estimates for radiopharmaceutical therapy by optimizing quantitative SPECT reconstruction parameters

    Science.gov (United States)

    Cheng, Lishui; Hobbs, Robert F.; Segars, Paul W.; Sgouros, George; Frey, Eric C.

    2013-06-01

    In radiopharmaceutical therapy, an understanding of the dose distribution in normal and target tissues is important for optimizing treatment. Three-dimensional (3D) dosimetry takes into account patient anatomy and the nonuniform uptake of radiopharmaceuticals in tissues. Dose-volume histograms (DVHs) provide a useful summary representation of the 3D dose distribution and have been widely used for external beam treatment planning. Reliable 3D dosimetry requires an accurate 3D radioactivity distribution as the input. However, activity distribution estimates from SPECT are corrupted by noise and partial volume effects (PVEs). In this work, we systematically investigated OS-EM based quantitative SPECT (QSPECT) image reconstruction in terms of its effect on DVHs estimates. A modified 3D NURBS-based Cardiac-Torso (NCAT) phantom that incorporated a non-uniform kidney model and clinically realistic organ activities and biokinetics was used. Projections were generated using a Monte Carlo (MC) simulation; noise effects were studied using 50 noise realizations with clinical count levels. Activity images were reconstructed using QSPECT with compensation for attenuation, scatter and collimator-detector response (CDR). Dose rate distributions were estimated by convolution of the activity image with a voxel S kernel. Cumulative DVHs were calculated from the phantom and QSPECT images and compared both qualitatively and quantitatively. We found that noise, PVEs, and ringing artifacts due to CDR compensation all degraded histogram estimates. Low-pass filtering and early termination of the iterative process were needed to reduce the effects of noise and ringing artifacts on DVHs, but resulted in increased degradations due to PVEs. Large objects with few features, such as the liver, had more accurate histogram estimates and required fewer iterations and more smoothing for optimal results. Smaller objects with fine details, such as the kidneys, required more iterations and less

  15. To investigate the dose difference by respiratory motion using overlap volume histogram

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Dong Seok; Kang, Seong Hee; Kim, Dong Su; Kim, Tae Ho; Kim, Kyeong Hyeon; Cho, Min Seok; Suh, Tae Suk [Dept. of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2015-04-15

    Four-dimensional dose (4D dose) which uses deformable image registration (DIR) algorithm from four-dimensional computed tomography (4DCT) images can consider dosimetric effect by respiratory motions. The dose difference between 3D dose and 4D dose can be varied according to geometrical relationship between a planning target volume (PTV) and an organ at risk (OAR). The purpose of this study is to investigate the dose difference between 3D and 4D dose using overlap volume histogram (OVH) which is an indicator that quantifies the geometrical relationship between a PTV and an OAR. The tendency of dose difference variation was verified according to OVH. OVH is seems to be an indicator that has a potential to predict the dose difference between 4D and 3D dose.

  16. Isobio software: biological dose distribution and biological dose volume histogram from physical dose conversion using linear-quadratic-linear model.

    Science.gov (United States)

    Jaikuna, Tanwiwat; Khadsiri, Phatchareewan; Chawapun, Nisa; Saekho, Suwit; Tharavichitkul, Ekkasit

    2017-02-01

    To develop an in-house software program that is able to calculate and generate the biological dose distribution and biological dose volume histogram by physical dose conversion using the linear-quadratic-linear (LQL) model. The Isobio software was developed using MATLAB version 2014b to calculate and generate the biological dose distribution and biological dose volume histograms. The physical dose from each voxel in treatment planning was extracted through Computational Environment for Radiotherapy Research (CERR), and the accuracy was verified by the differentiation between the dose volume histogram from CERR and the treatment planning system. An equivalent dose in 2 Gy fraction (EQD2) was calculated using biological effective dose (BED) based on the LQL model. The software calculation and the manual calculation were compared for EQD2 verification with pair t-test statistical analysis using IBM SPSS Statistics version 22 (64-bit). Two and three-dimensional biological dose distribution and biological dose volume histogram were displayed correctly by the Isobio software. Different physical doses were found between CERR and treatment planning system (TPS) in Oncentra, with 3.33% in high-risk clinical target volume (HR-CTV) determined by D90%, 0.56% in the bladder, 1.74% in the rectum when determined by D2cc, and less than 1% in Pinnacle. The difference in the EQD2 between the software calculation and the manual calculation was not significantly different with 0.00% at p-values 0.820, 0.095, and 0.593 for external beam radiation therapy (EBRT) and 0.240, 0.320, and 0.849 for brachytherapy (BT) in HR-CTV, bladder, and rectum, respectively. The Isobio software is a feasible tool to generate the biological dose distribution and biological dose volume histogram for treatment plan evaluation in both EBRT and BT.

  17. Internal Mammary Lymph Node Irradiation after Breast Conservation Surgery: Radiation Pneumonitis versus Dose-Volume Histogram Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joo Young; Lee, Ik Jae; Keum, Ki Chang; Kim, Yong Bae; Shim, Su Jung; Jeong, Kyoung Keun; Kim, Jong Dae; Suh, Chang Ok [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2007-12-15

    Purpose: To evaluate the association between radiation pneumonitis and dose-volume histogram parameters and to provide practical guidelines to prevent radiation pneumonitis following radiotherapy administered for breast cancer including internal mammary lymph nodes. Materials and Methods: Twenty patients with early breast cancer who underwent a partial mastectomy were involved in this study. The entire breast, supraclavicular lymph nodes, and internal mammary lymph nodes were irradiated with a dose of 50.4 Gy in 28 fractions. Radiation pneumonitis was assessed by both radiological pulmonary change (RPC) and by evaluation of symptomatic radiation pneumonitis. Dose-volume histogram parameters were compared between patients with grade <2 RPC and those with grade {>=}2 RPC. The parameters were the mean lung dose, V10 (percent lung volume receiving equal to and more than 10 Gy), V20, V30, V40, and normal tissue complication probability (NTCP). Results: Of the 20 patients, 9 (45%) developed grade 2 RPC and 11 (55%) did not develop RPC (grade 0). Only one patient developed grade 1 symptomatic radiation pneumonitis. Univariate analysis showed that among the dose-volume histogram parameters, NTCP was significantly different between the two RPC grade groups (p <0.05). Fisher's exact test indicated that an NTCP value of 45% was appropriate as an RPC threshold level. Conclusion: This study shows that NTCP can be used as a predictor of RPC after radiotherapy of the internal mammary lymph nodes in breast cancer. Clinically, it indicates that an RPC is likely to develop when the NTCP is greater than 45%.

  18. Extracting the normal lung dose-response curve from clinical DVH data: a possible role for low dose hyper-radiosensitivity, increased radioresistance

    Science.gov (United States)

    Gordon, J. J.; Snyder, K.; Zhong, H.; Barton, K.; Sun, Z.; Chetty, I. J.; Matuszak, M.; Ten Haken, R. K.

    2015-09-01

    In conventionally fractionated radiation therapy for lung cancer, radiation pneumonitis’ (RP) dependence on the normal lung dose-volume histogram (DVH) is not well understood. Complication models alternatively make RP a function of a summary statistic, such as mean lung dose (MLD). This work searches over damage profiles, which quantify sub-volume damage as a function of dose. Profiles that achieve best RP predictive accuracy on a clinical dataset are hypothesized to approximate DVH dependence. Step function damage rate profiles R(D) are generated, having discrete steps at several dose points. A range of profiles is sampled by varying the step heights and dose point locations. Normal lung damage is the integral of R(D) with the cumulative DVH. Each profile is used in conjunction with a damage cutoff to predict grade 2 plus (G2+) RP for DVHs from a University of Michigan clinical trial dataset consisting of 89 CFRT patients, of which 17 were diagnosed with G2+ RP. Optimal profiles achieve a modest increase in predictive accuracy—erroneous RP predictions are reduced from 11 (using MLD) to 8. A novel result is that optimal profiles have a similar distinctive shape: enhanced damage contribution from low doses (curves, which can be modeled using Joiner’s induced repair model. A novel search strategy is employed, which has the potential to estimate RP dependence on the normal lung DVH. When applied to a clinical dataset, identified profiles share a characteristic shape, which resembles HRS/IRR. This suggests that normal lung may have enhanced sensitivity to low doses, and that this sensitivity can affect RP risk.

  19. Technique for bone volume measurement from human femur head samples by classification of micro-CT image histograms

    Directory of Open Access Journals (Sweden)

    Franco Marinozzi

    2013-09-01

    Full Text Available INTRODUCTION: Micro-CT analysis is a powerful technique for a non-invasive evaluation of the morphometric parameters of trabecular bone samples. This elaboration requires a previous binarization of the images. A problem which arises from the binarization process is the partial volume artifact. Voxels at the external surface of the sample can contain both bone and air so thresholding operates an incorrect estimation of volume occupied by the two materials. AIM: The aim of this study is the extraction of bone volumetric information directly from the image histograms, by fitting them with a suitable set of functions. METHODS: Nineteen trabecular bone samples were extracted from femoral heads of eight patients subject to a hip arthroplasty surgery. Trabecular bone samples were acquired using micro-CT Scanner. Hystograms of the acquired images were computed and fitted by Gaussian-like functions accounting for: a gray levels produced by the bone x-ray absorption, b the portions of the image occupied by air and c voxels that contain a mixture of bone and air. This latter contribution can be considered such as an estimation of the partial volume effect. RESULTS: The comparison of the proposed technique to the bone volumes measured by a reference instrument such as by a helium pycnometer show the method as a good way for an accurate bone volume calculation of trabecular bone samples.

  20. SU-E-T-641: Development and Verification of Automatic Reading Dose of Interest From Eclipse's DVH

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Q [Department of Radiation Oncology, Beijing Hospital, Ministry of Health, Beijing (China)

    2014-06-15

    Purpose: According to clinical and research requirement, we develop a function of automatic reading dose of interest from dose volume histogram(DVH), to replace the traditional method with a mouse one by one point, and it's also verified. Methods: The DVH automatic reading function will be developed in an in-house developed radiotherapy information management system(RTIMS), which is based on Apache+PHP+MySQL. A DVH ASCII file is exported from Varian Eclipse V8.6, which includes the following contents: 1. basic information of patient; 2. dose information of plan; 3. dose information of structures, including basic information and dose volume data of target volume and organ at risk. And the default exported dose volume data also includes relative doses by 1% step and corresponding absolute doses and cumulative relative volumes, and the volumes are 4 decimal fraction. Clinically, we often need read the doses of some integer percent volumes, such as D50 and D30. So it couldn't be directly obtained from the above data, but we can use linear interpolation bye the near volumes and doses: Dx=D2−(V2−Vx)*(D2−D1)/(V2−V1), and program a function to search, read and calculate the corresponding data. And the doses of all preseted volume of interest of all structures can be automatically read one by one patient, and saved as a CSV file. To verify it, we select 24 IMRT plans for prostate cancer, and doses of interest are PTV D98/D95/D5/D2, bladder D30/D50, and rectum D25/D50. Two groups of data, using the automatic reading method(ARM) and pointed dose method(PDM), are analyzed with SPSS 16. The absolute difference=D-ARM-D-PDM, relative difference=absolute difference*100%/prescription dose(7600cGy). Results: The differences are as following: PTV D98/D95/D5/D2: −0.04%/− 0.04%/0.13%/0.19%, bladder D30/D50: −0.02%/0.01%, and rectum D25/D50: 0.03%/0.01%. Conclusion: Using this function, the error is very small, and can be neglected. It could greatly improve the

  1. Comp Plan: A computer program to generate dose and radiobiological metrics from dose-volume histogram files.

    Science.gov (United States)

    Holloway, Lois Charlotte; Miller, Julie-Anne; Kumar, Shivani; Whelan, Brendan M; Vinod, Shalini K

    2012-01-01

    Treatment planning studies often require the calculation of a large number of dose and radiobiological metrics. To streamline these calculations, a computer program called Comp Plan was developed using MATLAB. Comp Plan calculates common metrics, including equivalent uniform dose, tumor control probability, and normal tissue complication probability from dose-volume histogram data. The dose and radiobiological metrics can be calculated for the original data or for an adjusted fraction size using the linear quadratic model. A homogeneous boost dose can be added to a given structure if desired. The final output is written to an Excel file in a format convenient for further statistical analysis. Comp Plan was verified by independent calculations. A lung treatment planning study comparing 45 plans for 7 structures using up to 6 metrics for each structure was successfully analyzed within approximately 5 minutes with Comp Plan. The code is freely available from the authors on request.

  2. Structure Size Enhanced Histogram

    Science.gov (United States)

    Wesarg, Stefan; Kirschner, Matthias

    Direct volume visualization requires the definition of transfer functions (TFs) for the assignment of opacity and color. Multi-dimensional TFs are based on at least two image properties, and are specified by means of 2D histograms. In this work we propose a new type of a 2D histogram which combines gray value with information about the size of the structures. This structure size enhanced (SSE) histogram is an intuitive approach for representing anatomical features. Clinicians — the users we are focusing on — are much more familiar with selecting features by their size than by their gradient magnitude value. As a proof of concept, we employ the SSE histogram for the definition of two-dimensional TFs for the visualization of 3D MRI and CT image data.

  3. 3D DVH-based metric analysis versus per-beam planar analysis in IMRT pretreatment verification

    Energy Technology Data Exchange (ETDEWEB)

    Carrasco, Pablo; Jornet, Nuria; Latorre, Artur; Eudaldo, Teresa; Ruiz, Agusti; Ribas, Montserrat [Servei de Radiofisica i Radioproteccio, Hospital de la Santa Creu i Sant Pau, Sant Antoni Maria Claret, 167, 08025 Barcelona (Spain)

    2012-08-15

    Purpose: To evaluate methods of pretreatment IMRT analysis, using real measurements performed with a commercial 2D detector array, for clinical relevance and accuracy by comparing clinical DVH parameters. Methods: We divided the work into two parts. The first part consisted of six in-phantom tests aimed to study the sensitivity of the different analysis methods. Beam fluences, 3D dose distribution, and DVH of an unaltered original plan were compared to those of the delivered plan, in which an error had been intentionally introduced. The second part consisted of comparing gamma analysis with DVH metrics for 17 patient plans from various sites. Beam fluences were measured with the MapCHECK 2 detector, per-beam planar analysis was performed with the MapCHECK software, and 3D gamma analysis and the DVH evaluation were performed using 3DVH software. Results: In a per-beam gamma analysis some of the tests yielded false positives or false negatives. However, the 3DVH software correctly described the DVH of the plan which included the error. The measured DVH from the plan with controlled error agreed with the planned DVH within 2% dose or 2% volume. We also found that a gamma criterion of 3%/3 mm was too lax to detect some of the forced errors. Global analysis masked some problems, while local analysis magnified irrelevant errors at low doses. Small hotspots were missed for all metrics due to the spatial resolution of the detector panel. DVH analysis for patient plans revealed small differences between treatment plan calculations and 3DVH results, with the exception of very small volume structures such as the eyes and the lenses. Target coverage (D{sub 98} and D{sub 95}) of the measured plan was systematically lower than that predicted by the treatment planning system, while other DVH characteristics varied depending on the parameter and organ. Conclusions: We found no correlation between the gamma index and the clinical impact of a discrepancy for any of the gamma index

  4. Limits of dose escalation in lung cancer: a dose-volume histogram analysis comparing coplanar and non-coplanar techniques

    Energy Technology Data Exchange (ETDEWEB)

    Derycke, S.; Van Duyse, B.; Schelfhout, J.; De Neve, W.

    1995-12-01

    To evaluate the feasibility of dose escalation in radiotherapy of inoperable lung cancer, a dose-volume histogram analysis was performed comparing standard coplanar (2D) with non-coplanar (3D) beam arrangements on a non-selected group of 20 patients planned by Sherouse`s GRATISTM 3D-planning system. Serial CT-scanning was performed and 2 Target Volumes (Tvs) were defined. Gross Tumor Volume (GTV) defined a high-dose Target Volume (TV-1). GTV plus location of node stations with > 10% probability of invasion (Minet et al.) defined an intermediate-dose Target Volume (TV-2). However, nodal regions which are incompatible with cure were excluded from TV-2. These are ATS-regions 1, 8, 9 and 14 all left and right as well as heterolateral regions. For 3D-planning, Beam`s Eye View selected (by an experienced planner) beam arrangements were optimised using Superdot, a method of target dose-gradient annihilation developed by Sherouse. A second 3D-planning was performed using 4 beam incidences with maximal angular separation. The linac`s isocenter for the optimal arrangement was located at the geometrical center of gravity of a tetraheder, the tetraheder`s comers being the consecutive positions of the virtual source. This ideal beam arrangement was approximated as close as possible, taking into account technical limitations (patient-couch-gantry collisions). Criteria for tolerance were met if no points inside the spinal cord exceeded 50 Gy and if at least 50% of the lung volume received less than 20Gy. If dose regions below 50 Gy were judged acceptable at TV-2, 2D- as well as 3D-plans allow safe escalation to 80 Gy at TV-1. When TV-2 needed to be encompassed by isodose surfaces exceeding 50Gy, 3D-plans were necessary to limit dose at the spinal cord below tolerance. For large TVs dose is limited by lung tolerance for 3D-plans. An analysis (including NTCP-TCP as cost functions) of rival 3D-plans is being performed.

  5. True progression versus pseudoprogression in the treatment of glioblastomas: A comparison study of normalized cerebral blood volume and apparent diffusion coefficient by histogram analysis

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yong Sub; Choi, Seung Hong; Park, Chul Kee [Seoul National University College of Medicine, Seoul (Korea, Republic of); and others

    2013-08-15

    The purpose of this study was to differentiate true progression from pseudoprogression of glioblastomas treated with concurrent chemoradiotherapy (CCRT) with temozolomide (TMZ) by using histogram analysis of apparent diffusion coefficient (ADC) and normalized cerebral blood volume (nCBV) maps. Twenty patients with histopathologically proven glioblastoma who had received CCRT with TMZ underwent perfusion-weighted imaging and diffusion-weighted imaging (b = 0, 1000 sec/mm{sup 2}). The corresponding nCBV and ADC maps for the newly visible, entirely enhancing lesions were calculated after the completion of CCRT with TMZ. Two observers independently measured the histogram parameters of the nCBV and ADC maps. The histogram parameters between the true progression group (n = 10) and the pseudoprogression group (n = 10) were compared by use of an unpaired Student's t test and subsequent multivariable stepwise logistic regression analysis to determine the best predictors for the differential diagnosis between the two groups. Receiver operating characteristic analysis was employed to determine the best cutoff values for the histogram parameters that proved to be significant predictors for differentiating true progression from pseudoprogression. Intraclass correlation coefficient was used to determine the level of inter-observer reliability for the histogram parameters. The 5th percentile value (C5) of the cumulative ADC histograms was a significant predictor for the differential diagnosis between true progression and pseudoprogression (p 0.044 for observer 1; p = 0.011 for observer 2). Optimal cutoff values of 892 x 10{sup -6} mm{sup 2}/sec for observer 1 and 907 x 10{sup -6} mm{sup 2}/sec for observer 2 could help differentiate between the two groups with a sensitivity of 90% and 80%, respectively, a specificity of 90% and 80%, respectively, and an area under the curve of 0.880 and 0.840, respectively. There was no other significant differentiating parameter on the n

  6. Moving from gamma passing rates to patient DVH-based QA metrics in pretreatment dose QA

    Energy Technology Data Exchange (ETDEWEB)

    Zhen, Heming; Nelms, Benjamin E.; Tome, Wolfgang A. [Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705 (United States); Department of Human Oncology, University of Wisconsin, Madison, Wisconsin 53792 and Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705 and Department of Human Oncology, University of Wisconsin, Madison, Wisconsin 53792 (United States)

    2011-10-15

    Purpose: The purpose of this work is to explore the usefulness of the gamma passing rate metric for per-patient, pretreatment dose QA and to validate a novel patient-dose/DVH-based method and its accuracy and correlation. Specifically, correlations between: (1) gamma passing rates for three 3D dosimeter detector geometries vs clinically relevant patient DVH-based metrics; (2) Gamma passing rates of whole patient dose grids vs DVH-based metrics, (3) gamma passing rates filtered by region of interest (ROI) vs DVH-based metrics, and (4) the capability of a novel software algorithm that estimates corrected patient Dose-DVH based on conventional phan-tom QA data are analyzed. Methods: Ninety six unique ''imperfect'' step-and-shoot IMRT plans were generated by applying four different types of errors on 24 clinical Head/Neck patients. The 3D patient doses as well as the dose to a cylindrical QA phantom were then recalculated using an error-free beam model to serve as a simulated measurement for comparison. Resulting deviations to the planned vs simulated measured DVH-based metrics were generated, as were gamma passing rates for a variety of difference/distance criteria covering: dose-in-phantom comparisons and dose-in-patient comparisons, with the in-patient results calculated both over the whole grid and per-ROI volume. Finally, patient dose and DVH were predicted using the conventional per-beam planar data as input into a commercial ''planned dose perturbation'' (PDP) algorithm, and the results of these predicted DVH-based metrics were compared to the known values. Results: A range of weak to moderate correlations were found between clinically relevant patient DVH metrics (CTV-D95, parotid D{sub mean}, spinal cord D1cc, and larynx D{sub mean}) and both 3D detector and 3D patient gamma passing rate (3%/3 mm, 2%/2 mm) for dose-in-phantom along with dose-in-patient for both whole patient volume and filtered per-ROI. There was

  7. Optimization of the fractionated irradiation scheme considering physical doses to tumor and organ at risk based on dose–volume histograms

    Energy Technology Data Exchange (ETDEWEB)

    Sugano, Yasutaka [Graduate School of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan); Mizuta, Masahiro [Laboratory of Advanced Data Science, Information Initiative Center, Hokkaido University, Kita-11, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0811 (Japan); Takao, Seishin; Shirato, Hiroki; Sutherland, Kenneth L. [Department of Radiation Medicine, Graduate School of Medicine, Hokkaido University, Kita-15, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-8638 (Japan); Date, Hiroyuki, E-mail: date@hs.hokudai.ac.jp [Faculty of Health Sciences, Hokkaido University, Kita-12, Nishi-5, Kita-ku, Sapporo, Hokkaido 060-0812 (Japan)

    2015-11-15

    Purpose: Radiotherapy of solid tumors has been performed with various fractionation regimens such as multi- and hypofractionations. However, the ability to optimize the fractionation regimen considering the physical dose distribution remains insufficient. This study aims to optimize the fractionation regimen, in which the authors propose a graphical method for selecting the optimal number of fractions (n) and dose per fraction (d) based on dose–volume histograms for tumor and normal tissues of organs around the tumor. Methods: Modified linear-quadratic models were employed to estimate the radiation effects on the tumor and an organ at risk (OAR), where the repopulation of the tumor cells and the linearity of the dose-response curve in the high dose range of the surviving fraction were considered. The minimization problem for the damage effect on the OAR was solved under the constraint that the radiation effect on the tumor is fixed by a graphical method. Here, the damage effect on the OAR was estimated based on the dose–volume histogram. Results: It was found that the optimization of fractionation scheme incorporating the dose–volume histogram is possible by employing appropriate cell surviving models. The graphical method considering the repopulation of tumor cells and a rectilinear response in the high dose range enables them to derive the optimal number of fractions and dose per fraction. For example, in the treatment of prostate cancer, the optimal fractionation was suggested to lie in the range of 8–32 fractions with a daily dose of 2.2–6.3 Gy. Conclusions: It is possible to optimize the number of fractions and dose per fraction based on the physical dose distribution (i.e., dose–volume histogram) by the graphical method considering the effects on tumor and OARs around the tumor. This method may stipulate a new guideline to optimize the fractionation regimen for physics-guided fractionation.

  8. Influence of the choice of parameters of the TAC in the calculation of volumes for different planners; Influencia de la eleccion de los parametros del TAC en el calculo de volumenes para distintos planificadores

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Mazon, J.; Raba Diez, J. L.; Vazquez Rodriguez, J. A.; Pacheco Baldor, M. T.; Mendiguren Santiago, M. A.

    2011-07-01

    In the Protocol for the control treatment planning systems with ionizing radiation of the proposed SEFM tests to verify proper operation of the calculation in the evaluation of DVH (Dose Volume Histogram). The calculation of the volume that makes a planner may have important implications because it can trigger an overestimation of the dose or otherwise. We present a comparison of the calculation of volumes estimated with 4 different planners.

  9. Tolerance and dose-volume relationship of intrathoracic stomach irradiation after esophagectomy for patients with thoracic esophageal squamous cell carcinoma

    OpenAIRE

    Liu, Qi; Cai, Xu-Wei; Fu, Xiao-Long; Chen, Jun-Chao; Xiang, Jia-Qing

    2015-01-01

    Purpose To identify the tolerance of radiation with a high prescribed dose and predictors for the development of intrathoracic stomach toxicity in patients with thoracic esophageal squamous cell carcinoma (SCC) after esophagectomy followed by gastric conduit reconstruction. Methods and Materials From 2011 to 2013, 105 patients after esophagectomy were treated with postoperative radiotherapy. The intrathoracic stomach was outlined with the calculation of a dose-volume histogram (DVH) for the i...

  10. The analysis of correlation between changes of myocardial enzymes level in serum before and after radiation and dose-volume histogram parameters of the heart%三维放疗前后血清心肌酶谱变化与心脏体积剂量相关性分析

    Institute of Scientific and Technical Information of China (English)

    丁秀平; 李红军; 李宝生; 王冬青

    2012-01-01

    目的 探讨胸部肿瘤患者三维放疗前后血清心肌酶谱改变与心脏体积剂量的相关性.方法 102例胸部肿瘤患者(肺癌68例、食管癌34例)放疗前后检测血清天冬氨酸氨基转移酶(AST)、肌酸激酶(CK)、CK同工酶(CK-MB)、乳酸脱氢酶(LDH)及α-羟丁酸脱氢酶(α-HBDH)水平.放疗前后各种酶水平比较行配对t检验,组间比较行成组t检验.采用剂量体积直方图(DVH)参数[心脏接受≥x Gy照射体积占总体积百分比(Vx)]评价心脏体积剂量,各种酶与DVH参数相关性行Pearson法分析.结果 放疗后血清AST、CK-MB、LDH、α-HBDH水平较放疗前明显增高(19.42:27.89、14.72:19.57、178.80:217.57、140.32:176.25,t=-3.39~ -6.92,P均=0.000).调强放疗前后AST变化与V20、V25、V30相关(r=0.302~0.431,P=0.039~0.003),CK变化与V30相关(r=0.345,P=0.013),CK-MB、LDH、α-HBDH变化与V25、V30均相关(r--0.465~0.376,P=0.001~0.005);三维适形放疗前后CK-MB、LDH变化与V30相关(r=0.330、0.274,P=0.014、0.033),α-HBDH变化与V25、V30、V35相关(r=0.270~0.331,P=0.046~0.014).当放疗剂量>50 Gy时AST、LDH、α-HBDH变化与V25、V30相关(r=0.256~0.359,P=0.019~0.006),CK-MB变化与V30相关(r=0.233,P =0.037);≤50 Gy时仅V5 V45与CK变化相关(r=0.581、0.536,P=0.023、0.043).结论 心脏体积剂量与三维放疗前后心肌酶水平变化有一定相关性,提示心脏DVH参数有助于评价放疗诱导的心肌损伤.%Objective To analyze the correlation between the changes of myocardial enzyme level in serum before and after radiotherapy and dose - volume histogram ( DVH ) parameters of the heart.Methods A total of 102 patients with 68 cases of lung cancer and 34 cases of esophageal cancer were recruited.All patients received three-dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy (IMRT),with the radiation beams passing through the heart.Aspertate aminotransferase (AST),creatine kinase (CK

  11. Comparison of FDG PET metabolic tumour volume versus ADC histogram: prognostic value of tumour treatment response and survival in patients with locally advanced uterine cervical cancer.

    Science.gov (United States)

    Ueno, Yoshiko; Lisbona, Robert; Tamada, Tsutomu; Alaref, Amer; Sugimura, Kazuro; Reinhold, Caroline

    2017-07-01

    To evaluate the prognostic utility of volume-based parameters of fluorine-18 fludeoxyglucose positron emission tomography ((18)F-FDG PET) and apparent diffusion coefficient (ADC) histogram analysis for tumour response to therapy and event-free survival (EFS) in patients with uterine cervical cancer receiving chemoradiotherapy. The study included 21 patients diagnosed with locally advanced uterine cervical cancer who underwent pre-treatment MRI and (18)F-FDG PET and were treated with concurrent chemoradiotherapy. (18)F-FDG parameters: maximum and mean standardized uptake value; metabolic tumour volume (MTV); total lesion glycolysis (TLG); ADC parameters: maximum, mean and minimum values; percentile ADC values (10-90%); skewness and kurtosis of ADC were measured and compared between the responder and non-responder groups using a Wilcoxon rank-sum test. The Cox regression analysis and Kaplan-Meier survival curves were performed for EFS analysis. MTV and TLG of the primary tumour were significantly higher in the non-responder group than in the responder group (p = 0.04 and p = 0.01). Applying Cox regression multivariate analysis, MTV [hazard ratio (HR), 4.725; p = 0.036], TLG (HR, 4.725; p = 0.036) and 10-percentile ADC (HR, 5.207; p = 0.048) showed a statistically significant association with EFS. With the optimal cut-off value, the EFS rates above the cut-off value for MTV and TLG were significantly lower than that below the cut-off value (p = 0.002 and p = 0.002). Pre-treatment volume-based quantitative parameters of (18)F-FDG PET may have better potential than ADC histogram for predicting treatment response and EFS in patients with locally advanced cervical cancer. Advances in knowledge: In this study, pre-treatment volume-based quantitative parameters of (18)F-FDG PET had better potential than ADC histogram for predicting treatment response and survival in patients with locally advanced cervical cancer.

  12. SU-E-T-789: Validation of 3DVH Accuracy On Quantifying Delivery Errors Based On Clinical Relevant DVH Metrics

    Energy Technology Data Exchange (ETDEWEB)

    Ma, T; Kumaraswamy, L [Roswell Park Cancer Institute, Buffalo, NY (United States)

    2015-06-15

    Purpose: Detection of treatment delivery errors is important in radiation therapy. However, accurate quantification of delivery errors is also of great importance. This study aims to evaluate the 3DVH software’s ability to accurately quantify delivery errors. Methods: Three VMAT plans (prostate, H&N and brain) were randomly chosen for this study. First, we evaluated whether delivery errors could be detected by gamma evaluation. Conventional per-beam IMRT QA was performed with the ArcCHECK diode detector for the original plans and for the following modified plans: (1) induced dose difference error up to ±4.0% and (2) control point (CP) deletion (3 to 10 CPs were deleted) (3) gantry angle shift error (3 degree uniformly shift). 2D and 3D gamma evaluation were performed for all plans through SNC Patient and 3DVH, respectively. Subsequently, we investigated the accuracy of 3DVH analysis for all cases. This part evaluated, using the Eclipse TPS plans as standard, whether 3DVH accurately can model the changes in clinically relevant metrics caused by the delivery errors. Results: 2D evaluation seemed to be more sensitive to delivery errors. The average differences between ECLIPSE predicted and 3DVH results for each pair of specific DVH constraints were within 2% for all three types of error-induced treatment plans, illustrating the fact that 3DVH is fairly accurate in quantifying the delivery errors. Another interesting observation was that even though the gamma pass rates for the error plans are high, the DVHs showed significant differences between original plan and error-induced plans in both Eclipse and 3DVH analysis. Conclusion: The 3DVH software is shown to accurately quantify the error in delivered dose based on clinically relevant DVH metrics, where a conventional gamma based pre-treatment QA might not necessarily detect.

  13. Visualizing Contour Trees within Histograms

    DEFF Research Database (Denmark)

    Kraus, Martin

    2010-01-01

    Many of the topological features of the isosurfaces of a scalar volume field can be compactly represented by its contour tree. Unfortunately, the contour trees of most real-world volume data sets are too complex to be visualized by dot-and-line diagrams. Therefore, we propose a new visualization...... that is suitable for large contour trees and efficiently conveys the topological structure of the most important isosurface components. This visualization is integrated into a histogram of the volume data; thus, it offers strictly more information than a traditional histogram. We present algorithms...... to automatically compute the graph layout and to calculate appropriate approximations of the contour tree and the surface area of the relevant isosurface components. The benefits of this new visualization are demonstrated with the help of several publicly available volume data sets....

  14. Cardiac function after chemoradiation for esophageal cancer: comparison of heart dose-volume histogram parameters to multiple gated acquisition scan changes.

    Science.gov (United States)

    Tripp, P; Malhotra, H K; Javle, M; Shaukat, A; Russo, R; De Boer, S; Podgorsak, M; Nava, H; Yang, G Y

    2005-01-01

    In this paper we determine if preoperative chemoradiation for locally advanced esophageal cancer leads to changes in cardiac ejection fraction. This is a retrospective review of 20 patients treated at our institution for esophageal cancer between 2000 and 2002. Multiple gated acquisition cardiac scans were obtained before and after platinum-based chemoradiation (50.4 Gy). Dose-volume histograms for heart, left ventricle and left anterior descending artery were analyzed. Outcomes assessed included pre- and postchemoradiation ejection fraction ratio and percentage change in ejection fraction postchemoradiation. A statistically significant difference was found between median prechemoradiation ejection fraction (59%) and postchemoradiation ejection fraction (54%) (P = 0.01), but the magnitude of the difference was not clinically significant. Median percentage volume of heart receiving more than 20, 30 and 40 Gy were 61.5%, 58.5% and 53.5%, respectively. Our data showed a clinically insignificant decline in ejection fraction following chemoradiation for esophageal cancer. We did not observe statistically or clinically significant associations between radiation dose to heart, left ventricle or left anterior descending artery and postchemoradiation ejection fraction.

  15. Incorporating GSA-SPECT into CT-based dose-volume histograms for advanced hepatocellular carcinoma radiotherapy

    Institute of Scientific and Technical Information of China (English)

    Shintaro; Shirai; Morio; Sato; Yasutaka; Noda; Yoshitaka; Kumayama; Noritaka; Shimizu

    2014-01-01

    In single photon emission computed tomography-based three-dimensional radiotherapy(SPECT-B-3DCRT), im-ages of Tc-99 m galactosyl human serum albumin(GSA), which bind to receptors on functional liver cells, are merged with the computed tomography simulation im-ages. Functional liver is defined as the area of normal liver where GSA accumulation exceeds that of hepato-cellular carcinoma(HCC). In cirrhotic patients with a gigantic, proton-beam-untreatable HCC of ≥ 14 cm in diameter, the use of SPECT-B-3DCRT in combination with transcatheter arterial chemoembolization achieved a 2-year local tumor control rate of 78.6% and a 2-year survival rate of 33.3%. SPECT-B-3DCRT was applied to HCC to preserve as much functional liver as possible. Sixty-four patients with HCC, including 30 with Child B liver cirrhosis, received SPECT-B-3DCRT and none ex-perienced fatal radiation-induced liver disease(RILD). The Child-Pugh score deteriorated by 1 or 2 in > 20% of functional liver volume that was irradiated with ≥ 20 Gy. The deterioration in the Child-Pugh score decreased when the radiation plan was designed to irradiate ≤ 20% of the functional liver volume in patients givendoses of ≥ 20 Gy(FLV20Gy). Therefore, FLV20 Gy ≤ 20% may represent a safety index to prevent RILD during 3DCRT for HCC. To supplement FLV20 Gy as a qualitative index, we propose a quantitative indicator, F 20 Gy, which was calculated as F 20 Gy = 100% ×(the GSA count in the area irradiated with ≥ 20 Gy)/(the GSA count in the whole liver).

  16. TH-E-BRF-05: Comparison of Survival-Time Prediction Models After Radiotherapy for High-Grade Glioma Patients Based On Clinical and DVH Features

    Energy Technology Data Exchange (ETDEWEB)

    Magome, T; Haga, A; Igaki, H; Sekiya, N; Masutani, Y; Sakumi, A; Mukasa, A; Nakagawa, K [The University of Tokyo Hospital, Tokyo, JP (Japan)

    2014-06-15

    Purpose: Although many outcome prediction models based on dose-volume information have been proposed, it is well known that the prognosis may be affected also by multiple clinical factors. The purpose of this study is to predict the survival time after radiotherapy for high-grade glioma patients based on features including clinical and dose-volume histogram (DVH) information. Methods: A total of 35 patients with high-grade glioma (oligodendroglioma: 2, anaplastic astrocytoma: 3, glioblastoma: 30) were selected in this study. All patients were treated with prescribed dose of 30–80 Gy after surgical resection or biopsy from 2006 to 2013 at The University of Tokyo Hospital. All cases were randomly separated into training dataset (30 cases) and test dataset (5 cases). The survival time after radiotherapy was predicted based on a multiple linear regression analysis and artificial neural network (ANN) by using 204 candidate features. The candidate features included the 12 clinical features (tumor location, extent of surgical resection, treatment duration of radiotherapy, etc.), and the 192 DVH features (maximum dose, minimum dose, D95, V60, etc.). The effective features for the prediction were selected according to a step-wise method by using 30 training cases. The prediction accuracy was evaluated by a coefficient of determination (R{sup 2}) between the predicted and actual survival time for the training and test dataset. Results: In the multiple regression analysis, the value of R{sup 2} between the predicted and actual survival time was 0.460 for the training dataset and 0.375 for the test dataset. On the other hand, in the ANN analysis, the value of R{sup 2} was 0.806 for the training dataset and 0.811 for the test dataset. Conclusion: Although a large number of patients would be needed for more accurate and robust prediction, our preliminary Result showed the potential to predict the outcome in the patients with high-grade glioma. This work was partly supported by

  17. SU-E-T-596: P3DVHStats - a Novel, Automatic, Institution Customizable Program to Compute and Report DVH Quantities On Philips Pinnacle TPS

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C [Sutter Medical Foundation, Roseville, CA (United States)

    2015-06-15

    Purpose: To implement a novel, automatic, institutional customizable DVH quantities evaluation and PDF report tool on Philips Pinnacle treatment planning system (TPS) Methods: An add-on program (P3DVHStats) is developed by us to enable automatic DVH quantities evaluation (including both volume and dose based quantities, such as V98, V100, D2), and automatic PDF format report generation, for EMR convenience. The implementation is based on a combination of Philips Pinnacle scripting tool and Java language pre-installed on each Pinnacle Sun Solaris workstation. A single Pinnacle script provide user a convenient access to the program when needed. The activated script will first export DVH data for user selected ROIs from current Pinnacle plan trial; a Java program then provides a simple GUI interface, utilizes the data to compute any user requested DVH quantities, compare with preset institutional DVH planning goals; if accepted by users, the program will also generate a PDF report of the results and export it from Pinnacle to EMR import folder via FTP. Results: The program was tested thoroughly and has been released for clinical use at our institution (Pinnacle Enterprise server with both thin clients and P3PC access), for all dosimetry and physics staff, with excellent feedback. It used to take a few minutes to use MS-Excel worksheet to calculate these DVH quantities for IMRT/VMAT plans, and manually save them as PDF report; with the new program, it literally takes a few mouse clicks in less than 30 seconds to complete the same tasks. Conclusion: A Pinnacle scripting and Java language based program is successfully implemented, customized to our institutional needs. It is shown to dramatically reduce time and effort needed for DVH quantities computing and EMR reporting.

  18. Histogram analysis reveals a better delineation of tumor volume from background in {sup 18}F-FET PET compared to CBV maps in a hybrid PET–MR studie in gliomas

    Energy Technology Data Exchange (ETDEWEB)

    Filss, Christian P., E-mail: c.filss@fz-juelich.de [Institute of Neuroscience and Medicine (INM-3,-4,-5), Research Center Jülich, Jülich (Germany); Stoffels, Gabriele [Institute of Neuroscience and Medicine (INM-3,-4,-5), Research Center Jülich, Jülich (Germany); Galldiks, Norbert [Institute of Neuroscience and Medicine (INM-3,-4,-5), Research Center Jülich, Jülich (Germany); Department of Neurology, University of Cologne, Cologne (Germany); Sabel, Michael [Department of Neurosurgery, University Düsseldorf, Medical Faculty, Düsseldorf (Germany); Wittsack, Hans J. [Department of Diagnostic and Interventional Radiology, University Düsseldorf, Medical Faculty, Düsseldorf (Germany); Coenen, Heinz H. [Institute of Neuroscience and Medicine (INM-3,-4,-5), Research Center Jülich, Jülich (Germany); Jülich-Aachen Research Alliance (JARA) – Section JARA-Brain (Germany); Shah, Nadim J. [Institute of Neuroscience and Medicine (INM-3,-4,-5), Research Center Jülich, Jülich (Germany); Jülich-Aachen Research Alliance (JARA) – Section JARA-Brain (Germany); Department of Neurology, RWTH Aachen University Hospital, Aachen (Germany); Herzog, Hans [Institute of Neuroscience and Medicine (INM-3,-4,-5), Research Center Jülich, Jülich (Germany); Jülich-Aachen Research Alliance (JARA) – Section JARA-Brain (Germany); and others

    2014-01-11

    Anatomical imaging with magnetic resonance imaging (MRI) is currently the method of first choice for diagnostic investigation of glial tumors. However, different MR sequences may over- or underestimate tumor size and thus it may not be possible to delineate tumor from adjacent brain. In order to compensate this confinement additonal MR sequences like perfusion weighted MRI (PWI) with regional cerebral blood volume (rCBV) or positron emission tomography (PET) with aminoacids are used to gain further information. Recent studies suggest that both of theses image modalities provide similar diagnostic information. For comparison tumor to brain ratios (TBR) with mean and maximum values are frequently used but results from different studies can often not be checked against each other. Furthermore, especially the maximum TBR in rCBV is at risk to be falsified by artifacts (e.g. blood vessels). These confinements are reduced by the use of histograms since all information of the VOIs are equally displayed. In this study we measured and compared the intersection of tumor and reference tissue histograms in {sup 18}F-FET PET and rCBV maps in glioma patients. Methods: Twenty-seven glioma patients with contrast enhancing lesion on T1-weighted MR images were investigated using static {sup 18}F-FET PET and rCBV in MRI using a PET–MR hybrid scanner. In all patients diagnosis was confirmed histologically (7 grade II gliomas, 6 grade III gliomas and 14 grade IV gliomas). We generated a set of tumor and reference tissue Volumes-of-Interest (VOIs) based on T1 weighted images in MRI with the tumor VOI defined by contrast enhancement and transferred these VOIs to the corresponding {sup 18}F-FET PET scans and rCBV maps. From these VOIs we generated tumor and reference tissue histograms with a unity of one for each curve integral and measured the proportion of the area under the tumor curve that falls into the reference curve for {sup 18}F-FET PET and rCBV maps for each patient. Results

  19. Effect of Dosimetric Factors on Occurrence and Volume of Temporal Lobe Necrosis Following Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma: A Case-Control Study

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Xin; Ou, Xiaomin; Xu, Tingting; Wang, Xiaosheng; Shen, Chunying [Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai (China); Ding, Jianhui [Department of Diagnostic Radiology, Fudan University Shanghai Cancer Center, Shanghai (China); Hu, Chaosu, E-mail: hucsu62@yahoo.com [Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai (China)

    2014-10-01

    Purpose: To determine dosimetric risk factors for the occurrence of temporal lobe necrosis (TLN) among nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiation therapy (IMRT) and to investigate the impact of dose-volume histogram (DVH) parameters on the volume of TLN lesions (V-N). Methods and Materials: Forty-three NPC patients who had developed TLN following IMRT and 43 control subjects free of TLN were retrospectively assessed. DVH parameters included maximum dose (Dmax), minimum dose (Dmin), mean dose (Dmean), absolute volumes receiving specific dose (Vds) from 20 to 76 Gy (V20-V76), and doses covering certain volumes (Dvs) from 0.25 to 6.0 cm{sup 3} (D0.25-D6.0). V-Ns were quantified with axial magnetic resonance images. Results: DVH parameters were ubiquitously higher in temporal lobes with necrosis than in healthy temporal lobes. Increased Vds and Dvs were significantly associated with higher risk of TLN occurrence (P<.05). In particular, Vds at a dose of ≥70 Gy were found with the highest odds ratios. A common increasing trend was detected between V-N and DVH parameters through trend tests (P for trend of <.05). Linear regression analysis showed that V45 had the strongest predictive power for V-N (adjusted R{sup 2} = 0.305, P<.0001). V45 of <15.1 cm{sup 3} was relatively safe as the dose constraint for preventing large TLN lesions with V-N of >5 cm{sup 3}. Conclusions: Dosimetric parameters are significantly associated with TLN occurrence and the extent of temporal lobe injury. To better manage TLN, it would be important to avoid both focal high dose and moderate dose delivered to a large area in TLs.

  20. Accuracy of one algorithm used to modify a planned DVH with data from actual dose delivery.

    Science.gov (United States)

    Ma, Tianjun; Podgorsak, Matthew B; Kumaraswamy, Lalith K

    2016-09-08

    Detection and accurate quantification of treatment delivery errors is important in radiation therapy. This study aims to evaluate the accuracy of DVH based QA in quantifying delivery errors. Eighteen previously treated VMAT plans (prostate, H&N, and brain) were randomly chosen for this study. Conventional IMRT delivery QA was done with the ArcCHECK diode detector for error-free plans and plans with the following modifications: 1) induced monitor unit differences up to ± 3.0%, 2) control point deletion (3, 5, and 8 control points were deleted for each arc), and 3) gantry angle shift (2° uniform shift clockwise and counterclockwise). 2D and 3D distance-to-agreement (DTA) analyses were performed for all plans with SNC Patient software and 3DVH software, respectively. Subsequently, accuracy of the reconstructed DVH curves and DVH parameters in 3DVH software were analyzed for all selected cases using the plans in the Eclipse treatment planning system as standard. 3D DTA analysis for error-induced plans generally gave high pass rates, whereas the 2D evaluation seemed to be more sensitive to detecting delivery errors. The average differences for DVH parameters between each pair of Eclipse recalculation and 3DVH prediction were within 2% for all three types of error-induced treatment plans. This illustrates that 3DVH accurately quantifies delivery errors in terms of actual dose delivered to the patients. 2D DTA analysis should be routinely used for clinical evaluation. Any concerns or dose discrepancies should be further analyzed through DVH-based QA for clinically relevant results and confirmation of a conventional passing-rate-based QA.

  1. Fast tracking using edge histograms

    Science.gov (United States)

    Rokita, Przemyslaw

    1997-04-01

    This paper proposes a new algorithm for tracking objects and objects boundaries. This algorithm was developed and applied in a system used for compositing computer generated images and real world video sequences, but can be applied in general in all tracking systems where accuracy and high processing speed are required. The algorithm is based on analysis of histograms obtained by summing along chosen axles pixels of edge segmented images. Edge segmentation is done by spatial convolution using gradient operator. The advantage of such an approach is that it can be performed in real-time using available on the market hardware convolution filters. After edge extraction and histograms computation, respective positions of maximums in edge intensity histograms, in current and previous frame, are compared and matched. Obtained this way information about displacement of histograms maximums, can be directly converted into information about changes of target boundaries positions along chosen axles.

  2. Dose-volume histogram comparison between static 5-field IMRT with 18-MV X-rays and helical tomotherapy with 6-MV X-rays.

    Science.gov (United States)

    Hayashi, Akihiro; Shibamoto, Yuta; Hattori, Yukiko; Tamura, Takeshi; Iwabuchi, Michio; Otsuka, Shinya; Sugie, Chikao; Yanagi, Takeshi

    2015-03-01

    We treated prostate cancer patients with static 5-field intensity-modulated radiation therapy (IMRT) using linac 18-MV X-rays or tomotherapy with 6-MV X-rays. As X-ray energies differ, we hypothesized that 18-MV photon IMRT may be better for large patients and tomotherapy may be more suitable for small patients. Thus, we compared dose-volume parameters for the planning target volume (PTV) and organs at risk (OARs) in 59 patients with T1-3 N0M0 prostate cancer who had been treated using 5-field IMRT. For these same patients, tomotherapy plans were also prepared for comparison. In addition, plans of 18 patients who were actually treated with tomotherapy were analyzed. The evaluated parameters were homogeneity indicies and a conformity index for the PTVs, and D2 (dose received by 2% of the PTV in Gy), D98, Dmean and V10-70 Gy (%) for OARs. To evaluate differences by body size, patients with a known body mass index were grouped by that index ( 25 kg/m(2)). For the PTV, all parameters were higher in the tomotherapy plans compared with the 5-field IMRT plans. For the rectum, V10 Gy and V60 Gy were higher, whereas V20 Gy and V30 Gy were lower in the tomotherapy plans. For the bladder, all parameters were higher in the tomotherapy plans. However, both plans were considered clinically acceptable. Similar trends were observed in 18 patients treated with tomotherapy. Obvious trends were not observed for body size. Tomotherapy provides equivalent dose distributions for PTVs and OARs compared with 18-MV 5-field IMRT. Tomotherapy could be used as a substitute for high-energy photon IMRT for prostate cancer regardless of body size.

  3. A simple DVH generation technique from various radiotherapy treatment planning systems for independent information system

    CERN Document Server

    Min, Byung Jun; Jeong, Il Sun; Lee, Hyebin

    2015-01-01

    In recent years, the use of PACS for radiation therapy has become the norm in hospital environment and has suggested for collecting data and management from different TPSs with DICOM objects. However, some TPS does not provide the DVH exportation with text or other format. In addition, plan review systems for various TPSs often allow DVH recalculation with different algorithms. These algorithms result in the inevitable discrepancy between the values obtained with the recalculation and those obtained with TPS itself. The purpose of this study was to develop a simple method for generating reproducible DVH values obtained from the TPSs. Treatment planning information including structures and delivered dose was exported by the DICOM format from planning systems. The supersampling and trilinear interpolation methods were employed to calculate DVH data from 35 treatment plans. The discrepancies between DVHs extracted from each TPS and the proposed calculation method were evaluated with respect to the supersampling ...

  4. Comparative analysis of dose-volume histograms between 3D conformal and conventional non-conformal radiotherapy planning for prostate cancer; Analise comparativa dos histogramas de dose e volume entre planejamentos tridimensionais conformados e convencionais nao conformados na radioterapia do cancer de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Feitosa, Silvia Moreira; Giordani, Adelmo Jose; Dias, Rodrigo Sousa; Segreto, Helena Regina Comodo; Segreto, Roberto Araujo [Universidade Federal de Sao Paulo (UNIFESP-EPM), Sao Paulo, SP (Brazil)], e-mail: silviamfeitosa@yahoo.com.br

    2009-03-15

    Objective: The present study was aimed at comparing conformal and non-conformal radiotherapy plans designed for patients with prostate cancer, by analyzing radiation doses in target volumes and organs at risk. Materials and methods: Radiotherapy plans for 40 patients with prostate cancer were analyzed. Conformal, conformal isocentric and non-conformal plans utilizing the source-surface distance were simulated for each of the patients for comparison of radiation dose in target volumes and organs at risk. For comparison purposes, dose-volume histograms for target volumes and organs at risk were analyzed. Results: Median doses were significantly lower in the conformal planning, with 25%, 40% and 60% volumes in the rectum and 30% and 60% in the bladder. The median doses were significantly lower in the conformal planning analyzing the right and left coxofemoral joints. Maximum, mean and median doses in the clinical target volume and in the planned target volume were significantly higher in the conformal planning. Conclusion: The present study has demonstrated that the conformal radiotherapy planning for prostate cancer allows the delivery of higher doses to the target volume and lower doses to adjacent healthy tissues. (author)

  5. Bin recycling strategy for improving the histogram precision on GPU

    Science.gov (United States)

    Cárdenas-Montes, Miguel; Rodríguez-Vázquez, Juan José; Vega-Rodríguez, Miguel A.

    2016-07-01

    Histogram is an easily comprehensible way to present data and analyses. In the current scientific context with access to large volumes of data, the processing time for building histogram has dramatically increased. For this reason, parallel construction is necessary to alleviate the impact of the processing time in the analysis activities. In this scenario, GPU computing is becoming widely used for reducing until affordable levels the processing time of histogram construction. Associated to the increment of the processing time, the implementations are stressed on the bin-count accuracy. Accuracy aspects due to the particularities of the implementations are not usually taken into consideration when building histogram with very large data sets. In this work, a bin recycling strategy to create an accuracy-aware implementation for building histogram on GPU is presented. In order to evaluate the approach, this strategy was applied to the computation of the three-point angular correlation function, which is a relevant function in Cosmology for the study of the Large Scale Structure of Universe. As a consequence of the study a high-accuracy implementation for histogram construction on GPU is proposed.

  6. Multispectral histogram normalization contrast enhancement

    Science.gov (United States)

    Soha, J. M.; Schwartz, A. A.

    1979-01-01

    A multispectral histogram normalization or decorrelation enhancement which achieves effective color composites by removing interband correlation is described. The enhancement procedure employs either linear or nonlinear transformations to equalize principal component variances. An additional rotation to any set of orthogonal coordinates is thus possible, while full histogram utilization is maintained by avoiding the reintroduction of correlation. For the three-dimensional case, the enhancement procedure may be implemented with a lookup table. An application of the enhancement to Landsat multispectral scanning imagery is presented.

  7. Impact of different leaf velocities and dose rates on the number of monitor units and the dose-volume-histograms using intensity modulated radiotherapy with sliding-window technique

    Directory of Open Access Journals (Sweden)

    Hess Clemens F

    2008-09-01

    Full Text Available Abstract Background Intensity modulated radiotherapy (IMRT using sliding window technique utilises a leaf sequencing algorithm, which takes some control system limitations like dose rates (DR and velocity of the leafs (LV into account. The effect of altering these limitations on the number of monitor units and radiation dose to the organs at risk (OAR were analysed. Methods IMRT plans for different LVs from 1.0 cm/sec to 10.0 cm/sec and different DRs from 100 MU/min to 600 MU/min for two patients with prostate cancer and two patients with squamous cell cancer of the scalp (SCCscalp were calculated using the same "optimal fluence map". For each field the number of monitor units, the dose volume histograms and the differences in the "actual fluence maps" of the fields were analysed. Results With increase of the DR and decrease of the LV the number of monitor units increased and consequentially the radiation dose given to the OAR. In particular the serial OARs of patients with SCCscalp, which are located outside the end position of the leafs and inside the open field, received an additional dose of a higher DR and lower LV is used. Conclusion For best protection of organs at risk, a low DR and high LV should be applied. But the consequence of a low DR is both a long treatment time and also that a LV of higher than 3.0 cm/sec is mechanically not applicable. Our recommendation for an optimisation of the discussed parameters is a leaf velocity of 2.5 cm/sec and a dose rate of 300–400 MU/min (prostate cancer and 100–200 MU/min (SCCscalp for best protection of organs at risk, short treatment time and number of monitor units.

  8. Relationship between dose-volume parameters and pulmonary complications after neoadjuvant chemoradiotherapy followed by surgery for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Shigeo; Shibata, Toru [Kagawa University Hospital, Department of Radiation Oncology, Kagawa (Japan); Go, Tetsuhiko; Kasai, Yoshitaka; Yokomise, Hiroyasu [Kagawa University, Department of General Thoracic, Breast and Endocrine Surgery, Faculty of Medicine, Kagawa (Japan)

    2016-09-15

    This study evaluated the relationship between dose-volume histogram (DVH) parameters and pulmonary complications after neoadjuvant chemoradiotherapy (NACRT) followed by surgery for lung cancer. We also examined a new DVH parameter, because the unresected lung should be more spared than the later resected lung. Data from 43 non-small cell lung cancer patients were retrospectively analyzed. The DVH parameters of the lung were calculated from the total bilateral lung volume minus (1) the gross tumor volume (DVHg) or (2) the later resected lung volume (DVHr). Radiation pneumonitis (RP) and fistula, including bronchopleural and pulmonary fistula, were graded as the pulmonary complications. Factors affecting the incidences of grade 2 or higher RP (≥G2 RP) and fistula were analyzed. Sixteen patients (37 %) experienced ≥G2 RP and a V20 value of the total lung minus the later resected lung (V20r) ≥ 12 % was a significant factor affecting the incidence of ≥G2 RP (p = 0.032). Six patients (14 %) developed a fistula and a V35 value of the total lung minus the gross tumor (V35g) ≥ 19 % and a V40g ≥ 16 % were significant factors affecting the incidence of fistula (p = 0.002 and 0.009, respectively). These DVH parameters may be related to the incidences of ≥G2 RP and fistula. (orig.) [German] In dieser Studie wurde die Beziehung zwischen Dosis-Volumen-Histogramm-(DVH-)Parametern und pulmonalen Komplikationen nach neoadjuvanter Radiochemotherapie (NARCT) und nachfolgender Operation beim Lungenkarzinom untersucht. Zudem wurde ein neuer DVH-Parameter untersucht, da das nichtresezierte Lungengewebe mehr geschont werden sollte als reseziertes Gewebe. Daten von 43 Patienten mit nicht-kleinzelligem Bronchialkarzinom wurden retrospektiv analysiert. Die DVH-Parameter der Lunge wurden aus dem gesamten beidseitigen Lungenvolumen minus (1) das makroskopische Tumorvolumen (DVHg) oder (2) das resezierte Lungenvolumen (DVHr) ermittelt. Strahlenpneumonitis (RP) und Fisteln

  9. LHCb: Machine assisted histogram classification

    CERN Multimedia

    Somogyi, P; Gaspar, C

    2009-01-01

    LHCb is one of the four major experiments under completion at the Large Hadron Collider (LHC). Monitoring the quality of the acquired data is important, because it allows the verification of the detector performance. Anomalies, such as missing values or unexpected distributions can be indicators of a malfunctioning detector, resulting in poor data quality. Spotting faulty components can be either done visually using instruments such as the LHCb Histogram Presenter, or by automated tools. In order to assist detector experts in handling the vast monitoring information resulting from the sheer size of the detector, a graph-theoretic based clustering tool, combined with machine learning algorithms is proposed and demonstrated by processing histograms representing 2D event hitmaps. The concept is proven by detecting ion feedback events in the LHCb RICH subdetector.

  10. Discrimination of paediatric brain tumours using apparent diffusion coefficient histograms

    Energy Technology Data Exchange (ETDEWEB)

    Bull, Jonathan G.; Clark, Christopher A. [UCL Institute of Child Health, Imaging and Biophysics Unit, London (United Kingdom); Saunders, Dawn E. [Great Ormond Street Hospital for Children NHS Trust, Department of Radiology, London (United Kingdom)

    2012-02-15

    To determine if histograms of apparent diffusion coefficients (ADC) can be used to differentiate paediatric brain tumours. Imaging of histologically confirmed tumours with pre-operative ADC maps were reviewed (54 cases, 32 male, mean age 6.1 years; range 0.1-15.8 years) comprising 6 groups. Whole tumour ADC histograms were calculated; normalised for volume. Stepwise logistic regression analysis was used to differentiate tumour types using histogram metrics, initially for all groups and then for specific subsets. All 6 groups (5 dysembryoplastic neuroectodermal tumours, 22 primitive neuroectodermal tumours (PNET), 5 ependymomas, 7 choroid plexus papillomas, 4 atypical teratoid rhabdoid tumours (ATRT) and 9 juvenile pilocytic astrocytomas (JPA)) were compared. 74% (40/54) were correctly classified using logistic regression of ADC histogram parameters. In the analysis of posterior fossa tumours, 80% of ependymomas, 100% of astrocytomas and 94% of PNET-medulloblastoma were classified correctly. All PNETs were discriminated from ATRTs (22 PNET and 4 supratentorial ATRTs) (100%). ADC histograms are useful in differentiating paediatric brain tumours, in particular, the common posterior fossa tumours of childhood. PNETs were differentiated from supratentorial ATRTs, in all cases, which has important implications in terms of clinical management. (orig.)

  11. Quantitative histogram analysis of images

    Science.gov (United States)

    Holub, Oliver; Ferreira, Sérgio T.

    2006-11-01

    A routine for histogram analysis of images has been written in the object-oriented, graphical development environment LabVIEW. The program converts an RGB bitmap image into an intensity-linear greyscale image according to selectable conversion coefficients. This greyscale image is subsequently analysed by plots of the intensity histogram and probability distribution of brightness, and by calculation of various parameters, including average brightness, standard deviation, variance, minimal and maximal brightness, mode, skewness and kurtosis of the histogram and the median of the probability distribution. The program allows interactive selection of specific regions of interest (ROI) in the image and definition of lower and upper threshold levels (e.g., to permit the removal of a constant background signal). The results of the analysis of multiple images can be conveniently saved and exported for plotting in other programs, which allows fast analysis of relatively large sets of image data. The program file accompanies this manuscript together with a detailed description of two application examples: The analysis of fluorescence microscopy images, specifically of tau-immunofluorescence in primary cultures of rat cortical and hippocampal neurons, and the quantification of protein bands by Western-blot. The possibilities and limitations of this kind of analysis are discussed. Program summaryTitle of program: HAWGC Catalogue identifier: ADXG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADXG_v1_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computers: Mobile Intel Pentium III, AMD Duron Installations: No installation necessary—Executable file together with necessary files for LabVIEW Run-time engine Operating systems or monitors under which the program has been tested: WindowsME/2000/XP Programming language used: LabVIEW 7.0 Memory required to execute with typical data:˜16MB for starting and ˜160MB used for

  12. Análise comparativa dos histogramas de dose e volume entre planejamentos tridimensionais conformados e convencionais não conformados na radioterapia do câncer de próstata Comparative analysis of dose-volume histograms between 3D conformal and conventional non-conformal radiotherapy plannings for prostate cancer

    Directory of Open Access Journals (Sweden)

    Sílvia Moreira Feitosa

    2009-04-01

    , dose-volume histograms for target volumes and organs at risk were analyzed. RESULTS: Median doses were significantly lower in the conformal planning, with 25%, 40% and 60% volumes in the rectum and 30% and 60% in the bladder. The median doses were significantly lower in the conformal planning analyzing the right and left coxofemoral joints. Maximum, mean and median doses in the clinical target volume and in the planned target volume were significantly higher in the conformal planning. CONCLUSION: The present study has demonstrated that the conformal radiotherapy planning for prostate cancer allows the delivery of higher doses to the target volume and lower doses to adjacent healthy tissues.

  13. Simple DVH parameter addition as compared to deformable registration for bladder dose accumulation in cervix cancer brachytherapy

    DEFF Research Database (Denmark)

    Andersen, Else Stougård; Noe, Karsten Østergaaard; Sørensen, Thomas Sangild

    2013-01-01

    called "the worst case assumption") in fractionated BT. Materials and methods: Forty-seven patients treated for locally advanced cervical cancer were included. All patients received EBRT combined with two individually planned 3D image-guided adaptive BT fractions. D2 and D0.1 were estimated by DVH...... parameter addition and compared to dose accumulations based on an in-house developed biomechanical deformable image registration (DIR) algorithm. Results: DIR-based DVH analysis was possible in 42/47 patients. DVH parameter addition resulted in mean dose deviations relative to DIR of 0.4 ± 0.3 Gy (1.5 ± 1...

  14. Histogram-Based Calibration Method for Pipeline ADCs

    Science.gov (United States)

    Son, Hyeonuk; Jang, Jaewon; Kim, Heetae; Kang, Sungho

    2015-01-01

    Measurement and calibration of an analog-to-digital converter (ADC) using a histogram-based method requires a large volume of data and a long test duration, especially for a high resolution ADC. A fast and accurate calibration method for pipelined ADCs is proposed in this research. The proposed calibration method composes histograms through the outputs of each stage and calculates error sources. The digitized outputs of a stage are influenced directly by the operation of the prior stage, so the results of the histogram provide the information of errors in the prior stage. The composed histograms reduce the required samples and thus calibration time being implemented by simple modules. For 14-bit resolution pipelined ADC, the measured maximum integral non-linearity (INL) is improved from 6.78 to 0.52 LSB, and the spurious-free dynamic range (SFDR) and signal-to-noise-and-distortion ratio (SNDR) are improved from 67.0 to 106.2dB and from 65.6 to 84.8dB, respectively. PMID:26070196

  15. ACTION RECOGNITION USING SALIENT NEIGHBORING HISTOGRAMS

    DEFF Research Database (Denmark)

    Ren, Huamin; Moeslund, Thomas B.

    2013-01-01

    and temporal dimensions. Instead, we propose a salient vocabulary construction algorithm to select visual words from a global point of view, and form compact descriptors to represent discriminative histograms in the neighborhoods. Those salient neighboring histograms are then trained to model different actions...

  16. Interpreting Histograms. As Easy as It Seems?

    Science.gov (United States)

    Lem, Stephanie; Onghena, Patrick; Verschaffel, Lieven; Van Dooren, Wim

    2014-01-01

    Histograms are widely used, but recent studies have shown that they are not as easy to interpret as it might seem. In this article, we report on three studies on the interpretation of histograms in which we investigated, namely, (1) whether the misinterpretation by university students can be considered to be the result of heuristic reasoning, (2)…

  17. Spline smoothing of histograms by linear programming

    Science.gov (United States)

    Bennett, J. O.

    1972-01-01

    An algorithm for an approximating function to the frequency distribution is obtained from a sample of size n. To obtain the approximating function a histogram is made from the data. Next, Euclidean space approximations to the graph of the histogram using central B-splines as basis elements are obtained by linear programming. The approximating function has area one and is nonnegative.

  18. Normal lung dose-volume histogram varieties in the former and inter period of three dimensional conformal radiation therapy plans and their clinical significance in non-small cell lung cancer%非小细胞肺癌三维适形后程加速超分割放疗中肺剂量体积变化规律及临床意义探讨

    Institute of Scientific and Technical Information of China (English)

    胡银祥; 卢冰; 周华宁; 甘家应; 洪卫

    2009-01-01

    Objective To analyze the normal lung dose-volume histogram(DVH) varieties in the former and later period(P1 and P2)of three dimensional conformal radiation therapy(3DCRT) plans and the compound (Pc) plan in non-small cell lung cancer(NSCLC),and to access the feasibility to modify the target volume during the treatment course.Methods Twenty-one NSCLC patients who had received accelerated hyper-frationation 3DCRT in P2 were included in the study.Both of the P1 and P2 plans were redesigned to a total dose of 70 Gy with V20 smaller than 35%.When the target volume was modified and P2 plan was rede signed using accelerated hyper-frationation 3DCRT of 30 Gy after P1 plan of 40 Gy,the Pc plan was compoun ded by transmitting the parameters(such as target volume,irradiation field and dose) of P1 plan into P2 plan. Total lung volume and target volumes(GTV,PTV) of P1 and P2 were evaluated.MLD,V5,V10,V20 and V30 of P1,P2 and Pc were calculated.Results The total lung volume in P1 and P2 plans was not significantly dif ferent(t = 0.19,P = 0.850).The volumes of GTV,PTV in P2 were obviously smaller than P1 (t = 2.88,P = 0.009 ; t = 4.01 ,P = 0.001) .When comparing P2 with P1 ,MLD were 16.5 Gy Vs 17.8 Gy (t = 2.60, DOI:10.3760/cma.j.issn.1004-4221.2009.01.057 P = 0.017),V30 was significantly decreased (t = 2.19,P = 0.041),but V5,V10 and V20 had no significant difference.Similar differences were found in MLD,V5 ,V10 ,V20 and V30 when comparing Po to P1.P2 plans had significantly smaller MLD,Vs,V10,V20 and V30 than Pc plans.Fourteen patients with decreased PTV were further analyzed.The V30 and MLD decreased significantly (t = 3.00,P = 0.0 I 0;t = 2.38,P = 0.033), but V5 ,V10,V20 had no difference when comparing P1 and P2 plans.Among these 14 patients,the V10 and V30 decreased significantly(t = 2.76,P = 0.033 ; t = 3.60,P = 0.011) when P2 plans were generated using the same field number and beam angles in P1 plans in 7 patients.The parameters were similar in P1and Pc plans

  19. Histogram analysis of diffusion measures in clinically isolated syndromes and relapsing-remitting multiple sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Yu Chunshui [Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing (China); Education Ministry Key Laboratory for Neurodegenerative Disease, Beijing (China); Lin Fuchun [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China); Liu Yaou; Duan Yunyun [Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing (China); Lei Hao [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan (China); Li Kuncheng [Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing (China); Education Ministry Key Laboratory for Neurodegenerative Disease, Beijing (China)], E-mail: kunchengli1955@yahoo.com.cn

    2008-11-15

    Objective: The purposes of our study were to employ diffusion tensor imaging (DTI)-based histogram analysis to determine the presence of occult damage in clinically isolated syndrome (CIS), to compare its severity with relapsing-remitting multiple sclerosis (RRMS), and to determine correlations between DTI histogram measures and clinical and MRI indices in these two diseases. Materials and methods: DTI scans were performed in 19 CIS and 19 RRMS patients and 19 matched healthy volunteers. Histogram analyses of mean diffusivity and fractional anisotropy were performed in normal-appearing brain tissue (NABT), normal-appearing white matter (NAWM) and gray matter (NAGM). Correlations were analyzed between these measures and expanded disability status scale (EDSS) scores, T{sub 2}WI lesion volumes (LV) and normalized brain tissue volumes (NBTV) in CIS and RRMS patients. Results: Significant differences were found among CIS, RRMS and control groups in the NBTV and most of the DTI histogram measures of the NABT, NAWM and NAGM. In CIS patients, some DTI histogram measures showed significant correlations with LV and NBTV, but none of them with EDSS. In RRMS patients, however, some DTI histogram measures were significantly correlated with LV, NBTV and EDSS. Conclusion: Occult damage occurs in both NAGM and NAWM in CIS, but the severity is milder than that in RRMS. In CIS and RRMS, the occult damage might be related to both T2 lesion load and brain tissue atrophy. Some DTI histogram measures might be useful for assessing the disease progression in RRMS patients.

  20. Histogram-kernel Error and Its Application for Bin Width Selection in Histograms

    Institute of Scientific and Technical Information of China (English)

    Xiu-xiang Wang; Jian-fang Zhang

    2012-01-01

    Histogram and kernel estimators are usually regarded as the two main classical data-based nonparametric tools to estimate the underlying density functions for some given data sets.In this paper we will integrate them and define a histogram-kernel error based on the integrated square error between histogram and binned kernel density estimator,and then exploit its asymptotic properties. Just as indicated in this paper,the histogram-kernel error only depends on the choice of bin width and the data for the given prior kernel densities.The asymptotic optimal bin width is derived by minimizing the mean histogram-kernel error.By comparing with Scott's optimal bin width formula for a histogram,a new method is proposed to construct the data-based histogram without knowledge of the underlying density function.Monte Carlo study is used to verify the usefulness of our method for different kinds of density functions and sample sizes.

  1. Risk of second primary cancer following prostate cancer radiotherapy: DVH analysis using the competitive risk model

    Science.gov (United States)

    Takam, R.; Bezak, E.; Yeoh, E. E.

    2009-02-01

    This study aimed to estimate the risk of developing second primary cancer (SPC) corresponding to various radiation treatment techniques for prostate cancer. Estimation of SPC was done by analysing differential dose-volume histograms (DDVH) of normal tissues such as rectum, bladder and urethra with the competitive risk model. Differential DVHs were obtained from treatment planning systems for external beam radiotherapy (EBRT), low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy techniques. The average risk of developing SPC was no greater than 0.6% for all treatment techniques but was lower with either LDR or HDR brachytherapy alone compared with any EBRT technique. For LDR and HDR brachytherapy alone, the risk of SPC for the rectum was 2.0 × 10-4% and 8.3 × 10-5% respectively compared with 0.2% for EBRT using five-field 3D-CRT to a total dose of 74 Gy. Overall, the risk of developing SPC for urethra following all radiation treatment techniques was very low compared with the rectum and bladder. Treatment plans which deliver equivalent doses of around 3-5 Gy to normal tissues were associated with higher risks of development of SPC.

  2. Risk of second primary cancer following prostate cancer radiotherapy: DVH analysis using the competitive risk model

    Energy Technology Data Exchange (ETDEWEB)

    Takam, R; Bezak, E [School of Chemistry and Physics, University of Adelaide, Adelaide (Australia); Yeoh, E E [School of Medicine, University of Adelaide, Adelaide (Australia)], E-mail: Rungdham.Takam@health.sa.gov.au

    2009-02-07

    This study aimed to estimate the risk of developing second primary cancer (SPC) corresponding to various radiation treatment techniques for prostate cancer. Estimation of SPC was done by analysing differential dose-volume histograms (DDVH) of normal tissues such as rectum, bladder and urethra with the competitive risk model. Differential DVHs were obtained from treatment planning systems for external beam radiotherapy (EBRT), low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy techniques. The average risk of developing SPC was no greater than 0.6% for all treatment techniques but was lower with either LDR or HDR brachytherapy alone compared with any EBRT technique. For LDR and HDR brachytherapy alone, the risk of SPC for the rectum was 2.0 x 10{sup -4}% and 8.3 x 10{sup -5}% respectively compared with 0.2% for EBRT using five-field 3D-CRT to a total dose of 74 Gy. Overall, the risk of developing SPC for urethra following all radiation treatment techniques was very low compared with the rectum and bladder. Treatment plans which deliver equivalent doses of around 3-5 Gy to normal tissues were associated with higher risks of development of SPC.

  3. The equivalent Histograms in clinical practice; Los histogramas equivalentes en la practica clinica

    Energy Technology Data Exchange (ETDEWEB)

    Pizarro Trigo, F.; Teijeira Garcia, M.; Zaballos Carrera, S.

    2013-07-01

    Is frequently abused of The tolerances established for organ at risk [1] in diagrams of standard fractionation (2Gy/session, 5 sessions per week) when applied to Dose-Volume histograms non-standard schema. The purpose of this work is to establish when this abuse may be more important and realize a transformation of fractionation non-standard of histograms dosis-volumen. Is exposed a case that can be useful to make clinical decisions. (Author)

  4. STUDY OF RBC HISTOGRAM IN VARIOUS ANEMIAS

    Directory of Open Access Journals (Sweden)

    Sandhya

    2014-12-01

    Full Text Available Over the past few years complete blood count (CBC by the automated hematology analyzers and microscopic examination of peripheral smear have complemented each other to provide a comprehensive report on patients’ blood sample. Numerous classifications for anemia have been established and the important parameters involved in the classifications are Hb, HCT, MCV, RDW, MCH, MCHC, reticulocytes and IRF. Many of these values are obtained only by automated heamatology analyzers. One histogram graph is worth 1000 numbers. A large collection of data, displayed as a visual image, can convey information with far more impact than the numbers alone. In hematology, these data take on several forms, one of which is the RBC histogram. Therefore a study of variation in RBC histograms in various anemias. Many times it is seen that histogram patterns show varying features when a simultaneous peripheral smear is reported. It is also seen that there are many limitations when manual peripheral smears reporting is done for example: peripheral smear reports are subjective, labor intensive and statistically unreliable. However microscopic peripheral smear examination also has their advantages. This study intends to create a guide to laboratory personnel and clinicians with sufficient accuracy to presumptively diagnose morphological classes of anemia directly from the automated hematology cell counter forms and correlate with morphological features of peripheral smear examination. OBJECTIVE: 1. The objective of the study is to know the utility and advantage of red cell histograms. 2. To study the automated histogram patterns along with morphological features noticed on peripheral smear examination. SOURCE OF DATA: All anemic patients from Central Diagnostic Laboratory of A.J.IMS. METHOD OF COLLECTION OF DATA: A total of about 100 patients were included in the study. Complete blood count including HB, TC, DC, Platelet count hematocrit value, RBC indices was obtained

  5. Network histograms and universality of blockmodel approximation

    Science.gov (United States)

    Olhede, Sofia C.; Wolfe, Patrick J.

    2014-01-01

    In this paper we introduce the network histogram, a statistical summary of network interactions to be used as a tool for exploratory data analysis. A network histogram is obtained by fitting a stochastic blockmodel to a single observation of a network dataset. Blocks of edges play the role of histogram bins and community sizes that of histogram bandwidths or bin sizes. Just as standard histograms allow for varying bandwidths, different blockmodel estimates can all be considered valid representations of an underlying probability model, subject to bandwidth constraints. Here we provide methods for automatic bandwidth selection, by which the network histogram approximates the generating mechanism that gives rise to exchangeable random graphs. This makes the blockmodel a universal network representation for unlabeled graphs. With this insight, we discuss the interpretation of network communities in light of the fact that many different community assignments can all give an equally valid representation of such a network. To demonstrate the fidelity-versus-interpretability tradeoff inherent in considering different numbers and sizes of communities, we analyze two publicly available networks—political weblogs and student friendships—and discuss how to interpret the network histogram when additional information related to node and edge labeling is present. PMID:25275010

  6. Evaluation of late rectal toxicity after conformal radiotherapy for prostate cancer. A comparison between dose-volume constraints and NTCP use

    Energy Technology Data Exchange (ETDEWEB)

    Cambria, Raffaella; Cattani, Federica; Garibaldi, Cristina; Pedroli, Guido [Dept. of Medical Physics, Ist. Europeo di Oncologia, Milan (Italy); Jereczek-Fossa, Barbara A.; Orecchia, Roberto [Dept. of Radiation Oncology, Ist. Europeo di Oncologia, Milan (Italy); Univ. degli Studi di Milano, Milan (Italy); Zerini, Dario; Fodor, Cristiana; Serafini, Flavia [Dept. of Radiation Oncology, Ist. Europeo di Oncologia, Milan (Italy)

    2009-06-15

    Purpose: to analyze the reliability of different methods used in evaluating the risk of late rectal toxicity. Patients and methods: the treatment plans of 57 patients treated at the authors' institute between September 1999 and September 2000 for localized prostate cancer using three-dimensional conformal radiotherapy (3D-CRT) were analyzed retrospectively. The expected rate of late rectal toxicity was analyzed (a) by means of the dose-volume histogram (DVH) constraints; (b) by calculating the normal-tissue complication probability (NTCP) using the Lyman-Kutcher-Burman (LKB) model with the radiobiological parameters of either Emami (1991; for toxicity of grade {>=} 2) or Rancati (2004; for toxicity of grade {>=} 2 and {>=} 3). Patients were divided into high-/low-risk (HR/LR) groups and the results were compared to the clinical outcome. Results: (a) The HR percentages were 24% and 5% for radical and postsurgical 3D-CRT, respectively. When applying high-dose constraints only, HR percentages were 18% and 5%, respectively. (b) In the case of the NTCP (grade {>=} 2), Emami (1991) HR rates were 16% and 11%, and Rancati (2004) HR rates 29% and 11%, for radical and postsurgical treatment, respectively. Only one case with higher-grade toxicity was found. The reported clinical toxicity was 17.8% and 6.7% for grade {>=} 2 toxicity, and 3.7% and 0.7% for grade {>=} 3 toxicity, for radical and postsurgical treatment, respectively. Conclusion: this study demonstrated that there is an agreement between the toxicity rate evaluated by DVH constraints and by the LKB model and the clinical outcome. In this case, the use of the LKB model can be as reliable as the use of DVH constraints. (orig.)

  7. Local histograms and image occlusion models

    CERN Document Server

    Massar, Melody L; Fickus, Matthew; Kovacevic, Jelena

    2011-01-01

    The local histogram transform of an image is a data cube that consists of the histograms of the pixel values that lie within a fixed neighborhood of any given pixel location. Such transforms are useful in image processing applications such as classification and segmentation, especially when dealing with textures that can be distinguished by the distributions of their pixel intensities and colors. We, in particular, use them to identify and delineate biological tissues found in histology images obtained via digital microscopy. In this paper, we introduce a mathematical formalism that rigorously justifies the use of local histograms for such purposes. We begin by discussing how local histograms can be computed as systems of convolutions. We then introduce probabilistic image models that can emulate textures one routinely encounters in histology images. These models are rooted in the concept of image occlusion. A simple model may, for example, generate textures by randomly speckling opaque blobs of one color on ...

  8. Color Histogram Diffusion for Image Enhancement

    Science.gov (United States)

    Kim, Taemin

    2011-01-01

    Various color histogram equalization (CHE) methods have been proposed to extend grayscale histogram equalization (GHE) for color images. In this paper a new method called histogram diffusion that extends the GHE method to arbitrary dimensions is proposed. Ranges in a histogram are specified as overlapping bars of uniform heights and variable widths which are proportional to their frequencies. This diagram is called the vistogram. As an alternative approach to GHE, the squared error of the vistogram from the uniform distribution is minimized. Each bar in the vistogram is approximated by a Gaussian function. Gaussian particles in the vistoram diffuse as a nonlinear autonomous system of ordinary differential equations. CHE results of color images showed that the approach is effective.

  9. The Online Histogram Presenter for the ATLAS experiment a modular system for histogram visualization

    CERN Document Server

    Dotti, A; Vitillo, R A

    2010-01-01

    The Online Histogram Presenter (OHP) is the ATLAS tool to display histograms produced by the online monitoring system. In spite of the name, the Online Histogram Presenter is much more than just a histogram display. To cope with the large amount of data, the application has been designed to minimise the network traffic; sophisticated caching, hashing and filtering algorithms reduce memory and CPU usage. The system uses Qt and ROOT for histogram visualisation and manipulation. In addition, histogram visualisation can be extensively customised through configuration files. Finally, its very modular architecture features a lightweight plug-in system, allowing extensions to accommodate specific user needs. After an architectural overview of the application, the paper is going to present in detail the solutions adopted to increase the performance and a description of the plug-in system.

  10. The Online Histogram Presenter for the ATLAS experiment: A modular system for histogram visualization

    Science.gov (United States)

    Dotti, Andrea; Adragna, Paolo; Vitillo, Roberto A.

    2010-04-01

    The Online Histogram Presenter (OHP) is the ATLAS tool to display histograms produced by the online monitoring system. In spite of the name, the Online Histogram Presenter is much more than just a histogram display. To cope with the large amount of data, the application has been designed to minimise the network traffic; sophisticated caching, hashing and filtering algorithms reduce memory and CPU usage. The system uses Qt and ROOT for histogram visualisation and manipulation. In addition, histogram visualisation can be extensively customised through configuration files. Finally, its very modular architecture features a lightweight plug-in system, allowing extensions to accommodate specific user needs. After an architectural overview of the application, the paper is going to present in detail the solutions adopted to increase the performance and a description of the plug-in system.

  11. SU-E-T-318: Dosimetric Evaluation of ArcCHECK and 3DVH System Using Customized Polymer Gel Dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Ono, K; Fujimoto, S; Akagi, Y; Hirokawa, Y [Hiroshima Heiwa Clinic, Hiroshima, JP (Japan); Hayashi, S [Hiroshima International University, Hiroshima, JP (Japan); Miyazawa, M [R-TECH.INC, Tokyo, JP (Japan)

    2015-06-15

    Purpose: ArcCHECK and 3DVH system (Sun Nuclear) can reconstruct the three-dimensional (3D) dose distribution and provide the DVH analysis in a patient. The aim of this study was to evaluate dosimetric accuracy of this system using customized polymer gel dosimeter, and also Gafchromic EBT3 films. Methods: Polyacrylamide-based gel contained magnesium chloride as a sensitizer (iPAGAT) was used in this study. Volumetric-modulated arc therapy (VMAT) plan was performed for the C-shape structure by the Eclipse treatment planning system (Varian) and used to irradiate the ArcCHECK by the Novalis Tx linear accelerator (Varian/BrainLAB). The cubic phantom filled with iPAGAT and EBT3 films placed in three orthogonal planes (axial, sagittal, and coronal) inserted into the I’mRT Phantom (IBA Dosimetry) simulated a patient were irradiated with the same VMAT plan. The measurement-guided 3D dose distribution was reconstructed using 3DVH software from the measured data of the ArcCHECK. The 3D dose distribution in iPAGAT was read out by Signa 1.5 T MRI system (GE), and 2D dose distribution on EBT3 was read out by color scanner (Epson). The comparison of all the dose distributions was performed with dose profiles and gamma index analysis in orthogonal planes using in-house developed software. Results: A good agreement was observed by overlaying the dose profiles of 3DVH, EBT3, and iPAGAT. The mean pass rates by gamma index analysis with 3%/3 mm criteria in orthogonal planes were 94.3% (3DVH vs EBT3), 91.1% (3DVH vs iPAGAT), and 96.4% (iPAGAT vs EBT3), respectively. Conclusion: 3D dose distribution reconstructed by ArcCHECK and 3DVH system was estimated accurately in a patient. However, slightly differences were observed between 3DVH and iPAGAT because of MRI noise, therefore further study is required to improve the accuracy of MRI based polymer gel dosimetry for the DVH analysis.

  12. Rectal planning risk volume correlation with acute and late toxicity in 3-dimensional conformal radiation therapy for prostate cancer.

    Science.gov (United States)

    Dias, R S; Giordani, A J; Souhami, L; Segreto, R A; Segreto, H R C

    2011-12-01

    The purpose of this study was to evaluate rectum motion during 3-Dimensional conformal radiation therapy (3D-CRT) in prostate cancer patients, to derive a planning volume at risk (PRV) and to correlate the PRV dose-volume histograms (DVH) with treatment complications.This study was conducted in two phases. Initially, the PRV was defined prospectively in 50 consecutive prostate cancer patients (Group 1) who received a radical course of 3-D CRT. Then, the obtained PRV was used in the radiotherapy planning of these same 50 patients plus another 59 prostate cancer patients (Group 2) previously treated between 2004 and 2008. All these patients' data, including the rectum and PRV DVHs, were correlated to acute and late complications, according to the Common Toxicity Criteria (CTC) v4.0.The largest displacement occurred in the anterior axis. Long-term gastrointestinal (GI) complications grade ≥ 2 were seen in 9.2% of the cases. Factors that influenced acute GI reactions were: doses at 25% (p 5 0.011) and 40% (p 5 0.005) of the rectum volume and at 40% of the PRV (p 5 0.012). The dose at 25% of the rectum volume (p 5 0.033) and acute complications ≥ grade 2 (p 5 0.018) were prognostic factors for long-term complications. The PRV DVH did not correlate with late toxicity. The rectum showed a significant inter-fraction motion during 3D-CRT for prostate cancer. PRV dose correlated with acute gastrointestinal complications and may be a useful tool to predict and reduce their occurrence.

  13. SU-E-T-117: Analysis of the ArcCHECK Dosimetry Gamma Failure Using the 3DVH System

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S; Choi, W; Lee, H; Yoon, J; Lee, E; Park, K; Keum, K [Yonsei University Health System, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: To evaluate gamma analysis failure for the VMAT patient specific QA using ArcCHECK cylindrical phantom. The 3DVH system(Sun Nuclear, FL) was used to analyze the dose difference statistic between measured dose and treatment planning system calculated dose. Methods: Four case of gamma analysis failure were selected retrospectively. Our institution gamma analysis indexes were absolute dose, 3%/3mm and 90%pass rate in the ArcCHECK dosimetry. The collapsed cone convolution superposition (CCCS) dose calculation algorithm for VMAT was used. Dose delivery was performed with Elekta Agility. The A1SL(standard imaging, WI) and cavity plug were used for point dose measurement. Delivery QA plans and images were used for 3DVH Reference data instead of patient plan and image. The measured data of ‘.txt’ file was used for comparison at diodes to acquire a global dose level. The,.acml’ file was used for AC-PDP and to calculated point dose. Results: The global dose of 3DVH was calculated as 1.10 Gy, 1.13, 1.01 and 0.2 Gy respectively. The global dose of 0.2 Gy case was induced by distance discrepancy. The TPS calculated point dose of was 2.33 Gy to 2.77 Gy and 3DVH calculated dose was 2.33 Gy to 2.68 Gy. The maximum dose differences were −2.83% and −3.1% for TPS vs. measured dose and TPS vs. 3DVH calculated respectively in the same case. The difference between measured and 3DVH was 0.1% in that case. The 3DVH gamma pass rate was 98% to 99.7%. Conclusion: We found the TPS calculation error by 3DVH calculation using ArcCHECK measured dose. It seemed that our CCCS algorithm RTP system over estimated at the central region and underestimated scattering at the peripheral diode detector point. The relative gamma analysis and point dose measurement would be recommended for VMAT DQA in the gamma failure case of ArcCHECK dosimetry.

  14. HEBS: Histogram Equalization for Backlight Scaling

    CERN Document Server

    Iranli, Ali; Pedram, Massoud

    2011-01-01

    In this paper, a method is proposed for finding a pixel transformation function that maximizes backlight dimming while maintaining a pre-specified image distortion level for a liquid crystal display. This is achieved by finding a pixel transformation function, which maps the original image histogram to a new histogram with lower dynamic range. Next the contrast of the transformed image is enhanced so as to compensate for brightness loss that would arise from backlight dimming. The proposed approach relies on an accurate definition of the image distortion which takes into account both the pixel value differences and a model of the human visual system and is amenable to highly efficient hardware realization. Experimental results show that the histogram equalization for backlight scaling method results in about 45% power saving with an effective distortion rate of 5% and 65% power saving for a 20% distortion rate. This is significantly higher power savings compared to previously reported backlight dimming approa...

  15. Oriented Shape Index Histograms for Cell Classification

    DEFF Research Database (Denmark)

    Larsen, Anders Boesen Lindbo; Dahl, Anders Bjorholm; Larsen, Rasmus

    2015-01-01

    evaluate our new feature descriptor using a public dataset consisting of HEp-2 cell images from indirect immunoflourescence lighting. Our results show that we can improve classification performance significantly when including the shape index orientation. Notably, we show that shape index orientation......We propose a novel extension to the shape index histogram feature descriptor where the orientation of the second-order curvature is included in the histograms. The orientation of the shape index is reminiscent but not equal to gradient orientation which is widely used for feature description. We...

  16. Efficient visibility-driven medical image visualisation via adaptive binned visibility histogram.

    Science.gov (United States)

    Jung, Younhyun; Kim, Jinman; Kumar, Ashnil; Feng, David Dagan; Fulham, Michael

    2016-07-01

    'Visibility' is a fundamental optical property that represents the observable, by users, proportion of the voxels in a volume during interactive volume rendering. The manipulation of this 'visibility' improves the volume rendering processes; for instance by ensuring the visibility of regions of interest (ROIs) or by guiding the identification of an optimal rendering view-point. The construction of visibility histograms (VHs), which represent the distribution of all the visibility of all voxels in the rendered volume, enables users to explore the volume with real-time feedback about occlusion patterns among spatially related structures during volume rendering manipulations. Volume rendered medical images have been a primary beneficiary of VH given the need to ensure that specific ROIs are visible relative to the surrounding structures, e.g. the visualisation of tumours that may otherwise be occluded by neighbouring structures. VH construction and its subsequent manipulations, however, are computationally expensive due to the histogram binning of the visibilities. This limits the real-time application of VH to medical images that have large intensity ranges and volume dimensions and require a large number of histogram bins. In this study, we introduce an efficient adaptive binned visibility histogram (AB-VH) in which a smaller number of histogram bins are used to represent the visibility distribution of the full VH. We adaptively bin medical images by using a cluster analysis algorithm that groups the voxels according to their intensity similarities into a smaller subset of bins while preserving the distribution of the intensity range of the original images. We increase efficiency by exploiting the parallel computation and multiple render targets (MRT) extension of the modern graphical processing units (GPUs) and this enables efficient computation of the histogram. We show the application of our method to single-modality computed tomography (CT), magnetic resonance

  17. Use of the 3DVH Software as a complementary method of IMRT pretreatment evaluation; Utilizacao do Software 3DVH como metodo complementar de avaliacao de pre-tratamento de IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Lyra, Jesse G.P.; Bruning, Fabio F.; Funchal, Melissa; Toledo, Hugo V.; Bornatto, Pricila; Fernandes, Tatiane C.O., E-mail: jesse_lyra@hotmail.com [Hospital Erasto Gaertner / Liga Paranaense de Combate ao Cancer (LPCC), Departamento de Radioterapia, Curitiba, PR (Brazil)

    2013-04-15

    The aim of this study is to compare the method of treatment planning evaluation for IMRT using the gamma index to the method of the 3DVH Software. The 3DVH Software was used with the MapCheck2 detector 2D array under a 6MV x-ray beam of linear accelerator equipped with 120 leafs MLC. Nine treatment plans of prostate patients chose randomly and fully anonimatize were performed in the Eclipse planning system, using the AAA calculation algorithm in IMRT sliding window technique. These plans were approved and treated according to the gamma analysis criteria of the institution. The comparisons were made in absolute dose and normalized at maximum dose for each field and then with the 3DVH Software the Dmax, Dmean, D15%, D25%, D35% and D50% parameters for the bladder and rectum, Dmean for the bulb, Dmax for the femur and D95% for the PTV were evaluated. In the planar analysis by field, the plans studied had a minimum of 97.5% approval. The PTV-related differences have relative variation from 1.3 to 2.2%, that is, greater coverage than expected for this structure. For the organs at risk, the relative differences observed were between -5.3 to 25.8%, which could result in a non-approved plan if these variations are close to the clinical tolerances of the OAR. The results show that even a plan compatible with greater than or equal to 95% of the points, the gamma analysis does not give enough information if this plan can or cannot be approved for treatment and that there is a need for more detailed verification of the plan which considers not only the planar evaluation, but also the evaluation of the DVH measured, and the 3DVH Software proved be adequate for this analysis. (author)

  18. The Development of Cluster and Histogram Methods

    Science.gov (United States)

    Swendsen, Robert H.

    2003-11-01

    This talk will review the history of both cluster and histogram methods for Monte Carlo simulations. Cluster methods are based on the famous exact mapping by Fortuin and Kasteleyn from general Potts models onto a percolation representation. I will discuss the Swendsen-Wang algorithm, as well as its improvement and extension to more general spin models by Wolff. The Replica Monte Carlo method further extended cluster simulations to deal with frustrated systems. The history of histograms is quite extensive, and can only be summarized briefly in this talk. It goes back at least to work by Salsburg et al. in 1959. Since then, it has been forgotten and rediscovered several times. The modern use of the method has exploited its ability to efficiently determine the location and height of peaks in various quantities, which is of prime importance in the analysis of critical phenomena. The extensions of this approach to the multiple histogram method and multicanonical ensembles have allowed information to be obtained over a broad range of parameters. Histogram simulations and analyses have become standard techniques in Monte Carlo simulations.

  19. SU-E-J-164: Estimation of DVH Variation for PTV Due to Interfraction Organ Motion in Prostate VMAT Using Gaussian Error Function

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, C [Ryerson University, Toronto, Ontario (Canada); Jiang, R [Grand River Regional Cancer Center, Kitchener, Ontario (Canada); Chow, J [Princess Margaret Cancer Center, Toronto, ON (Canada)

    2015-06-15

    Purpose: We developed a method to predict the change of DVH for PTV due to interfraction organ motion in prostate VMAT without repeating the CT scan and treatment planning. The method is based on a pre-calculated patient database with DVH curves of PTV modelled by the Gaussian error function (GEF). Methods: For a group of 30 patients with different prostate sizes, their VMAT plans were recalculated by shifting their PTVs 1 cm with 10 increments in the anterior-posterior, left-right and superior-inferior directions. The DVH curve of PTV in each replan was then fitted by the GEF to determine parameters describing the shape of curve. Information of parameters, varying with the DVH change due to prostate motion for different prostate sizes, was analyzed and stored in a database of a program written by MATLAB. Results: To predict a new DVH for PTV due to prostate interfraction motion, prostate size and shift distance with direction were input to the program. Parameters modelling the DVH for PTV were determined based on the pre-calculated patient dataset. From the new parameters, DVH curves of PTVs with and without considering the prostate motion were plotted for comparison. The program was verified with different prostate cases involving interfraction prostate shifts and replans. Conclusion: Variation of DVH for PTV in prostate VMAT can be predicted using a pre-calculated patient database with DVH curve fitting. The computing time is fast because CT rescan and replan are not required. This quick DVH estimation can help radiation staff to determine if the changed PTV coverage due to prostate shift is tolerable in the treatment. However, it should be noted that the program can only consider prostate interfraction motions along three axes, and is restricted to prostate VMAT plan using the same plan script in the treatment planning system.

  20. Method of infrared image enhancement based on histogram

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; YAN Jie

    2011-01-01

    Aiming at the problem in infrared image enhancement, a new method is given based on histogram. Using the gray character- istics of target, the upper-bouod threshold is selected adaptively and the histogram is processed by the threshold. After choosing the gray transform function based on the gray level distribution of image, the gray transformation is done during histogram equalization. Finally, the enhanced image is obtained. Compared with histogram equalization (HE), histogram double equalization (HDE) and plateau histogram equalization (PE), the simulation results demonstrate that the image enhancement effect of this method has obvious superiority. At the same time, its operation speed is fast and real-time ability is excellent.

  1. Underwater sonar image recognition based on gray-spatial histograms

    Institute of Scientific and Technical Information of China (English)

    LIU Zhuo-fu; SANG En-fang

    2003-01-01

    A new gray-spatial histogram is proposed, which incorporates spatial information with gray compositions without sacrificing the robustness of traditional gray histograms. The purpose is to consider the representation role of gray compositions and spatial information simultaneously. Each entry in the gray-spatial histogram is the gray frequency and corresponding position information of images. In the experiments of sonar image recognition, the results show that the gray-spatial histogram is effective in practical use.

  2. Efficient CBIR Using Color Histogram Processing

    Directory of Open Access Journals (Sweden)

    Neetu Sharma. S

    2011-03-01

    Full Text Available The need for efficient content-based image retrieval system has increased hugely. Efficient and effectiveretrieval techniques of images are desired because of the explosive growth of digital images. content basedimage retrieval (CBIR is a promising approach because of its automatic indexing retrieval based on theirsemantic features and visual appearance. The similarity of images depends on the featurerepresentation.However users have difficulties in representing their information needs in queries to contentbased image retrieval systems. In this paper we investigate two methods for describing the contents ofimages. The first one characterizes images by global descriptor attributes, while the second is based oncolor histogram approach.To compute feature vectors for Global descriptor, required time is much less ascompared to color histogram. Hence cross correlation value & image descriptor attributes are calculatedprior histogram implementation to make CBIR system more efficient.The performance of this approach ismeasured and results are shown. The aim of this paper is to compare various global descriptor attributesand to make CBIR system more efficient. It is found that further modifications are needed to produce betterperformance in searching images.

  3. SU-E-T-634: Analysis of Volume Based GYN HDR Brachytherapy Plans for Dose Calculation to Organs At Risk(OAR)

    Energy Technology Data Exchange (ETDEWEB)

    Nair, M; Li, C; White, M; Davis, J [Joe Arrington Cancer Center, Lubbock, TX (United States)

    2014-06-15

    Purpose: We have analyzed the dose volume histogram of 140 CT based HDR brachytherapy plans and evaluated the dose received to OAR ; rectum, bladder and sigmoid colon based on recommendations from ICRU and Image guided brachytherapy working group for cervical cancer . Methods: Our treatment protocol consist of XRT to whole pelvis with 45 Gy at 1.8Gy/fraction followed by 30 Gy at 6 Gy per fraction by HDR brachytherapy in 2 weeks . The CT compatible tandem and ovoid applicators were used and stabilized with radio opaque packing material. The patient was stabilized using special re-locatable implant table and stirrups for reproducibility of the geometry during treatment. The CT scan images were taken at 3mm slice thickness and exported to the treatment planning computer. The OAR structures, bladder, rectum and sigmoid colon were outlined on the images along with the applicators. The prescription dose was targeted to A left and A right as defined in Manchester system and optimized on geometry . The dosimetry was compared on all plans using the parameter Ci.sec.cGy-1 . Using the Dose Volume Histogram (DVH) obtained from the plans the doses to rectum, sigmoid colon and bladder for ICRU defined points and 2cc volume were analyzed and reported. The following criteria were used for limiting the tolerance dose by volume (D2cc) were calculated. The rectum and sigmoid colon doses were limited to <75Gy. The bladder dose was limited to < 90Gy from both XRT and HDR brachytherapy. Results: The average total (XRT+HDRBT) BED values to prescription volume was 120 Gy. Dose 2cc to rectum was 70Gy +/− 17Gy, dose to 2cc bladder was 82+/−32 Gy. The average Ci.sec.cGy-1 calculated for the HDR plans was 6.99 +/− 0.5 Conclusion: The image based treatment planning enabled to evaluati volume based dose to critical structures for clinical interpretation.

  4. Glioma grade assessment by using histogram analysis of diffusion tensor imaging-derived maps.

    Science.gov (United States)

    Jakab, András; Molnár, Péter; Emri, Miklós; Berényi, Ervin

    2011-07-01

    Current endeavors in neuro-oncology include morphological validation of imaging methods by histology, including molecular and immunohistochemical techniques. Diffusion tensor imaging (DTI) is an up-to-date methodology of intracranial diagnostics that has gained importance in studies of neoplasia. Our aim was to assess the feasibility of discriminant analysis applied to histograms of preoperative diffusion tensor imaging-derived images for the prediction of glioma grade validated by histomorphology. Tumors of 40 consecutive patients included 13 grade II astrocytomas, seven oligoastrocytomas, six grade II oligodendrogliomas, three grade III oligoastrocytomas, and 11 glioblastoma multiformes. Preoperative DTI data comprised: unweighted (B (0)) images, fractional anisotropy, longitudinal and radial diffusivity maps, directionally averaged diffusion-weighted imaging, and trace images. Sampling consisted of generating histograms for gross tumor volumes; 25 histogram bins per scalar map were calculated. The histogram bins that allowed the most precise determination of low-grade (LG) or high-grade (HG) classification were selected by multivariate discriminant analysis. Accuracy of the model was defined by the success rate of the leave-one-out cross-validation. Statistical descriptors of voxel value distribution did not differ between LG and HG tumors and did not allow classification. The histogram model had 88.5% specificity and 85.7% sensitivity in the separation of LG and HG gliomas; specificity was improved when cases with oligodendroglial components were omitted. Constructing histograms of preoperative radiological images over the tumor volume allows representation of the grade and enables discrimination of LG and HG gliomas which has been confirmed by histopathology.

  5. Glioma grade assessment by using histogram analysis of diffusion tensor imaging-derived maps

    Energy Technology Data Exchange (ETDEWEB)

    Jakab, Andras; Berenyi, Ervin [University of Debrecen Medical and Health Science Center, Department of Biomedical Laboratory and Imaging Science, Faculty of Medicine, Debrecen (Hungary); Molnar, Peter [University of Debrecen Medical and Health Science Center, Institute of Pathology, Faculty of Medicine, Debrecen (Hungary); Emri, Miklos [University of Debrecen Medical and Health Science Center, Institute of Nuclear Medicine, Faculty of Medicine, Debrecen (Hungary)

    2011-07-15

    Current endeavors in neuro-oncology include morphological validation of imaging methods by histology, including molecular and immunohistochemical techniques. Diffusion tensor imaging (DTI) is an up-to-date methodology of intracranial diagnostics that has gained importance in studies of neoplasia. Our aim was to assess the feasibility of discriminant analysis applied to histograms of preoperative diffusion tensor imaging-derived images for the prediction of glioma grade validated by histomorphology. Tumors of 40 consecutive patients included 13 grade II astrocytomas, seven oligoastrocytomas, six grade II oligodendrogliomas, three grade III oligoastrocytomas, and 11 glioblastoma multiformes. Preoperative DTI data comprised: unweighted (B{sub 0}) images, fractional anisotropy, longitudinal and radial diffusivity maps, directionally averaged diffusion-weighted imaging, and trace images. Sampling consisted of generating histograms for gross tumor volumes; 25 histogram bins per scalar map were calculated. The histogram bins that allowed the most precise determination of low-grade (LG) or high-grade (HG) classification were selected by multivariate discriminant analysis. Accuracy of the model was defined by the success rate of the leave-one-out cross-validation. Statistical descriptors of voxel value distribution did not differ between LG and HG tumors and did not allow classification. The histogram model had 88.5% specificity and 85.7% sensitivity in the separation of LG and HG gliomas; specificity was improved when cases with oligodendroglial components were omitted. Constructing histograms of preoperative radiological images over the tumor volume allows representation of the grade and enables discrimination of LG and HG gliomas which has been confirmed by histopathology. (orig.)

  6. Gliomas: Histogram analysis of apparent diffusion coefficient maps with standard- or high-b-value diffusion-weighted MR imaging--correlation with tumor grade

    National Research Council Canada - National Science Library

    Kang, Yusuhn; Choi, Seung Hong; Kim, Young-Jae; Kim, Kwang Gi; Sohn, Chul-Ho; Kim, Ji-Hoon; Yun, Tae Jin; Chang, Kee-Hyun

    2011-01-01

    To explore the role of histogram analysis of apparent diffusion coefficient (ADC) maps based on entire tumor volume data in determining glioma grade and to evaluate the diagnostic performance of ADC maps at standard...

  7. Research on scale effect of histogram

    Institute of Scientific and Technical Information of China (English)

    张颢; 焦子锑; 杨华; 李小文; 王锦地; 苏理宏; 阎广建; 赵红蕊

    2002-01-01

    To describe the spatial relationship among the earth objects compactly, in this paper, we raised the concept of histo-variogram based on the analysis of the characteristics of other spatial analyzing methods such as variogram, information entropy. And we also raised a new spatial analysis method of histogram decomposition based on the definition of standing pixel and contour pixel. At the end of this paper, we demonstrated the characteristics of histo-variogram by two experiments, one for spatial analysis, the other for image fusion.

  8. Intensity modulated radiotherapy for localized prostate cancer: rigid compliance to dose-volume constraints as a warranty of acceptable toxicity?

    Directory of Open Access Journals (Sweden)

    Moreira Frederico R

    2007-01-01

    Full Text Available Abstract Background To report the toxicity after intensity modulated radiotherapy (IMRT for patients with localized prostate cancer, as a sole treatment or after radical prostatectomy. Methods Between August 2001 and December 2003, 132 patients with prostate cancer were treated with IMRT and 125 were evaluable to acute and late toxicity analysis, after a minimum follow-up time of one year. Clinical and treatment data, including normal tissue dose-volume histogram (DVH constraints, were reviewed. Gastro-intestinal (GI and genito-urinary (GU signs and symptoms were evaluated according to the Radiation Therapy Oncology Group (RTOG toxicity scales. Median prescribed dose was 76 Gy. Median follow-up time was of 26.1 months. Results From the 125 patients, 73 (58.4% presented acute Grade 1 or Grade 2 GI and 97 (77.2% presented acute Grade 1 or Grade 2 GU toxicity. Grade 3 GI acute toxicity occurred in only 2 patients (1.6% and Grade 3 GU acute toxicity in only 3 patients (2.4%. Regarding Grade 1 and 2 late toxicity, 26 patients (20.8% and 21 patients (16.8% presented GI and GU toxicity, respectively. Grade 2 GI late toxicity occurred in 6 patients (4.8% and Grade 2 GU late toxicity in 4 patients (3.2%. None patient presented any Grade 3 or higher late toxicity. Non-conformity to DVH constraints occurred in only 11.2% of treatment plans. On univariate analysis, no significant risk factor was identified for Grade 2 GI late toxicity, but mean dose delivered to the PTV was associated to higher Grade 2 GU late toxicity (p = 0.042. Conclusion IMRT is a well tolerable technique for routine treatment of localized prostate cancer, with short and medium-term acceptable toxicity profiles. According to the data presented here, rigid compliance to DHV constraints might prevent higher incidences of normal tissue complication.

  9. Comparison with dose-volume histograms of two conformal irradiation techniques used for the treatment of T2N0M0 nasopharyngeal cancer, one with association of photons and protons and another with photons alone; Comparaison par les histogrammes dose-volume de deux techniques d'irradiation conformationnelle des cancers du nasopharynx classes T4N0M0, l'une par photons et protons et l'autre par photons seuls

    Energy Technology Data Exchange (ETDEWEB)

    Noel, G.; Ferrand, R.; Desblancs, C.L.; Mazeron, J.J. [Centre de protontherapie, 91 - Orsay (France); Boisserie, G.; Dessard-Diana, B.; Gasowski, M.; Simon, J.M.; Baillet, F.; Mazeron, J.J. [Groupe Hospitalier la Pitie-Salpetriere, Service des Tumeurs, 75 - Paris (France); Hasboun, D. [Groupe Hospitalier la Pitie-Salpetriere, Service de Radiologie, 75 - Paris (France)

    2002-12-01

    There is a relationship between the local control rate of the nasopharyngeal cancer and the total dose delivered within tue tumoral volume. In contrast, the relation between the dose and the irradiated volume and the risk of complication is not clearly defined. That is why, in patients presenting with a locally advanced nasopharyngeal cancer, we compared the dose-volume distribution of irradiated tissues, obtained from two 3D conformal irradiation techniques. Between January 2000 and June 2001, 5 patients, 3 males and 2 females, with a median age of 32 years and presenting with a T4N0M0 nasopharyngeal cancer received a chemoradiotherapy. Radiotherapy combined photons and protons beams and the platin-based chemotherapy was delivered in three intravenous injections at d1, 22, 43 of the irradiation. To calculate the dosimetry, a CT scan and a MRI were performed in all the patients. The gross tumor volume (GTV) was delineated from the imagery, three clinical tumor volumes were defined, the CTV1 was the GTV and the whole nasopharynx, the CTV2 was the CTV plus a 10 mm-margin and the CTV3 was the CTV2 and the nodes areas (cervical and sub-clavicular). Prophylactic dose within node areas was 44 Gy. Prescribed doses within CTV2 and GTV or CTV1 were 54 Gy/CGE (Cobalt Gy Equivalent, for an EBR = 1,1) and 70 Gy/CGE, respectively. Irradiation was delivered with fractions of 1.8 or 2.0 Gy/CGE, with 44 Gy by photons and with 16 or 26 CGE by protons. According to dose-volume histograms obtained from the dosimetry planning by protons and photons and from the theoretical dosimetry by photons lonely, for the different volumes of interest, GTV, CTV2, and organs at risk (optic nerves, chiasm, internal ears, brainstem, temporal lobes), we compared the averages of the maximum, minimum and mean doses and the averages of the volumes of organs of interest encompassed by different isodoses. Calculated averages of minimum, maximum and mean doses delivered within GTV were superior for the

  10. Text Anomalies Detection Using Histograms of Words

    Directory of Open Access Journals (Sweden)

    Abdulwahed Faraj Almarimi

    2016-01-01

    Full Text Available Authors of written texts mainly can be characterized by some collection of attributes obtained from texts. Texts of the same author are very similar from the style point of view. We can consider that attributes of a full text are very similar to attributes of parts in the same text. In the same thoughts can be compared different parts of the same text. In the paper, we describe an algorithm based on histograms of a mapped text to interval. In the mapping, it is kipped the word order as in the text. Histograms are analyzed from a cluster point of view. If a cluster dispersion is not large, the text is probably written by the same author. If the cluster dispersion is large, the text will be split in two or more parts and the same analysis will be done for the text parts.  The experiments were done on English and Arabic texts. For combined English texts our algorithm covers that texts were not written by one author. We have got the similar results for combined Arabic texts. Our algorithm can be used to basic text analysis if the text was written by one author.       

  11. Contrast Enhancement of Color Images with Bi-Histogram

    Directory of Open Access Journals (Sweden)

    Paramjit Singh,

    2014-06-01

    Full Text Available Histogram equalization is a widely used scheme for contrast enhancement in a variety of applications due to its simple function and effectiveness. One possible drawback of the histogram equalization is that it can change the mean brightness of an image significantly as a consequence of histogram flattening. Clearly, this is not a desirable property when preserving the original mean brightness of a given image is necessary. Bi-histogram equalization is able to overcome this drawback for gray scale images. In this paper, we explore the use of bi-histogram equalization based technique for enhancing RGB color images. The technique is based on cumulative density function of a quantized image. From the results it is concluded that bi-histogram equalization is able to improve the contrast of colored images significantly.

  12. COLOR PERCEPTION HISTOGRAM FOR IMAGE RETRIEVAL USING MULTIPLE SIMILARITY MEASURES

    Directory of Open Access Journals (Sweden)

    R. Malini

    2014-01-01

    Full Text Available This study aims to increase the retrieval efficiency of proposed image retrieval system on the basis of color content. A new idea of feature extraction based on color perception histogram is proposed. First, the color histogram is constructed for HSV image. Secondly, the true color and grey color components are identified based on hue and intensity. The weight for true and grey color components is calculated using NBS distance. An updated histogram is constructed using weighted true and grey color values. The color features extracted from the updated histogram of query image and for all the images in image database are compared with existing color histogram based technique by using multiple similarity measures. Experimental results show that proposed image retrieval based on the color perception histogram gives higher retrieval performance in terms of high average precision and average recall with less computational complexity.

  13. Calculating Method of Moments Uniform Bin Width Histograms

    OpenAIRE

    James S. Weber

    2016-01-01

    A clear articulation of Method of Moments (MOM) Histograms is instructive and has waited 121 years since 1895. Also of interest are enabling uniform bin width (UBW) shape level sets. Mean-variance MOM uniform bin width frequency and density histograms are not unique, however ranking them by histogram skewness compared to data skewness helps. Although theoretical issues rarely take second place to calculations, here calculations based on shape level sets are central and challenge uncritically ...

  14. SU-E-T-578: On Definition of Minimum and Maximum Dose for Target Volume

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Y; Yu, J; Xiao, Y [Thomas Jefferson University Hospital, Philadelphia, PA (United States)

    2015-06-15

    Purpose: This study aims to investigate the impact of different minimum and maximum dose definitions in radiotherapy treatment plan quality evaluation criteria by using tumor control probability (TCP) models. Methods: Dosimetric criteria used in RTOG 1308 protocol are used in the investigation. RTOG 1308 is a phase III randomized trial comparing overall survival after photon versus proton chemoradiotherapy for inoperable stage II-IIIB NSCLC. The prescription dose for planning target volume (PTV) is 70Gy. Maximum dose (Dmax) should not exceed 84Gy and minimum dose (Dmin) should not go below 59.5Gy in order for the plan to be “per protocol” (satisfactory).A mathematical model that simulates the characteristics of PTV dose volume histogram (DVH) curve with normalized volume is built. The Dmax and Dmin are noted as percentage volumes Dη% and D(100-δ)%, with η and d ranging from 0 to 3.5. The model includes three straight line sections and goes through four points: D95%= 70Gy, Dη%= 84Gy, D(100-δ)%= 59.5 Gy, and D100%= 0Gy. For each set of η and δ, the TCP value is calculated using the inhomogeneously irradiated tumor logistic model with D50= 74.5Gy and γ50=3.52. Results: TCP varies within 0.9% with η; and δ values between 0 and 1. With η and η varies between 0 and 2, TCP change was up to 2.4%. With η and δ variations from 0 to 3.5, maximum of 8.3% TCP difference is seen. Conclusion: When defined maximum and minimum volume varied more than 2%, significant TCP variations were seen. It is recommended less than 2% volume used in definition of Dmax or Dmin for target dosimetric evaluation criteria. This project was supported by NIH grants U10CA180868, U10CA180822, U24CA180803, U24CA12014 and PA CURE Grant.

  15. Lymphopenia Association With Gross Tumor Volume and Lung V5 and Its Effects on Non-Small Cell Lung Cancer Patient Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chad [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing, E-mail: zliao@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Gomez, Daniel; Levy, Lawrence; Zhuang, Yan; Gebremichael, Rediet A. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Hong, David S. [Department of Investigational Cancer Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Komaki, Ritsuko; Welsh, James W. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-08-01

    Purpose: Radiation therapy (RT) can both suppress and stimulate the immune system. We sought to investigate the mechanisms underlying radiation-induced lymphopenia and its associations with patient outcomes in non-small cell lung cancer (NSCLC). Methods and Materials: Subjects consisted of 711 patients who had received definitive RT for NSCLC. A lymphocyte nadir was calculated as the minimum lymphocyte value measured during definitive RT. Associations between gross tumor volumes (GTVs) and lung dose-volume histogram (DVH) parameters with lymphocyte nadirs were assessed with Spearman correlation coefficients. Relationships between lymphocyte nadirs with overall survival (OS) and event free survival (EFS) were evaluated with Kaplan-Meier analysis and compared with log-rank test results. Multivariate regressions were conducted with linear and Cox regression analyses. All variables were analyzed as continuous if possible. Results: Larger GTVs were correlated with lower lymphocyte nadirs regardless of concurrent chemotherapy receipt (with concurrent: r = −0.26, P<.0001; without: r = −0.48, P<.0001). Analyses of lung DVH parameters revealed significant correlations at lower doses (lung V5-V10: P<.0001) that incrementally decreased and became nonsignificant at higher doses (lung V60-V70: P>.05). Of note, no significant associations were detected between GTV and lung DVH parameters with total leukocyte, neutrophil, or monocyte nadirs during RT or with lymphocyte count prior to RT. Multivariate analysis revealed larger GTV (P<.0001), receipt of concurrent chemotherapy (P<.0001), twice-daily radiation fractionation (P=.02), and stage III disease (P=.05) to be associated with lower lymphocyte nadirs. On univariate analysis, patients with higher lymphocyte nadirs exhibited significantly improved OS (hazard ratio [HR] = 0.51 per 10{sup 3} lymphocytes/μL, P=.01) and EFS (HR = 0.46 per 10{sup 3} lymphocytes/μL, P<.0001). These differences held on multivariate analyses

  16. Devnagari document segmentation using histogram approach

    CERN Document Server

    Dongre, Vikas J; 10.5121/ijcseit.2011.1305

    2011-01-01

    Document segmentation is one of the critical phases in machine recognition of any language. Correct segmentation of individual symbols decides the accuracy of character recognition technique. It is used to decompose image of a sequence of characters into sub images of individual symbols by segmenting lines and words. Devnagari is the most popular script in India. It is used for writing Hindi, Marathi, Sanskrit and Nepali languages. Moreover, Hindi is the third most popular language in the world. Devnagari documents consist of vowels, consonants and various modifiers. Hence proper segmentation of Devnagari word is challenging. A simple histogram based approach to segment Devnagari documents is proposed in this paper. Various challenges in segmentation of Devnagari script are also discussed.

  17. Magnetic resonance (MR) imaging for tumor staging and definition of tumor volumes on radiation treatment planning in nonsmall cell lung cancer: A prospective radiographic cohort study of single center clinical outcome.

    Science.gov (United States)

    Zhao, Dan; Hu, Qiaoqiao; Qi, Liping; Wang, Juan; Wu, Hao; Zhu, Guangying; Yu, Huiming

    2017-02-01

    We investigate the impact of magnetic resonance (MR) on the staging and radiotherapy planning for patients with nonsmall cell lung cancer (NSCLC).A total of 24 patients with NSCLC underwent MRI, which was fused with radiotherapy planning CT using rigid registration. Gross tumor volume (GTV) was delineated not only according to CT image alone (GTVCT), but also based on both CT and MR image (GTVCT/MR). For each patient, 2 conformal treatment plans were made according to GTVCT and GTVCT/MR, respectively. Dose-volume histograms (DVH) for lesion and normal organs were generated using both GTVCT and GTVCT/MR treatment plans. All patients were irradiated according to GTVCT/MR plan.Median volume of the GTVCT/MR and GTVCT were 105.42 cm and 124.45 cm, respectively, and the mean value of GTVCT/MR was significantly smaller than that of GTVCT (145.71 ± 145.04 vs 174.30 ± 150.34, P definition of tumor volume, reduces organs at risk dose and does not increase the local recurrence rate.

  18. Dose-volume parameters and clinical outcome of CT-guided free-hand high-dose-rate interstitial brachytherapy for cervical cancer

    Science.gov (United States)

    Wang, Yi; Ye, Wei-Jun; Du, Le-Hui; Li, Ai-Ju; Ren, Yu-Feng; Cao, Xin-Ping

    2012-01-01

    Currently, image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer. In this study, we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-dose-rate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach. Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer. Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied. With a median of 5 (range, 4–7) implanted needles for each patient, the median dose of brachytherapy alone delivered to 90% of the target volume (D90) was 45 (range, 33–54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range, 20–36) Gyα/β10 for intermediate-risk clinical target volume (IR-CTV). The percentage of the CTV covered by the prescribed dose (V100) of HR-CTV with brachytherapy alone was 81.9%–99.2% (median, 96.7%). With an additional dose of external beam radiotherapy (EBRT), the median D90 was 94 (range, 83–104) Gyα/β10 for HR-CTV and 77 (range, 70–87) Gyα/β10 for IR-CTV; the median dose delivered to 100% of the target volume (D100) was 75 (range, 66–84) Gyα/β10 for HR-CTV and 65 (range, 57–73) Gyα/β10 for IR-CTV. The minimum dose to the most irradiated 2 cc volume (D2cc) was 73–96 (median, 83) Gyα/β3 for the bladder, 64–98 (median, 73) Gyα/β3 for the rectum, and 52–69 (median, 61) Gyα/β3 for the sigmoid colon. After a median follow-up of 15 months (range, 3–24 months), two patients experienced local failure, and 1 showed internal iliac nodal metastasis. Despite the relatively small number of needles used, CT-guided HDRISBT for cervical cancer showed favorable

  19. Dose-volume parameters and clinical outcome of CT-guided freehand high-dose-rate interstitial brachytherapy for cervical cancer

    Institute of Scientific and Technical Information of China (English)

    Yi Wang; Wei-Jun Ye; Le-Hui Du; Ai-Ju Li; Yu-Feng Ren; Xin-Ping Cao

    2012-01-01

    Currently,image-based 3-dimentional (3D) planning brachytherapy allows for a better assessment of gross tumor volume (GTV) and the definition and delineation of target volume in cervix cancer.In this study,we investigated the feasibility of our novel computed tomography (CT)-guided free-hand high-doserate interstitial brachytherapy (HDRISBT) technique for cervical cancer by evaluating the dosimetry and preliminary clinical outcome of this approach.Dose-volume histogram (DVH) parameters were analyzed according to the Gynecological GEC-ESTRO Working Group recommendations for image-based 3D treatment in cervical cancer.Twenty cervical cancer patients who underwent CT-guided free-hand HDRISBT between March 2009 and June 2010 were studied.With a median of 5 (range,4-7) implanted needles for each patient,the median dose of brachytherapy alone delivered to 90% of the target volume (D90) was 45 (range,33-54) Gyα/β10 for high-risk clinical target volume (HR-CTV) and 30 (range,20-36)Gyα/β10 for intermediate-risk clinical target volume (IR-CTV).The percentage of the CTV covered by the prescribed dose (V100) of HR-CTV with brachytherapy alone was 81.9%-99.2% (median,96.7%).With an additional dose of external beam radiotherapy (EBRT),the median D90 was 94 (range,83-104) Gyα/β10 for HR-CTV and 77 (range,70-87) Gyα/β10 for IR-CTV; the median dose delivered to 100% of the target volume (D100) was 75 (range,66-84) Gyα/β10 for HR-CTV and 65 (range,57-73) Gyα/β10 for IR-CTV.The minimum dose to the most irradiated 2 cc volume (D2cc) was 73-96 (median,83) Gyα/β3 for the bladder,64-98 (median,73) Gyα/β3 for the rectum,and 52-69 (median,61) Gyα/β3 for the sigmoid colon.After a median follow-up of 15 months (range,3-24 months),two patients experienced local failure,and 1 showed internal lilac nodal metastasis.Despite the relatively small number of needles used,CT-guided HDRISBT for cervical cancer showed favorable DVH parameters and clinical outcome.

  20. Correlation Between the Ratio of Target Volume to Lung and Lung Dose-volume Histogram in Middle Esophageal Cancer%中段食管癌放疗时靶区与肺的体积比与肺受照剂量的相关性分析

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    [目的]比较中段食管癌三维适形放疗(3DCRT)中三野与四野、固定野调强放疗(IMRT)、容积弧形调强放疗(VMAT)的剂量学差异,并研究肺与靶区的体积比对肺受照剂量的影响,从而探索有效的个体化临床放疗方法.[方法]选取10例中段食管癌患者,在Varian Eclipse 11.0计划系统中分别制定4种放疗计划(VMAT/IMRT/3F-3DCRT/4F-3DCRT),所有计划均使95%靶区达到处方剂量.比较不同计划的靶区、脊髓、肺等的剂量一体积直方图(DVH).[结果]与3DCRT相比,VMAT 、IMRT计划的脊髓最大剂量及肺V5、V10、V20、V30都有显著降低(P<0.05);而VMAT、IMRT计划之间各危及器官的受照剂量无统计学差异(P>0.05),但VMAT的机器跳数(Mu)及治疗时间有明显优势(P<0.05);对于靶区剂量VMAT、IMRT的适形指数与均匀指数无统计学意义(P>0.05),但均优于3DCRT计划(P<0.05).3DCRT的肺V5、V10、V20、V30与体积比具有强相关性(Rs>0.6),VMAT、IMRT计划中肺的DVH与体积比具有弱相关性(Rs>0.3).[结论]对于中段食管癌放疗患者,VMAT、IMRT在危及器官保护及靶区剂量覆盖方面均优于3DCRT;与IMRT比较,VMAT在缩短治疗时间、降低机器跳数上有优势.不同计划随肺与靶区的体积比的变化,其危及器官受量表现出不同的优势,这些差异同体积比具有相关性,而这种相关性为个体化制定中段食管癌放疗计划提供了参考.

  1. Contrast enhancement via texture region based histogram equalization

    Science.gov (United States)

    Singh, Kuldeep; Vishwakarma, Dinesh K.; Singh Walia, Gurjit; Kapoor, Rajiv

    2016-08-01

    This paper presents two novel contrast enhancement approaches using texture regions-based histogram equalization (HE). In HE-based contrast enhancement methods, the enhanced image often contains undesirable artefacts because an excessive number of pixels in the non-textured areas heavily bias the histogram. The novel idea presented in this paper is to suppress the impact of pixels in non-textured areas and to exploit texture features for the computation of histogram in the process of HE. The first algorithm named as Dominant Orientation-based Texture Histogram Equalization (DOTHE), constructs the histogram of the image using only those image patches having dominant orientation. DOTHE categories image patches into smooth, dominant or non-dominant orientation patches by using the image variance and singular value decomposition algorithm and utilizes only dominant orientation patches in the process of HE. The second method termed as Edge-based Texture Histogram Equalization, calculates significant edges in the image and constructs the histogram using the grey levels present in the neighbourhood of edges. The cumulative density function of the histogram formed from texture features is mapped on the entire dynamic range of the input image to produce the contrast-enhanced image. Subjective as well as objective performance assessment of proposed methods is conducted and compared with other existing HE methods. The performance assessment in terms of visual quality, contrast improvement index, entropy and measure of enhancement reveals that the proposed methods outperform the existing HE methods.

  2. Optimization Algorithms Testing and Convergence by Using a Stacked Histogram

    Directory of Open Access Journals (Sweden)

    ZAPLATILEK, K.

    2011-02-01

    Full Text Available The article describes an original method of optimization algorithms testing and convergence. The method is based on so-called stacked histogram. Stacked histogram is a histogram with its features marked by a chosen colour scheme. Thus, the histogram maintains the information on the input digital sequence. This approach enables an easy identification of the hidden defects in the random process statistical distribution. The stacked histogram is used for the testing of the convergent quality of various optimization techniques. Its width, position and colour scheme provides enough information on the chosen algorithm optimization trajectory. Both the classic iteration techniques and the stochastic optimization algorithm with the adaptation were used as examples.

  3. DPCube: Differentially Private Histogram Release through Multidimensional Partitioning

    CERN Document Server

    Xiao, Yonghui; Fan, Liyue; Goryczka, Slawomir

    2012-01-01

    Differential privacy is a strong notion for protecting individual privacy in privacy preserving data analysis or publishing. In this paper, we study the problem of differentially private histogram release for random workloads. We study two multidimensional partitioning strategies including: 1) a baseline cell-based partitioning strategy for releasing an equi-width cell histogram, and 2) an innovative 2-phase kd-tree based partitioning strategy for releasing a v-optimal histogram. We formally analyze the utility of the released histograms and quantify the errors for answering linear queries such as counting queries. We formally characterize the property of the input data that will guarantee the optimality of the algorithm. Finally, we implement and experimentally evaluate several applications using the released histograms, including counting queries, classification, and blocking for record linkage and show the benefit of our approach.

  4. Principal component analysis of the CT density histogram to generate parametric response maps of COPD

    Science.gov (United States)

    Zha, N.; Capaldi, D. P. I.; Pike, D.; McCormack, D. G.; Cunningham, I. A.; Parraga, G.

    2015-03-01

    Pulmonary x-ray computed tomography (CT) may be used to characterize emphysema and airways disease in patients with chronic obstructive pulmonary disease (COPD). One analysis approach - parametric response mapping (PMR) utilizes registered inspiratory and expiratory CT image volumes and CT-density-histogram thresholds, but there is no consensus regarding the threshold values used, or their clinical meaning. Principal-component-analysis (PCA) of the CT density histogram can be exploited to quantify emphysema using data-driven CT-density-histogram thresholds. Thus, the objective of this proof-of-concept demonstration was to develop a PRM approach using PCA-derived thresholds in COPD patients and ex-smokers without airflow limitation. Methods: Fifteen COPD ex-smokers and 5 normal ex-smokers were evaluated. Thoracic CT images were also acquired at full inspiration and full expiration and these images were non-rigidly co-registered. PCA was performed for the CT density histograms, from which the components with the highest eigenvalues greater than one were summed. Since the values of the principal component curve correlate directly with the variability in the sample, the maximum and minimum points on the curve were used as threshold values for the PCA-adjusted PRM technique. Results: A significant correlation was determined between conventional and PCA-adjusted PRM with 3He MRI apparent diffusion coefficient (p<0.001), with CT RA950 (p<0.0001), as well as with 3He MRI ventilation defect percent, a measurement of both small airways disease (p=0.049 and p=0.06, respectively) and emphysema (p=0.02). Conclusions: PRM generated using PCA thresholds of the CT density histogram showed significant correlations with CT and 3He MRI measurements of emphysema, but not airways disease.

  5. Correlation of histogram analysis of apparent diffusion coefficient with uterine cervical pathologic finding.

    Science.gov (United States)

    Lin, Yuning; Li, Hui; Chen, Ziqian; Ni, Ping; Zhong, Qun; Huang, Huijuan; Sandrasegaran, Kumar

    2015-05-01

    The purpose of this study was to investigate the application of histogram analysis of apparent diffusion coefficient (ADC) in characterizing pathologic features of cervical cancer and benign cervical lesions. This prospective study was approved by the institutional review board, and written informed consent was obtained. Seventy-three patients with cervical cancer (33-69 years old; 35 patients with International Federation of Gynecology and Obstetrics stage IB cervical cancer) and 38 patients (38-61 years old) with normal cervix or cervical benign lesions (control group) were enrolled. All patients underwent 3-T diffusion-weighted imaging (DWI) with b values of 0 and 800 s/mm(2). ADC values of the entire tumor in the patient group and the whole cervix volume in the control group were assessed. Mean ADC, median ADC, 25th and 75th percentiles of ADC, skewness, and kurtosis were calculated. Histogram parameters were compared between different pathologic features, as well as between stage IB cervical cancer and control groups. Mean ADC, median ADC, and 25th percentile of ADC were significantly higher for adenocarcinoma (p = 0.021, 0.006, and 0.004, respectively), and skewness was significantly higher for squamous cell carcinoma (p = 0.011). Median ADC was statistically significantly higher for well or moderately differentiated tumors (p = 0.044), and skewness was statistically significantly higher for poorly differentiated tumors (p = 0.004). No statistically significant difference of ADC histogram was observed between lymphovascular space invasion subgroups. All histogram parameters differed significantly between stage IB cervical cancer and control groups (p < 0.05). Distribution of ADCs characterized by histogram analysis may help to distinguish early-stage cervical cancer from normal cervix or cervical benign lesions and may be useful for evaluating the different pathologic features of cervical cancer.

  6. Contrast Enhancement through Clustered Histogram Equalization

    Directory of Open Access Journals (Sweden)

    Shen-Chuan Tai

    2012-09-01

    Full Text Available This study proposed a contrast enhancement algorithm. Some methods enhance images depending on only the global or the local information, therefore it would cause over-enhancement usually and make the image look unnatural. The proposed method enhances image based on the global and local information. For the global part, we proposed mapping curves to find the new average, maximum and minimum intensity to try to suit the concept of Human Visual System (HVS for obtaining the better perceptual results. For the local part, we utilized fuzzy c-means clustering algorithm to group image and we can obtain the information of intensity distribution and pixel number from each group. Then we calculate weights according to the information and enhance images by Histogram Equalization (HE depending on the weights. The experiment results show that our method can enhance the contrast of image steadily and it causes over-enhancement with lower probability than other methods. The whole image not only looks natural but also shows detail texture more clearly after applying our method.

  7. Dose-Volume Analysis of Predictors for Gastrointestinal Toxicity After Concurrent Full-Dose Gemcitabine and Radiotherapy for Locally Advanced Pancreatic Adenocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Huang Jiayi [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Robertson, John M., E-mail: jrobertson@beaumont.edu [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Ye Hong [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Margolis, Jeffrey; Nadeau, Laura [Division of Medical Oncology, William Beaumont Hospital, Royal Oak, MI (United States); Yan Di [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, MI (United States)

    2012-07-15

    Purpose: To identify dosimetric predictors for the development of gastrointestinal (GI) toxicity in patients with locally advanced pancreatic adenocarcinoma (LAPC) treated with concurrent full-dose gemcitabine and radiotherapy (GemRT). Methods and Materials: From June 2002 to June 2009, 46 LAPC patients treated with definitive GemRT were retrospectively analyzed. The stomach and duodenum were retrospectively contoured separately to determine their dose-volume histogram (DVH) parameters. GI toxicity was defined as Grade 3 or higher GI toxicity. The follow-up time was calculated from the start of RT to the date of death or last contact. Univariate analysis (UVA) and multivariate analysis (MVA) using Kaplan-Meier and Cox regression models were performed to identify risk factors associated with GI toxicity. The receiver operating characteristic curve and the area under the receiver operating characteristic curve (AUC) were used to determine the best DVH parameter to predict for GI toxicity. Results: Of the patients, 28 (61%) received concurrent gemcitabine alone, and 18 (39%) had concurrent gemcitabine with daily erlotinib. On UVA, only the V{sub 20Gy} to V{sub 35Gy} of duodenum were significantly associated with GI toxicity (all p {<=} 0.05). On MVA, the V{sub 25Gy} of duodenum and the use of erlotinib were independent risk factors for GI toxicity (p = 0.006 and 0.02, respectively). For the entire cohort, the V{sub 25Gy} of duodenum is the best predictor for GI toxicity (AUC = 0.717), and the 12-month GI toxicity rate was 8% vs. 48% for V{sub 25Gy} {<=} 45% and V{sub 25Gy} > 45%, respectively (p = 0.03). However, excluding the erlotinib group, the V{sub 35Gy} is the best predictor (AUC = 0.725), and the 12-month GI toxicity rate was 0% vs. 41% for V{sub 35Gy} {<=} 20% and V{sub 35Gy} > 20%, respectively (p = 0.04). Conclusions: DVH parameters of duodenum may predict Grade 3 GI toxicity after GemRT for LAPC. Concurrent use of erlotinib during GemRT may increase GI

  8. A Learning Framework for Self-Tuning Histograms

    CERN Document Server

    Viswanathan, Raajay; Laxman, Srivatsan; Arasu, Arvind

    2011-01-01

    We propose a general learning theoretic formulation for estimating self-tuning histograms. Our formulation uses query feedback from a workload as training data to estimate a histogram that minimizes the expected error on future queries. Our formulation is flexible in the sense that it allows the design and comparison of different methods (possibly specialized for different settings). We first study the simple class of equi-width histograms in our learning framework and present a learning algorithm (EquiHist) that is competitive in many settings and that has formal error guarantees. We then go beyond equi-width histograms and present a novel learning algorithm (SpHist) for estimating general histograms. Here we use Haar wavelets to reduce the problem of learning histograms to a sparse vectory recovery problem. Both algorithms have multiple advantages over existing methods: 1) simple and scalable extensions to multi-dimensional data, 2) scale with number of histogram buckets and size of query feedback, 3) natur...

  9. Comparing measurement-derived (3DVH) and machine log file-derived dose reconstruction methods for VMAT QA in patient geometries.

    Science.gov (United States)

    Tyagi, Neelam; Yang, Kai; Yan, Di

    2014-07-08

    The purpose of this study was to compare the measurement-derived (3DVH) dose reconstruction method with machine log file-derived dose reconstruction method in patient geometries for VMAT delivery. A total of ten patient plans were selected from a regular fractionation plan to complex SBRT plans. Treatment sites in the lung and abdomen were chosen to explore the effects of tissue heterogeneity on the respective dose reconstruction algorithms. Single- and multiple-arc VMAT plans were generated to achieve the desired target objectives. Delivered plan in the patient geometry was reconstructed by using ArcCHECK Planned Dose Perturbation (ACPDP) within 3DVH software, and by converting the machine log file to Pinnacle3 9.0 treatment plan format and recalculating dose with CVSP algorithm. In addition, delivered gantry angles between machine log file and 3DVH 4D measurement were also compared to evaluate the accuracy of the virtual inclinometer within the 3DVH. Measured ion chamber and 3DVH-derived isocenter dose agreed with planned dose within 0.4% ± 1.2% and -1.0% ± 1.6%, respectively. 3D gamma analysis showed greater than 98% between log files and 3DVH reconstructed dose. Machine log file reconstructed doses and TPS dose agreed to within 2% in PTV and OARs over the entire treatment. 3DVH reconstructed dose showed an average maximum dose difference of 3% ± 1.2% in PTV, and an average mean difference of -4.5% ± 10.5% in OAR doses. The average virtual inclinometer error (VIE) was -0.65° ± 1.6° for all patients, with a maximum error of -5.16° ± 4.54° for an SRS case. The time averaged VIE was within 1°-2°, and did not have a large impact on the overall accuracy of the estimated patient dose from ACPDP algorithm. In this study, we have compared two independent dose reconstruction methods for VMAT QA. Both methods are capable of taking into account the measurement and delivery parameter discrepancy, and display the delivered dose in CT patient geometry rather than

  10. Size histograms of gold nanoparticles measured by gravitational sedimentation.

    Science.gov (United States)

    Alexander, Colleen M; Goodisman, Jerry

    2014-03-15

    Sedimentation curves of gold nanoparticles in water were obtained by measuring the optical density of a suspension over time. The results are not subject to sampling errors, and refer to the particles in situ. Curves obtained simultaneously at several wave lengths were analyzed together to derive the size histogram of the sedimenting particles. The bins in the histogram were 5 nm wide and centered at diameters 60, 65, …, 110 nm. To get the histogram, we weighted previously calculated solutions to the Mason-Weaver sedimentation-diffusion equation for various particle diameters with absorption/scattering coefficients and size (diameter) abundances {c(j)}, and found the {c(j)} which gave the best fit to all the theoretical sedimentation curves. The effects of changing the number of bins and the wave lengths used were studied. Going to smaller bins would mean determining more parameters and require more wave lengths. The histograms derived from sedimentation agreed quite well in general with the histogram derived from TEM. Differences found for the smallest particle diameters are partly due to statistical fluctuations (TEM found only 1-2 particles out of 103 with these diameters). More important is that the TEM histogram indicates 12% of the particles have diameters of 75±2.5 nm, and the sedimentation histogram shows none. We show that this reflects the difference between the particles in situ, which possess a low-density shell about 1 nm thick, and the bare particles on the TEM stage. Correcting for this makes agreement between the two histograms excellent. Comparing sedimentation-derived with TEM-derived histograms thus shows differences between the particles in situ and on the TEM stage.

  11. Recommendations from gynaecological (GYN) GEC ESTRO working group (II): concepts and terms in 3D image-based treatment planning in cervix cancer brachytherapy-3D dose volume parameters and aspects of 3D image-based anatomy, radiation physics, radiobiology.

    Science.gov (United States)

    Pötter, Richard; Haie-Meder, Christine; Van Limbergen, Erik; Barillot, Isabelle; De Brabandere, Marisol; Dimopoulos, Johannes; Dumas, Isabelle; Erickson, Beth; Lang, Stefan; Nulens, An; Petrow, Peter; Rownd, Jason; Kirisits, Christian

    2006-01-01

    The second part of the GYN GEC ESTRO working group recommendations is focused on 3D dose-volume parameters for brachytherapy of cervical carcinoma. Methods and parameters have been developed and validated from dosimetric, imaging and clinical experience from different institutions (University of Vienna, IGR Paris, University of Leuven). Cumulative dose volume histograms (DVH) are recommended for evaluation of the complex dose heterogeneity. DVH parameters for GTV, HR CTV and IR CTV are the minimum dose delivered to 90 and 100% of the respective volume: D90, D100. The volume, which is enclosed by 150 or 200% of the prescribed dose (V150, V200), is recommended for overall assessment of high dose volumes. V100 is recommended for quality assessment only within a given treatment schedule. For Organs at Risk (OAR) the minimum dose in the most irradiated tissue volume is recommended for reporting: 0.1, 1, and 2 cm3; optional 5 and 10 cm3. Underlying assumptions are: full dose of external beam therapy in the volume of interest, identical location during fractionated brachytherapy, contiguous volumes and contouring of organ walls for >2 cm3. Dose values are reported as absorbed dose and also taking into account different dose rates. The linear-quadratic radiobiological model-equivalent dose (EQD2)-is applied for brachytherapy and is also used for calculating dose from external beam therapy. This formalism allows systematic assessment within one patient, one centre and comparison between different centres with analysis of dose volume relations for GTV, CTV, and OAR. Recommendations for the transition period from traditional to 3D image-based cervix cancer brachytherapy are formulated. Supplementary data (available in the electronic version of this paper) deals with aspects of 3D imaging, radiation physics, radiation biology, dose at reference points and dimensions and volumes for the GTV and CTV (adding to [Haie-Meder C, Pötter R, Van Limbergen E et al. Recommendations from

  12. Data analysis recipes: Choosing the binning for a histogram

    CERN Document Server

    Hogg, David W

    2008-01-01

    Data points are placed in bins when a histogram is created, but there is always a decision to be made about the number or width of the bins. This decision is often made arbitrarily or subjectively, but it need not be. A jackknife or leave-one-out cross-validation likelihood is defined and employed as a scalar objective function for optimization of the locations and widths of the bins. The objective is justified as being related to the histogram's usefulness for predicting future data. The method works for data or histograms of any dimensionality.

  13. 2000 fps multi-object tracking based on color histogram

    Science.gov (United States)

    Gu, Qingyi; Takaki, Takeshi; Ishii, Idaku

    2012-06-01

    In this study, we develop a real-time, color histogram-based tracking system for multiple color-patterned objects in a 512×512 image at 2000 fps. Our system can simultaneously extract the positions, areas, orientation angles, and color histograms of multiple objects in an image using the hardware implementation of a multi-object, color histogram extraction circuit module on a high-speed vision platform. It can both label multiple objects in an image consisting of connected components and calculate their moment features and 16-bin hue-based color histograms using cell-based labeling. We demonstrate the performance of our system by showing several experimental results: (1) tracking of multiple color-patterned objects on a plate rotating at 16 rps, and (2) tracking of human hand movement with two color-patterned drinking bottles.

  14. Content-based Image Retrieval Using Color Histogram

    Institute of Scientific and Technical Information of China (English)

    HUANG Wen-bei; HE Liang; GU Jun-zhong

    2006-01-01

    This paper introduces the principles of using color histogram to match images in CBIR. And a prototype CBIR system is designed with color matching function. A new method using 2-dimensional color histogram based on hue and saturation to extract and represent color information of an image is presented. We also improve the Euclidean-distance algorithm by adding Center of Color to it. The experiment shows modifications made to Euclidean-distance significantly elevate the quality and efficiency of retrieval.

  15. A study of the relationship between dose-volume histogram parameter V5 and radiation-induced pneumonitis%肺剂量体积直方图参数V5与放射性肺炎关系的研究

    Institute of Scientific and Technical Information of China (English)

    苗慧; 耿冲; 陈宏林; 刘亚洲; 张文; 张旭光

    2012-01-01

    目的 分析剂量体积直方图(DVH)参数V5与胸部肿瘤放射性肺炎(RIP)之间的关系.方法 回顾性分析行了调强放疗的85例胸部肿瘤患者的临床资料,其中未限制V5(V5未限制组)共43例,限制V5(V5限制组)共42例,观察2组RIP的发生情况.结果 根据放射治疗肿瘤协作组(RTOG)诊断标准,V5未限制组发生2级及以上RIP 19例,发生率为44.2%,V5限制组发生2级及以上RIP 12例,发生率为28.6%,2组相比差异无统计学意义(P>0.05),但Spearman等级相关分析研究表明V5与RIP发生具有明显相关性(P0. 05). However, Spearman correlation analysis showed a remarkable correlation between V 5 and RIP (P <0. 01). Conclusion There is association between the V5 and RIP.

  16. Non-Rigid Medical Image Registration with Joint Histogram Estimation Based on Mutual Information

    Institute of Scientific and Technical Information of China (English)

    LU Xuesong; ZHANG Su; SU He; CHEN Yazhu

    2007-01-01

    A mutual information-based non-rigid medical image registration algorithm is presented. An approximate function of Harming windowed sinc is used as kernel function of partial volume (PV)interpolation to estimate the joint histogram, which is the key to calculating the mutual information. And a new method is proposed to compute the gradient of mutual information with respect to themodel parameters. The transformation of object is modeled by a free-form deformation (FFD) based on B-splines. The experiments on 3D synthetic and real image data show that the algorithm can con-verge at the global optimum and restrain the emergency of local extreme.

  17. Should unfolded histograms be used to test hypotheses?

    CERN Document Server

    Cousins, Robert D; Sun, Yipeng

    2016-01-01

    In many analyses in high energy physics, attempts are made to remove the effects of detector smearing in data by techniques referred to as "unfolding" histograms, thus obtaining estimates of the true values of histogram bin contents. Such unfolded histograms are then compared to theoretical predictions, either to judge the goodness of fit of a theory, or to compare the abilities of two or more theories to describe the data. When doing this, even informally, one is testing hypotheses. However, a more fundamentally sound way to test hypotheses is to smear the theoretical predictions by simulating detector response and then comparing to the data without unfolding; this is also frequently done in high energy physics, particularly in searches for new physics. One can thus ask: to what extent does hypothesis testing after unfolding data materially reproduce the results obtained from testing by smearing theoretical predictions? We argue that this "bottom-line-test" of unfolding methods should be studied more commonl...

  18. Histogram bin width selection for time-dependent Poisson processes

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Shinsuke; Shinomoto, Shigeru [Department of Physics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)

    2004-07-23

    In constructing a time histogram of the event sequences derived from a nonstationary point process, we wish to determine the bin width such that the mean squared error of the histogram from the underlying rate of occurrence is minimized. We find that the optimal bin widths obtained for a doubly stochastic Poisson process and a sinusoidally regulated Poisson process exhibit different scaling relations with respect to the number of sequences, time scale and amplitude of rate modulation, but both diverge under similar parametric conditions. This implies that under these conditions, no determination of the time-dependent rate can be made. We also apply the kernel method to these point processes, and find that the optimal kernels do not exhibit any critical phenomena, unlike the time histogram method.

  19. Histogram bin width selection for time-dependent Poisson processes

    Science.gov (United States)

    Koyama, Shinsuke; Shinomoto, Shigeru

    2004-07-01

    In constructing a time histogram of the event sequences derived from a nonstationary point process, we wish to determine the bin width such that the mean squared error of the histogram from the underlying rate of occurrence is minimized. We find that the optimal bin widths obtained for a doubly stochastic Poisson process and a sinusoidally regulated Poisson process exhibit different scaling relations with respect to the number of sequences, time scale and amplitude of rate modulation, but both diverge under similar parametric conditions. This implies that under these conditions, no determination of the time-dependent rate can be made. We also apply the kernel method to these point processes, and find that the optimal kernels do not exhibit any critical phenomena, unlike the time histogram method.

  20. Face recognition with histograms of fractional differential gradients

    Science.gov (United States)

    Yu, Lei; Ma, Yan; Cao, Qi

    2014-05-01

    It has proved that fractional differentiation can enhance the edge information and nonlinearly preserve textural detailed information in an image. This paper investigates its ability for face recognition and presents a local descriptor called histograms of fractional differential gradients (HFDG) to extract facial visual features. HFDG encodes a face image into gradient patterns using multiorientation fractional differential masks, from which histograms of gradient directions are computed as the face representation. Experimental results on Yale, face recognition technology (FERET), Carnegie Mellon University pose, illumination, and expression (CMU PIE), and A. Martinez and R. Benavente (AR) databases validate the feasibility of the proposed method and show that HFDG outperforms local binary patterns (LBP), histograms of oriented gradients (HOG), enhanced local directional patterns (ELDP), and Gabor feature-based methods.

  1. Click-iT assay with improved DNA distribution histograms.

    Science.gov (United States)

    Hamelik, Ronald M; Krishan, Awtar

    2009-10-01

    The Click-iT Assay developed and commercialized by Invitrogen is based on incorporation of a new 5-bromo-2'-deoxyuridine analog, 5-ethynyl-2'-deoxyuridine (EdU) into newly synthesized DNA and its recognition by azide dyes via a copper mediated "click" reaction. This relatively convenient and useful procedure depends on fixation of cells with paraformaldehyde and staining of the DNA with 7-aminoactinomycin-D (7-AAD). Both of these procedures result in DNA histograms with broad coefficients of variation (CV's). In this report, we have shown that after EdU incorporation, nuclei isolated by lysis can be incubated with the Click-iT Assay and stained with propidium iodide for generation of DNA histograms with low CV's. This modified procedure results in better DNA histograms by replacing 7-AAD with propidium iodide and also saves processing time by eliminating the fixation and permeabilization steps.

  2. Blind Digital Image Watermarking Robust Against Histogram Equalization

    Directory of Open Access Journals (Sweden)

    H. Sadawarti

    2012-01-01

    Full Text Available Problem statement: Piracy in the presence of internet and computers proves to be a biggest damage to the industry. Easy editing and copying of images yields a great damage to the owner as original images can be distributed through internet very easily. To reduce the piracy and duplicity of the digital multimedia files, digital watermarking technique is dominating over the other available techniques. There are certain methods or attacks which are used to damage the watermark. One of the major attacks is histogram equalization and reducing the number of histogram equalized levels. Thus, there is a need to develop a method so that the watermark can be protected after histogram equalization. Approach: A blind digital watermarking algorithm is presented which embed the watermark in frequency domain. Firstly, DWT is applied on the original image and then DCT on the 4×4 blocks to target the particular frequencies of the image for embedding the watermark which does not have more effect after histogram equalization. Also, to enhance the security of the watermark dual encryption technique is deployed. Results: Algorithm applied to four images which are Lena, Cameraman, Baboon and Peppers. The evaluation of the algorithm is calculated in terms of peak signal to noise ratio and non correlation. The results prove that the algorithm is robust to histogram equalization attack up to 2 grey levels. Conclusion/Recommendations: The developed algorithm proved its performance against histogram equalization but the algorithm can also be checked for the other attacks which can be addition of white noise, Gaussian noise, filtering.

  3. Remote logo detection using angle-distance histograms

    Science.gov (United States)

    Youn, Sungwook; Ok, Jiheon; Baek, Sangwook; Woo, Seongyoun; Lee, Chulhee

    2016-05-01

    Among all the various computer vision applications, automatic logo recognition has drawn great interest from industry as well as various academic institutions. In this paper, we propose an angle-distance map, which we used to develop a robust logo detection algorithm. The proposed angle-distance histogram is invariant against scale and rotation. The proposed method first used shape information and color characteristics to find the candidate regions and then applied the angle-distance histogram. Experiments show that the proposed method detected logos of various sizes and orientations.

  4. Resolving Histogram Binning Dilemmas with Binless and Binfull Algorithms

    CERN Document Server

    Krislock, Abram

    2014-01-01

    The histogram is an analysis tool in widespread use within many sciences, with high energy physics as a prime example. However, there exists an inherent bias in the choice of binning for the histogram, with different choices potentially leading to different interpretations. This paper aims to eliminate this bias using two "debinning" algorithms. Both algorithms generate an observed cumulative distribution function from the data, and use it to construct a representation of the underlying probability distribution function. The strengths and weaknesses of these two algorithms are compared and contrasted. The applicability and future prospects of these algorithms is also discussed.

  5. Integral Histogram with Random Projection for Pedestrian Detection

    Science.gov (United States)

    Liu, Chang-Hua; Lin, Jian-Kun

    2015-01-01

    In this paper, we give a systematic study to report several deep insights into the HOG, one of the most widely used features in the modern computer vision and image processing applications. We first show that, its magnitudes of gradient can be randomly projected with random matrix. To handle over-fitting, an integral histogram based on the differences of randomly selected blocks is proposed. The experiments show that both the random projection and integral histogram outperform the HOG feature obviously. Finally, the two ideas are combined into a new descriptor termed IHRP, which outperforms the HOG feature with less dimensions and higher speed. PMID:26569486

  6. Color and Edge Histograms Based Medicinal Plants' Image Retrieval

    Directory of Open Access Journals (Sweden)

    Basavaraj S. Anami

    2012-08-01

    Full Text Available In this paper, we propose a methodology for color and edge histogram based medicinal plants image retrieval. The medicinal plants are divided into herbs, shrubs and trees. The medicinal plants are used in ayurvedic medicines. Manual identification of medicinal plants requires a priori knowledge. Automatic recognition of medicinal plants is useful. We have considered medicinal plant species, such as Papaya, Neem, Tulasi and Aloevera are considered for identification and retrieval. The color histograms are obtained in RGB, HSV and YCbCr color spaces. The number of valleys and peaks in the color histograms are used as features. But, these features alone are not helpful in discriminating plant images, since majority plant images are green in color. We have used edge and edge direction histograms in the work to get edges in the stem and leafy parts. Finally, these features are used in retrieval of medicinal plant images. Absolute distance, Euclidean distance and mean square error, similarity distance measures are deployed in the work. The results show an average retrieval efficiency of 94% and 98% for edge and edge direction features respectively.

  7. Reversible Watermarking dengan Metode Modifikasi Histogram pada Difference Image

    Directory of Open Access Journals (Sweden)

    Yustina Retno

    2011-07-01

    Full Text Available Abstract— Reversible watermarking schemes are widely used to maintain the authenticity of the digital image. This research will discuss a method on histogram modification of difference image in which the difference image is created from the difference value of adjacent pixels of the image grayscale.  Embedding process begins by dividing the host image and watermark into b blocks, followed by making a difference image of the host image block. From the difference image histogram, determine the peak value, and modify the histogram based on the peak value. Then, insert each block of the watermark to the difference image that has been modified and transform back into the grayscale image. Extraction and recovery process is the inverted version of the embedding stage. This process begins by dividing the watermarked image into b blocks, followed by making a difference image of each block. Then, extract the data and shift difference image histogram using a peak value. That difference image is transformed back into a grayscale image. Experimental results demonstrate that the average insertion capacity is 14% greater than Xue's with PSNR value over 48 dB for 4 x 4 pixels and 23 % greater with PSNR over 46 dB for 8 x 8 pixels. From the comparison of robustness to line and salt n’ pepper on the density of 0.05 noises is obtained that the watermark with ECC is more robust than a watermark without ECC. JPEG compression in lossless mode may be applied to the watermarked image. Multiple insertion of watermark can be done with the consequence that the more insertions will result in lower PSNR values. Keywords—difference image, histogram modification, reversible watermarking

  8. Content Based Radiographic Images Indexing and Retrieval Using Pattern Orientation Histogram

    Directory of Open Access Journals (Sweden)

    Abolfazl Lakdashti

    2008-06-01

    Full Text Available Introduction: Content Based Image Retrieval (CBIR is a method of image searching and retrieval in a  database. In medical applications, CBIR is a tool used by physicians to compare the previous and current  medical images associated with patients pathological conditions. As the volume of pictorial information  stored in medical image databases is in progress, efficient image indexing and retrieval is increasingly  becoming a necessity.  Materials and Methods: This paper presents a new content based radiographic image retrieval approach  based on histogram of pattern orientations, namely pattern orientation histogram (POH. POH represents  the  spatial  distribution  of  five  different  pattern  orientations:  vertical,  horizontal,  diagonal  down/left,  diagonal down/right and non-orientation. In this method, a given image is first divided into image-blocks  and  the  frequency  of  each  type  of  pattern  is  determined  in  each  image-block.  Then,  local  pattern  histograms for each of these image-blocks are computed.   Results: The method was compared to two well known texture-based image retrieval methods: Tamura  and  Edge  Histogram  Descriptors  (EHD  in  MPEG-7  standard.  Experimental  results  based  on  10000  IRMA  radiography  image  dataset,  demonstrate  that  POH  provides  better  precision  and  recall  rates  compared to Tamura and EHD. For some images, the recall and precision rates obtained by POH are,  respectively, 48% and 18% better than the best of the two above mentioned methods.    Discussion and Conclusion: Since we exploit the absolute location of the pattern in the image as well as  its global composition, the proposed matching method can retrieve semantically similar medical images.

  9. User Aligned Histogram Stacks for Visualization of Abdominal Organs via MRI

    Science.gov (United States)

    Özdemir, M.; Akay, O.; Güzeliş, C.; Dicle, O.; Selver, M. A.

    2016-08-01

    Multi-dimensional transfer functions (MDTF) are occasionally designed as two-step approaches. At the first step, the constructed domain is modelled coarsely using global volume statistics and an initial transfer function (TF) is designed. Then, a finer classification is performed using local information to refine the TF design. In this study, both a new TF domain and a novel two-step MDTF strategy are proposed for visualization of abdominal organs. The proposed domain is generated by aligning the histograms of the slices, which are reconstructed based on user aligned majority axis/regions through an interactive Multi-Planar Reconstruction graphical user interface. It is shown that these user aligned histogram stacks (UAHS) exploit more a priori information by providing tissue specific inter-slice spatial domain knowledge. For initial TF design, UAHS are approximated using a multi-scale hierarchical Gaussian mixture model, which is designed to work in quasi real time. Then, a finer classification step is carried out for refinement of the initial result. Applications to several MRI data sets acquired with various sequences demonstrate improved visualization of abdomen.

  10. Content Based Image Retrieval Using Local Color Histogram

    Directory of Open Access Journals (Sweden)

    Metty Mustikasari, Eri Prasetyo,, Suryadi Harmanto

    2014-01-01

    Full Text Available —This paper proposes a technique to retrieve images based on color feature using local histogram. The image is divided into nine sub blocks of equal size. The color of each sub-block is extracted by quantifying the HSV color space into 12x6x6 histogram. In this retrieval system Euclidean distance and City block distance are used to measure similarity of images. This algorithm is tested by using Corel image database. The performance of retrieval system is measured in terms of its recall and precision. The effectiveness of retrieval system is also measured based on AVRR (Average Rank of Relevant Images and IAVRR (Ideal Average Rank of Relevant Images which is proposed by Faloutsos. The experimental results show that the retrieval system has a good performance and the evaluation results of city block has achieved higher retrieval performance than the evaluation results of the Euclidean distance.

  11. Metamorphic Virus Variants Classification Using Opcode Frequency Histogram

    CERN Document Server

    Rad, Babak Bashari

    2011-01-01

    In order to prevent detection and evade signature-based scanning methods, which are normally exploited by antivirus software, metamorphic viruses use several various obfuscation approaches. They transform their code in new instances as look entirely or partly different and contain dissimilar sequences of string, but their behavior and function remain unchanged. This obfuscation process allows them to stay away from the string based signature detection. In this research, we use a statistical technique to compare the similarity between two files infected by two morphed versions of a given metamorphic virus. Our proposed solution based on static analysis and it uses the histogram of machine instructions frequency in various offspring of obfuscated viruses. We use Euclidean histogram distance metric to compare a pair of portable executable (PE) files. The aim of this study is to show that for some particular obfuscation methods, the presented solution can be exploited to detect morphed varieties of a file. Hence,...

  12. Contrast Enhancement Using Brightness Preserving Histogram Plateau Limit Technique

    Directory of Open Access Journals (Sweden)

    K. Santhi

    2014-07-01

    Full Text Available Contrast enhancement is an important factor in the gray scale images. One of the widely accepted contrast enhancement method is the Histogram equalization (HE. HE achieves comparatively better performance on almost all types of image but sometimes produces excessive visual deterioration. The proposed Contrast Enhancement using Brightness Preserving Histogram Plateau Limit (CEBPHPL method provides better brightness preservation without allowing in excess of contrast improvement measure. This method decomposes the input image by computing the local maxima of the smoothed image using Gaussian filter which reduces the noise. Then the clipping process has been implemented which provides the good enhancement rate than the conventional methods. The experimental result of the proposed CEBPHPL is better than the existing methods.

  13. Head Tracking Using Shapes and Adaptive Color Histograms

    Institute of Scientific and Technical Information of China (English)

    刘青山; 马颂德; 卢汉青

    2002-01-01

    A new method is presented for tracking a person's head in real-time. Thehead is shaped as an ellipse, and the adaptively modified RGB color histogram is used torepresent the tracked object (head). The method is composed of two parts. First, a robustnonparametric technique, called mean shift algorithm, is adopted for histogram matching toestimate the head's location in the current frame. Second, a local search is performed afterhistogram matching to maximize the normalized gradient magnitude around the boundary ofthe elliptical head, so that a more accurate location and the best scale size of the head can beobtained. The method is demonstrated to be a real-time tracker and robust to clutter, scalevariation, occlusion, rotation and camera motion, for several test sequences.

  14. Accelerated weight histogram method for exploring free energy landscapes

    CERN Document Server

    Lindahl, Viveca; Hess, Berk

    2014-01-01

    Calculating free energies is an important and notoriously difficult task for molecular simulations. The rapid increase in computational power has made it possible to probe increasingly complex systems, yet extracting accurate free energies from these simulations remains a major challenge. Fully exploring the free energy landscape of, say, a biological macromolecule typically requires sampling large conformational changes and slow transitions. Often, the only feasible way to study such a system is to simulate it using an enhanced sampling method. The accelerated weight histogram (AWH) method is a new, efficient extended ensemble sampling technique which adaptively biases the simulation to promote exploration of the free energy landscape. The AWH method uses a probability weight histogram which allows for efficient free energy updates and results in an easy discretization procedure. A major advantage of the method is its general formulation, making it a powerful platform for developing further extensions and an...

  15. Histogram Equalization to Model Adaptation for Robust Speech Recognition

    Directory of Open Access Journals (Sweden)

    Hoirin Kim

    2010-01-01

    Full Text Available We propose a new model adaptation method based on the histogram equalization technique for providing robustness in noisy environments. The trained acoustic mean models of a speech recognizer are adapted into environmentally matched conditions by using the histogram equalization algorithm on a single utterance basis. For more robust speech recognition in the heavily noisy conditions, trained acoustic covariance models are efficiently adapted by the signal-to-noise ratio-dependent linear interpolation between trained covariance models and utterance-level sample covariance models. Speech recognition experiments on both the digit-based Aurora2 task and the large vocabulary-based task showed that the proposed model adaptation approach provides significant performance improvements compared to the baseline speech recognizer trained on the clean speech data.

  16. Accelerating Monte Carlo Renderers by Ray Histogram Fusion

    Directory of Open Access Journals (Sweden)

    Mauricio Delbracio

    2015-03-01

    Full Text Available This paper details the recently introduced Ray Histogram Fusion (RHF filter for accelerating Monte Carlo renderers [M. Delbracio et al., Boosting Monte Carlo Rendering by Ray Histogram Fusion, ACM Transactions on Graphics, 33 (2014]. In this filter, each pixel in the image is characterized by the colors of the rays that reach its surface. Pixels are compared using a statistical distance on the associated ray color distributions. Based on this distance, it decides whether two pixels can share their rays or not. The RHF filter is consistent: as the number of samples increases, more evidence is required to average two pixels. The algorithm provides a significant gain in PSNR, or equivalently accelerates the rendering process by using many fewer Monte Carlo samples without observable bias. Since the RHF filter depends only on the Monte Carlo samples color values, it can be naturally combined with all rendering effects.

  17. Histogram method in finite density QCD with phase quenched simulations

    CERN Document Server

    Nakagawa, Y; Aoki, S; Kanaya, K; Ohno, H; Saito, H; Hatsuda, T; Umeda, T

    2011-01-01

    We propose a new approach to finite density QCD based on a histogram method with phase quenched simulations at finite chemical potential. Integrating numerically the derivatives of the logarithm of the quark determinant with respect to the chemical potential, we calculate the reweighting factor and the complex phase of the quark determinant. The complex phase is handled with a cumulant expansion to avoid the sign problem. We examine the applicability of this method.

  18. Extraction of Facial Feature Points Using Cumulative Histogram

    CERN Document Server

    Paul, Sushil Kumar; Bouakaz, Saida

    2012-01-01

    This paper proposes a novel adaptive algorithm to extract facial feature points automatically such as eyebrows corners, eyes corners, nostrils, nose tip, and mouth corners in frontal view faces, which is based on cumulative histogram approach by varying different threshold values. At first, the method adopts the Viola-Jones face detector to detect the location of face and also crops the face region in an image. From the concept of the human face structure, the six relevant regions such as right eyebrow, left eyebrow, right eye, left eye, nose, and mouth areas are cropped in a face image. Then the histogram of each cropped relevant region is computed and its cumulative histogram value is employed by varying different threshold values to create a new filtering image in an adaptive way. The connected component of interested area for each relevant filtering image is indicated our respective feature region. A simple linear search algorithm for eyebrows, eyes and mouth filtering images and contour algorithm for nos...

  19. Independent histogram pursuit for segmentation of skin lesions

    DEFF Research Database (Denmark)

    Gomez, D.D.; Butakoff, C.; Ersbøll, Bjarne Kjær;

    2008-01-01

    In this paper, an unsupervised algorithm, called the Independent Histogram Pursuit (HIP), for segmenting dermatological lesions is proposed. The algorithm estimates a set of linear combinations of image bands that enhance different structures embedded in the image. In particular, the first estima...... to deal with different types of dermatological lesions. The boundary detection precision using k-means segmentation was close to 97%. The proposed algorithm can be easily combined with the majority of classification algorithms.......In this paper, an unsupervised algorithm, called the Independent Histogram Pursuit (HIP), for segmenting dermatological lesions is proposed. The algorithm estimates a set of linear combinations of image bands that enhance different structures embedded in the image. In particular, the first...... estimated combination enhances the contrast of the lesion to facilitate its segmentation. Given an N-band image, this first combination corresponds to a line in N dimensions, such that the separation between the two main modes of the histogram obtained by projecting the pixels onto this line, is maximized...

  20. Conformational thermodynamics of biomolecular complexes: The histogram-based method

    Science.gov (United States)

    Das, Amit; Sikdar, Samapan; Ghosh, Mahua; Chakrabarti, J.

    2015-09-01

    Conformational changes in biomacromolecules govern majority of biological processes. Complete characterization of conformational contributions to thermodynamics of complexation of biomacromolecules has been challenging. Although, advances in NMR relaxation experiments and several computational studies have revealed important aspects of conformational entropy changes, efficient and large-scale estimations still remain an intriguing facet. Recent histogram-based method (HBM) offers a simple yet rigorous route to estimate both conformational entropy and free energy changes from same set of histograms in an efficient manner. The HBM utilizes the power of histograms which can be generated as accurately as desired from an arbitrarily large sample space from atomistic simulation trajectories. Here we discuss some recent applications of the HBM, using dihedral angles of amino acid residues as conformational variables, which provide good measure of conformational thermodynamics of several protein-peptide complexes, obtained from NMR, metal-ion binding to an important metalloprotein, interfacial changes in protein-protein complex and insight to protein function, coupled with conformational changes. We conclude the paper with a few future directions worth pursuing.

  1. Histogram Analysis of CT Perfusion of Hepatocellular Carcinoma for Predicting Response to Transarterial Radioembolization: Value of Tumor Heterogeneity Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Reiner, Caecilia S., E-mail: caecilia.reiner@usz.ch; Gordic, Sonja; Puippe, Gilbert; Morsbach, Fabian; Wurnig, Moritz [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology (Switzerland); Schaefer, Niklaus; Veit-Haibach, Patrick [University Hospital Zurich, Division of Nuclear Medicine (Switzerland); Pfammatter, Thomas; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology (Switzerland)

    2016-03-15

    PurposeTo evaluate in patients with hepatocellular carcinoma (HCC), whether assessment of tumor heterogeneity by histogram analysis of computed tomography (CT) perfusion helps predicting response to transarterial radioembolization (TARE).Materials and MethodsSixteen patients (15 male; mean age 65 years; age range 47–80 years) with HCC underwent CT liver perfusion for treatment planning prior to TARE with Yttrium-90 microspheres. Arterial perfusion (AP) derived from CT perfusion was measured in the entire tumor volume, and heterogeneity was analyzed voxel-wise by histogram analysis. Response to TARE was evaluated on follow-up imaging (median follow-up, 129 days) based on modified Response Evaluation Criteria in Solid Tumors (mRECIST). Results of histogram analysis and mean AP values of the tumor were compared between responders and non-responders. Receiver operating characteristics were calculated to determine the parameters’ ability to discriminate responders from non-responders.ResultsAccording to mRECIST, 8 patients (50 %) were responders and 8 (50 %) non-responders. Comparing responders and non-responders, the 50th and 75th percentile of AP derived from histogram analysis was significantly different [AP 43.8/54.3 vs. 27.6/34.3 mL min{sup −1} 100 mL{sup −1}); p < 0.05], while the mean AP of HCCs (43.5 vs. 27.9 mL min{sup −1} 100 mL{sup −1}; p > 0.05) was not. Further heterogeneity parameters from histogram analysis (skewness, coefficient of variation, and 25th percentile) did not differ between responders and non-responders (p > 0.05). If the cut-off for the 75th percentile was set to an AP of 37.5 mL min{sup −1} 100 mL{sup −1}, therapy response could be predicted with a sensitivity of 88 % (7/8) and specificity of 75 % (6/8).ConclusionVoxel-wise histogram analysis of pretreatment CT perfusion indicating tumor heterogeneity of HCC improves the pretreatment prediction of response to TARE.

  2. ADC histogram analysis for adrenal tumor histogram analysis of apparent diffusion coefficient in differentiating adrenal adenoma from pheochromocytoma.

    Science.gov (United States)

    Umanodan, Tomokazu; Fukukura, Yoshihiko; Kumagae, Yuichi; Shindo, Toshikazu; Nakajo, Masatoyo; Takumi, Koji; Nakajo, Masanori; Hakamada, Hiroto; Umanodan, Aya; Yoshiura, Takashi

    2017-04-01

    To determine the diagnostic performance of apparent diffusion coefficient (ADC) histogram analysis in diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiating adrenal adenoma from pheochromocytoma. We retrospectively evaluated 52 adrenal tumors (39 adenomas and 13 pheochromocytomas) in 47 patients (21 men, 26 women; mean age, 59.3 years; range, 16-86 years) who underwent DW 3.0T MRI. Histogram parameters of ADC (b-values of 0 and 200 [ADC200 ], 0 and 400 [ADC400 ], and 0 and 800 s/mm(2) [ADC800 ])-mean, variance, coefficient of variation (CV), kurtosis, skewness, and entropy-were compared between adrenal adenomas and pheochromocytomas, using the Mann-Whitney U-test. Receiver operating characteristic (ROC) curves for the histogram parameters were generated to differentiate adrenal adenomas from pheochromocytomas. Sensitivity and specificity were calculated by using a threshold criterion that would maximize the average of sensitivity and specificity. Variance and CV of ADC800 were significantly higher in pheochromocytomas than in adrenal adenomas (P < 0.001 and P = 0.001, respectively). With all b-value combinations, the entropy of ADC was significantly higher in pheochromocytomas than in adrenal adenomas (all P ≤ 0.001), and showed the highest area under the ROC curve among the ADC histogram parameters for diagnosing adrenal adenomas (ADC200 , 0.82; ADC400 , 0.87; and ADC800 , 0.92), with sensitivity of 84.6% and specificity of 84.6% (cutoff, ≤2.82) with ADC200 ; sensitivity of 89.7% and specificity of 84.6% (cutoff, ≤2.77) with ADC400 ; and sensitivity of 94.9% and specificity of 92.3% (cutoff, ≤2.67) with ADC800 . ADC histogram analysis of DW MRI can help differentiate adrenal adenoma from pheochromocytoma. 3 J. Magn. Reson. Imaging 2017;45:1195-1203. © 2016 International Society for Magnetic Resonance in Medicine.

  3. ADC histograms predict response to anti-angiogenic therapy in patients with recurrent high-grade glioma

    Energy Technology Data Exchange (ETDEWEB)

    Nowosielski, Martha; Tinkhauser, Gerd; Stockhammer, Guenther [Innsbruck Medical University, Department of Neurology, Innsbruck (Austria); Recheis, Wolfgang; Schocke, Michael; Gotwald, Thaddaeus [Innsbruck Medical University, Department of Radiology, Innsbruck (Austria); Goebel, Georg [Innsbruck Medical University, Department of Medical Statistics, Informatics and Health Economics, Innsbruck (Austria); Gueler, Oezguer [Innsbruck Medical University, 4D Visualization Laboratory, University Clinic of Oto-, Rhino- and Laryngology, Innsbruck (Austria); Kostron, Herwig [Innsbruck Medical University, Department of Neurosurgery, Innsbruck (Austria); Hutterer, Markus [Innsbruck Medical University, Department of Neurology, Innsbruck (Austria); Paracelsus Medical University Salzburg-Christian Doppler Hospital, Department of Neurology, Salzburg (Austria)

    2011-04-15

    The purpose of this study is to evaluate apparent diffusion coefficient (ADC) maps to distinguish anti-vascular and anti-tumor effects in the course of anti-angiogenic treatment of recurrent high-grade gliomas (rHGG) as compared to standard magnetic resonance imaging (MRI). This retrospective study analyzed ADC maps from diffusion-weighted MRI in 14 rHGG patients during bevacizumab/irinotecan (B/I) therapy. Applying image segmentation, volumes of contrast-enhanced lesions in T1 sequences and of hyperintense T2 lesions (hT2) were calculated. hT2 were defined as regions of interest (ROI) and registered to corresponding ADC maps (hT2-ADC). Histograms were calculated from hT2-ADC ROIs. Thereafter, histogram asymmetry termed ''skewness'' was calculated and compared to progression-free survival (PFS) as defined by the Response Assessment Neuro-Oncology (RANO) Working Group criteria. At 8-12 weeks follow-up, seven (50%) patients showed a partial response, three (21.4%) patients were stable, and four (28.6%) patients progressed according to RANO criteria. hT2-ADC histograms demonstrated statistically significant changes in skewness in relation to PFS at 6 months. Patients with increasing skewness (n = 11) following B/I therapy had significantly shorter PFS than did patients with decreasing or stable skewness values (n = 3, median percentage change in skewness 54% versus -3%, p = 0.04). In rHGG patients, the change in ADC histogram skewness may be predictive for treatment response early in the course of anti-angiogenic therapy and more sensitive than treatment assessment based solely on RANO criteria. (orig.)

  4. Histogram Modification and Wavelet Transform for High Performance Watermarking

    Directory of Open Access Journals (Sweden)

    Ying-Shen Juang

    2012-01-01

    Full Text Available This paper proposes a reversible watermarking technique for natural images. According to the similarity of neighbor coefficients’ values in wavelet domain, most differences between two adjacent pixels are close to zero. The histogram is built based on these difference statistics. As more peak points can be used for secret data hiding, the hiding capacity is improved compared with those conventional methods. Moreover, as the differences concentricity around zero is improved, the transparency of the host image can be increased. Experimental results and comparison show that the proposed method has both advantages in hiding capacity and transparency.

  5. Colorfulness Enhancement Using Image Classifier Based on Chroma-histogram

    Institute of Scientific and Technical Information of China (English)

    Moon-cheol KIM; Kyoung-won LIM

    2010-01-01

    The paper proposes a colorfulness enhancement of pictorial images using image classifier based on chroma histogram.This ap-poach firstly estimates strength of colorfulness of images and their types.With such determined information,the algorithm automatically adjusts image colorfulness for a better natural image look.With the help of an additional detection of skin colors and a pixel chroma adaptive local processing,the algorithm produces more natural image look.The algorithm performance had been tested with an image quality judgment experiment of 20 persons.The experimental result indicates a better image preference.

  6. Text-Independent Speaker Identification Using the Histogram Transform Model

    DEFF Research Database (Denmark)

    Ma, Zhanyu; Yu, Hong; Tan, Zheng-Hua;

    2017-01-01

    In this paper, we propose a novel probabilistic method for the task of text-independent speaker identification (SI). In order to capture the dynamic information during SI, we design a super-MFCCs features by cascading three neighboring Mel-frequency Cepstral coefficients (MFCCs) frames together....... These super-MFCC vectors are utilized for probabilistic model training such that the speaker’s characteristics can be sufficiently captured. The probability density function (PDF) of the aforementioned super-MFCCs features is estimated by the recently proposed histogram transform (HT) method. To recedes...

  7. An Improved Double-Threshold Method Based on Gradient Histogram

    Institute of Scientific and Technical Information of China (English)

    YANG Shen; CHEN Shu-zhen; ZHANG Bing

    2004-01-01

    This paper analyzes the characteristics of the output gradient histogram and shortages of several traditional automatic threshold methods in order to segment the gradient image better. Then an improved double-threshold method is proposed, which is combined with the method of maximum classes variance, estimating-area method and double-threshold method. This method can automatically select two different thresholds to segment gradient images. The computer simulation is performed on the traditional methods and this algorithm and proves that this method can get satisfying result.

  8. Phase structure of finite density QCD with a histogram method

    CERN Document Server

    Nakagawa, Yoshiyuki; Ejiri, Shinji; Hatsuda, Tetsuo; Kanaya, Kazuyuki; Ohno, Hiroshi; Saito, Hana; Umeda, Takashi

    2012-01-01

    We study the phase structure of QCD in the $T-\\mu$ plane using a histogram method and the reweighting technique by performing phase quenched simulations of two-flavor QCD with RG-improved gauge action and O($a$) improved Wilson quark action. Taking the effects of the complex phase of the quark determinant using the cumulant expansion method, we calculate the probability distribution function of plaquette and phase-quenched determinant as a function of $T$ and $\\mu$. We discuss the order of the QCD phase transition consulting the shape of the probability distribution function.

  9. Efficient local statistical analysis via integral histograms with discrete wavelet transform.

    Science.gov (United States)

    Lee, Teng-Yok; Shen, Han-Wei

    2013-12-01

    Histograms computed from local regions are commonly used in many visualization applications, and allowing the user to query histograms interactively in regions of arbitrary locations and sizes plays an important role in feature identification and tracking. Computing histograms in regions with arbitrary location and size, nevertheless, can be time consuming for large data sets since it involves expensive I/O and scan of data elements. To achieve both performance- and storage-efficient query of local histograms, we present a new algorithm called WaveletSAT, which utilizes integral histograms, an extension of the summed area tables (SAT), and discrete wavelet transform (DWT). Similar to SAT, an integral histogram is the histogram computed from the area between each grid point and the grid origin, which can be be pre-computed to support fast query. Nevertheless, because one histogram contains multiple bins, it will be very expensive to store one integral histogram at each grid point. To reduce the storage cost for large integral histograms, WaveletSAT treats the integral histograms of all grid points as multiple SATs, each of which can be converted into a sparse representation via DWT, allowing the reconstruction of axis-aligned region histograms of arbitrary sizes from a limited number of wavelet coefficients. Besides, we present an efficient wavelet transform algorithm for SATs that can operate on each grid point separately in logarithmic time complexity, which can be extended to parallel GPU-based implementation. With theoretical and empirical demonstration, we show that WaveletSAT can achieve fast preprocessing and smaller storage overhead than the conventional integral histogram approach with close query performance.

  10. Variational Histogram Equalization for Single Color Image Defogging

    Directory of Open Access Journals (Sweden)

    Li Zhou

    2016-01-01

    Full Text Available Foggy images taken in the bad weather inevitably suffer from contrast loss and color distortion. Existing defogging methods merely resort to digging out an accurate scene transmission in ignorance of their unpleasing distortion and high complexity. Different from previous works, we propose a simple but powerful method based on histogram equalization and the physical degradation model. By revising two constraints in a variational histogram equalization framework, the intensity component of a fog-free image can be estimated in HSI color space, since the airlight is inferred through a color attenuation prior in advance. To cut down the time consumption, a general variation filter is proposed to obtain a numerical solution from the revised framework. After getting the estimated intensity component, it is easy to infer the saturation component from the physical degradation model in saturation channel. Accordingly, the fog-free image can be restored with the estimated intensity and saturation components. In the end, the proposed method is tested on several foggy images and assessed by two no-reference indexes. Experimental results reveal that our method is relatively superior to three groups of relevant and state-of-the-art defogging methods.

  11. Accelerated weight histogram method for exploring free energy landscapes

    Science.gov (United States)

    Lindahl, V.; Lidmar, J.; Hess, B.

    2014-07-01

    Calculating free energies is an important and notoriously difficult task for molecular simulations. The rapid increase in computational power has made it possible to probe increasingly complex systems, yet extracting accurate free energies from these simulations remains a major challenge. Fully exploring the free energy landscape of, say, a biological macromolecule typically requires sampling large conformational changes and slow transitions. Often, the only feasible way to study such a system is to simulate it using an enhanced sampling method. The accelerated weight histogram (AWH) method is a new, efficient extended ensemble sampling technique which adaptively biases the simulation to promote exploration of the free energy landscape. The AWH method uses a probability weight histogram which allows for efficient free energy updates and results in an easy discretization procedure. A major advantage of the method is its general formulation, making it a powerful platform for developing further extensions and analyzing its relation to already existing methods. Here, we demonstrate its efficiency and general applicability by calculating the potential of mean force along a reaction coordinate for both a single dimension and multiple dimensions. We make use of a non-uniform, free energy dependent target distribution in reaction coordinate space so that computational efforts are not wasted on physically irrelevant regions. We present numerical results for molecular dynamics simulations of lithium acetate in solution and chignolin, a 10-residue long peptide that folds into a β-hairpin. We further present practical guidelines for setting up and running an AWH simulation.

  12. Accelerated weight histogram method for exploring free energy landscapes

    Energy Technology Data Exchange (ETDEWEB)

    Lindahl, V.; Lidmar, J.; Hess, B. [Department of Theoretical Physics and Swedish e-Science Research Center, KTH Royal Institute of Technology, 10691 Stockholm (Sweden)

    2014-07-28

    Calculating free energies is an important and notoriously difficult task for molecular simulations. The rapid increase in computational power has made it possible to probe increasingly complex systems, yet extracting accurate free energies from these simulations remains a major challenge. Fully exploring the free energy landscape of, say, a biological macromolecule typically requires sampling large conformational changes and slow transitions. Often, the only feasible way to study such a system is to simulate it using an enhanced sampling method. The accelerated weight histogram (AWH) method is a new, efficient extended ensemble sampling technique which adaptively biases the simulation to promote exploration of the free energy landscape. The AWH method uses a probability weight histogram which allows for efficient free energy updates and results in an easy discretization procedure. A major advantage of the method is its general formulation, making it a powerful platform for developing further extensions and analyzing its relation to already existing methods. Here, we demonstrate its efficiency and general applicability by calculating the potential of mean force along a reaction coordinate for both a single dimension and multiple dimensions. We make use of a non-uniform, free energy dependent target distribution in reaction coordinate space so that computational efforts are not wasted on physically irrelevant regions. We present numerical results for molecular dynamics simulations of lithium acetate in solution and chignolin, a 10-residue long peptide that folds into a β-hairpin. We further present practical guidelines for setting up and running an AWH simulation.

  13. Lean histogram of oriented gradients features for effective eye detection

    Science.gov (United States)

    Sharma, Riti; Savakis, Andreas

    2015-11-01

    Reliable object detection is very important in computer vision and robotics applications. The histogram of oriented gradients (HOG) is established as one of the most popular hand-crafted features, which along with support vector machine (SVM) classification provides excellent performance for object recognition. We investigate dimensionality deduction on HOG features in combination with SVM classifiers to obtain efficient feature representation and improved classification performance. In addition to lean HOG features, we explore descriptors resulting from dimensionality reduction on histograms of binary descriptors. We consider three-dimensionality reduction techniques: standard principal component analysis, random projections, a computationally efficient linear mapping that is data independent, and locality preserving projections (LPP), which learns the manifold structure of the data. Our methods focus on the application of eye detection and were tested on an eye database created using the BioID and FERET face databases. Our results indicate that manifold learning is beneficial to classification utilizing HOG features. To demonstrate the broader usefulness of lean HOG features for object class recognition, we evaluated our system's classification performance on the CalTech-101 dataset with favorable outcomes.

  14. The Transition Matrix in Flat-histogram Sampling

    Science.gov (United States)

    Brown, Gregory; Eisenbach, M.; Li, Y. W.; Stocks, G. M.; Nicholson, D. M.; Odbadrakh, Kh.; Rikvold, P. A.

    2015-03-01

    Calculating the thermodynamic density of states (DOS) via flat-histogram sampling is a powerful numerical method for characterizing the temperature-dependent properties of materials. Since the calculated DOS is refined directly from the statistics of the sampling, methods of accelerating the sampling, e.g. through windowing and slow forcing, skew the resulting DOS. Calculating the infinite-temperature transition matrix during the flat-histogram sampling decouples the sampling from estimating the DOS, and allows the techniques of Transition Matrix Monte Carlo to be applied. This enables the calculation of the properties for very large system sizes and thus finite-size scaling analysis of the specific heat, magnetic susceptibility, and cumulant crossings at critical points. We discuss these developments in the context of models for magnetocaloric and spin-crossover materials. This work was performed at the Oak Ridge National Laboratory, which is managed by UT-Battelle for the U.S. Department of Energy. It was sponsored by the U.S. Department of Energy, Office of Basic Energy Sciences, Office of Advanced Scientific Computing Research, and the Oak Ridge Leadership Computing Facility. PAR is supported by the National Science Foundation.

  15. Adaptive edge histogram descriptor for landmine detection using GPR

    Science.gov (United States)

    Frigui, Hichem; Fadeev, Aleksey; Karem, Andrew; Gader, Paul

    2009-05-01

    The Edge Histogram Detector (EHD) is a landmine detection algorithm for sensor data generated by ground penetrating radar (GPR). It uses edge histograms for feature extraction and a possibilistic K-Nearest Neighbors (K-NN) rule for confidence assignment. To reduce the computational complexity of the EHD and improve its generalization, the K-NN classifier uses few prototypes that can capture the variations of the signatures within each class. Each of these prototypes is assigned a label in the class of mines and a label in the class of clutter to capture its degree of sharing among these classes. The EHD has been tested extensively. It has demonstrated excellent performance on large real world data sets, and has been implemented in real time versions in hand-held and vehicle mounted GPR. In this paper, we propose two modifications to the EHD to improve its performance and adaptability. First, instead of using a fixed threshold to decide if the edge at a certain location is strong enough, we use an adaptive threshold that is learned from the background surrounding the target. This modification makes the EHD more adaptive to different terrains and to mines buried at different depths. Second, we introduce an additional training component that tunes the prototype features and labels to different environments. Results on large and diverse GPR data collections show that the proposed adaptive EHD outperforms the baseline EHD. We also show that the edge threshold can vary significantly according to the edge type, alarm depth, and soil conditions.

  16. Microcanonical thermostatistics analysis without histograms: cumulative distribution and Bayesian approaches

    CERN Document Server

    Alves, Nelson A; Rizzi, Leandro G

    2015-01-01

    Microcanonical thermostatistics analysis has become an important tool to reveal essential aspects of phase transitions in complex systems. An efficient way to estimate the microcanonical inverse temperature $\\beta(E)$ and the microcanonical entropy $S(E)$ is achieved with the statistical temperature weighted histogram analysis method (ST-WHAM). The strength of this method lies on its flexibility, as it can be used to analyse data produced by algorithms with generalised sampling weights. However, for any sampling weight, ST-WHAM requires the calculation of derivatives of energy histograms $H(E)$, which leads to non-trivial and tedious binning tasks for models with continuous energy spectrum such as those for biomolecular and colloidal systems. Here, we discuss two alternative methods that avoid the need for such energy binning to obtain continuous estimates for $H(E)$ in order to evaluate $\\beta(E)$ by using ST-WHAM: (i) a series expansion to estimate probability densities from the empirical cumulative distrib...

  17. Chi-Squared Distance Metric Learning for Histogram Data

    Directory of Open Access Journals (Sweden)

    Wei Yang

    2015-01-01

    Full Text Available Learning a proper distance metric for histogram data plays a crucial role in many computer vision tasks. The chi-squared distance is a nonlinear metric and is widely used to compare histograms. In this paper, we show how to learn a general form of chi-squared distance based on the nearest neighbor model. In our method, the margin of sample is first defined with respect to the nearest hits (nearest neighbors from the same class and the nearest misses (nearest neighbors from the different classes, and then the simplex-preserving linear transformation is trained by maximizing the margin while minimizing the distance between each sample and its nearest hits. With the iterative projected gradient method for optimization, we naturally introduce the l2,1 norm regularization into the proposed method for sparse metric learning. Comparative studies with the state-of-the-art approaches on five real-world datasets verify the effectiveness of the proposed method.

  18. Illumination Invariant Face Recognition using SQI and Weighted LBP Histogram

    Directory of Open Access Journals (Sweden)

    Mohsen Biglari

    2014-12-01

    Full Text Available Face recognition under uneven illumination is still an open problem. One of the main challenges in real-world face recognition systems is illumination variation. In this paper, a novel illumination invariant face recognition approach base on Self Quotient Image (SQI and weighted Local Binary Pattern (WLBP histogram has been proposed. In this system, the performance of the system is increased by using different sigma values of SQI for training and testing. Furthermore, using two multi-region uniform LBP operators for feature extraction simultaneously, made the system more robust to illumination variation. This approach gathers information of the image in different local and global levels. The weighted Chi square statistic is used for histogram comparison and NN (1-NN is used as classifier. The weighted approach emphasizes on the more important regions in the faces. The proposed approach is compared with some new and traditional methods like QI, SQI, QIR, MQI, DMQI, DSFQI, PCA and LDA on Yale face database B and CMU-PIE database. The experimental results show that the proposed method outperforms other tested methods.

  19. Visual Contrast Enhancement Algorithm Based on Histogram Equalization

    Directory of Open Access Journals (Sweden)

    Chih-Chung Ting

    2015-07-01

    Full Text Available Image enhancement techniques primarily improve the contrast of an image to lend it a better appearance. One of the popular enhancement methods is histogram equalization (HE because of its simplicity and effectiveness. However, it is rarely applied to consumer electronics products because it can cause excessive contrast enhancement and feature loss problems. These problems make the images processed by HE look unnatural and introduce unwanted artifacts in them. In this study, a visual contrast enhancement algorithm (VCEA based on HE is proposed. VCEA considers the requirements of the human visual perception in order to address the drawbacks of HE. It effectively solves the excessive contrast enhancement problem by adjusting the spaces between two adjacent gray values of the HE histogram. In addition, VCEA reduces the effects of the feature loss problem by using the obtained spaces. Furthermore, VCEA enhances the detailed textures of an image to generate an enhanced image with better visual quality. Experimental results show that images obtained by applying VCEA have higher contrast and are more suited to human visual perception than those processed by HE and other HE-based methods.

  20. Quantitatively assessed CT imaging measures of pulmonary interstitial pneumonia: Effects of reconstruction algorithms on histogram parameters

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, Hisanobu [Department of Radiology, Hyogo Kaibara Hospital, 5208-1 Kaibara, Kaibara-cho, Tanba 669-3395 (Japan)], E-mail: hisanobu19760104@yahoo.co.jp; Ohno, Yoshiharu [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)], E-mail: yosirad@kobe-u.ac.jp; Yamazaki, Youichi [Department of Medical Physics and Engineering, Faculty of Health Sciences, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita 565-0871 (Japan)], E-mail: y.yamazk@sahs.med.osaka-u.ac.jp; Nogami, Munenobu [Division of PET, Institute of Biomedical Research and Innovation, 2-2 MInamimachi, Minatojima, Chu0-ku, Kobe 650-0047 (Japan)], E-mail: aznogami@fbri.org; Kusaka, Akiko [Division of Radiology, Kobe University Hospital, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)], E-mail: a.kusaka@hosp.kobe-u.ac.jp; Murase, Kenya [Department of Medical Physics and Engineering, Faculty of Health Sciences, Graduate School of Medicine, Osaka University, 1-7 Yamadaoka, Suita 565-0871 (Japan)], E-mail: murase@sahs.med.osaka-u.ac.jp; Sugimura, Kazuro [Department of Radiology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe 650-0017 (Japan)], E-mail: sugimura@med.kobe-u.ac.jp

    2010-04-15

    This study aimed the influences of reconstruction algorithm for quantitative assessments in interstitial pneumonia patients. A total of 25 collagen vascular disease patients (nine male patients and 16 female patients; mean age, 57.2 years; age range 32-77 years) underwent thin-section MDCT examinations, and MDCT data were reconstructed with three kinds of reconstruction algorithm (two high-frequencies [A and B] and one standard [C]). In reconstruction algorithm B, the effect of low- and middle-frequency space was suppressed compared with reconstruction algorithm A. As quantitative CT parameters, kurtosis, skewness, and mean lung density (MLD) were acquired from a frequency histogram of the whole lung parenchyma in each reconstruction algorithm. To determine the difference of quantitative CT parameters affected by reconstruction algorithms, these parameters were compared statistically. To determine the relationships with the disease severity, these parameters were correlated with PFTs. In the results, all the histogram parameters values had significant differences each other (p < 0.0001) and those of reconstruction algorithm C were the highest. All MLDs had fair or moderate correlation with all parameters of PFT (-0.64 < r < -0.45, p < 0.05). Though kurtosis and skewness in high-frequency reconstruction algorithm A had significant correlations with all parameters of PFT (-0.61 < r < -0.45, p < 0.05), there were significant correlations only with diffusing capacity of carbon monoxide (DLco) and total lung capacity (TLC) in reconstruction algorithm C and with forced expiratory volume in 1 s (FEV1), DLco and TLC in reconstruction algorithm B. In conclusion, reconstruction algorithm has influence to quantitative assessments on chest thin-section MDCT examination in interstitial pneumonia patients.

  1. Implementing a 3D histogram version of the Energy-Test in ROOT

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, E.O., E-mail: cohen.erez7@gmail.com [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Reid, I.D., E-mail: ivan.reid@brunel.ac.uk [College of Engineering, Design and Physical Sciences, Brunel University London, Uxbridge UB8 3PH (United Kingdom); Piasetzky, E., E-mail: eip@tauphy.tau.ac.il [School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel)

    2016-08-21

    Comparing simulation and data histograms is of interest in nuclear and particle physics experiments; however, the leading three-dimensional histogram comparison tool available in ROOT, the 3D Kolmogorov–Smirnov test, exhibits shortcomings. Throughout the following, we present and discuss the implementation of an alternative comparison test for three-dimensional histograms, based on the Energy-Test by Aslan and Zech. The software package can be found at (http://www-nuclear.tau.ac.il/ecohen/).

  2. Hand Vein Images Enhancement Based on Local Gray-level Information Histogram

    OpenAIRE

    Jun Wang; Guoqing Wang; Ming Li; Wenkai Du; Wenhui Yu

    2015-01-01

    Based on the Histogram equalization theory, this paper presents a novel concept of histogram to realize the contrast enhancement of hand vein images, avoiding the lost of topological vein structure or importing the fake vein information. Firstly, we propose the concept of gray-level information histogram, the fundamental characteristic of which is that the amplitudes of the components can objectively reflect the contribution of the gray levels and information to the representation of image in...

  3. A CMOS VLSI IC for real-time opto-electronic two-dimensional histogram generation

    OpenAIRE

    1993-01-01

    Approved for public release; distribution is unlimited. Histogram generation, a standard image processing operation, is a record of the intensity distribution in the image. Histogram generation has straight forward implementations on digital computers using high level languages. A prototype of an optical-electronic histogram generator has been designed and tested for 1-D objects using wirewrapped MSI TTL components. The system has shown to be fairly modular in design. The aspects of the ex...

  4. Feasibility of CBCT-based proton dose calculation using a histogram-matching algorithm in proton beam therapy.

    Science.gov (United States)

    Arai, Kazuhiro; Kadoya, Noriyuki; Kato, Takahiro; Endo, Hiromitsu; Komori, Shinya; Abe, Yoshitomo; Nakamura, Tatsuya; Wada, Hitoshi; Kikuchi, Yasuhiro; Takai, Yoshihiro; Jingu, Keiichi

    2017-01-01

    The aim of this study was to confirm On-Board Imager cone-beam computed tomography (CBCT) using the histogram-matching algorithm as a useful method for proton dose calculation. We studied one head and neck phantom, one pelvic phantom, and ten patients with head and neck cancer treated using intensity-modulated radiation therapy (IMRT) and proton beam therapy. We modified Hounsfield unit (HU) values of CBCT and generated two modified CBCTs (mCBCT-RR, mCBCT-DIR) using the histogram-matching algorithm: modified CBCT with rigid registration (mCBCT-RR) and that with deformable image registration (mCBCT-DIR). Rigid and deformable image registration were applied to match the CBCT to planning CT. To evaluate the accuracy of the proton dose calculation, we compared dose differences in the dosimetric parameters (D2% and D98%) for clinical target volume (CTV) and planning target volume (PTV). We also evaluated the accuracy of the dosimetric parameters (Dmean and D2%) for some organs at risk, and compared the proton ranges (PR) between planning CT (reference) and CBCT or mCBCTs, and the gamma passing rates of CBCT and mCBCTs. For patients, the average dose and PR differences of mCBCTs were smaller than those of CBCT. Additionally, the average gamma passing rates of mCBCTs were larger than those of CBCT (e.g., 94.1±3.5% in mCBCT-DIR vs. 87.8±7.4% in CBCT). We evaluated the accuracy of the proton dose calculation in CBCT and mCBCTs for two phantoms and ten patients. Our results showed that HU modification using the histogram-matching algorithm could improve the accuracy of the proton dose calculation.

  5. Evaluation of low-grade glioma structural changes after chemotherapy using DTI-based histogram analysis and functional diffusion maps

    Energy Technology Data Exchange (ETDEWEB)

    Castellano, Antonella; Iadanza, Antonella; Falini, Andrea [San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Neuroradiology Unit and CERMAC, Milano (Italy); Donativi, Marina [University of Salento, Department of Mathematics and Physics ' ' Ennio De Giorgi' ' and A.D.A.M. (Advanced Data Analysis in Medicine), Lecce (Italy); Ruda, Roberta; Bertero, Luca; Soffietti, Riccardo [University of Torino, Department of Neuro-oncology, Turin (Italy); De Nunzio, Giorgio [University of Salento, Department of Mathematics and Physics ' ' Ennio De Giorgi' ' and A.D.A.M. (Advanced Data Analysis in Medicine), Lecce (Italy); INFN (National Institute of Nuclear Physics), Lecce (Italy); Riva, Marco; Bello, Lorenzo [Universita degli Studi di Milano, Milan, and Humanitas Research Hospital, Department of Medical Biotechnology and Translational Medicine, Rozzano, MI (Italy); Rucco, Matteo [University of Camerino, School of Science and Technology, Computer Science Division, Camerino, MC (Italy)

    2016-05-15

    To explore the role of diffusion tensor imaging (DTI)-based histogram analysis and functional diffusion maps (fDMs) in evaluating structural changes of low-grade gliomas (LGGs) receiving temozolomide (TMZ) chemotherapy. Twenty-one LGG patients underwent 3T-MR examinations before and after three and six cycles of dose-dense TMZ, including 3D-fluid-attenuated inversion recovery (FLAIR) sequences and DTI (b = 1000 s/mm{sup 2}, 32 directions). Mean diffusivity (MD), fractional anisotropy (FA), and tensor-decomposition DTI maps (p and q) were obtained. Histogram and fDM analyses were performed on co-registered baseline and post-chemotherapy maps. DTI changes were compared with modifications of tumour area and volume [according to Response Assessment in Neuro-Oncology (RANO) criteria], and seizure response. After three cycles of TMZ, 20/21 patients were stable according to RANO criteria, but DTI changes were observed in all patients (Wilcoxon test, P ≤ 0.03). After six cycles, DTI changes were more pronounced (P ≤ 0.005). Seventy-five percent of patients had early seizure response with significant improvement of DTI values, maintaining stability on FLAIR. Early changes of the 25th percentiles of p and MD predicted final volume change (R{sup 2} = 0.614 and 0.561, P < 0.0005, respectively). TMZ-related changes were located mainly at tumour borders on p and MD fDMs. DTI-based histogram and fDM analyses are useful techniques to evaluate the early effects of TMZ chemotherapy in LGG patients. (orig.)

  6. Maximum-likelihood fits to histograms for improved parameter estimation

    CERN Document Server

    Fowler, Joseph W

    2013-01-01

    Straightforward methods for adapting the familiar chi^2 statistic to histograms of discrete events and other Poisson distributed data generally yield biased estimates of the parameters of a model. The bias can be important even when the total number of events is large. For the case of estimating a microcalorimeter's energy resolution at 6 keV from the observed shape of the Mn K-alpha fluorescence spectrum, a poor choice of chi^2 can lead to biases of at least 10% in the estimated resolution when up to thousands of photons are observed. The best remedy is a Poisson maximum-likelihood fit, through a simple modification of the standard Levenberg-Marquardt algorithm for chi^2 minimization. Where the modification is not possible, another approach allows iterative approximation of the maximum-likelihood fit.

  7. Fast Graph Partitioning Active Contours for Image Segmentation Using Histograms

    Directory of Open Access Journals (Sweden)

    Nath SumitK

    2009-01-01

    Full Text Available Abstract We present a method to improve the accuracy and speed, as well as significantly reduce the memory requirements, for the recently proposed Graph Partitioning Active Contours (GPACs algorithm for image segmentation in the work of Sumengen and Manjunath (2006. Instead of computing an approximate but still expensive dissimilarity matrix of quadratic size, , for a 2D image of size and regular image tiles of size , we use fixed length histograms and an intensity-based symmetric-centrosymmetric extensor matrix to jointly compute terms associated with the complete dissimilarity matrix. This computationally efficient reformulation of GPAC using a very small memory footprint offers two distinct advantages over the original implementation. It speeds up convergence of the evolving active contour and seamlessly extends performance of GPAC to multidimensional images.

  8. TSimpleAnalysis: histogramming many trees in parallel

    CERN Document Server

    Giommi, Luca

    2016-01-01

    I worked inside the ROOT team of EP-SFT group. My project focuses on writing a ROOT class that has the aim of creating histograms from a TChain. The name of the class is TSimpleAnalysis and it is already integrated in ROOT. The work that I have done was to write the source, the header le of the class and also a python script, that allows to the user to use the class through the command line. This represents a great improvement respect to the usual user code that counts lines and lines of code to do the same thing. (Link for the class: https://root.cern.ch/doc/master/classTSimpleAnalysis.html)

  9. HISTOGRAM TECHNIQUE WITH PIXEL INDICATOR FOR HIGH FIDELITY STEGANOGRAPHY

    Directory of Open Access Journals (Sweden)

    V.Meiamai

    2013-06-01

    Full Text Available In this current world of increasing technology trends and the “internet age”, the security of our personal information has become more important than it has ever been there are media reports ofidentity theft and fraud and the numbers of innocent victims are increasing exponentially. Steganography plays an important role in preventing such information destruction by implementing a principle ofimperceptible secret sharing. By this security can be established by clearly embedding data in such a way that the quality of the image is not affected. The existing methodology prevailing now is based on pixel indicator and number of data to be embedded is by pixel value differencing technique. A limitation in this methodology is that the pixel indicator channel is manually selected. The proposed methodology uses pixel indicator channel which is decided using histogram technique and the secret message file has to be embedded in the plane which has the highest color intensity.

  10. Robust Reversible Watermarking Using Integer Wavelet Transform and Histogram Shifting

    Directory of Open Access Journals (Sweden)

    Deepali T. Biradar

    2014-02-01

    Full Text Available Along with the rapid development of multimedia technology, digital image is becoming an important vector of network information communication. But meanwhile, the security and reliability of the information are more and more unable to be guaranteed. Images often suffer certain degree destruction in the transmission process which influences the correct extraction of hiding information as well as the image authentication. As a good digital media copyright protection method, information hiding technology already has become a research hotspot. In medical, legal and some other sensitive fields, however, slightly modify to carrier image may cause irreparable damage. Consequently, robust reversible watermarking technology seems more important. However, conventional RRW methods have some drawbacks like- unsatisfactory reversibility, limited robustness, and invisibility for watermarked images. Therefore, it is necessary to have a method to address these problems. So we proposed a novel method using IWT, Histogram Shifting and clustering for watermark embedding and extraction.

  11. Quantitative analysis of 3 dimensional volumetry and histogram of thyroid gland on neck computed tomography for patients with Hashimoto's thyroiditis

    Energy Technology Data Exchange (ETDEWEB)

    Nam, In Chul; Lee, Kwang Hwi; Ryu, Ji Hwa; Kim, Ok Hwa; Kim, Seung Ho; Baek, Hye Jin; Lee, Ye Daum; Kim, Tae Nyun; Kim, Mi Kyung [Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of); Kim, Seon Jeong [Dept. of Radiology, Myongji Hospital, Seonam University College of Medicine, Goyang (Korea, Republic of); Kim, Sung Mok [Dept. of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2015-12-15

    To analyze three-dimensional (3D) volume and histogram of thyroid gland on neck computed tomography (CT) for patients with Hashimoto's thyroiditis. A total of 121 subjects who underwent neck CT between March 2013 and February 2014 were included in this study. These subjects were divided into the following two groups: 1) control group (n = 76); 2) Hashimoto's thyroiditis group (n = 45). Non-enhanced and contrast-enhanced CT images were obtained. On contrast-enhanced images, the 3D volume of thyroid gland was semi-automatically calculated. On CT histogram, attenuation number, mean, median, standard deviation (SD), and coefficient of variation (CV) of thyroid gland were calculated. These values were compared between the two groups. Total 3D volume of thyroid gland was 14.9 ± 4.8 cm{sup 3} in the control group, which was significantly (p = 0.002) lower than that (19.2 ± 8 cm{sup 3}) in the Hashimoto's thyroiditis group. On CT histogram, the mean, median, SD, and CV of thyroid gland on non-enhanced images were 95.8, 99.3, 21.7, and 0.226, respectively, in the control group and 72.2, 72.6, 19.6, and 0.28 in the Hashimoto's thyroiditis group (p < 0.05). Histogram parameters on contrast-enhanced images were not significantly (p > 0.05) different. Median at cut-off value of 83 revealed the largest Az value (Az: 0.905; 95% confidence interval: 0.837-0.951; sensitivity: 84.4%; specificity: 85.5%). The Hashimoto's thyroiditis group had larger volume but lower CT attenuation number with more prominent parenchymal heterogeneity of thyroid gland than the control group.

  12. Classification of amyloid status using machine learning with histograms of oriented 3D gradients

    Directory of Open Access Journals (Sweden)

    Liam Cattell

    2016-01-01

    Full Text Available Brain amyloid burden may be quantitatively assessed from positron emission tomography imaging using standardised uptake value ratios. Using these ratios as an adjunct to visual image assessment has been shown to improve inter-reader reliability, however, the amyloid positivity threshold is dependent on the tracer and specific image regions used to calculate the uptake ratio. To address this problem, we propose a machine learning approach to amyloid status classification, which is independent of tracer and does not require a specific set of regions of interest. Our method extracts feature vectors from amyloid images, which are based on histograms of oriented three-dimensional gradients. We optimised our method on 133 18F-florbetapir brain volumes, and applied it to a separate test set of 131 volumes. Using the same parameter settings, we then applied our method to 209 11C-PiB images and 128 18F-florbetaben images. We compared our method to classification results achieved using two other methods: standardised uptake value ratios and a machine learning method based on voxel intensities. Our method resulted in the largest mean distances between the subjects and the classification boundary, suggesting that it is less likely to make low-confidence classification decisions. Moreover, our method obtained the highest classification accuracy for all three tracers, and consistently achieved above 96% accuracy.

  13. Uranium in US surface, ground, and domestic waters. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Drury, J.S.; Reynolds, S.; Owen, P.T.; Ross, R.H.; Ensminger, J.T.

    1981-04-01

    The report Uranium in US Surface, Ground, and Domestic Waters comprises four volumes. Volumes 2, 3, and 4 contain data characterizing the location, sampling date, type, use, and uranium conentrations of 89,994 individual samples presented in tabular form. The tabular data in volumes 2, 3, and 4 are summarized in volume 1 in narrative form and with maps and histograms.

  14. Modified Dynamic Histogram Equalization For Image Enhancement in Gray-scale Images

    Directory of Open Access Journals (Sweden)

    R.M. Meenal

    2012-12-01

    Full Text Available To improve the quality of digital images captured in low light environment from consumer electronics devices like cell phone cameras, Modified Dynamic Histogram Equalization (MDHE is proposed. Initially, the proposed method divides the histogram into two sub-histograms based on median. Then 2nd subhistogram is further divided into two sub-histograms based on median of it. The resultant sub-histograms are clipped according to the mean of the intensity occurrence of the input image independently. The new dynamic range is allocated to each sub-histogram. The first sub-histogram is equalized independently using Global Histogram Equalization (GHE method. GHE is found the better enhancement for lower gray-levels and suffers over-enhancement problem in higher gray-level. The proposed method utilizes the advantages of both GHE and QDHE. This method utilizes GHE for enhancing lower gray-levels and QDHE for enhancing higher gray-levels. Simulation results show that the proposed method yields better quality images in terms of Discrete Entropy value compared with other conventional methods.

  15. Hand Vein Images Enhancement Based on Local Gray-level Information Histogram

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2015-06-01

    Full Text Available Based on the Histogram equalization theory, this paper presents a novel concept of histogram to realize the contrast enhancement of hand vein images, avoiding the lost of topological vein structure or importing the fake vein information. Firstly, we propose the concept of gray-level information histogram, the fundamental characteristic of which is that the amplitudes of the components can objectively reflect the contribution of the gray levels and information to the representation of image information. Then, we propose the histogram equalization method that is composed of an automatic histogram separation module and an intensity transformation module, and the histogram separation module is a combination of the proposed prompt multiple threshold procedure and an optimum peak signal-to-noise (PSNR calculation to separate the histogram into small-scale detail, the use of the intensity transformation module can enhance the vein images with vein topological structure and gray information preservation for each generated sub-histogram. Experimental results show that the proposed method can achieve extremely good contrast enhancement effect.

  16. Symbol recognition via statistical integration of pixel-level constraint histograms: a new descriptor.

    Science.gov (United States)

    Yang, Su

    2005-02-01

    A new descriptor for symbol recognition is proposed. 1) A histogram is constructed for every pixel to figure out the distribution of the constraints among the other pixels. 2) All the histograms are statistically integrated to form a feature vector with fixed dimension. The robustness and invariance were experimentally confirmed.

  17. A Method for Evaluating the Magnetic Field Homogeneity of a Radiofrequency Coil by Its Field Histogram

    Science.gov (United States)

    Yang, Q. X.; Li, S. H.; Smith, M. B.

    The magnetic field homogeneity of a radiofrequency coil is very important in both magnetic resonance imaging and spectroscopy. In this report, a method is proposed for quantitatively evaluating the RF magnetic field homogeneity from its histogram, which is obtained by either experimental measurement or theoretical calculation. The experimental histogram and theoretical histogram can be compared directly to verify the theoretical findings. The RF field homogeneities of the bird-cage coil, slotted-tube resonator, cosine wire coil, and a new radial plate coil design were evaluated using this method. The results showed that the experimental histograms and the corresponding theoretical histograms are consistent. This method provides an easy and sensitive way of evaluating the magnetic field homogeneity and facilitates the design and evaluation of new RF coil configurations.

  18. An automated detection of glaucoma using histogram features

    Institute of Scientific and Technical Information of China (English)

    Karthikeyan; Sakthivel; Rengarajan; Narayanan

    2015-01-01

    Glaucoma is a chronic and progressive optic neurodegenerative disease leading to vision deterioration and in most cases produce increased pressure within the eye. This is due to the backup of fluid in the eye; it causes damage to the optic nerve. Hence, early detection diagnosis and treatment of an eye help to prevent the loss of vision. In this paper, a novel method is proposed for the early detection of glaucoma using a combination of magnitude and phase features from the digital fundus images. Local binary patterns(LBP) and Daugman’s algorithm are used to perform the feature set extraction.The histogram features are computed for both the magnitude and phase components. The Euclidean distance between the feature vectors are analyzed to predict glaucoma. The performance of the proposed method is compared with the higher order spectra(HOS)features in terms of sensitivity, specificity, classification accuracy and execution time. The proposed system results 95.45% output for sensitivity, specificity and classification. Also, the execution time for the proposed method takes lesser time than the existing method which is based on HOS features. Hence, the proposed system is accurate, reliable and robust than the existing approach to predict the glaucoma features.

  19. Extended census transform histogram for land-use scene classification

    Science.gov (United States)

    Yuan, Baohua; Li, Shijin

    2017-04-01

    With the popular use of high-resolution satellite images, more and more research efforts have been focused on land-use scene classification. In scene classification, effective visual features can significantly boost the final performance. As a typical texture descriptor, the census transform histogram (CENTRIST) has emerged as a very powerful tool due to its effective representation ability. However, the most prominent limitation of CENTRIST is its small spatial support area, which may not necessarily be adept at capturing the key texture characteristics. We propose an extended CENTRIST (eCENTRIST), which is made up of three subschemes in a greater neighborhood scale. The proposed eCENTRIST not only inherits the advantages of CENTRIST but also encodes the more useful information of local structures. Meanwhile, multichannel eCENTRIST, which can capture the interactions from multichannel images, is developed to obtain higher categorization accuracy rates. Experimental results demonstrate that the proposed method can achieve competitive performance when compared to state-of-the-art methods.

  20. Histogram Planimetry Method for the Measurement of Irregular Wounds.

    Science.gov (United States)

    Yesiloglu, Nebil; Yildiz, Kemalettin; Cem Akpinar, Ali; Gorgulu, Tahsin; Sirinoglu, Hakan; Ozcan, Arzu

    2016-09-01

    Irregularly shaped wounds or flap borders usually require specified software or devices to measure their area and follow-up wound healing. In this study, an easy way of area measurement called histogram planimetry (HP) for wounds with irregular geometric shapes is defined and compared to conventional millimetric wound measurement. Ten irregularly bordered geometric shapes were measured by 4 different individuals working as surgical assistants using both HP and manual millimetric measurement tools. The amount of time for each wound shape calculation as well as the measurements of the wound areas were noted. All measurements were compared for each method and between each individual using the Wilcoxon signed-rank test. There was no statistically significant difference between 2 measurement methods by means of measured areas; however, measurement time was significantly lower when the HP method was used. There also was no significant difference between the individuals' measurements and calculation times. These results indicated that HP is useful as a conventional millimetric square wound measurement technique with significantly lower measurement times. Due to the development of photo-editor software technologies, measurements in the surgical field have become more accurate and rapid than conventional manual methods without consuming the time and energy needed for other studies. A future study including comparisons between the presented method and complex computerized measurement methods, in terms of duration and accuracy, may provide additional supportive data for the authors' method.

  1. Using color histograms and SPA-LDA to classify bacteria.

    Science.gov (United States)

    de Almeida, Valber Elias; da Costa, Gean Bezerra; de Sousa Fernandes, David Douglas; Gonçalves Dias Diniz, Paulo Henrique; Brandão, Deysiane; de Medeiros, Ana Claudia Dantas; Véras, Germano

    2014-09-01

    In this work, a new approach is proposed to verify the differentiating characteristics of five bacteria (Escherichia coli, Enterococcus faecalis, Streptococcus salivarius, Streptococcus oralis, and Staphylococcus aureus) by using digital images obtained with a simple webcam and variable selection by the Successive Projections Algorithm associated with Linear Discriminant Analysis (SPA-LDA). In this sense, color histograms in the red-green-blue (RGB), hue-saturation-value (HSV), and grayscale channels and their combinations were used as input data, and statistically evaluated by using different multivariate classifiers (Soft Independent Modeling by Class Analogy (SIMCA), Principal Component Analysis-Linear Discriminant Analysis (PCA-LDA), Partial Least Squares Discriminant Analysis (PLS-DA) and Successive Projections Algorithm-Linear Discriminant Analysis (SPA-LDA)). The bacteria strains were cultivated in a nutritive blood agar base layer for 24 h by following the Brazilian Pharmacopoeia, maintaining the status of cell growth and the nature of nutrient solutions under the same conditions. The best result in classification was obtained by using RGB and SPA-LDA, which reached 94 and 100 % of classification accuracy in the training and test sets, respectively. This result is extremely positive from the viewpoint of routine clinical analyses, because it avoids bacterial identification based on phenotypic identification of the causative organism using Gram staining, culture, and biochemical proofs. Therefore, the proposed method presents inherent advantages, promoting a simpler, faster, and low-cost alternative for bacterial identification.

  2. Quadrant Dynamic with Automatic Plateau Limit Histogram Equalization for Image Enhancement

    Directory of Open Access Journals (Sweden)

    P. Jagatheeswari

    2014-01-01

    Full Text Available The fundamental and important preprocessing stage in image processing is the image contrast enhancement technique. Histogram equalization is an effective contrast enhancement technique. In this paper, a histogram equalization based technique called quadrant dynamic with automatic plateau limit histogram equalization (QDAPLHE is introduced. In this method, a hybrid of dynamic and clipped histogram equalization methods are used to increase the brightness preservation and to reduce the overenhancement. Initially, the proposed QDAPLHE algorithm passes the input image through a median filter to remove the noises present in the image. Then the histogram of the filtered image is divided into four subhistograms while maintaining second separated point as the mean brightness. Then the clipping process is implemented by calculating automatically the plateau limit as the clipped level. The clipped portion of the histogram is modified to reduce the loss of image intensity value. Finally the clipped portion is redistributed uniformly to the entire dynamic range and the conventional histogram equalization is executed in each subhistogram independently. Based on the qualitative and the quantitative analysis, the QDAPLHE method outperforms some existing methods in literature.

  3. Parameterization of the Age-Dependent Whole Brain Apparent Diffusion Coefficient Histogram

    Directory of Open Access Journals (Sweden)

    Uwe Klose

    2015-01-01

    Full Text Available Purpose. The distribution of apparent diffusion coefficient (ADC values in the brain can be used to characterize age effects and pathological changes of the brain tissue. The aim of this study was the parameterization of the whole brain ADC histogram by an advanced model with influence of age considered. Methods. Whole brain ADC histograms were calculated for all data and for seven age groups between 10 and 80 years. Modeling of the histograms was performed for two parts of the histogram separately: the brain tissue part was modeled by two Gaussian curves, while the remaining part was fitted by the sum of a Gaussian curve, a biexponential decay, and a straight line. Results. A consistent fitting of the histograms of all age groups was possible with the proposed model. Conclusions. This study confirms the strong dependence of the whole brain ADC histograms on the age of the examined subjects. The proposed model can be used to characterize changes of the whole brain ADC histogram in certain diseases under consideration of age effects.

  4. Using the Bootstrap Method for a Statistical Significance Test of Differences between Summary Histograms

    Science.gov (United States)

    Xu, Kuan-Man

    2006-01-01

    A new method is proposed to compare statistical differences between summary histograms, which are the histograms summed over a large ensemble of individual histograms. It consists of choosing a distance statistic for measuring the difference between summary histograms and using a bootstrap procedure to calculate the statistical significance level. Bootstrapping is an approach to statistical inference that makes few assumptions about the underlying probability distribution that describes the data. Three distance statistics are compared in this study. They are the Euclidean distance, the Jeffries-Matusita distance and the Kuiper distance. The data used in testing the bootstrap method are satellite measurements of cloud systems called cloud objects. Each cloud object is defined as a contiguous region/patch composed of individual footprints or fields of view. A histogram of measured values over footprints is generated for each parameter of each cloud object and then summary histograms are accumulated over all individual histograms in a given cloud-object size category. The results of statistical hypothesis tests using all three distances as test statistics are generally similar, indicating the validity of the proposed method. The Euclidean distance is determined to be most suitable after comparing the statistical tests of several parameters with distinct probability distributions among three cloud-object size categories. Impacts on the statistical significance levels resulting from differences in the total lengths of satellite footprint data between two size categories are also discussed.

  5. HEp-2 Cell Classification Using Shape Index Histograms With Donut-Shaped Spatial Pooling

    DEFF Research Database (Denmark)

    Larsen, Anders Boesen Lindbo; Vestergaard, Jacob Schack; Larsen, Rasmus

    2014-01-01

    We present a new method for automatic classification of indirect immunoflourescence images of HEp-2 cells into different staining pattern classes. Our method is based on a new texture measure called shape index histograms that captures second-order image structure at multiple scales. Moreover, we...... datasets. Our results show that shape index histograms are superior to other popular texture descriptors for HEp-2 cell classification. Moreover, when comparing to other automated systems for HEp-2 cell classification we show that shape index histograms are very competitive; especially considering...

  6. CUDA implementation of histogram stretching function for improving X-ray image.

    Science.gov (United States)

    Lee, Yong H; Kim, Kwan W; Kim, Soon S

    2013-01-01

    This paper presents a method to improve the contrast of digital X-ray image using CUDA program on a GPU. The histogram is commonly used to get the statistical distribution of the contrast in image processing. To increase the visibility of the image in real time, we use the histogram stretching function. It is difficult to implement the function on a GPU because the CUDA program is due to handle the complex process to transfer the source data and the processed results between the memory of GPU and the host system. As a result, we show to operate the histogram stretching function quickly on GPU by the CUDA program.

  7. Histogram-driven cupping correction (HDCC) in CT

    Science.gov (United States)

    Kyriakou, Y.; Meyer, M.; Lapp, R.; Kalender, W. A.

    2010-04-01

    Typical cupping correction methods are pre-processing methods which require either pre-calibration measurements or simulations of standard objects to approximate and correct for beam hardening and scatter. Some of them require the knowledge of spectra, detector characteristics, etc. The aim of this work was to develop a practical histogram-driven cupping correction (HDCC) method to post-process the reconstructed images. We use a polynomial representation of the raw-data generated by forward projection of the reconstructed images; forward and backprojection are performed on graphics processing units (GPU). The coefficients of the polynomial are optimized using a simplex minimization of the joint entropy of the CT image and its gradient. The algorithm was evaluated using simulations and measurements of homogeneous and inhomogeneous phantoms. For the measurements a C-arm flat-detector CT (FD-CT) system with a 30×40 cm2 detector, a kilovoltage on board imager (radiation therapy simulator) and a micro-CT system were used. The algorithm reduced cupping artifacts both in simulations and measurements using a fourth-order polynomial and was in good agreement to the reference. The minimization algorithm required less than 70 iterations to adjust the coefficients only performing a linear combination of basis images, thus executing without time consuming operations. HDCC reduced cupping artifacts without the necessity of pre-calibration or other scan information enabling a retrospective improvement of CT image homogeneity. However, the method can work with other cupping correction algorithms or in a calibration manner, as well.

  8. Recursive histogram modification: establishing equivalency between reversible data hiding and lossless data compression.

    Science.gov (United States)

    Zhang, Weiming; Hu, Xiaocheng; Li, Xiaolong; Yu, Nenghai

    2013-07-01

    State-of-the-art schemes for reversible data hiding (RDH) usually consist of two steps: first construct a host sequence with a sharp histogram via prediction errors, and then embed messages by modifying the histogram with methods, such as difference expansion and histogram shift. In this paper, we focus on the second stage, and propose a histogram modification method for RDH, which embeds the message by recursively utilizing the decompression and compression processes of an entropy coder. We prove that, for independent identically distributed (i.i.d.) gray-scale host signals, the proposed method asymptotically approaches the rate-distortion bound of RDH as long as perfect compression can be realized, i.e., the entropy coder can approach entropy. Therefore, this method establishes the equivalency between reversible data hiding and lossless data compression. Experiments show that this coding method can be used to improve the performance of previous RDH schemes and the improvements are more significant for larger images.

  9. Bridge recognition of median-resolution SAR images using pun histogram entropy

    Institute of Scientific and Technical Information of China (English)

    Wenyu Wu; Dong Yin; Rong Zhang; Yan Liu; Jia Pan

    2009-01-01

    A novel algorithm for bridge recognition of median synthetic aperture radar (SAR) images using histogram entropy presented by Pun is proposed. Firstly, Lee filter and histogram proportion are used to denoise the original image and to make the target evident. Then, water regions are gained through histogram segmentation and the contours of water regions are extracted. After these, the potential bridge targets are obtained based on the space relativity between bridges and water regions using improved contour search. At last, bridges are recognized by extracting the feature of Pun histogram entropy (PHE) of these potential bridge targets. Experimental results show the good qualities of the algorithm, such as fast speed, high rate of recognition, and low rate of false target.

  10. Color Histograms Adapted to Query-Target Images for Object Recognition across Illumination Changes

    Directory of Open Access Journals (Sweden)

    Jack-Gérard Postaire

    2005-08-01

    Full Text Available Most object recognition schemes fail in case of illumination changes between the color image acquisitions. One of the most widely used solutions to cope with this problem is to compare the images by means of the intersection between invariant color histograms. The main originality of our approach is to cope with the problem of illumination changes by analyzing each pair of query and target images constructed during the retrieval, instead of considering each image of the database independently from each other. In this paper, we propose a new approach which determines color histograms adapted to each pair of images. These adapted color histograms are obtained so that their intersection is higher when the two images are similar than when they are different. The adapted color histograms processing is based on an original model of illumination changes based on rank measures of the pixels within the color component images.

  11. Face verification system for Android mobile devices using histogram based features

    Science.gov (United States)

    Sato, Sho; Kobayashi, Kazuhiro; Chen, Qiu

    2016-07-01

    This paper proposes a face verification system that runs on Android mobile devices. In this system, facial image is captured by a built-in camera on the Android device firstly, and then face detection is implemented using Haar-like features and AdaBoost learning algorithm. The proposed system verify the detected face using histogram based features, which are generated by binary Vector Quantization (VQ) histogram using DCT coefficients in low frequency domains, as well as Improved Local Binary Pattern (Improved LBP) histogram in spatial domain. Verification results with different type of histogram based features are first obtained separately and then combined by weighted averaging. We evaluate our proposed algorithm by using publicly available ORL database and facial images captured by an Android tablet.

  12. Background Extraction Method Based on Block Histogram Analysis for Video Image

    Institute of Scientific and Technical Information of China (English)

    Li Hua; Peng Qiang

    2005-01-01

    A novel method of histogram analysis for background extraction in video image is proposed, which is derived from the pixelbased histogram analysis. Not only the statistical property of pixels between temporal frames, but also the correlation of local pixels in a single frame is exploited in this method. When carrying out histogram analysis for background extraction, the proposed method is not based on a single pixel but on a 2×2 block that has much less computational quantities and can extract a sound background image from video sequence simultaneously. A comparative experiment between the proposed method and the pixel-based histogram analysis shows that the proposed method has a faster speed in background extraction and the obtained background image is better in quantity.

  13. Adaptive gamma correction based on cumulative histogram for enhancing near-infrared images

    Science.gov (United States)

    Huang, Zhenghua; Zhang, Tianxu; Li, Qian; Fang, Hao

    2016-11-01

    Histogram-based methods have been proven their ability in image enhancement. To improve low contrast while preserving details and high brightness in near-infrared images, a novel method called adaptive gamma correction based on cumulative histogram (AGCCH) is studied in this paper. This novel image enhancement method improves the contrast of local pixels through adaptive gamma correction (AGC), which is formed by incorporating a cumulative histogram or cumulative sub-histogram into the weighting distribution. Both qualitatively and quantitatively, experimental results demonstrate that the proposed image enhancement with the AGCCH method can perform well in brightness preservation, contrast enhancement, and detail preservation, and it is superior to previous state-of-the-art methods.

  14. Infrared image gray adaptive adjusting enhancement algorithm based on gray redundancy histogram-dealing technique

    Science.gov (United States)

    Hao, Zi-long; Liu, Yong; Chen, Ruo-wang

    2016-11-01

    In view of the histogram equalizing algorithm to enhance image in digital image processing, an Infrared Image Gray adaptive adjusting Enhancement Algorithm Based on Gray Redundancy Histogram-dealing Technique is proposed. The algorithm is based on the determination of the entire image gray value, enhanced or lowered the image's overall gray value by increasing appropriate gray points, and then use gray-level redundancy HE method to compress the gray-scale of the image. The algorithm can enhance image detail information. Through MATLAB simulation, this paper compares the algorithm with the histogram equalization method and the algorithm based on gray redundancy histogram-dealing technique , and verifies the effectiveness of the algorithm.

  15. SU-D-201-02: Prediction of Delivered Dose Based On a Joint Histogram of CT and FDG PET Images

    Energy Technology Data Exchange (ETDEWEB)

    Park, M [Brigham and Women’s Hospital and Harvard Medical School, Boston, MA (United States); Choi, Y; Cho, A; Hwang, S; Cha, J; Lee, N; Yun, M [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: To investigate whether pre-treatment images can be used in predicting microsphere distribution in tumors. When intra-arterial radioembolization using Y90 microspheres was performed, the microspheres were often delivered non-uniformly within the tumor, which could lead to an inefficient therapy. Therefore, it is important to estimate the distribution of microspheres. Methods: Early arterial phase CT and FDG PET images were acquired for patients with primary liver cancer prior to radioembolization (RE) using Y90 microspheres. Tumor volume was delineated on CT images and fused with FDG PET images. From each voxel (3.9×3.9×3.3 mm3) in the tumor, the Hounsfield unit (HU) from the CT and SUV values from the FDG PET were harvested. We binned both HU and SUV into 11 bins and then calculated a normalized joint-histogram in an 11×11 array.Patients also underwent a post-treatment Y90 PET imaging. Radiation dose for the tumor was estimated using convolution of the Y90 distribution with a dose-point kernel. We also calculated a fraction of the tumor volume that received a radiation dose great than 100Gy. Results: Averaged over 40 patients, 55% of tumor volume received a dose greater than 100Gy (range : 1.1 – 100%). The width of the joint histogram was narrower for patients with a high dose. For patients with a low dose, the width was wider and a larger fraction of tumor volume had low HU. Conclusion: We have shown the pattern of joint histogram of the HU and SUV depends on delivered dose. The patterns can predict the efficacy of uniform intra-arterial delivery of Y90 microspheres.

  16. Region of Interest Detection Based on Histogram Segmentation for Satellite Image

    Science.gov (United States)

    Kiadtikornthaweeyot, Warinthorn; Tatnall, Adrian R. L.

    2016-06-01

    High resolution satellite imaging is considered as the outstanding applicant to extract the Earth's surface information. Extraction of a feature of an image is very difficult due to having to find the appropriate image segmentation techniques and combine different methods to detect the Region of Interest (ROI) most effectively. This paper proposes techniques to classify objects in the satellite image by using image processing methods on high-resolution satellite images. The systems to identify the ROI focus on forests, urban and agriculture areas. The proposed system is based on histograms of the image to classify objects using thresholding. The thresholding is performed by considering the behaviour of the histogram mapping to a particular region in the satellite image. The proposed model is based on histogram segmentation and morphology techniques. There are five main steps supporting each other; Histogram classification, Histogram segmentation, Morphological dilation, Morphological fill image area and holes and ROI management. The methods to detect the ROI of the satellite images based on histogram classification have been studied, implemented and tested. The algorithm is be able to detect the area of forests, urban and agriculture separately. The image segmentation methods can detect the ROI and reduce the size of the original image by discarding the unnecessary parts.

  17. Scintigraphic image contrast-enhancement techniques: Global and local area histogram equalization

    Energy Technology Data Exchange (ETDEWEB)

    Verdenet, J.; Cardot, J.C.; Baud, M.; Chervet, H.; Bidet, R.; Duvernoy, J.

    1981-06-01

    This article develops two contrast-modification techniques for the display of scintigraphic images. Based on histogram-modification techniques, histogram equalization, where each level of gray is used to the same extent, gives maximum entropy. The first technique uses the application of histogram equalization in the whole image. To eliminate contrast attenuation in image areas that represent a statistically small but important portion of the gray scale histogram, local area histogram equalization has been applied to images with differences in intensity. Both techniques were tested using a phantom with known characteristics. The global equalization technique is more suitable to bone scintigraphies, and some well-chosen boundaries improved the difference between two comparable areas. For liver scintigraphies, where intensity is quite equal in every pixel, a local area equalization was chosen that allowed detection of heterogeneous structures. The image resulting from histogram-equalization techniques improve the readability of data, but are often far from usual images and necessitate an apprenticeship for the physician.

  18. DE-STRIPING FOR TDICCD REMOTE SENSING IMAGE BASED ON STATISTICAL FEATURES OF HISTOGRAM

    Directory of Open Access Journals (Sweden)

    H.-T. Gao

    2016-06-01

    Full Text Available Aim to striping noise brought by non-uniform response of remote sensing TDI CCD, a novel de-striping method based on statistical features of image histogram is put forward. By analysing the distribution of histograms,the centroid of histogram is selected to be an eigenvalue representing uniformity of ground objects,histogrammic centroid of whole image and each pixels are calculated first,the differences between them are regard as rough correction coefficients, then in order to avoid the sensitivity caused by single parameter and considering the strong continuity and pertinence of ground objects between two adjacent pixels,correlation coefficient of the histograms is introduces to reflect the similarities between them,fine correction coefficient is obtained by searching around the rough correction coefficient,additionally,in view of the influence of bright cloud on histogram,an automatic cloud detection based on multi-feature including grey level,texture,fractal dimension and edge is used to pre-process image.Two 0-level panchromatic images of SJ-9A satellite with obvious strip noise are processed by proposed method to evaluate the performance, results show that the visual quality of images are improved because the strip noise is entirely removed,we quantitatively analyse the result by calculating the non-uniformity ,which has reached about 1% and is better than histogram matching method.

  19. De-Striping for Tdiccd Remote Sensing Image Based on Statistical Features of Histogram

    Science.gov (United States)

    Gao, Hui-ting; Liu, Wei; He, Hong-yan; Zhang, Bing-xian; Jiang, Cheng

    2016-06-01

    Aim to striping noise brought by non-uniform response of remote sensing TDI CCD, a novel de-striping method based on statistical features of image histogram is put forward. By analysing the distribution of histograms,the centroid of histogram is selected to be an eigenvalue representing uniformity of ground objects,histogrammic centroid of whole image and each pixels are calculated first,the differences between them are regard as rough correction coefficients, then in order to avoid the sensitivity caused by single parameter and considering the strong continuity and pertinence of ground objects between two adjacent pixels,correlation coefficient of the histograms is introduces to reflect the similarities between them,fine correction coefficient is obtained by searching around the rough correction coefficient,additionally,in view of the influence of bright cloud on histogram,an automatic cloud detection based on multi-feature including grey level,texture,fractal dimension and edge is used to pre-process image.Two 0-level panchromatic images of SJ-9A satellite with obvious strip noise are processed by proposed method to evaluate the performance, results show that the visual quality of images are improved because the strip noise is entirely removed,we quantitatively analyse the result by calculating the non-uniformity ,which has reached about 1% and is better than histogram matching method.

  20. Interpretation of erythrocyte histograms obtained from automated hematology analyzers in hematologic diseases

    Directory of Open Access Journals (Sweden)

    Ali Maleki

    2015-12-01

    Full Text Available Background: Presently, the graphical data of blood cells (histograms and cytograms or/ scattergrams that they are usually available in all modern automated hematology analyzers are an integral a part of automated complete blood count (CBC. To find incorrect results from automated hematology analyzer and establish the samples that require additional analysis, Laboratory employees will use those data for quality control of obtaining results, to assist identification of complex and troublesome cases. Methods: During this descriptive analytic study, in addition to erythrocyte graphs from variety of patients, referring from March 2013 to Feb 2014 to our clinical laboratory, Zagros Hospital, Kermanshah, Iran, are given, the papers published in relevant literature as well as available published manuals of automatic blood cell counters were used. articles related to the key words of erythrocyte graphs and relevant literature as well as available published manuals of automatic blood cell counters were searched from valid databases such as Springer Link, google scholar, Pubmed and Sciencedirect. Then, the articles related to erythrogram, erythrocyte histogram and hematology analyzer graphs are involved in diagnosis of hematological disorder were searched and selected for this study. Results: Histograms and different automated CBC parameter become abnormal in various pathologic conditions, and can present important clues for diagnosis and treatment of hematologic and non-hematologic disorders. In several instances, these histograms have characteristic appearances in an exceedingly wide range of pathological conditions. In some hematologic disorders like iron deficiency or megaloblastic anemia, a sequential histogram can clearly show the progressive treatment and management. Conclusion: These graphical data are often accompanied by other automated CBC parameter and microscopic examination of peripheral blood smears (PBS, and can help in monitoring and

  1. Improved Steganographic Method Preserving Pixel-Value Differencing Histogram with Modulus Function

    Directory of Open Access Journals (Sweden)

    Heung-Kyu Lee

    2010-01-01

    Full Text Available We herein advance a secure steganographic algorithm that uses a turnover policy and a novel adjusting process. Although the method of Wang et al. uses Pixel-Value Differencing (PVD and their modulus function provides high capacity and good image quality, the embedding process causes a number of artifacts, such as abnormal increases and fluctuations in the PVD histogram, which may reveal the existence of the hidden message. In order to enhance the security of the algorithm, a turnover policy is used that prevents abnormal increases in the histogram values and a novel adjusting process is devised to remove the fluctuations at the border of the subrange in the PVD histogram. The proposed method therefore eliminates all the weaknesses of the PVD steganographic methods thus far proposed and guarantees secure communication. In the experiments described herein, the proposed algorithm is compared with other PVD steganographic algorithms by using well-known steganalysis techniques, such as RS-analysis, steganalysis for LSB matching, and histogram-based attacks. The results support our contention that the proposed method enhances security by keeping the PVD histogram similar to the cover, while also providing high embedding capacity and good imperceptibility to the naked eye.

  2. Improved Steganographic Method Preserving Pixel-Value Differencing Histogram with Modulus Function

    Directory of Open Access Journals (Sweden)

    Lee Hae-Yeoun

    2010-01-01

    Full Text Available Abstract We herein advance a secure steganographic algorithm that uses a turnover policy and a novel adjusting process. Although the method of Wang et al. uses Pixel-Value Differencing (PVD and their modulus function provides high capacity and good image quality, the embedding process causes a number of artifacts, such as abnormal increases and fluctuations in the PVD histogram, which may reveal the existence of the hidden message. In order to enhance the security of the algorithm, a turnover policy is used that prevents abnormal increases in the histogram values and a novel adjusting process is devised to remove the fluctuations at the border of the subrange in the PVD histogram. The proposed method therefore eliminates all the weaknesses of the PVD steganographic methods thus far proposed and guarantees secure communication. In the experiments described herein, the proposed algorithm is compared with other PVD steganographic algorithms by using well-known steganalysis techniques, such as RS-analysis, steganalysis for LSB matching, and histogram-based attacks. The results support our contention that the proposed method enhances security by keeping the PVD histogram similar to the cover, while also providing high embedding capacity and good imperceptibility to the naked eye.

  3. The L_infinity constrained global optimal histogram equalization technique for real time imaging

    Science.gov (United States)

    Ren, Qiongwei; Niu, Yi; Liu, Lin; Jiao, Yang; Shi, Guangming

    2015-08-01

    Although the current imaging sensors can achieve 12 or higher precision, the current display devices and the commonly used digital image formats are still only 8 bits. This mismatch causes significant waste of the sensor precision and loss of information when storing and displaying the images. For better usage of the precision-budget, tone mapping operators have to be used to map the high-precision data into low-precision digital images adaptively. In this paper, the classic histogram equalization tone mapping operator is reexamined in the sense of optimization. We point out that the traditional histogram equalization technique and its variants are fundamentally improper by suffering from local optimum problems. To overcome this drawback, we remodel the histogram equalization tone mapping task based on graphic theory which achieves the global optimal solutions. Another advantage of the graphic-based modeling is that the tone-continuity is also modeled as a vital constraint in our approach which suppress the annoying boundary artifacts of the traditional approaches. In addition, we propose a novel dynamic programming technique to solve the histogram equalization problem in real time. Experimental results shows that the proposed tone-preserved global optimal histogram equalization technique outperforms the traditional approaches by exhibiting more subtle details in the foreground while preserving the smoothness of the background.

  4. Recovery of the histogram of hourly ozone distribution from weekly average concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Olcese, Luis E. [Departamento de Fisico Quimica/INFIQC, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina)]. E-mail: lolcese@fcq.unc.edu.ar; Toselli, Beatriz M. [Departamento de Fisico Quimica/INFIQC, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, 5000 Cordoba (Argentina)

    2006-05-15

    A simple method is presented for estimating hourly distribution of air pollutants, based on data collected by passive sensors on a weekly or bi-weekly basis with no need for previous measurements at a site. In order for this method to be applied to locations where no hourly records are available, reference data from other sites are required to generate calibration histograms. The proposed procedure allows one to obtain the histogram of hourly ozone values during a given week with an error of about 30%, which is good considering the simplicity of this approach. This method can be a valuable tool for sites that lack previous hourly records of pollutant ambient concentrations, where it can be used to verify compliance with regulations or to estimate the AOT40 index with an acceptable degree of exactitude. - The histogram of hourly ozone distribution can be obtained based on passive sensor data.

  5. A novel JPEG steganography method based on modulus function with histogram analysis

    Directory of Open Access Journals (Sweden)

    V. Banoci

    2012-06-01

    Full Text Available In this paper, we present a novel steganographic method for embedding of secret data in still grayscale JPEG image. In order to provide large capacity of the proposed method while maintaining good visual quality of stego-image, the embedding process is performed in quantized transform coefficients of Discrete Cosine transform (DCT by modifying coefficients according to modulo function, what gives to the steganography system blind extraction predisposition. After-embedding histogram of proposed Modulo Histogram Fitting (MHF method is analyzed to secure steganography system against steganalysis attacks. In addition, AES ciphering was implemented to increase security and improve histogram after-embedding characteristics of proposed steganography system as experimental results show.

  6. Energy degeneracies from Broad Histogram Method and Wang-Landau Sampling

    CERN Document Server

    Lima, Alexandre Pereira; Girardi, Daniel

    2016-01-01

    In this work, we present a comparative study of the accuracy provided by the Wang-Landau sampling and the Broad Histogram method to estimate de density of states of the two dimensional Ising ferromagnet. The microcanonical averages used to describe the thermodynamic behaviour and to use the Broad Histogram method were obtained using the single spin-flip Wang-Landau sampling, attempting to convergence issues and accuracy improvements. We compare the results provided by both techniques with the exact ones for thermodynamic properties and critical exponents. Our results, within the Wang-Landau sampling, reveal that the Broad Histogram approach provides a better description of the density of states for all cases analysed.

  7. PERFORMANCE MEASUREMENTS OF FEATURE TRACKING AND HISTOGRAM BASED TRAFFIC CONGESTION ALGORITHMS

    Directory of Open Access Journals (Sweden)

    Ozgur Altun

    2015-05-01

    Full Text Available In this paper, feature tracking based and histogram based traffic congestion detection systems are developed. Developed all system are designed to run as real time application. In this work, ORB (Oriented FAST and Rotated BRIEF feature extraction method have been used to develop feature tracking based traffic congestion solution. ORB is a rotation invariant, fast and resistant to noise method and contains the power of FAST and BRIEF feature extraction methods. Also, two different approaches, which are standard deviation and weighed average, have been applied to find out the congestion information by using histogram of the image to develop histogram based traffic congestion solution. Both systems have been tested on different weather conditions such as cloudy, sunny and rainy to provide various illumination at both daytime and night. For all developed systems performance results are examined to show the advantages and drawbacks of these systems

  8. HSV Color Histogram and Directional Binary Wavelet Patterns for Content Based Image Retrieval

    Directory of Open Access Journals (Sweden)

    P.Vijaya Bhaskar Reddy

    2012-08-01

    Full Text Available This paper presents a new image indexing and retrieval algorithm by integrating color (HSV color histogram and texture (directional binary wavelet patterns (DBWP features. For color feature,first the RGB image is converted to HSV image, and then histograms are constructed from HSV spaces. For texture feature, an 8-bit grayscale image is divided into eight binary bit-planes, and then binary wavelet transform (BWT on each bitplane to extract the multi-resolution binary images. The local binary pattern (LBP features are extracted from the resultant BWT sub-bands. Two experiments have beencarried out for proving the worth of our algorithm. It is further mentioned that the database considered for experiments are Corel 1000 database (DB1, and MIT VisTex database (DB2. The results after beinginvestigated show a significant improvement in terms of their evaluation measures as compared to HSV histogram and DBWP.

  9. Multi-radius centralized binary pattern histogram projection for face recognition

    Institute of Scientific and Technical Information of China (English)

    Xiaofeng Fu; Wei Wei

    2009-01-01

    The existing local binary pattern (LBP) operators have several disadvantages such as rather long histograms,lower discrimination,and sensitivity to noise.Aiming at these problems,we propose the centralized binary pattern (CBP) operator.CBP operator can significantly rcduce the histograms' dimensionality,offer stronger discrimination,and decrease the white noise's influence on face images.Moreover,for increasing the recognition accuracy and speed,we use multi-radius CBP histogram as face representation and project it onto locality preserving projection (LPP) space to obtain lower dimensional features.Experiments on FERET and CAS-PEAL databases demonstrate that the proposed method is superior to other modern approaches not only in recognition accuracy but also in recognition speed.

  10. Reversible Data Hiding Based on Two-level HDWT Coefficient Histograms

    Directory of Open Access Journals (Sweden)

    Xu-Ren Luo

    2011-05-01

    Full Text Available In recent years, reversible data hiding has attracted much more attention than before. Reversibilitysignifies that the original media can be recovered without any loss from the marked media afterextracting the embedded message. This paper presents a new method that adopts two-level wavelettransform and exploits the feature of large wavelet coefficient variance to achieve the goal of highcapacity with imperceptibility. Our method differs from those of previous ones in which the waveletcoefficients histogram not gray-level histogram is manipulated. Besides, clever shifting rules areintroduced into histogram to avoid the decimal problem in pixel values after recovery to achievereversibility. With small alteration of the wavelet coefficients in the embedding process, and therefore lowvisual distortion is obtained in the marked image. In addition, an important feature of our design is thatthe use of threshold is much different from previous studies. The results indicate that our design issuperior to many other state-of-the-art reversible data hiding schemes.

  11. Histogram Bins Matching Approach for CBIR Based on Linear grouping for Dimensionality Reduction

    Directory of Open Access Journals (Sweden)

    H. B. Kekre

    2013-11-01

    Full Text Available This paper describes the histogram bins matching approach for CBIR. Histogram bins are reduced from 256 to 32 and 16 by linear grouping and effect of this dimensionality reduction is analyzed, compared, and evaluated. Work presented in this paper contributes in all three main phases of CBIR that are feature extraction, similarity matching and performance evaluation. Feature extraction explores the idea of histogram bins matching for three colors R, G and B. Histogram bin contents are used to represent the feature vector in three forms. First form of feature is count of pixels, and then other forms are obtained by computing the total and mean of intensities for the pixels falling in each of the histogram bins. Initially the size of the feature vector is 256 components as histogram with the all 256 bins. Further the size of the feature vector is reduced to 32 bins and then 16 bins by simple linear grouping of the bins. Feature extraction processes for each size and type of the feature vector is executed over the database of 2000 BMP images having 20 different classes. It prepares the feature vector databases as preprocessing part of this work. Similarity matching between query and database image feature vectors is carried out by means of first five orders of Minkowski distance and also with the cosine correlation distance. Same set of 200 query images are executed for all types of feature vector and for all similarity measures. Performance of all aspects addressed in this paper are evaluated using three parameters PRCP (Precision Recall Cross over Point, LS (longest string, LSRR (Length of String to Retrieve all Relevant images.

  12. Adapting histogram for automatic noise data removal in building interior point cloud data

    Science.gov (United States)

    Shukor, S. A. Abdul; Rushforth, E. J.

    2015-05-01

    3D point cloud data is now preferred by researchers to generate 3D models. These models can be used throughout a variety of applications including 3D building interior models. The rise of Building Information Modeling (BIM) for Architectural, Engineering, Construction (AEC) applications has given 3D interior modelling more attention recently. To generate a 3D model representing the building interior, a laser scanner is used to collect the point cloud data. However, this data often comes with noise. This is due to several factors including the surrounding objects, lighting and specifications of the laser scanner. This paper highlights on the usage of the histogram to remove the noise data. Histograms, used in statistics and probability, are regularly being used in a number of applications like image processing, where a histogram can represent the total number of pixels in an image at each intensity level. Here, histograms represent the number of points recorded at range distance intervals in various projections. As unwanted noise data has a sparser cloud density compared to the required data and is usually situated at a notable distance from the required data, noise data will have lower frequencies in the histogram. By defining the acceptable range using the average frequency, points below this range can be removed. This research has shown that these histograms have the capabilities to remove unwanted data from 3D point cloud data representing building interiors automatically. This feature will aid the process of data preprocessing in producing an ideal 3D model from the point cloud data.

  13. Spline Histogram Method for Reconstruction of Probability Density Functions of Clusters of Galaxies

    Science.gov (United States)

    Docenko, Dmitrijs; Berzins, Karlis

    We describe the spline histogram algorithm which is useful for visualization of the probability density function setting up a statistical hypothesis for a test. The spline histogram is constructed from discrete data measurements using tensioned cubic spline interpolation of the cumulative distribution function which is then differentiated and smoothed using the Savitzky-Golay filter. The optimal width of the filter is determined by minimization of the Integrated Square Error function. The current distribution of the TCSplin algorithm written in f77 with IDL and Gnuplot visualization scripts is available from www.virac.lv/en/soft.html.

  14. Spline histogram method for reconstruction of probability density function of clusters of galaxies

    CERN Document Server

    Docenko, D; Docenko, Dmitrijs; Berzins, Karlis

    2003-01-01

    We describe the spline histogram algorithm which is useful for visualization of the probability density function setting up a statistical hypothesis for a test. The spline histogram is constructed from discrete data measurements using tensioned cubic spline interpolation of the cumulative distribution function which is then differentiated and smoothed using the Savitzky-Golay filter. The optimal width of the filter is determined by minimization of the Integrated Square Error function. The current distribution of the TCSplin algorithm written in f77 with IDL and Gnuplot visualization scripts is available from http://www.virac.lv/en/soft.html

  15. Similarity Estimation Between DNA Sequences Based on Local Pattern Histograms of Binary Images

    Institute of Scientific and Technical Information of China (English)

    Yusei Kobori; Satoshi Mizuta

    2016-01-01

    Graphical representation of DNA sequences is one of the most popular techniques for alignment-free sequence comparison. Here, we propose a new method for the feature extraction of DNA sequences represented by binary images, by estimating the similarity between DNA sequences using the frequency histograms of local bitmap patterns of images. Our method shows linear time complexity for the length of DNA sequences, which is practical even when long sequences, such as whole genome sequences, are compared. We tested five distance measures for the estimation of sequence similarities, and found that the histogram intersection and Manhattan distance are the most appropriate ones for phylogenetic analyses.

  16. Universality and diversity in a phonon-transmission histogram of isotope-disordered carbon nanotubes.

    Science.gov (United States)

    Yamamoto, Takahiro; Sasaoka, Kenji; Watanabe, Satoshi

    2011-05-27

    Universal fluctuations in phonon transmission and other features of phonon-transmission histograms are investigated by performing numerical simulations of coherent-phonon transport in isotope-disordered carbon nanotubes. Interestingly, the phonon-transmission fluctuation in the diffusive regime is universal, irrespective of the average phonon transmission, the tube chirality, and the concentrations, and masses of isotopes. We also find that the histogram, which has a Gaussian distribution in the diffusive regime, has a log-normal distribution in the localization regime. © 2011 American Physical Society

  17. WE-B-304-02: Treatment Planning Evaluation and Optimization Should Be Biologically and Not Dose/volume Based

    Energy Technology Data Exchange (ETDEWEB)

    Deasy, J. [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2015-06-15

    The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor control probability (TCP) with an acceptable normal tissue complication probability (NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. It has been suggested that treatment planning evaluation and optimization would be more effective if they were biologically and not dose/volume based, and this is the claim debated in this month’s Point/Counterpoint. After a brief overview of biologically and DVH based treatment planning by the Moderator Colin Orton, Joseph Deasy (for biological planning) and Charles Mayo (against biological planning) will begin the debate. Some of the arguments in support of biological planning include: this will result in more effective dose distributions for many patients DVH-based measures of plan quality are known to have little predictive value there is little evidence that either D95 or D98 of the PTV is a good predictor of tumor control sufficient validated outcome prediction models are now becoming available and should be used to drive planning and optimization Some of the arguments against biological planning include: several decades of experience with DVH-based planning should not be discarded we do not know enough about the reliability and errors associated with biological models the radiotherapy community in general has little direct experience with side by side comparisons of DVH vs biological metrics and outcomes it is unlikely that a clinician would accept extremely cold regions in a CTV or hot regions in a PTV, despite having acceptable TCP values Learning Objectives: To understand dose/volume based treatment planning and its potential limitations To understand biological metrics such as EUD, TCP, and NTCP To understand biologically based treatment planning and its potential limitations.

  18. WE-B-304-01: Treatment Planning Evaluation and Optimization Should Be Dose/volume and Not Biologically Based

    Energy Technology Data Exchange (ETDEWEB)

    Mayo, C. [Mayo Clinic (United States)

    2015-06-15

    The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor control probability (TCP) with an acceptable normal tissue complication probability (NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. It has been suggested that treatment planning evaluation and optimization would be more effective if they were biologically and not dose/volume based, and this is the claim debated in this month’s Point/Counterpoint. After a brief overview of biologically and DVH based treatment planning by the Moderator Colin Orton, Joseph Deasy (for biological planning) and Charles Mayo (against biological planning) will begin the debate. Some of the arguments in support of biological planning include: this will result in more effective dose distributions for many patients DVH-based measures of plan quality are known to have little predictive value there is little evidence that either D95 or D98 of the PTV is a good predictor of tumor control sufficient validated outcome prediction models are now becoming available and should be used to drive planning and optimization Some of the arguments against biological planning include: several decades of experience with DVH-based planning should not be discarded we do not know enough about the reliability and errors associated with biological models the radiotherapy community in general has little direct experience with side by side comparisons of DVH vs biological metrics and outcomes it is unlikely that a clinician would accept extremely cold regions in a CTV or hot regions in a PTV, despite having acceptable TCP values Learning Objectives: To understand dose/volume based treatment planning and its potential limitations To understand biological metrics such as EUD, TCP, and NTCP To understand biologically based treatment planning and its potential limitations.

  19. A Concise Guide to Feature Histograms with Applications to LIDAR-Based Spacecraft Relative Navigation

    Science.gov (United States)

    Rhodes, Andrew P.; Christian, John A.; Evans, Thomas

    2017-01-01

    With the availability and popularity of 3D sensors, it is advantageous to re-examine the use of point cloud descriptors for the purpose of pose estimation and spacecraft relative navigation. One popular descriptor is the oriented unique repeatable clustered viewpoint feature histogram (OUR-CVFH), which is most often utilized in personal and industrial robotics to simultaneously recognize and navigate relative to an object. Recent research into using the OUR-CVFH descriptor for spacecraft navigation has produced favorable results. Since OUR-CVFH is the most recent innovation in a large family of feature histogram point cloud descriptors, discussions of parameter settings and insights into its functionality are spread among various publications and online resources. This paper organizes the history of feature histogram point cloud descriptors for a straightforward explanation of their evolution. This article compiles all the requisite information needed to implement OUR-CVFH into one location, as well as providing useful suggestions on how to tune the generation parameters. This work is beneficial for anyone interested in using this histogram descriptor for object recognition or navigation - may it be personal robotics or spacecraft navigation.

  20. Three-dimensional histogram visualization in different color spaces and applications

    Science.gov (United States)

    Marcu, Gabriel G.; Abe, Satoshi

    1995-10-01

    A visualization procedure for the 3D histogram of color images is presented. The procedure assumes that the histogram is available as a table that associates to a pixel color the number of its appearance in the image. The procedure runs for the RGB, YMC, HSV, HSL, L*a*b, and L*u*v color spaces and it is easily extendable to other color spaces if the analytical form of color transformations is available. Each histogram value is represented in the color space as a colored ball, in a position corresponding to the place of the color in the space. A simple drawing procedure is used instead of more complicated 3D rendering techniques. The 3D histogram visualization offers a clear and intuitive representation of the color distribution of the image. The procedure is applied to derive a clusterization technique for color classification and visualize its results, to display comparatively the gamut of different color devices, and to detect the misalignment of the RGB planes of a color image. Diagrams illustrating the visualization procedure are presented for each application.

  1. 3D histogram visualization in different color spaces with application in color clustering classification

    Science.gov (United States)

    Marcu, Gabriel G.; Abe, Satoshi

    1995-04-01

    The paper presents a dynamically visualization procedure for 3D histogram of color images. The procedure runs for RGB, YMC, HSV, HSL device dependent color spaces and for Lab, Luv device independent color spaces and it is easily extendable to other color spaces if the analytical form of color transformations is available. Each histogram value is represented in the color space as a colored ball, in a position corresponding to the place of color in the color space. The paper presents the procedures for nonlinear ball normalization, ordering of drawing, space edges drawing, translation, scaling and rotation of the histogram. The 3D histogram visualization procedure can be used in different applications described in the second part of the paper. It enables to get a clear representation of the range of colors of one image, to derive and compare the efficiency of different clusterization procedures for color classification, to display comparatively the gamut of different color devices, to select the color space for an optimal mapping procedure of the outside gamut colors for minimizing the hue error, to detect bad-alignment in RGB planes for a sequential process.

  2. Effect of molecular organization on the image histograms of polarization SHG microscopy.

    Science.gov (United States)

    Psilodimitrakopoulos, Sotiris; Amat-Roldan, Ivan; Loza-Alvarez, Pablo; Artigas, David

    2012-10-01

    Based on its polarization dependency, second harmonic generation (PSHG) microscopy has been proven capable to structurally characterize molecular architectures in different biological samples. By exploiting this polarization dependency of the SHG signal in every pixel of the image, average quantitative structural information can be retrieved in the form of PSHG image histograms. In the present study we experimentally show how the PSHG image histograms can be affected by the organization of the SHG active molecules. Our experimental scenario grounds on two inherent properties of starch granules. Firstly, we take advantage of the radial organization of amylopectin molecules (the SHG source in starch) to attribute shifts of the image histograms to the existence of tilted off the plane molecules. Secondly, we use the property of starch to organize upon hydration to demonstrate that the degree of structural order at the molecular level affects the width of the PSHG image histograms. The shorter the width is the more organized the molecules in the sample are, resulting in a reliable method to measure order. The implication of this finding is crucial to the interpretation of PSHG images used for example in tissue diagnostics.

  3. Histogram of oriented phase (HOP): a new descriptor based on phase congruency

    Science.gov (United States)

    Ragb, Hussin K.; Asari, Vijayan K.

    2016-05-01

    In this paper we present a low level image descriptor called Histogram of Oriented Phase based on phase congruency concept and the Principal Component Analysis (PCA). Since the phase of the signal conveys more information regarding signal structure than the magnitude, the proposed descriptor can precisely identify and localize image features over the gradient based techniques, especially in the regions affected by illumination changes. The proposed features can be formed by extracting the phase congruency information for each pixel in the image with respect to its neighborhood. Histograms of the phase congruency values of the local regions in the image are computed with respect to its orientation. These histograms are concatenated to construct the Histogram of Oriented Phase (HOP) features. The dimensionality of HOP features is reduced using PCA algorithm to form HOP-PCA descriptor. The dimensionless quantity of the phase congruency leads the HOP-PCA descriptor to be more robust to the image scale variations as well as contrast and illumination changes. Several experiments were performed using INRIA and DaimlerChrysler datasets to evaluate the performance of the HOP-PCA descriptor. The experimental results show that the proposed descriptor has better detection performance and less error rates than a set of the state of the art feature extraction methodologies.

  4. Explicit optimization of plan quality measures in intensity-modulated radiation therapy treatment planning.

    Science.gov (United States)

    Engberg, Lovisa; Forsgren, Anders; Eriksson, Kjell; Hårdemark, Björn

    2017-06-01

    To formulate convex planning objectives of treatment plan multicriteria optimization with explicit relationships to the dose-volume histogram (DVH) statistics used in plan quality evaluation. Conventional planning objectives are designed to minimize the violation of DVH statistics thresholds using penalty functions. Although successful in guiding the DVH curve towards these thresholds, conventional planning objectives offer limited control of the individual points on the DVH curve (doses-at-volume) used to evaluate plan quality. In this study, we abandon the usual penalty-function framework and propose planning objectives that more closely relate to DVH statistics. The proposed planning objectives are based on mean-tail-dose, resulting in convex optimization. We also demonstrate how to adapt a standard optimization method to the proposed formulation in order to obtain a substantial reduction in computational cost. We investigated the potential of the proposed planning objectives as tools for optimizing DVH statistics through juxtaposition with the conventional planning objectives on two patient cases. Sets of treatment plans with differently balanced planning objectives were generated using either the proposed or the conventional approach. Dominance in the sense of better distributed doses-at-volume was observed in plans optimized within the proposed framework. The initial computational study indicates that the DVH statistics are better optimized and more efficiently balanced using the proposed planning objectives than using the conventional approach. © 2017 American Association of Physicists in Medicine.

  5. Direct-space methods in phase extension and phase refinement. IV. The double-histogram method.

    Science.gov (United States)

    Refaat, L S; Tate, C; Woolfson, M M

    1996-03-01

    In the conventional histogram-matching technique for phase extension and refinement for proteins a simple one-to-one transformation is made in the protein region to modify calculated density so that it will have some target histogram in addition to solvent flattening. This work describes an investigation where the density modification takes into account not only the current calculated density at a grid point but also some characteristic of the environment of the grid point within some distance R. This characteristic can be one of the local maximum density, the local minimum density or the local variance of density. The grid points are divided into ten groups, each containing the same number of grid points, for ten different ranges of value of the local characteristic. The ten groups are modified to give different histograms, each corresponding to that obtained under the same circumstances from a structure similar to the one under investigation. This process is referred to as the double-histogram matching method. Other processes which have been investigated are the weighting of structure factors when calculating maps with estimated phases and also the use of a factor to dampen the change of density and so control the refinement process. Two protein structures were used in numerical trials, RNApl [Bezborodova, Ermekbaeva, Shlyapnikov, Polyakov & Bezborodov (1988). Biokhimiya, 53, 965-973] and 2-Zn insulin [Baker, Blundell, Cutfield, Cutfield, Dodson, Dodson, Hodgkin, Hubbard, lsaacs, Reynolds, Sakabe, Sakabe & Vijayan (1988). Philos. Trans. R. Soc. London Ser. B, 319, 456--469]. Comparison of the proposed procedures with the normal histogram-matching technique without structure-factor weighting or damping gives mean phase errors reduced by up to 10 degrees with map correlation coefficients improved by as much as 0.14. Compared to the normal histogram used with weighting of structure factors and damping, the improvement due to the use of the double-histogram method is

  6. Stochastic learning of multi-instance dictionary for earth mover’s distance-based histogram comparison

    KAUST Repository

    Fan, Jihong

    2016-09-17

    Dictionary plays an important role in multi-instance data representation. It maps bags of instances to histograms. Earth mover’s distance (EMD) is the most effective histogram distance metric for the application of multi-instance retrieval. However, up to now, there is no existing multi-instance dictionary learning methods designed for EMD-based histogram comparison. To fill this gap, we develop the first EMD-optimal dictionary learning method using stochastic optimization method. In the stochastic learning framework, we have one triplet of bags, including one basic bag, one positive bag, and one negative bag. These bags are mapped to histograms using a multi-instance dictionary. We argue that the EMD between the basic histogram and the positive histogram should be smaller than that between the basic histogram and the negative histogram. Base on this condition, we design a hinge loss. By minimizing this hinge loss and some regularization terms of the dictionary, we update the dictionary instances. The experiments over multi-instance retrieval applications shows its effectiveness when compared to other dictionary learning methods over the problems of medical image retrieval and natural language relation classification. © 2016 The Natural Computing Applications Forum

  7. A CMOS VLSI IC for real-time opto-electronic two-dimensional histogram generation

    Science.gov (United States)

    Richstein, James K.

    1993-12-01

    Histogram generation, a standard image processing operation, is a record of the intensity distribution in the image. Histogram generation has straightforward implementations on digital computers using high level languages. A prototype of an optical-electronic histogram generator was designed and tested for 1-D objects using wirewrapped MSI TTL components. The system has shown to be fairly modular in design. The aspects of the extension to two dimensions and the VLSI implementation of this design are discussed. In this paper, we report a VLSI design to be used in a two-dimensional real-time histogram generation scheme. The overall system design is such that the electronic signal obtained from the optically scanned two-dimensional semi-opaque image is processed and displayed within a period of one cycle of the scanning process. Specifically, in the VLSI implementation of the two-dimensional histogram generator, modifications were made to the original design. For the two-dimensional application, the output controller was analyzed as a finite state machine. The process used to describe the required timing signals and translate them to a VLSI finite state machine using Computer Aided Design Tools is discussed. In addition, the circuitry for sampling, binning, and display were combined with the timing circuitry on one IC. In the original design, the pulse width of the electronically sampled photodetector is limited with an analog one-shot. The high sampling rates associated with the extension to two dimensions requires significant reduction in the original 1-D prototype's sample pulse width of approximately 75 ns. The alternate design using VLSI logic gates will provide one-shot pulse widths of approximately 3 ns.

  8. Histogram and gray level co-occurrence matrix on gray-scale ultrasound images for diagnosing lymphocytic thyroiditis.

    Science.gov (United States)

    Shin, Young Gyung; Yoo, Jaeheung; Kwon, Hyeong Ju; Hong, Jung Hwa; Lee, Hye Sun; Yoon, Jung Hyun; Kim, Eun-Kyung; Moon, Hee Jung; Han, Kyunghwa; Kwak, Jin Young

    2016-08-01

    The objective of the study was to evaluate whether texture analysis using histogram and gray level co-occurrence matrix (GLCM) parameters can help clinicians diagnose lymphocytic thyroiditis (LT) and differentiate LT according to pathologic grade. The background thyroid pathology of 441 patients was classified into no evidence of LT, chronic LT (CLT), and Hashimoto's thyroiditis (HT). Histogram and GLCM parameters were extracted from the regions of interest on ultrasound. The diagnostic performances of the parameters for diagnosing and differentiating LT were calculated. Of the histogram and GLCM parameters, the mean on histogram had the highest Az (0.63) and VUS (0.303). As the degrees of LT increased, the mean decreased and the standard deviation and entropy increased. The mean on histogram from gray-scale ultrasound showed the best diagnostic performance as a single parameter in differentiating LT according to pathologic grade as well as in diagnosing LT.

  9. Gastrointestinal Dose-Histogram Effects in the Context of Dose-Volume–Constrained Prostate Radiation Therapy: Analysis of Data From the RADAR Prostate Radiation Therapy Trial

    Energy Technology Data Exchange (ETDEWEB)

    Ebert, Martin A., E-mail: Martin.Ebert@health.wa.gov.au [Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia (Australia); School of Physics, University of Western Australia, Perth, Western Australia (Australia); Foo, Kerwyn [Sydney Medical School, University of Sydney, Sydney, New South Wales (Australia); Haworth, Annette [Department of Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne, Victoria (Australia); Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria (Australia); Gulliford, Sarah L. [Joint Department of Physics, Institute of Cancer Research and Royal Marsden National Health Service Foundation Trust, Sutton, Surrey (United Kingdom); Kennedy, Angel [Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia (Australia); Joseph, David J. [Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, Western Australia (Australia); School of Surgery, University of Western Australia, Perth, Western Australia (Australia); Denham, James W. [School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales (Australia)

    2015-03-01

    Purpose: To use a high-quality multicenter trial dataset to determine dose-volume effects for gastrointestinal (GI) toxicity following radiation therapy for prostate carcinoma. Influential dose-volume histogram regions were to be determined as functions of dose, anatomical location, toxicity, and clinical endpoint. Methods and Materials: Planning datasets for 754 participants in the TROG 03.04 RADAR trial were available, with Late Effects of Normal Tissues (LENT) Subjective, Objective, Management, and Analytic (SOMA) toxicity assessment to a median of 72 months. A rank sum method was used to define dose-volume cut-points as near-continuous functions of dose to 3 GI anatomical regions, together with a comprehensive assessment of significance. Univariate and multivariate ordinal regression was used to assess the importance of cut-points at each dose. Results: Dose ranges providing significant cut-points tended to be consistent with those showing significant univariate regression odds-ratios (representing the probability of a unitary increase in toxicity grade per percent relative volume). Ranges of significant cut-points for rectal bleeding validated previously published results. Separation of the lower GI anatomy into complete anorectum, rectum, and anal canal showed the impact of mid-low doses to the anal canal on urgency and tenesmus, completeness of evacuation and stool frequency, and mid-high doses to the anorectum on bleeding and stool frequency. Derived multivariate models emphasized the importance of the high-dose region of the anorectum and rectum for rectal bleeding and mid- to low-dose regions for diarrhea and urgency and tenesmus, and low-to-mid doses to the anal canal for stool frequency, diarrhea, evacuation, and bleeding. Conclusions: Results confirm anatomical dependence of specific GI toxicities. They provide an atlas summarizing dose-histogram effects and derived constraints as functions of anatomical region, dose, toxicity, and endpoint for

  10. A Novel Imaging Marker for Small Vessel Disease Based on Skeletonization of White Matter Tracts and Diffusion Histograms.

    Science.gov (United States)

    Baykara, Ebru; Gesierich, Benno; Adam, Ruth; Tuladhar, Anil Man; Biesbroek, J Matthijs; Koek, Huiberdina L; Ropele, Stefan; Jouvent, Eric; Chabriat, Hugues; Ertl-Wagner, Birgit; Ewers, Michael; Schmidt, Reinhold; de Leeuw, Frank-Erik; Biessels, Geert Jan; Dichgans, Martin; Duering, Marco

    2016-10-01

    To establish a fully automated, robust imaging marker for cerebral small vessel disease (SVD) and related cognitive impairment that is easy to implement, reflects disease burden, and is strongly associated with processing speed, the predominantly affected cognitive domain in SVD. We developed a novel magnetic resonance imaging marker based on diffusion tensor imaging, skeletonization of white matter tracts, and histogram analysis. The marker (peak width of skeletonized mean diffusivity [PSMD]) was assessed along with conventional SVD imaging markers. We first evaluated associations with processing speed in patients with genetically defined SVD (n = 113). Next, we validated our findings in independent samples of inherited SVD (n = 57), sporadic SVD (n = 444), and memory clinic patients with SVD (n = 105). The new marker was further applied to healthy controls (n = 241) and to patients with Alzheimer's disease (n = 153). We further conducted a longitudinal analysis and interscanner reproducibility study. PSMD was associated with processing speed in all study samples with SVD (p-values between 2.8 × 10(-3) and 1.8 × 10(-10) ). PSMD explained most of the variance in processing speed (R(2) ranging from 8.8% to 46%) and consistently outperformed conventional imaging markers (white matter hyperintensity volume, lacune volume, and brain volume) in multiple regression analyses. Increases in PSMD were linked to vascular but not to neurodegenerative disease. In longitudinal analysis, PSMD captured SVD progression better than other imaging markers. PSMD is a new, fully automated, and robust imaging marker for SVD. PSMD can easily be applied to large samples and may be of great utility for both research studies and clinical use. Ann Neurol 2016;80:581-592. © 2016 American Neurological Association.

  11. Mass and fat infiltration of intercostal muscles measured by CT histogram analysis and their correlations with COPD severity.

    Science.gov (United States)

    Park, Mi Jung; Cho, Jae Min; Jeon, Kyung Nyeo; Bae, Kyung Soo; Kim, Ho Cheol; Choi, Dae Seob; Na, Jae Boem; Choi, Ho Cheol; Choi, Hye Young; Kim, Ji Eun; Shin, Hwa Seon

    2014-06-01

    Chronic obstructive pulmonary disease (COPD) is characterized by progressive respiratory function impairment and respiratory muscle dysfunction. We hypothesized that the mass and fat infiltration of respiratory muscles correlates with COPD severity and emphysema extent. Ninety-eight male patients with COPD underwent chest computed tomography (CT) and spirometry. The mass and fat infiltrations of intercostal and latissimus muscles were quantified as the cross-sectional area (CSA) and attenuation of these muscles using CT histogram analysis. Intercostal index and latissimus index were defined as intercostal CSAs and latissimus CSAs divided by body mass index. The emphysema extent was measured as the ratio of the emphysematous lung volume to the total lung volume using a density-mask technique. Pearson correlation analyses were performed to evaluate the relationships between these parameters. Multiple regression analysis was performed using forced expiratory volume in 1 second (FEV1) as the dependent parameter and the clinical and CT data as the independent parameters. FEV1 was significantly correlated with intercostal index (r = 0.57), latissimus index (r = 0.34), intercostal attenuation (r = 0.62), and latissimus attenuation (r = 0.38). Emphysema extent was significantly correlated with intercostal index (r = -0.36) and intercostal attenuation (r = -0.50). Multiple regression analysis showed that FEV1 was predicted by intercostal attenuation (B = 0.40), intercostal CSA (B = 0.23), emphysema extent (B = -0.23), and age (B = -0.21, R(2) = 0.64, P increase in intercostal fat are associated with worsening of COPD severity. Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.

  12. Bins Approach for CBIR by Shifting the Histogram to Lower Intensities using proposed polynomials

    Directory of Open Access Journals (Sweden)

    H. B. Kekre

    2012-09-01

    Full Text Available This paper describes the novel approach of feature extraction for CBIR systems. It also suggests the use of newly designed polynomial function to modify the image histogram so that the result of the CBIR systemcan be improved. To support this suggestion multiple polynomial functions have been tried. Out of which the best polynomial can be selected to modify the histogram for feature extraction. This gives better performance for the image retrieval based on contents. The separate histograms are obtained for each of the three color planes of the image so that the color information can be handled separately. These histograms are then divided into two equal parts by calculating the centre of gravity. This division of the R, G and B histograms into two parts lead towards the generation of eight bins. Eight bins are designed to hold different types of information like ‘Count of pixels’, ‘Total of intensities’ and ‘Average of intensities’. The work done includes the set of three polynomial functions used modify the histograms. Based on eachpolynomial function and the variation of the information used to represent the eight bin feature vector we could generate the multiple feature vector databases. Two types of bin sets based on type of the bin contents Total and Average of intensities with respect to each of the three polynomial functions for three colors we have 2x3x3 = 18 plus for count of pixels for each polynomial function giving 3 feature vector databases; like this total 18 + 3= 21 feature vector databases are prepared for the system testing. To demonstrate the performance of the system we have used database of 2000 BMP images from 20 different classes where each class has 100 images. 200 images are selected randomly as 10 images from each of the 20 classes to be given as query to the system. To compare the database and query image feature vectors and facilitate the retrieval three similarity measures are used namely Euclidean

  13. Histogram analysis of apparent diffusion coefficient at 3.0t: Correlation with prognostic factors and subtypes of invasive ductal carcinoma.

    Science.gov (United States)

    Kim, Eun Jeong; Kim, Sung Hun; Park, Ga Eun; Kang, Bong Joo; Song, Byung Joo; Kim, Yun Ju; Lee, Dongeon; Ahn, Hyunsoo; Kim, Inah; Son, Yo Han; Grimm, Robert

    2015-12-01

    To evaluate apparent diffusion coefficient (ADC) histogram parameters that show correlations with prognostic factors and subtypes of breast cancer. At 3.0T, various ADC histogram parameters were calculated including the entire tumor volume in 173 invasive ductal carcinomas: the minimum, 10th percentile, mean, median, 90th percentile, and maximum. ADC parameters were correlated with prognostic factors and subtype. The mean ADCmedian value was significantly higher in the group with lymph node metastasis, HER2 positivity, and a Ki-67 value correlation between ADCmedian and tumor size, histologic grade, estrogen receptor expression, and progesterone receptor expression (P = 0.272, 0.113, 0.261, and 0.181, respectively). For most ADC parameters except for ADCmin , the mean of variable ADC parameters of HER2-positive, luminal A, luminal B-HER2(+), triple-negative, and luminal B-HER2(-) diseases were arranged in descending order (1.175, 0.936, 0.863, 0.811, and 0.665 × 10(-3) mm(2) /s in ADCmedian , respectively) with statistical significant difference (P coefficient = -0.317). Various ADC parameters were correlated with prognostic factors and subtype, except for ADCmin . HER2 positivity showed high ADC values and high Ki-67 index revealed low ADC values. © 2015 Wiley Periodicals, Inc.

  14. Novel 3-D Object Recognition Methodology Employing a Curvature-Based Histogram

    Directory of Open Access Journals (Sweden)

    Liang-Chia Chen

    2013-07-01

    Full Text Available In this paper, a new object recognition algorithm employing a curvature-based histogram is presented. Recognition of three-dimensional (3-D objects using range images remains one of the most challenging problems in 3-D computer vision due to its noisy and cluttered scene characteristics. The key breakthroughs for this problem mainly lie in defining unique features that distinguish the similarity among various 3-D objects. In our approach, an object detection scheme is developed to identify targets underlining an automated search in the range images using an initial process of object segmentation to subdivide all possible objects in the scenes and then applying a process of object recognition based on geometric constraints and a curvature-based histogram for object recognition. The developed method has been verified through experimental tests for its feasibility confirmation.

  15. A novel scheme for binarization of vehicle images using hierarchical histogram equalization technique

    CERN Document Server

    Saha, Satadal; Nasipuri, Mita; Basu, Dipak Kumar

    2010-01-01

    Automatic License Plate Recognition system is a challenging area of research now-a-days and binarization is an integral and most important part of it. In case of a real life scenario, most of existing methods fail to properly binarize the image of a vehicle in a congested road, captured through a CCD camera. In the current work we have applied histogram equalization technique over the complete image and also over different hierarchy of image partitioning. A novel scheme is formulated for giving the membership value to each pixel for each hierarchy of histogram equalization. Then the image is binarized depending on the net membership value of each pixel. The technique is exhaustively evaluated on the vehicle image dataset as well as the license plate dataset, giving satisfactory performances.

  16. 3D facial expression recognition based on histograms of surface differential quantities

    KAUST Repository

    Li, Huibin

    2011-01-01

    3D face models accurately capture facial surfaces, making it possible for precise description of facial activities. In this paper, we present a novel mesh-based method for 3D facial expression recognition using two local shape descriptors. To characterize shape information of the local neighborhood of facial landmarks, we calculate the weighted statistical distributions of surface differential quantities, including histogram of mesh gradient (HoG) and histogram of shape index (HoS). Normal cycle theory based curvature estimation method is employed on 3D face models along with the common cubic fitting curvature estimation method for the purpose of comparison. Based on the basic fact that different expressions involve different local shape deformations, the SVM classifier with both linear and RBF kernels outperforms the state of the art results on the subset of the BU-3DFE database with the same experimental setting. © 2011 Springer-Verlag.

  17. High Capacity Reversible Watermarking for Audio by Histogram Shifting and Predicted Error Expansion

    Directory of Open Access Journals (Sweden)

    Fei Wang

    2014-01-01

    Full Text Available Being reversible, the watermarking information embedded in audio signals can be extracted while the original audio data can achieve lossless recovery. Currently, the few reversible audio watermarking algorithms are confronted with following problems: relatively low SNR (signal-to-noise of embedded audio; a large amount of auxiliary embedded location information; and the absence of accurate capacity control capability. In this paper, we present a novel reversible audio watermarking scheme based on improved prediction error expansion and histogram shifting. First, we use differential evolution algorithm to optimize prediction coefficients and then apply prediction error expansion to output stego data. Second, in order to reduce location map bits length, we introduced histogram shifting scheme. Meanwhile, the prediction error modification threshold according to a given embedding capacity can be computed by our proposed scheme. Experiments show that this algorithm improves the SNR of embedded audio signals and embedding capacity, drastically reduces location map bits length, and enhances capacity control capability.

  18. The GNAM monitoring system and the OHP histogram presenter for ATLAS

    CERN Document Server

    Zema, P F; Crosetti, G; Della Pietra, M; Dotti, A; Ferrari, R; Gaudio, G; Roda, R; Salvatore, D; Sarri, F; Vandelli, W; 14th IEEE-NPSS Real Time Conference 2005

    2005-01-01

    ATLAS is one of the four experiments under construction along the Large Hadron Collider at CERN. During the 2004 Combined Test Beam, GNAM and OHP were widely used for the online monitoring of both the hardware setup and the data quality. GNAM is a modular framework where detector specific code can be easily plugged into obtain complete online low-level monitoring applications. It is based on the monitoring tools provided by the ATLAS Trigger and Data Acquisition (TDAQ) software. OHP is a histogram presenter, capable to perform both as a configurable display and as a browser. From OHP, requests to execute simple interactive perations (such as reset, rebin or update) on histograms, can be sent to GNAM.

  19. Minimum Error Thresholding Segmentation Algorithm Based on 3D Grayscale Histogram

    Directory of Open Access Journals (Sweden)

    Jin Liu

    2014-01-01

    Full Text Available Threshold segmentation is a very important technique. The existing threshold algorithms do not work efficiently for noisy grayscale images. This paper proposes a novel algorithm called three-dimensional minimum error thresholding (3D-MET, which is used to solve the problem. The proposed approach is implemented by an optimal threshold discriminant based on the relative entropy theory and the 3D histogram. The histogram is comprised of gray distribution information of pixels and relevant information of neighboring pixels in an image. Moreover, a fast recursive method is proposed to reduce the time complexity of 3D-MET from O(L6 to O(L3, where L stands for gray levels. Experimental results demonstrate that the proposed approach can provide superior segmentation performance compared to other methods for gray image segmentation.

  20. Kernel Learning of Histogram of Local Gabor Phase Patterns for Face Recognition

    Directory of Open Access Journals (Sweden)

    Bineng Zhong

    2008-06-01

    Full Text Available This paper proposes a new face recognition method, named kernel learning of histogram of local Gabor phase pattern (K-HLGPP, which is based on Daugman’s method for iris recognition and the local XOR pattern (LXP operator. Unlike traditional Gabor usage exploiting the magnitude part in face recognition, we encode the Gabor phase information for face classification by the quadrant bit coding (QBC method. Two schemes are proposed for face recognition. One is based on the nearest-neighbor classifier with chi-square as the similarity measurement, and the other makes kernel discriminant analysis for HLGPP (K-HLGPP using histogram intersection and Gaussian-weighted chi-square kernels. The comparative experiments show that K-HLGPP achieves a higher recognition rate than other well-known face recognition systems on the large-scale standard FERET, FERET200, and CAS-PEAL-R1 databases.

  1. Multi-stream LSTM-HMM decoding and histogram equalization for noise robust keyword spotting.

    Science.gov (United States)

    Wöllmer, Martin; Marchi, Erik; Squartini, Stefano; Schuller, Björn

    2011-09-01

    Highly spontaneous, conversational, and potentially emotional and noisy speech is known to be a challenge for today's automatic speech recognition (ASR) systems, which highlights the need for advanced algorithms that improve speech features and models. Histogram Equalization is an efficient method to reduce the mismatch between clean and noisy conditions by normalizing all moments of the probability distribution of the feature vector components. In this article, we propose to combine histogram equalization and multi-condition training for robust keyword detection in noisy speech. To better cope with conversational speaking styles, we show how contextual information can be effectively exploited in a multi-stream ASR framework that dynamically models context-sensitive phoneme estimates generated by a long short-term memory neural network. The proposed techniques are evaluated on the SEMAINE database-a corpus containing emotionally colored conversations with a cognitive system for "Sensitive Artificial Listening".

  2. Image Restoration and Denoising By Using Nonlocally Centralized Sparse Representation and Histogram Clipping

    Directory of Open Access Journals (Sweden)

    Dr. T. V. S. Prasad Gupta

    2014-10-01

    Full Text Available Due to the degradation of observed image the noisy, blurred, Distorted image can be occurred .for restoring image information we propose the sparse representations by conventional modelsmay not be accurate enough for a faithful reconstruction of the original image. To improve the performance of sparse representation-based image restoration,In this method the sparse coding noise is added for image restoration, due to this image restoration the sparse coefficients of original image can be detected. The so-called nonlocally centralized sparse representation (NCSR model is as simple as the standard sparse representation model,for denoising the image here we use the Histogram clipping method by using histogram based sparse representation effectively reduce the noise.and also implement the TMR filter for Quality image.various types of image restoration problems, including denoising, deblurring and super-resolution, validate the generality and state-of-the-art performance of the proposed algorithm.

  3. Automatic Contrast Enhancement of Brain MR Images Using Hierarchical Correlation Histogram Analysis.

    Science.gov (United States)

    Chen, Chiao-Min; Chen, Chih-Cheng; Wu, Ming-Chi; Horng, Gwoboa; Wu, Hsien-Chu; Hsueh, Shih-Hua; Ho, His-Yun

    Parkinson's disease is a progressive neurodegenerative disorder that has a higher probability of occurrence in middle-aged and older adults than in the young. With the use of a computer-aided diagnosis (CAD) system, abnormal cell regions can be identified, and this identification can help medical personnel to evaluate the chance of disease. This study proposes a hierarchical correlation histogram analysis based on the grayscale distribution degree of pixel intensity by constructing a correlation histogram, that can improves the adaptive contrast enhancement for specific objects. The proposed method produces significant results during contrast enhancement preprocessing and facilitates subsequent CAD processes, thereby reducing recognition time and improving accuracy. The experimental results show that the proposed method is superior to existing methods by using two estimation image quantitative methods of PSNR and average gradient values. Furthermore, the edge information pertaining to specific cells can effectively increase the accuracy of the results.

  4. High capacity reversible watermarking for audio by histogram shifting and predicted error expansion.

    Science.gov (United States)

    Wang, Fei; Xie, Zhaoxin; Chen, Zuo

    2014-01-01

    Being reversible, the watermarking information embedded in audio signals can be extracted while the original audio data can achieve lossless recovery. Currently, the few reversible audio watermarking algorithms are confronted with following problems: relatively low SNR (signal-to-noise) of embedded audio; a large amount of auxiliary embedded location information; and the absence of accurate capacity control capability. In this paper, we present a novel reversible audio watermarking scheme based on improved prediction error expansion and histogram shifting. First, we use differential evolution algorithm to optimize prediction coefficients and then apply prediction error expansion to output stego data. Second, in order to reduce location map bits length, we introduced histogram shifting scheme. Meanwhile, the prediction error modification threshold according to a given embedding capacity can be computed by our proposed scheme. Experiments show that this algorithm improves the SNR of embedded audio signals and embedding capacity, drastically reduces location map bits length, and enhances capacity control capability.

  5. Reversible watermarking based on invariant image classification and dynamical error histogram shifting.

    Science.gov (United States)

    Pan, W; Coatrieux, G; Cuppens, N; Cuppens, F; Roux, Ch

    2011-01-01

    In this article, we present a novel reversible watermarking scheme. Its originality stands in identifying parts of the image that can be watermarked additively with the most adapted lossless modulation between: Pixel Histogram Shifting (PHS) or Dynamical Error Histogram Shifting (DEHS). This classification process makes use of a reference image derived from the image itself, a prediction of it, which has the property to be invariant to the watermark addition. In that way, watermark embedded and reader remain synchronized through this image of reference. DEHS is also an original contribution of this work. It shifts predict-errors between the image and its reference image taking care of the local specificities of the image, thus dynamically. Conducted experiments, on different medical image test sets issued from different modalities and some natural images, show that our method can insert more data with lower distortion than the most recent and efficient methods of the literature.

  6. Recovery of the histogram of hourly ozone distribution from weekly average concentrations.

    Science.gov (United States)

    Olcese, Luis E; Toselli, Beatriz M

    2006-05-01

    A simple method is presented for estimating hourly distribution of air pollutants, based on data collected by passive sensors on a weekly or bi-weekly basis with no need for previous measurements at a site. In order for this method to be applied to locations where no hourly records are available, reference data from other sites are required to generate calibration histograms. The proposed procedure allows one to obtain the histogram of hourly ozone values during a given week with an error of about 30%, which is good considering the simplicity of this approach. This method can be a valuable tool for sites that lack previous hourly records of pollutant ambient concentrations, where it can be used to verify compliance with regulations or to estimate the AOT40 index with an acceptable degree of exactitude.

  7. Histograms in heavy-quark QCD at finite temperature and density

    CERN Document Server

    Saito, H; Aoki, S; Kanaya, K; Nakagawa, Y; Ohno, H; Okuno, K; Umeda, T

    2013-01-01

    We study the phase structure of lattice QCD with heavy quarks at finite temperature and density by a histogram method. We determine the location of the critical point at which the first-order deconfining transition in the heavy-quark limit turns into a crossover at intermediate quark masses through a change of the shape of the histogram under variation of coupling parameters. We estimate the effect of the complex phase factor which causes the sign problem at finite density, and show that, in heavy-quark QCD, the effect is small around the critical point. We determine the critical surface in 2+1 flavor QCD in the heavy-quark region at all values of the chemical potential mu including mu=infty.

  8. Evaluation of the S phase distribution of flow cytometric DNA histograms by autoradiography and computer algorithms.

    Science.gov (United States)

    Sheck, L E; Muirhead, K A; Horan, P K

    1980-09-01

    Cell sorting and tritiated thymidine autoradiography were used to define the distribution of S phase cells in flow cytometric DNA histograms obtained from exponential mouse lymphoma cells (L5178Y). The numbers of labeled S phase cells, autoradiographically determined from cells sorted at 2-channel intervals in the G1/early S and late S/G2M regions of the histogram, were compared with the numbers of computed S phase cells in comparable 2-channel intervals as predicted by several computer algorithms used to extract cell cycle phase distributions from DNA histograms. Polynomial and multirectangle algorithms gave computed estimates of total %S in close agreement with the tritiated thymidine labeling index for the cell population, while multi-Gaussian algorithms underestimated %S. Interval autoradiographic and algorithm studies confirmed these results in that no significant differences were found between the autoradiographic S phase distribution and S phase distributions calculated by the polynomial and multirectangle models. However, S phase cells were significantly underestimated in G1/early S by a constrained multi-Gaussian model and in both G1/early S and late S/G2 by an unconstrained multi-Gaussian model. For the particular cell line (L5178Y), staining protocol (mithramycin following ethanol fixation) and instrumentation (Coulter TPS-2 cell sorter) used in this study, close agreement between computed %S and tritiated thymidine labeling index was found to be a reliable indicator of an algorithm's success in resolving S phase cells in the G1/S and S/G2 transition regions of the DNA histograms.

  9. Benign-Malignant Lung Nodule Classification with Geometric and Appearance Histogram Features

    OpenAIRE

    Shewaye, Tizita Nesibu; Mekonnen, Alhayat Ali

    2016-01-01

    Lung cancer accounts for the highest number of cancer deaths globally. Early diagnosis of lung nodules is very important to reduce the mortality rate of patients by improving the diagnosis and treatment of lung cancer. This work proposes an automated system to classify lung nodules as malignant and benign in CT images. It presents extensive experimental results using a combination of geometric and histogram lung nodule image features and different linear and non-linear discriminant classifier...

  10. EVALUATION OF DISTRIBUTION HISTOGRAMS FOR INCREMENT OF CHROMATICITY COORDINATES IN DISPLAY TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    I. O. Zharinov

    2016-05-01

    Full Text Available We consider evaluation problem of chromaticity coordinates increment for an image displayed by indicating means (liquid crystal panels and etc.. Display device profile set by the weight matrix for components of primary colors serves as basic data for quantitative calculation. Research results have the form of mathematical expressions allowing calculation of increment values of chromaticity coordinates of the image displayed on indicating means and histograms of increment distribution.

  11. Histogram analysis of apparent diffusion coefficient map of diffusion-weighted MRI in endometrial cancer: a preliminary correlation study with histological grade.

    Science.gov (United States)

    Woo, Sungmin; Cho, Jeong Yeon; Kim, Sang Youn; Kim, Seung Hyup

    2014-12-01

    Until now, several investigators have explored the value of diffusion-weighted magnetic resonance imaging (DWI) for the preoperative tumor grading of endometrial cancer. However, the diagnostic value of DWI with quantitative analysis of apparent diffusion coefficient (ADC) has been controversial. To explore the role of histogram analysis of ADC maps based on entire tumor volume in determining the grade of endometrial cancer. This study was IRB-approved with waiver of informed consent. Thirty-three patients with endometrial cancer underwent DWI (b = 0, 600, 1000 s/mm(2)), and corresponding ADC maps were acquired. Regions of interest (ROIs) were drawn on all slices of the ADC map in which the tumor was visualized including areas of necrosis to derive volume-based histographic ADC data. Histogram parameters (5th-95th percentiles, mean, standard deviation, skewness, kurtosis) were correlated with histological grade using one-way ANOVA with Tukey-Kramer test for post hoc comparisons, and were compared between high (grade 3) and low (grades 1/2) grade using Student t-test. ROC curve analysis was performed to determine the optimum threshold value for each parameter, and their corresponding sensitivity and specificity. The standard deviation, quartile, 75th, 90th, and 95th percentiles of ADC showed significant differences between grades (P ≤ 0.03 for all) and between high and low grades (P ≤ 0.024 for all). There were no significant correlations between tumor grade and other parameters. ROC curve analysis yielded sensitivities and specificities of 75% and 96%, 62.5% and 92%, 100% and 52%, 100% and 72%, and 100% and 88%, using standard deviation, quartile, 75th, 90th, and 95th percentiles for determining high grade with corresponding areas under the curve (AUCs) of 0.787, 0.792, 0.765, 0.880, and 0.925, respectively. Histogram analysis of ADC maps based on entire tumor volume can be useful for predicting the histological grade of endometrial cancer. The 90th and 95th

  12. On the characteristic form of histograms appearing at the culmination of solar eclipse

    CERN Document Server

    Shnoll, S E

    2006-01-01

    As shown in a number of our works, the form of histograms - distributions of amplitude fluctuations - varies regularly in time, with these variations being similar for processes of any nature, from biochemical reactions to noise in the gravitational antenna and all types of the radioactive decay. In particular, we have revealed basic laws, suggesting a cosmo-physical nature of these phenomena, in the time series created by the noise generators of the global GCP net. On the basis of all the results obtained, a conclusion has been made that the histogram form is determined by fluctuations of the spacetime, which depend on the movement of the measured system (laboratory) relative to the heavenly bodies. An important step to understand the nature of these phenomena was the finding that at the moments of the new Moon, a specific histogram form appears practically simultaneously at different geographical points, from Arctic to Antarctic, in middle latitudes of West and East hemispheres. This effect seems to be not ...

  13. Image Enhancement Pada Screen Capture CCTV Dengan Menggunakan Metode Histogram EKualisasi

    Directory of Open Access Journals (Sweden)

    Hendro Nugroho

    2017-05-01

    Full Text Available Penggunaan kamera Closed Circuit Television (CCTV banyak digunakan saat ini terutama perusahaan atau industry, pertokoan dan tempat-temapat strategis lainnya. Dengan menggunakan kamera CCTV keamanan tempat tersebut akan terjamin. Akan tetapi kekurangan dari kamera CCTV adalah apabila ruangan tidak memiliki cahaya kurang (gelap maka hasil objek yang terekam tidak maksimal. Untuk mengatasi permasalahan diatas maka perlu adanya Histogram Ekualisasi yang dapat memberikan perbaikan kualitas citra (Image Enhancement. Untuk citra yang diambil sebagai Image Enhancement sebagai contoh uji coba penelitian adalah citra Screen Capture CCTV. Dari citra Screen Capture CCTV tersebut dilakukan tahap-tahap pemrosesan citra untuk menghasilkan perbaikan kualitas citra yang baik. Rencana pengambilan data citra screen Capture CCTV sejumlah 5 citra. Cara kerja sistem informasi Image Enhancement adalah citra screen Capture CCTV di praproses dengan ukuran 200x260 piksel BMP, kemudia citra di GarayScale untuk dijadikan nilai piksel yang seragam, selajatunya citra di histogram ekualisasi untuk intensitas menjadi seragam. Untuk menguji tingkat kualitas citra menggunakan metode ekstraksi tekstur histogram berbasis rata-rata intensitas dan deviasi standar.

  14. Temporal evolution for the phase histogram of ECG during human ventricular fibrillation

    Science.gov (United States)

    Wu, Ming-Chya; Struzik, Zbigniew R.; Watanabe, Eiichi; Yamamoto, Yoshiharu; Hu, Chin-Kun

    2007-07-01

    A novel approach to momentary/instantaneous morphological assessment of phase histograms, extending phase statistics analysis, is used to investigate electrocardiograms during ventricular fibrillation (VF) in humans. By using empirical mode decomposition (EMD) and the Hilbert transform, we calculate the instantaneous phase of intrinsic mode functions (IMFs) in Holter data from 16 individuals, and construct the corresponding momentary phase histograms, enabling us to inspect the evolution of the waveform of the time series. A measure defined as the difference between the integrals of the probability distribution density of phase in different regions is then used to characterize the morphology of the momentary histograms and their temporal evolution. We find that the measure of morphology difference allows near perfect classification of the VF data into survivor and non-survivor groups. The technique offers a new possibility to improve the effectiveness of intervention in defibrillation treatment and limit the negative side effects of unnecessary interventions. The approach can be implemented in real time and should provide a useful method for early evaluation of (fatal) VF.

  15. Digital image classification with the help of artificial neural network by simple histogram.

    Science.gov (United States)

    Dey, Pranab; Banerjee, Nirmalya; Kaur, Rajwant

    2016-01-01

    Visual image classification is a great challenge to the cytopathologist in routine day-to-day work. Artificial neural network (ANN) may be helpful in this matter. In this study, we have tried to classify digital images of malignant and benign cells in effusion cytology smear with the help of simple histogram data and ANN. A total of 404 digital images consisting of 168 benign cells and 236 malignant cells were selected for this study. The simple histogram data was extracted from these digital images and an ANN was constructed with the help of Neurointelligence software [Alyuda Neurointelligence 2.2 (577), Cupertino, California, USA]. The network architecture was 6-3-1. The images were classified as training set (281), validation set (63), and test set (60). The on-line backpropagation training algorithm was used for this study. A total of 10,000 iterations were done to train the ANN system with the speed of 609.81/s. After the adequate training of this ANN model, the system was able to identify all 34 malignant cell images and 24 out of 26 benign cells. The ANN model can be used for the identification of the individual malignant cells with the help of simple histogram data. This study will be helpful in the future to identify malignant cells in unknown situations.

  16. Control system of hexacopter using color histogram footprint and convolutional neural network

    Science.gov (United States)

    Ruliputra, R. N.; Darma, S.

    2017-07-01

    The development of unmanned aerial vehicles (UAV) has been growing rapidly in recent years. The use of logic thinking which is implemented into the program algorithms is needed to make a smart system. By using visual input from a camera, UAV is able to fly autonomously by detecting a target. However, some weaknesses arose as usage in the outdoor environment might change the target's color intensity. Color histogram footprint overcomes the problem because it divides color intensity into separate bins that make the detection tolerant to the slight change of color intensity. Template matching compare its detection result with a template of the reference image to determine the target position and use it to position the vehicle in the middle of the target with visual feedback control based on Proportional-Integral-Derivative (PID) controller. Color histogram footprint method localizes the target by calculating the back projection of its histogram. It has an average success rate of 77 % from a distance of 1 meter. It can position itself in the middle of the target by using visual feedback control with an average positioning time of 73 seconds. After the hexacopter is in the middle of the target, Convolutional Neural Networks (CNN) classifies a number contained in the target image to determine a task depending on the classified number, either landing, yawing, or return to launch. The recognition result shows an optimum success rate of 99.2 %.

  17. Digital image classification with the help of artificial neural network by simple histogram

    Directory of Open Access Journals (Sweden)

    Pranab Dey

    2016-01-01

    Full Text Available Background: Visual image classification is a great challenge to the cytopathologist in routine day-to-day work. Artificial neural network (ANN may be helpful in this matter. Aims and Objectives: In this study, we have tried to classify digital images of malignant and benign cells in effusion cytology smear with the help of simple histogram data and ANN. Materials and Methods: A total of 404 digital images consisting of 168 benign cells and 236 malignant cells were selected for this study. The simple histogram data was extracted from these digital images and an ANN was constructed with the help of Neurointelligence software [Alyuda Neurointelligence 2.2 (577, Cupertino, California, USA]. The network architecture was 6-3-1. The images were classified as training set (281, validation set (63, and test set (60. The on-line backpropagation training algorithm was used for this study. Result: A total of 10,000 iterations were done to train the ANN system with the speed of 609.81/s. After the adequate training of this ANN model, the system was able to identify all 34 malignant cell images and 24 out of 26 benign cells. Conclusion: The ANN model can be used for the identification of the individual malignant cells with the help of simple histogram data. This study will be helpful in the future to identify malignant cells in unknown situations.

  18. Efficient descriptor of histogram of salient edge orientation map for finger vein recognition.

    Science.gov (United States)

    Lu, Yu; Yoon, Sook; Xie, Shan Juan; Yang, Jucheng; Wang, Zhihui; Park, Dong Sun

    2014-07-10

    Finger vein images are rich in orientation and edge features. Inspired by the edge histogram descriptor proposed in MPEG-7, this paper presents an efficient orientation-based local descriptor, named histogram of salient edge orientation map (HSEOM). HSEOM is based on the fact that human vision is sensitive to edge features for image perception. For a given image, HSEOM first finds oriented edge maps according to predefined orientations using a well-known edge operator and obtains a salient edge orientation map by choosing an orientation with the maximum edge magnitude for each pixel. Then, subhistograms of the salient edge orientation map are generated from the nonoverlapping submaps and concatenated to build the final HSEOM. In the experiment of this paper, eight oriented edge maps were used to generate a salient edge orientation map for HSEOM construction. Experimental results on our available finger vein image database, MMCBNU_6000, show that the performance of HSEOM outperforms that of state-of-the-art orientation-based methods (e.g., Gabor filter, histogram of oriented gradients, and local directional code). Furthermore, the proposed HSEOM has advantages of low feature dimensionality and fast implementation for a real-time finger vein recognition system.

  19. Adaptive local backlight dimming algorithm based on local histogram and image characteristics

    Science.gov (United States)

    Nadernejad, Ehsan; Burini, Nino; Korhonen, Jari; Forchhammer, Søren; Mantel, Claire

    2013-02-01

    Liquid Crystal Display (LCDs) with Light Emitting Diode (LED) backlight is a very popular display technology, used for instance in television sets, monitors and mobile phones. This paper presents a new backlight dimming algorithm that exploits the characteristics of the target image, such as the local histograms and the average pixel intensity of each backlight segment, to reduce the power consumption of the backlight and enhance image quality. The local histogram of the pixels within each backlight segment is calculated and, based on this average, an adaptive quantile value is extracted. A classification into three classes based on the average luminance value is performed and, depending on the image luminance class, the extracted information on the local histogram determines the corresponding backlight value. The proposed method has been applied on two modeled screens: one with a high resolution direct-lit backlight, and the other screen with 16 edge-lit backlight segments placed in two columns and eight rows. We have compared the proposed algorithm against several known backlight dimming algorithms by simulations; and the results show that the proposed algorithm provides better trade-off between power consumption and image quality preservation than the other algorithms representing the state of the art among feature based backlight algorithms.

  20. Plastic Flowlike Deformation and Its Relation to Aperiodic Peaks in Conductance Histograms of Molybdenum Nanocontacts

    Science.gov (United States)

    Yamada, Kohei; Kizuka, Tokushi

    2016-10-01

    We observed the tensile deformation of molybdenum (Mo) nanocontacts (NCs) and simultaneously measured their conductance by in situ transmission electron microscopy. During deformation, the contact width decreased from several nanometers to a single-atom size. Mo NCs were thinned via a plastic flowlike deformation process. The process differs from the slip on lattice planes, which is frequently observed in NCs made of noble metals. We plotted histograms of the time-conductance traces measured during the tensile deformation of Mo NCs. In the conductance histograms, we observed peaks at 1.8G0 (G0 = 2e2/h, where e is the electron charge and h is Planck's constant), 3.6G0, and 4.4G0. When the minimum conductance (1.8G0) was measured, the minimum cross-sectional widths of the NCs were 3-7 atoms. These NCs exhibited relaxed structures that formed irregularly after the plastic flowlike deformation occurred in the final stage of the tensile process. We inferred that the aperiodic peaks observed in the conductance histograms originated from irregular variations in the contact areas and atomic configurations of the NCs during the plastic flowlike deformation. Moreover, the conductance value of the single-atom contacts was less than 0.1G0.

  1. Statistical Analysis of Photopyroelectric Signals using Histogram and Kernel Density Estimation for differentiation of Maize Seeds

    Science.gov (United States)

    Rojas-Lima, J. E.; Domínguez-Pacheco, A.; Hernández-Aguilar, C.; Cruz-Orea, A.

    2016-09-01

    Considering the necessity of photothermal alternative approaches for characterizing nonhomogeneous materials like maize seeds, the objective of this research work was to analyze statistically the amplitude variations of photopyroelectric signals, by means of nonparametric techniques such as the histogram and the kernel density estimator, and the probability density function of the amplitude variations of two genotypes of maize seeds with different pigmentations and structural components: crystalline and floury. To determine if the probability density function had a known parametric form, the histogram was determined which did not present a known parametric form, so the kernel density estimator using the Gaussian kernel, with an efficiency of 95 % in density estimation, was used to obtain the probability density function. The results obtained indicated that maize seeds could be differentiated in terms of the statistical values for floury and crystalline seeds such as the mean (93.11, 159.21), variance (1.64× 103, 1.48× 103), and standard deviation (40.54, 38.47) obtained from the amplitude variations of photopyroelectric signals in the case of the histogram approach. For the case of the kernel density estimator, seeds can be differentiated in terms of kernel bandwidth or smoothing constant h of 9.85 and 6.09 for floury and crystalline seeds, respectively.

  2. Statistical Moments Extracted from Eight Bins Formed by CG Partitioning of Histogram Modified using Linear Equations

    Directory of Open Access Journals (Sweden)

    H. B. Kekre

    2012-09-01

    Full Text Available This paper explores the novel idea for feature extraction based on bins approach for CBIR. This work has fulfilled all the criterion of efficient feature extraction method like dimensionality reduction, fast extraction and efficient retrieval. Main idea used in feature extraction is based on the histogram and the linear functions used to modify it. Each BMP image in database is separated in R, G and B planes. We have calculated the histogram for each of them which are modified using linear equations. These modified histograms are partitioned using CG so that mass of intensities of the image pixels will be distributed uniformly in two parts. This CG partitioning of three image planes leads to generate the eight bins. Information extracted from these bins is in the form of statistical first four absolute moments namely MEAN (MEAN, Standard deviation (STD, Skewness (SKEW, and Kurtosis (KURTO. Each of these moments are computed separately for R, G and B colors. This generates four types of feature vectors of dimension eight. Database of 2000 BMP images is used for the experimentation. Multiple feature vector databases are prepared as part of preprocessing work of this CBIR system. Comparison of query and database feature vector is carried out using three similarity measures namely Euclidean distance (ED, Absolute distance (AD and Cosine correlation distance (CD. To evaluate the retrieval efficiency of this system we have used three parameters, Precision Recall Cross over Point (PRCP, Longest String (LS and Length of String to Retrieve all Relevant (LSRR.

  3. Conductance histogram evolution of an EC-MCBJ fabricated Au atomic point contact

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yang; Liu Junyang; Chen Zhaobin; Tian Jinghua; Jin Xi; Liu Bo; Yang Fangzu; Tian Zhongqun [State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Li Xiulan; Tao Nongjian [Center for Bioelectronics and Biosensors, Biodesign Institute, Department of Electrical Engineering, Arizona State University, Tempe, AZ 85287-6206 (United States); Luo Zhongzi; Lu Miao, E-mail: zqtian@xmu.edu.cn [Micro-Electro-Mechanical Systems Research Center, Pen-Tung Sah Micro-Nano Technology Institute, Xiamen University, Xiamen 361005 (China)

    2011-07-08

    This work presents a study of Au conductance quantization based on a combined electrochemical deposition and mechanically controllable break junction (MCBJ) method. We describe the microfabrication process and discuss improved features of our microchip structure compared to the previous one. The improved structure prolongs the available life of the microchip and also increases the success rate of the MCBJ experiment. Stepwise changes in the current were observed at the last stage of atomic point contact breakdown and conductance histograms were constructed. The evolution of 1G{sub 0} peak height in conductance histograms was used to investigate the probability of formation of an atomic point contact. It has been shown that the success rate in forming an atomic point contact can be improved by decreasing the stretching speed and the degree that the two electrodes are brought into contact. The repeated breakdown and formation over thousands of cycles led to a distinctive increase of 1G{sub 0} peak height in the conductance histograms, and this increased probability of forming a single atomic point contact is discussed.

  4. Sistem Pendeteksi Kualitas Daging Dengan Ekualisasi Histogram Dan Thresholding Berbasis Android

    Directory of Open Access Journals (Sweden)

    Anggit Sri Herlambang

    2016-04-01

    Full Text Available Kebutuhan daging sapi yang meningkat sering dimanfaatkan oleh penjual daging sapi untuk melakukan kecurangan. Kecurangan yang sering dimanfaatkan biasanya dalam hal kualitas daging sapi. Kualitas daging ditentukan oleh beberapa parameter, termasuk parameter ukuran, tekstur, karakteristik warna, bau daging dan lain - lain. Parameter adalah salah satu faktor penting untuk menentukan kualitas daging. Umumnya dalam menentukan kualitas daging dilakukan dengan menggunakan indra penglihatan. Sehingga cara manual masih bersifat subjektif dalam menilai kualitas daging. Penelitian ini bertujuan untuk merancang aplikasi sistem pendeteksi kualitas daging dengan sampel 20 citra daging data uji. Sistem pendeteksi kualitas daging dengan ekualisasi histogram dan thresholding berbasis android ini dibangun dengan menggunakan bahasa pemrograman berbasis Android yang terintegrasi dengan SDK Android, Eclipse dan library OpenCV. Metode yang digunakan menggunakan metode pra-pengolahan ekualisasi histogram dan segmentasi thresholding pengolahan citra. Deteksi kualitas daging dilakukan dengan mencari nilai statistik ekstraksi ciri citra berdasarkan data citra daging dari penelitian. Hasil penelitian ini adalah dapat menentukan nilai statistik mean dan standar deviasi dari hasil citra olahan ekualisasi histogram dan thresholding disertai analisis kualitas citra daging sapi. Pengujian black box dari aplikasi sistem pendeteksi kualitas daging ini menunjukkan bahwa semua fungsi yang terdapat pada aplikasi ini telah berhasil berjalan sesuai fungsinya. Penelitian ini harapannya bisa digunakan untuk membantu penelitian tahap selanjutnya.

  5. Local Histogram of Figure/Ground Segmentations for Dynamic Background Subtraction

    Directory of Open Access Journals (Sweden)

    Bineng Zhong

    2010-01-01

    Full Text Available We propose a novel feature, local histogram of figure/ground segmentations, for robust and efficient background subtraction (BGS in dynamic scenes (e.g., waving trees, ripples in water, illumination changes, camera jitters, etc.. We represent each pixel as a local histogram of figure/ground segmentations, which aims at combining several candidate solutions that are produced by simple BGS algorithms to get a more reliable and robust feature for BGS. The background model of each pixel is constructed as a group of weighted adaptive local histograms of figure/ground segmentations, which describe the structure properties of the surrounding region. This is a natural fusion because multiple complementary BGS algorithms can be used to build background models for scenes. Moreover, the correlation of image variations at neighboring pixels is explicitly utilized to achieve robust detection performance since neighboring pixels tend to be similarly affected by environmental effects (e.g., dynamic scenes. Experimental results demonstrate the robustness and effectiveness of the proposed method by comparing with four representatives of the state of the art in BGS.

  6. Local Histogram of Figure/Ground Segmentations for Dynamic Background Subtraction

    Directory of Open Access Journals (Sweden)

    Yuan Xiaotong

    2010-01-01

    Full Text Available Abstract We propose a novel feature, local histogram of figure/ground segmentations, for robust and efficient background subtraction (BGS in dynamic scenes (e.g., waving trees, ripples in water, illumination changes, camera jitters, etc.. We represent each pixel as a local histogram of figure/ground segmentations, which aims at combining several candidate solutions that are produced by simple BGS algorithms to get a more reliable and robust feature for BGS. The background model of each pixel is constructed as a group of weighted adaptive local histograms of figure/ground segmentations, which describe the structure properties of the surrounding region. This is a natural fusion because multiple complementary BGS algorithms can be used to build background models for scenes. Moreover, the correlation of image variations at neighboring pixels is explicitly utilized to achieve robust detection performance since neighboring pixels tend to be similarly affected by environmental effects (e.g., dynamic scenes. Experimental results demonstrate the robustness and effectiveness of the proposed method by comparing with four representatives of the state of the art in BGS.

  7. Whole brain magnetization transfer histogram analysis of pediatric acute lymphoblastic leukemia patients receiving intrathecal methotrexate therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Akira [Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto-shi Kyoto 606-8507 (Japan)]. E-mail: yakira@kuhp.kyoto-u.ac.jp; Miki, Yukio [Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto-shi Kyoto 606-8507 (Japan)]. E-mail: mikiy@kuhp.kyoto-u.ac.jp; Adachi, Souichi [Department of Pediatrics, Graduate School of Medicine, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto-shi Kyoto 606-8507 (Japan)]. E-mail: sadachi@kuhp.kyoto-u.ac.jp (and others)

    2006-03-15

    Background and purpose: The purpose of this prospective study was to evaluate the hypothesis that magnetization transfer ratio (MTR) histogram analysis of the whole brain could detect early and subtle brain changes nonapparent on conventional magnetic resonance imaging (MRI) in children with acute lymphoblastic leukemia (ALL) receiving methotrexate (MTX) therapy. Materials and methods: Subjects in this prospective study comprised 10 children with ALL (mean age, 6 years; range, 0-16 years). In addition to conventional MRI, magnetization transfer images were obtained before and after intrathecal and intravenous MTX therapy. MTR values were calculated and plotted as a histogram, and peak height and location were calculated. Differences in peak height and location between pre- and post-MTX therapy scans were statistically analyzed. Conventional MRI was evaluated for abnormal signal area in white matter. Results: MTR peak height was significantly lower on post-MTX therapy scans than on pre-MTX therapy scans (p = 0.002). No significant differences in peak location were identified between pre- and post-chemotherapy imaging. No abnormal signals were noted in white matter on either pre- or post-MTX therapy conventional MRI. Conclusions: This study demonstrates that MTR histogram analysis allows better detection of early and subtle brain changes in ALL patients who receive MTX therapy than conventional MRI.

  8. Organ volume estimation using SPECT

    CERN Document Server

    Zaidi, H

    1996-01-01

    Knowledge of in vivo thyroid volume has both diagnostic and therapeutic importance and could lead to a more precise quantification of absolute activity contained in the thyroid gland. In order to improve single-photon emission computed tomography (SPECT) quantitation, attenuation correction was performed according to Chang's algorithm. The dual-window method was used for scatter subtraction. We used a Monte Carlo simulation of the SPECT system to accurately determine the scatter multiplier factor k. Volume estimation using SPECT was performed by summing up the volume elements (voxels) lying within the contour of the object, determined by a fixed threshold and the gray level histogram (GLH) method. Thyroid phantom and patient studies were performed and the influence of 1) fixed thresholding, 2) automatic thresholding, 3) attenuation, 4) scatter, and 5) reconstruction filter were investigated. This study shows that accurate volume estimation of the thyroid gland is feasible when accurate corrections are perform...

  9. Investigation on improved infrared image detail enhancement algorithm based on adaptive histogram statistical stretching and gradient filtering

    Science.gov (United States)

    Zeng, Bangze; Zhu, Youpan; Li, Zemin; Hu, Dechao; Luo, Lin; Zhao, Deli; Huang, Juan

    2014-11-01

    Duo to infrared image with low contrast, big noise and unclear visual effect, target is very difficult to observed and identified. This paper presents an improved infrared image detail enhancement algorithm based on adaptive histogram statistical stretching and gradient filtering (AHSS-GF). Based on the fact that the human eyes are very sensitive to the edges and lines, the author proposed to extract the details and textures by using the gradient filtering. New histogram could be acquired by calculating the sum of original histogram based on fixed window. With the minimum value for cut-off point, author carried on histogram statistical stretching. After the proper weights given to the details and background, the detail-enhanced results could be acquired finally. The results indicate image contrast could be improved and the details and textures could be enhanced effectively as well.

  10. Comparison and Limitations of DVH-Based NTCP Models Derived From 3D-CRT and IMRT Data for Prediction of Gastrointestinal Toxicities in Prostate Cancer Patients by Using Propensity Score Matched Pair Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Troeller, Almut [Department of Radiation Oncology, William Beaumont Health System, Royal Oak, Michigan (United States); Department of Radiotherapy and Radiation Oncology, Ludwig-Maximilians-Universität, Munich (Germany); Yan, Di, E-mail: dyan@beaumont.edu [Department of Radiation Oncology, William Beaumont Health System, Royal Oak, Michigan (United States); Marina, Ovidiu; Schulze, Derek [Department of Radiation Oncology, William Beaumont Health System, Royal Oak, Michigan (United States); Alber, Markus [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Parodi, Katia [Department of Medical Physics, Ludwig-Maximilians-Universität, Munich (Germany); Belka, Claus; Söhn, Matthias [Department of Radiotherapy and Radiation Oncology, Ludwig-Maximilians-Universität, Munich (Germany)

    2015-02-01

    Purpose: This study compared normal tissue complication probability (NTCP) modeling of chronic gastrointestinal toxicities following prostate cancer treatment for 2 treatment modalities. Possible factors causing discrepancies in optimal NTCP model parameters between 3-dimensional conformal radiation therapy (3D-CRT) and intensity modulated RT (IMRT) were analyzed and discussed, including the impact of patient characteristics, image guidance, toxicity scoring bias, and NTCP model limitations. Methods and Materials: Rectal wall dose-volume histograms of 1115 patients treated for prostate cancer under an adaptive radiation therapy protocol were used to model gastrointestinal toxicity grade ≥2 (according to Common Terminology Criteria for Adverse Events). A total of 457 patients were treated with 3D-CRT and 658 with IMRT. 3D-CRT patients were matched to IMRT patients based on various patient characteristics, using a propensity score–based algorithm. Parameters of the Lyman equivalent uniform dose and cut-off dose logistic regression NTCP models were estimated for the 2 matched treatment modalities and the combined group. Results: After they were matched, the 3D-CRT and IMRT groups contained 275 and 550 patients with a large discrepancy of 28.7% versus 7.8% toxicities, respectively (P<.001). For both NTCP models, optimal parameters found for the 3D-CRT groups did not fit the IMRT patients well and vice versa. Models developed for the combined data overestimated NTCP for the IMRT patients and underestimated NTCP for the 3D-CRT group. Conclusions: Our analysis did not reveal a single definitive cause for discrepancies of model parameters between 3D-CRT and IMRT. Patient characteristics and bias in toxicity scoring, as well as image guidance alone, are unlikely causes of the large discrepancy of toxicities. Whether the cause was inherent to the specific NTCP models used in this study needs to be verified by future investigations. Because IMRT is increasingly used

  11. BIN PIXEL COUNT, MEAN AND TOTAL OF INTENSITIES EXTRACTED FROM PARTITIONED EQUALIZED HISTOGRAM FOR CBIR

    Directory of Open Access Journals (Sweden)

    H. B. Kekre

    2012-03-01

    Full Text Available In this paper we have introduced three simple feature vector extraction ideas to retrieve the images from database of 2000 images includes 20 different classes into it. The feature extraction process mainly based on splitting the image into three planes, for each plane an equalized histogram will be calculated which is divided in two, three and four equal parts to form the 8, 27 and 64 bins respectively. Three simple ways are used to extract the information in these three different sizes of bin sets. One is, ‘Count’ of the pixels falling in specific range of the histogram of each plane into its destination bin. Second, ‘Total’ intensities of these pixels in each of these bins is taken into consideration, and in third variation is the ‘Mean’ of these intensities is considered to represent the feature vector. Determination of the destination bin address for each pixel under process depends upon the R,G, B value of that pixel which falls in any one part of the equalized partitioned histogram, because based on it the 3digits flag will be assigned to that pixel with respect to its R, G, and B values. This way, sixfeature vector databases are prepared for 2000 images with three variable sizes and 3 variations in the extraction methods. We have maintained the separate set of bins for each plane and that way we have 3 more variations in databases. Means in all we have 18 feature vector databases that is six databases for each Red, Green and Blueplane. Experimentation uses image database of 20 classes having 100 images of each of the following classes: Flower, Sunset, Mountain, Buliding, Bus, Dinosaur, Elephant, Barbie, Mickey, Horses,Kingfisher, Dove, Crow, Rainbowrose, Pyramids, Plates, Car, Trees, Ship and Waterfall. Performance of our approaches is evaluated using two parameters LIRS and LSRR and results are refined and combined using three criteria Criterion1, 2 and 3.

  12. Using Relational Histogram Features and Action Labelled Data to Learn Preconditions for Means-End Actions

    DEFF Research Database (Denmark)

    Fichtl, Severin; Kraft, Dirk; Krüger, Norbert;

    2015-01-01

    that capture and represent the spatial relationships in an easily accessible way. We are interested in learning to predict the success of “means end” actions that manipulate two objects at once, from exploratory actions, and the observed sensorimo- tor contingencies. In this paper, we use relational histogram...... features and illustrate their effect on learning to predict a variety of “means end” actions’ outcomes. The results show that our vision features can make the learning problem significantly easier, leading to increased learning rates and higher maximum performance. This work is in particular important...

  13. Frontal Face Detection using Haar Wavelet Coefficients and Local Histogram Correlation

    Directory of Open Access Journals (Sweden)

    Iwan Setyawan

    2011-12-01

    Full Text Available Face detection is the main building block on which all automatic systems dealing with human faces is built. For example, a face recognition system must rely on face detection to process an input image and determine which areas contain human faces. These areas then become the input for the face recognition system for further processing. This paper presents a face detection system designed to detect frontal faces. The system uses Haar wavelet coefficients and local histogram correlation as differentiating features. Our proposed system is trained using 100 training images. Our experiments show that the proposed system performed well during testing, achieving a detection rate of 91.5%.

  14. Fitting simulated random events to experimental histograms by means of parametric models

    Energy Technology Data Exchange (ETDEWEB)

    Kortner, Oliver E-mail: oliver.kortner@cern.chkortner@mppmu.mpg.de; Zupancic, Crtomir

    2003-05-11

    Classical chi-square quantities are appropriate tools for fitting analytical parameter-dependent models to (multidimensional) measured histograms. In contrast, this article proposes a family of special chi-squares suitable for fits with models which simulate experimental data by Monte Carlo methods, thus introducing additional randomness. We investigate the dependence of such chi-squares on the number of experimental and simulated events in each bin, and on the theoretical parameter-dependent weight linking the two kinds of events. We identify the unknown probability distributions of the weights and their inter-bin correlations as the main obstacle to a general performance analysis of the proposed chi-square quantities.

  15. Yet Another Method for Image Segmentation based on Histograms and Heuristics

    Directory of Open Access Journals (Sweden)

    Horia-Nicolai L. Teodorescu

    2012-07-01

    Full Text Available We introduce a method for image segmentation that requires little computations, yet providing comparable results to other methods. While the proposed method resembles to the known ones based on histograms, it is still different in the use of the gray level distribution. When to the basic procedure we add several heuristic rules, the method produces results that, in some cases, may outperform the results produced by the known methods. The paper reports preliminary results. More details on the method, improvements, and results will be presented in a future paper.

  16. Histogram Monte Carlo position-space renormalization group: Applications to the site percolation

    Science.gov (United States)

    Hu, Chin-Kun; Chen, Chi-Ning; Wu, F. Y.

    1996-02-01

    We study site percolation on the square lattice and show that, when augmented with histogram Monte Carlo simulations for large lattices, the cell-to-cell renormalization group approach can be used to determine the critical probability accurately. Unlike the cell-to-site method and an alternate renormalization group approach proposed recently by Sahimi and Rassamdana, both of which rely on ab initio numerical inputs, the cell-to-cell scheme is free of prior knowledge and thus can be applied more widely.

  17. Numerical study of QCD phase diagram at high temperature and density by a histogram method

    CERN Document Server

    Ejiri, Shinji; Hatsuda, Tetsuo; Kanaya, Kazuyuki; Nakagawa, Yoshiyuki; Ohno, Hiroshi; Saito, Hana; Umeda, Takashi

    2012-01-01

    We study the QCD phase structure at high temperature and density adopting a histogram method. Because the quark determinant is complex at finite density, the Monte-Carlo method cannot be applied directly. We use a reweighting method and try to solve the problems which arise in the reweighting method, i.e. the sign problem and the overlap problem. We discuss the chemical potential dependence of the probability distribution function in the heavy quark mass region and examine the applicability of the approach in the light quark region.

  18. DNA IMAGE CYTOMETRY IN PROGNOSTICATION OF COLORECTAL CANCER: PRACTICAL CONSIDERATIONS OF THE TECHNIQUE AND INTERPRETATION OF THE HISTOGRAMS

    Directory of Open Access Journals (Sweden)

    Abdelbaset Buhmeida

    2011-05-01

    Full Text Available The role of DNA content as a prognostic factor in colorectal cancer (CRC is highly controversial. Some of these controversies are due to purely technical reasons, e.g. variable practices in interpreting the DNA histograms, which is problematic particularly in advanced cases. In this report, we give a detailed account on various options how these histograms could be optimally interpreted, with the idea of establishing the potential value of DNA image cytometry in prognosis and in selection of proper treatment. Material consists of nuclei isolated from 50 ƒĘm paraffin sections from 160 patients with stage II, III or IV CRC diagnosed, treated and followed-up in our clinic. The nuclei were stained with the Feulgen stain. Nuclear DNA was measured using computer-assisted image cytometry. We applied 4 different approaches to analyse the DNA histograms: 1 appearance of the histogram (ABCDE approach, 2 range of DNA values, 3 peak evaluation, and 4 events present at high DNA values. Intra-observer reproducibility of these four histogram interpretation was 89%, 95%, 96%, and 100%, respectively. We depicted selected histograms to illustrate the four analytical approaches in cases with different stages of CRC, with variable disease outcome. In our analysis, the range of DNA values was the best prognosticator, i.e., the tumours with the widest histograms had the most ominous prognosis. These data implicate that DNA cytometry based on isolated nuclei is valuable in predicting the prognosis of CRC. Different interpretation techniques differed in their reproducibility, but the method showing the best prognostic value also had high reproducibility in our analysis.

  19. The application of age distribution theory in the analysis of cytofluorimetric DNA histogram data.

    Science.gov (United States)

    Watson, J V

    1977-03-01

    Age distribution theory has been employed in a model to analyse a variety of histograms of the DNA content of single cells in samples from experimental tumours growing in tissue culture. The method has produced satisfactory correspondence with the experimental data in which there was a wide variation in the proportions of cells in the intermitotic phases, and generally good agreement between the 3H-thymidine labelling index and the computed proportion in S phase. The model has the capacity to analyse data from populations which contain a proportion of non-cycling cells. However, it is concluded that reliable results for the growth fraction and also for the relative durations of the intermitotic phase times cannot be obtained for the data reported here from the DNA histograms alone. To obtain reliable estimates of the growth fraction the relative durations of the phase time must be known, and conversely, reliable estimates of the relative phase durations can only be obtained if the growth fraction is known.

  20. Predicting low-temperature free energy landscapes with flat-histogram Monte Carlo methods

    Science.gov (United States)

    Mahynski, Nathan A.; Blanco, Marco A.; Errington, Jeffrey R.; Shen, Vincent K.

    2017-02-01

    We present a method for predicting the free energy landscape of fluids at low temperatures from flat-histogram grand canonical Monte Carlo simulations performed at higher ones. We illustrate our approach for both pure and multicomponent systems using two different sampling methods as a demonstration. This allows us to predict the thermodynamic behavior of systems which undergo both first order and continuous phase transitions upon cooling using simulations performed only at higher temperatures. After surveying a variety of different systems, we identify a range of temperature differences over which the extrapolation of high temperature simulations tends to quantitatively predict the thermodynamic properties of fluids at lower ones. Beyond this range, extrapolation still provides a reasonably well-informed estimate of the free energy landscape; this prediction then requires less computational effort to refine with an additional simulation at the desired temperature than reconstruction of the surface without any initial estimate. In either case, this method significantly increases the computational efficiency of these flat-histogram methods when investigating thermodynamic properties of fluids over a wide range of temperatures. For example, we demonstrate how a binary fluid phase diagram may be quantitatively predicted for many temperatures using only information obtained from a single supercritical state.

  1. Color Histogram and DBC Co-Occurrence Matrix for Content Based Image Retrieval

    Directory of Open Access Journals (Sweden)

    K. Prasanthi Jasmine

    2014-12-01

    Full Text Available This paper presents the integration of color histogram and DBC co-occurrence matrix for content based image retrieval. The exit DBC collect the directional edges which are calculated by applying the first-order derivatives in 0º, 45º, 90º and 135º directions. The feature vector length of DBC for a particular direction is 512 which are more for image retrieval. To avoid this problem, we collect the directional edges by excluding the center pixel and further applied the rotation invariant property. Further, we calculated the co-occurrence matrix to form the feature vector. Finally, the HSV color histogram and the DBC co-occurrence matrix are integrated to form the feature database. The retrieval results of the proposed method have been tested by conducting three experiments on Brodatz, MIT VisTex texture databases and Corel-1000 natural database. The results after being investigated show a significant improvement in terms of their evaluation measures as compared to LBP, DBC and other transform domain features.

  2. Contrast enhancement based on layered difference representation of 2D histograms.

    Science.gov (United States)

    Lee, Chulwoo; Lee, Chul; Kim, Chang-Su

    2013-12-01

    A novel contrast enhancement algorithm based on the layered difference representation of 2D histograms is proposed in this paper. We attempt to enhance image contrast by amplifying the gray-level differences between adjacent pixels. To this end, we obtain the 2D histogram h(k, k + l ) from an input image, which counts the pairs of adjacent pixels with gray-levels k and k + l , and represent the gray-level differences in a tree-like layered structure. Then, we formulate a constrained optimization problem based on the observation that the gray-level differences, occurring more frequently in the input image, should be more emphasized in the output image. We first solve the optimization problem to derive the transformation function at each layer. We then combine the transformation functions at all layers into the unified transformation function, which is used to map input gray-levels to output gray-levels. Experimental results demonstrate that the proposed algorithm enhances images efficiently in terms of both objective quality and subjective quality.

  3. Radial polar histogram: obstacle avoidance and path planning for robotic cognition and motion control

    Science.gov (United States)

    Wang, Po-Jen; Keyawa, Nicholas R.; Euler, Craig

    2012-01-01

    In order to achieve highly accurate motion control and path planning for a mobile robot, an obstacle avoidance algorithm that provided a desired instantaneous turning radius and velocity was generated. This type of obstacle avoidance algorithm, which has been implemented in California State University Northridge's Intelligent Ground Vehicle (IGV), is known as Radial Polar Histogram (RPH). The RPH algorithm utilizes raw data in the form of a polar histogram that is read from a Laser Range Finder (LRF) and a camera. A desired open block is determined from the raw data utilizing a navigational heading and an elliptical approximation. The left and right most radii are determined from the calculated edges of the open block and provide the range of possible radial paths the IGV can travel through. In addition, the calculated obstacle edge positions allow the IGV to recognize complex obstacle arrangements and to slow down accordingly. A radial path optimization function calculates the best radial path between the left and right most radii and is sent to motion control for speed determination. Overall, the RPH algorithm allows the IGV to autonomously travel at average speeds of 3mph while avoiding all obstacles, with a processing time of approximately 10ms.

  4. Decoding brain cancer dynamics: a quantitative histogram-based approach using temporal MRI

    Science.gov (United States)

    Zhou, Mu; Hall, Lawrence O.; Goldgof, Dmitry B.; Russo, Robin; Gillies, Robert J.; Gatenby, Robert A.

    2015-03-01

    Brain tumor heterogeneity remains a challenge for probing brain cancer evolutionary dynamics. In light of evolution, it is a priority to inspect the cancer system from a time-domain perspective since it explicitly tracks the dynamics of cancer variations. In this paper, we study the problem of exploring brain tumor heterogeneity from temporal clinical magnetic resonance imaging (MRI) data. Our goal is to discover evidence-based knowledge from such temporal imaging data, where multiple clinical MRI scans from Glioblastoma multiforme (GBM) patients are generated during therapy. In particular, we propose a quantitative histogram-based approach that builds a prediction model to measure the difference in histograms obtained from pre- and post-treatment. The study could significantly assist radiologists by providing a metric to identify distinctive patterns within each tumor, which is crucial for the goal of providing patient-specific treatments. We examine the proposed approach for a practical application - clinical survival group prediction. Experimental results show that our approach achieved 90.91% accuracy.

  5. Beyond histograms: Efficiently estimating radial distribution functions via spectral Monte Carlo

    Science.gov (United States)

    Patrone, Paul N.; Rosch, Thomas W.

    2017-03-01

    Despite more than 40 years of research in condensed-matter physics, state-of-the-art approaches for simulating the radial distribution function (RDF) g(r) still rely on binning pair-separations into a histogram. Such methods suffer from undesirable properties, including subjectivity, high uncertainty, and slow rates of convergence. Moreover, such problems go undetected by the metrics often used to assess RDFs. To address these issues, we propose (I) a spectral Monte Carlo (SMC) quadrature method that yields g(r) as an analytical series expansion and (II) a Sobolev norm that assesses the quality of RDFs by quantifying their fluctuations. Using the latter, we show that, relative to histogram-based approaches, SMC reduces by orders of magnitude both the noise in g(r) and the number of pair separations needed for acceptable convergence. Moreover, SMC reduces subjectivity and yields simple, differentiable formulas for the RDF, which are useful for tasks such as coarse-grained force-field calibration via iterative Boltzmann inversion.

  6. Histogram analysis of pharmacokinetic parameters by bootstrap resampling from one-point sampling data in animal experiments.

    Science.gov (United States)

    Takemoto, Seiji; Yamaoka, Kiyoshi; Nishikawa, Makiya; Takakura, Yoshinobu

    2006-12-01

    A bootstrap method is proposed for assessing statistical histograms of pharmacokinetic parameters (AUC, MRT, CL and V(ss)) from one-point sampling data in animal experiments. A computer program, MOMENT(BS), written in Visual Basic on Microsoft Excel, was developed for the bootstrap calculation and the construction of histograms. MOMENT(BS) was applied to one-point sampling data of the blood concentration of three physiologically active proteins ((111)In labeled Hsp70, Suc(20)-BSA and Suc(40)-BSA) administered in different doses to mice. The histograms of AUC, MRT, CL and V(ss) were close to a normal (Gaussian) distribution with the bootstrap resampling number (200), or more, considering the skewness and kurtosis of the histograms. A good agreement of means and SD was obtained between the bootstrap and Bailer's approaches. The hypothesis test based on the normal distribution clearly demonstrated that the disposition of (111)In-Hsp70 and Suc(20)-BSA was almost independent of dose, whereas that of (111)In-Suc(40)-BSA was definitely dose-dependent. In conclusion, the bootstrap method was found to be an efficient method for assessing the histogram of pharmacokinetic parameters of blood or tissue disposition data by one-point sampling.

  7. The histogram analysis of diffusion-weighted intravoxel incoherent motion (IVIM) imaging for differentiating the gleason grade of prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu-Dong; Wang, Qing; Wu, Chen-Jiang; Wang, Xiao-Ning; Zhang, Jing; Liu, Xi-Sheng; Shi, Hai-Bin [First Affiliated Hospital with Nanjing Medical University, Department of Radiology, Nanjing, Jiangsu Province (China); Liu, Hui [Siemens Healthcare, MR Collaborations NE Asia, Shanghai (China)

    2015-04-01

    To evaluate histogram analysis of intravoxel incoherent motion (IVIM) for discriminating the Gleason grade of prostate cancer (PCa). A total of 48 patients pathologically confirmed as having clinically significant PCa (size > 0.5 cm) underwent preoperative DW-MRI (b of 0-900 s/mm{sup 2}). Data was post-processed by monoexponential and IVIM model for quantitation of apparent diffusion coefficients (ADCs), perfusion fraction f, diffusivity D and pseudo-diffusivity D*. Histogram analysis was performed by outlining entire-tumour regions of interest (ROIs) from histological-radiological correlation. The ability of imaging indices to differentiate low-grade (LG, Gleason score (GS) ≤6) from intermediate/high-grade (HG, GS > 6) PCa was analysed by ROC regression. Eleven patients had LG tumours (18 foci) and 37 patients had HG tumours (42 foci) on pathology examination. HG tumours had significantly lower ADCs and D in terms of mean, median, 10th and 75th percentiles, combined with higher histogram kurtosis and skewness for ADCs, D and f, than LG PCa (p < 0.05). Histogram D showed relatively higher correlations (n = 0.641-0.668 vs. ADCs: 0.544-0.574) with ordinal GS of PCa; and its mean, median and 10th percentile performed better than ADCs did in distinguishing LG from HG PCa. It is feasible to stratify the pathological grade of PCa by IVIM with histogram metrics. D performed better in distinguishing LG from HG tumour than conventional ADCs. (orig.)

  8. Considerations on the calculation of volumes in two planning systems; Consideraciones sobre el calculo de volumenes en dos sistemas de planificacion

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Tenedor Alonso, S.; Rincon Perez, M.; Penedo Cobos, J. M.; Garcia Castejon, M. A.

    2011-07-01

    The discrepancies in the calculation of the same volume between different planning systems impact on dose-volume histograms and therefore clinical assessment of dosimetry for patients. The transfer, by a local network, tomographic study (CT) and contours of critical organs of patients, between our two planning systems allows us to evaluate the calculation of identical volumes.

  9. Expression robust 3D face recognition via mesh-based histograms of multiple order surface differential quantities

    KAUST Repository

    Li, Huibin

    2011-09-01

    This paper presents a mesh-based approach for 3D face recognition using a novel local shape descriptor and a SIFT-like matching process. Both maximum and minimum curvatures estimated in the 3D Gaussian scale space are employed to detect salient points. To comprehensively characterize 3D facial surfaces and their variations, we calculate weighted statistical distributions of multiple order surface differential quantities, including histogram of mesh gradient (HoG), histogram of shape index (HoS) and histogram of gradient of shape index (HoGS) within a local neighborhood of each salient point. The subsequent matching step then robustly associates corresponding points of two facial surfaces, leading to much more matched points between different scans of a same person than the ones of different persons. Experimental results on the Bosphorus dataset highlight the effectiveness of the proposed method and its robustness to facial expression variations. © 2011 IEEE.

  10. Influence of Sampling Practices on the Appearance of DNA Image Histograms of Prostate Cells in FNAB Samples

    Directory of Open Access Journals (Sweden)

    Abdelbaset Buhmeida

    1999-01-01

    Full Text Available Twenty‐one fine needle aspiration biopsies (FNAB of the prostate, diagnostically classified as definitely malignant, were studied. The Papanicolaou or H&E stained samples were destained and then stained for DNA with the Feulgen reaction. DNA cytometry was applied after different sampling rules. The histograms varied according to the sampling rule applied. Because free cells between cell groups were easier to measure than cells in the cell groups, two sampling rules were tested in all samples: (i cells in the cell groups were measured, and (ii free cells between cell groups were measured. Abnormal histograms were more common after the sampling rule based on free cells, suggesting that abnormal patterns are best revealed through the free cells in these samples. The conclusions were independent of the applied histogram interpretation method.

  11. Condition monitoring of face milling tool using K-star algorithm and histogram features of vibration signal

    Directory of Open Access Journals (Sweden)

    C.K. Madhusudana

    2016-09-01

    Full Text Available This paper deals with the fault diagnosis of the face milling tool based on machine learning approach using histogram features and K-star algorithm technique. Vibration signals of the milling tool under healthy and different fault conditions are acquired during machining of steel alloy 42CrMo4. Histogram features are extracted from the acquired signals. The decision tree is used to select the salient features out of all the extracted features and these selected features are used as an input to the classifier. K-star algorithm is used as a classifier and the output of the model is utilised to study and classify the different conditions of the face milling tool. Based on the experimental results, K-star algorithm is provided a better classification accuracy in the range from 94% to 96% with histogram features and is acceptable for fault diagnosis.

  12. 3D analysis of apparent diffusion coefficient histograms in hepatocellular carcinoma: correlation with histological grade.

    Science.gov (United States)

    Moriya, Tomohisa; Saito, Kazuhiro; Tajima, Yu; Harada, Taiyo L; Araki, Yoichi; Sugimoto, Katsutoshi; Tokuuye, Koichi

    2017-01-05

    To evaluate the usefulness of differentiation of histological grade in hepatocellular carcinoma (HCC) using three-dimensional (3D) analysis of apparent diffusion coefficient (ADC) histograms retrospectively. The subjects consisted of 53 patients with 56 HCCs. The subjects included 12 well-differentiated, 35 moderately differentiated, and nine poorly differentiated HCCs. Diffusion-weighted imaging (b-values of 100 and 800 s/mm(2)) were obtained within 3 months before surgery. Regions of interest (ROIs) covered the entire tumor. The data acquired from each slice were summated to derive voxel-by-voxel ADCs for the entire tumor. The following parameters were derived from the ADC histogram: mean, standard deviation, minimum, maximum, mode, percentiles (5th, 10th, 25th, 50th, 75th, and 90th), skew, and kurtosis. These parameters were analyzed according to histological grade. After eliminating steatosis lesions, these parameters were re-analyzed. A weak correlation was observed in minimum ADC and 5th percentile for each histological grade (r = -0.340 and r = -0.268, respectively). The minimum ADCs of well, moderately, and poorly differentiated HCC were 585 ± 388, 411 ± 278, and 235 ± 102 × 10(-6) mm(2)/s, respectively. Minimum ADC showed significant differences among tumor histological grades (P = 0.009). The minimum ADC of poorly differentiated HCC and that of combined well and moderately differentiated HCC were 236 ± 102 and 437 ± 299 × 10(-6) mm(2)/s. The minimum ADC of poorly differentiated HCC was significantly lower than that of combined well and moderately differentiated HCC (P = 0.001). The sensitivity and specificity, when a minimum ADC of 400 × 10(-6) mm(2)/s or lower was considered to be poorly differentiated HCC, were 100 and 54%, respectively. After exclusion of the effect of steatosis, the sensitivity and specificity did not change, although the statistical differences became strong (P < 0

  13. Changes in the Shape of Histograms Constructed from the Results of 239-Pu Alpha-Activity Measurements Correlate with the Deviations of the Moon from the Keplerian Orbit

    Directory of Open Access Journals (Sweden)

    Shapovalov S. N.

    2009-10-01

    Full Text Available We have found that the shape of the histograms, constructed on the basis of the results of radioactivity measurements, changes in correlation with the distortions of the lunar Keplerian orbit (due to the gravitational influence of the Sun. Taking into account that the phenomenon of "macroscopic fluctuations" (regular changes in the fine structure of histograms constructed from the results of measurements of natural processes does not depend on the nature of the process under study, one can consider the correlation of the histogram shape with the Moon's deviations from the Keplerian orbit to be independent from the nature of the process the histograms were obtained on.

  14. Changes in the Shape of Histograms Constructed from the Results of 239-Pu Alpha-Activity Measurements Correlate with the Deviations of the Moon from the Keplerian Orbit

    Directory of Open Access Journals (Sweden)

    Shapovalov S. N.

    2009-10-01

    Full Text Available We have found that the shape of the histograms, constructed on the basis of the results of radioactivity measurements, changes in correlation with the distortions of the lunar Keplerian orbit (due to the gravitational influence of the Sun. Taking into account that the phenomenon of “macroscopic fluctuations” (regular changes in the fine structure of histograms constructed from the results of measurements of natural processes does not depend on the nature of the process under study, one can consider the correlation of the histogram shape with the Moon’s deviations from the Keplerian orbit to be independent from the nature of the process the histograms were obtained on.

  15. Wavelength-Adaptive Dehazing Using Histogram Merging-Based Classification for UAV Images

    Directory of Open Access Journals (Sweden)

    Inhye Yoon

    2015-03-01

    Full Text Available Since incoming light to an unmanned aerial vehicle (UAV platform can be scattered by haze and dust in the atmosphere, the acquired image loses the original color and brightness of the subject. Enhancement of hazy images is an important task in improving the visibility of various UAV images. This paper presents a spatially-adaptive dehazing algorithm that merges color histograms with consideration of the wavelength-dependent atmospheric turbidity. Based on the wavelength-adaptive hazy image acquisition model, the proposed dehazing algorithm consists of three steps: (i image segmentation based on geometric classes; (ii generation of the context-adaptive transmission map; and (iii intensity transformation for enhancing a hazy UAV image. The major contribution of the research is a novel hazy UAV image degradation model by considering the wavelength of light sources. In addition, the proposed transmission map provides a theoretical basis to differentiate visually important regions from others based on the turbidity and merged classification results.

  16. Wavelength-adaptive dehazing using histogram merging-based classification for UAV images.

    Science.gov (United States)

    Yoon, Inhye; Jeong, Seokhwa; Jeong, Jaeheon; Seo, Doochun; Paik, Joonki

    2015-03-19

    Since incoming light to an unmanned aerial vehicle (UAV) platform can be scattered by haze and dust in the atmosphere, the acquired image loses the original color and brightness of the subject. Enhancement of hazy images is an important task in improving the visibility of various UAV images. This paper presents a spatially-adaptive dehazing algorithm that merges color histograms with consideration of the wavelength-dependent atmospheric turbidity. Based on the wavelength-adaptive hazy image acquisition model, the proposed dehazing algorithm consists of three steps: (i) image segmentation based on geometric classes; (ii) generation of the context-adaptive transmission map; and (iii) intensity transformation for enhancing a hazy UAV image. The major contribution of the research is a novel hazy UAV image degradation model by considering the wavelength of light sources. In addition, the proposed transmission map provides a theoretical basis to differentiate visually important regions from others based on the turbidity and merged classification results.

  17. A 124 Mpixels/s VLSI design for histogram-based joint bilateral filtering.

    Science.gov (United States)

    Tseng, Yu-Cheng; Hsu, Po-Hsiung; Chang, Tian-Sheuan

    2011-11-01

    This paper presents an efficient and scalable design for histogram-based bilateral filtering (BF) and joint BF (JBF) by memory reduction methods and architecture design techniques to solve the problems of high memory cost, high computational complexity, high bandwidth, and large range table. The presented memory reduction methods exploit the progressive computing characteristics to reduce the memory cost to 0.003%-0.020%, as compared with the original approach. Furthermore, the architecture design techniques adopt range domain parallelism and take advantage of the computing order and the numerical properties to solve the complexity, bandwidth, and range-table problems. The example design with a 90-nm complementary metal-oxide-semiconductor process can deliver the throughput to 124 Mpixels/s with 356-K gate counts and 23-KB on-chip memory.

  18. Ship detection and extraction using visual saliency and histogram of oriented gradient

    Science.gov (United States)

    Xu, Fang; Liu, Jing-hong

    2016-11-01

    A novel unsupervised ship detection and extraction method is proposed. A combination model based on visual saliency is constructed for searching the ship target regions and suppressing the false alarms. The salient target regions are extracted and marked through segmentation. Radon transform is applied to confirm the suspected ship targets with symmetry profiles. Then, a new descriptor, improved histogram of oriented gradient (HOG), is introduced to discriminate the real ships. The experimental results on real optical remote sensing images demonstrate that plenty of ships can be extracted and located successfully, and the number of ships can be accurately acquired. Furthermore, the proposed method is superior to the contrastive methods in terms of both accuracy rate and false alarm rate.

  19. Scale and Orientation-Based Background Weighted Histogram for Human Tracking

    Science.gov (United States)

    Laaroussi, Khadija; Saaidi, Abderrahim; Masrar, Mohamed; Satori, Khalid

    2016-09-01

    The Mean Shift procedure is a popular object tracking algorithm since it is fast, easy to implement and performs well in a range of conditions. However, classic Mean Shift tracking algorithm fixes the size and orientation of the tracking window, which limits the performance when the target's orientation and scale change. In this paper, we present a new human tracking algorithm based on Mean Shift technique in order to estimate the position, scale and orientation changes of the target. This work combines moment features of the weight image with background information to design a robust tracking algorithm entitled Scale and Orientation-based Background Weighted Histogram (SOBWH). The experimental results show that the proposed approach SOBWH presents a good compromise between tracking precision and calculation time, also they validate its robustness, especially to large background variation, scale and orientation changes and similar background scenes.

  20. Confidence level fusion of edge histogram descriptor, hidden Markov model, spectral correlation feature, and NUKEv6

    Science.gov (United States)

    Ho, K. C.; Gader, P. D.; Frigui, H.; Wilson, J. N.

    2007-04-01

    This paper examines the confidence level fusion of several promising algorithms for the vehiclemounted ground penetrating radar landmine detection system. The detection algorithms considered here include Edge Histogram Descriptor (EHD), Hidden Markov Model (HMM), Spectral Correlation Feature (SCF) and NUKEv6. We first form a confidence vector by collecting the confidence values from the four individual detectors. The fused confidence is assigned to be the difference in the square of the Mahalanobis distance to the non-mine class and the square of the Mahalanobis distance to the mine class. Experimental results on a data collection that contains over 1500 mine encounters indicate that the proposed fusion technique can reduce the false alarm rate by a factor of two at 90% probability of detection when compared to the best individual detector.

  1. A New Steganography Technique Based on Difference Scheme of RGB Channels and Text Using Histogram Analysis

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Sharma,

    2014-05-01

    Full Text Available Steganography is the art of hiding the fact that communication is taking place, by hiding information in other information. The motivation for this work includes provision of protection of information during transmission without any detection of information. We also propose a new technique namely „A New Steganography Technique Based on Difference Scheme of RGB Channels and Text Using Histogram Analysis‟. The proposed technique can encode any colored image files in order to protect confidential text data from unauthorized access. It can be applied to a very small images (24 × 24 as well as large images (1024 × 1024. We use Image quality parameters Peak Signal to Noise Ratio and Mean Square Error. The proposed method has higher PSNR value and lower MSE values. The PSNR value is greater than 50 and MSE value is in fractions.

  2. Context-sensitive patch histograms for detecting rare events in histopathological data

    Science.gov (United States)

    Diaz, Kristians; Baust, Maximilian; Navab, Nassir

    2017-03-01

    Assessment of histopathological data is not only difficult due to its varying appearance, e.g. caused by staining artifacts, but also due to its sheer size: Common whole slice images feature a resolution of 6000x4000 pixels. Therefore, finding rare events in such data sets is a challenging and tedious task and developing sophisticated computerized tools is not easy, especially when no or little training data is available. In this work, we propose learning-free yet effective approach based on context sensitive patch-histograms in order to find extramedullary hematopoiesis events in Hematoxylin-Eosin-stained images. When combined with a simple nucleus detector, one can achieve performance levels in terms of sensitivity 0.7146, specificity 0.8476 and accuracy 0.8353 which are very well comparable to a recently published approach based on random forests.

  3. Spectral Analysis of Projection Histogram for Enhancing Close matching character Recognition in Malayalam

    CERN Document Server

    Divakaran, Sajilal

    2012-01-01

    The success rates of Optical Character Recognition (OCR) systems for printed Malayalam documents is quite impressive with the state of the art accuracy levels in the range of 85-95% for various. However for real applications, further enhancement of this accuracy levels are required. One of the bottle necks in further enhancement of the accuracy is identified as close-matching characters. In this paper, we delineate the close matching characters in Malayalam and report the development of a specialised classifier for these close-matching characters. The output of a state of the art of OCR is taken and characters falling into the close-matching character set is further fed into this specialised classifier for enhancing the accuracy. The classifier is based on support vector machine algorithm and uses feature vectors derived out of spectral coefficients of projection histogram signals of close-matching characters.

  4. A hardware-oriented histogram of oriented gradients algorithm and its VLSI implementation

    Science.gov (United States)

    Zhang, Xiangyu; An, Fengwei; Nakashima, Ikki; Luo, Aiwen; Chen, Lei; Ishii, Idaku; Jürgen Mattausch, Hans

    2017-04-01

    A challenging and important issue for object recognition is feature extraction on embedded systems. We report a hardware implementation of the histogram of oriented gradients (HOG) algorithm for real-time object recognition, which is known to provide high efficiency and accuracy. The developed hardware-oriented algorithm exploits the cell-based scan strategy which enables image-sensor synchronization and extraction-speed acceleration. Furthermore, buffers for image frames or integral images are avoided. An image-size scalable hardware architecture with an effective bin-decoder and a parallelized voting element (PVE) is developed and used to verify the hardware-oriented HOG implementation with the application of human detection. The fabricated test chip in 180 nm CMOS technology achieves fast processing speed and large flexibility for different image resolutions with substantially reduced hardware cost and energy consumption.

  5. REAL-TIME FACE RECOGNITION BASED ON OPTICAL FLOW AND HISTOGRAM EQUALIZATION

    Directory of Open Access Journals (Sweden)

    D. Sathish Kumar

    2013-05-01

    Full Text Available Face recognition is one of the intensive areas of research in computer vision and pattern recognition but many of which are focused on recognition of faces under varying facial expressions and pose variation. A constrained optical flow algorithm discussed in this paper, recognizes facial images involving various expressions based on motion vector computation. In this paper, an optical flow computation algorithm which computes the frames of varying facial gestures, and integrating with synthesized image in a probabilistic environment has been proposed. Also Histogram Equalization technique has been used to overcome the effect of illuminations while capturing the input data using camera devices. It also enhances the contrast of the image for better processing. The experimental results confirm that the proposed face recognition system is more robust and recognizes the facial images under varying expressions and pose variations more accurately.

  6. Gender Perception From Faces Using Boosted LBPH (Local Binary Patten Histograms

    Directory of Open Access Journals (Sweden)

    U. U. Tariq

    2013-06-01

    Full Text Available Automatic Gender classification from faces has several applications such as surveillance, human computer interaction, targeted advertisement etc. Humans can recognize gender from faces quite accurately but for computer vision it is a difficult task. Many studies have targeted this problem but most of these studies used images of faces taken under constrained conditions. Real-world applications however require to process images from real-world, that have significant variation in lighting and pose, which makes the gender classification task very difficult. We have examined the problem of automatic gender classification from faces on real-world images. Using a face detector faces from images are extracted aligned and represented using Local binary pattern histogram. Discriminative features are selected using Adaboost and the boosted LBP features are used to train a support vector machine that provides a recognition rate of 93.29%.

  7. Monitoring pig movement at the slaughterhouse using optical flow and modified angular histograms

    DEFF Research Database (Denmark)

    Gronskyte, Ruta; Clemmensen, Line Katrine Harder; Hviid, Marchen Sonja

    2016-01-01

    use the OF vectors to describe points of movement on all pigs and thereby analyse the herd movement. Subsequently, the OF vectors are used to identify abnormal movements of individual pigs. The OF vectors, obtained from the pigs, point in multiple directions rather than in one movement direction....... To accommodate the multiple directions of the OF vectors, we propose to quantify OF using a summation of the vectors into bins according to their angles, which we call modified angular histograms. Sequential feature selection is used to select angle ranges, which identify pigs that are moving abnormally...... in the herd. The vector lengths from the selected angle ranges are compared to the corresponding median, 25th and 75th percentiles from a training set, which contains only normally moving pigs. We show that the method is capable of locating stationary pigs in the recordings regardless of the number of pigs...

  8. Convergence and error estimation in free energy calculations using the weighted histogram analysis method.

    Science.gov (United States)

    Zhu, Fangqiang; Hummer, Gerhard

    2012-02-05

    The weighted histogram analysis method (WHAM) has become the standard technique for the analysis of umbrella sampling simulations. In this article, we address the challenges (1) of obtaining fast and accurate solutions of the coupled nonlinear WHAM equations, (2) of quantifying the statistical errors of the resulting free energies, (3) of diagnosing possible systematic errors, and (4) of optimally allocating of the computational resources. Traditionally, the WHAM equations are solved by a fixed-point direct iteration method, despite poor convergence and possible numerical inaccuracies in the solutions. Here, we instead solve the mathematically equivalent problem of maximizing a target likelihood function, by using superlinear numerical optimization algorithms with a significantly faster convergence rate. To estimate the statistical errors in one-dimensional free energy profiles obtained from WHAM, we note that for densely spaced umbrella windows with harmonic biasing potentials, the WHAM free energy profile can be approximated by a coarse-grained free energy obtained by integrating the mean restraining forces. The statistical errors of the coarse-grained free energies can be estimated straightforwardly and then used for the WHAM results. A generalization to multidimensional WHAM is described. We also propose two simple statistical criteria to test the consistency between the histograms of adjacent umbrella windows, which help identify inadequate sampling and hysteresis in the degrees of freedom orthogonal to the reaction coordinate. Together, the estimates of the statistical errors and the diagnostics of inconsistencies in the potentials of mean force provide a basis for the efficient allocation of computational resources in free energy simulations.

  9. Seismic remote sensing image segmentation based on spectral histogram and dynamic region merging

    Science.gov (United States)

    Wang, Peng; Sun, Genyun; Wang, Zhenjie

    2015-12-01

    Image segmentation is the foundation of seismic information extraction from high-resolution remote sensing images. While the complexity of the seismic image brings great challenges to its segmentation. Compared with the traditional pixel-level approaches, the region-level approaches are found prevailing in dealing with the complexity. This paper addresses the seismic image segmentation problem in a region-merging style. Starting from many over-segmented regions, the image segmentation is performed by iteratively merging the neighboring regions. In the proposed algorithm, the merging criterion and merging order are two essential issues to be emphatically considered. An effective merging criterion is largely depends on the region feature and neighbor homogeneity measure. The region's spectral histogram represents the global feature of each region and enhances the discriminability of neighboring regions. Therefore, we utilize it to solve the merging criterion. Under a certain the merging criterion, a better performance could be obtained if the most similar regions are always ensured to be merged first, which can be transformed into a least-cost problem. Rather than predefine an order queue, we solve the order problem with a dynamic scheme. The proposed approach mainly contains three parts. Firstly, starting from the over-segmented regions, the spectral histograms are constructed to represent each region. Then, we use the homogeneity that combines the distance and shape measure to conduct the merge criterion. Finally, neighbor regions are dynamically merged following the dynamic program (DP) theory and breadth-first strategy. Experiments are conducted using the earthquake images, including collapsed buildings and seismic secondary geological disaster. The experimental results show that, the proposed method segments the seismic image more correctly.

  10. 2D matrix based indexing with color spectral histogram for efficient image retrieval

    Institute of Scientific and Technical Information of China (English)

    Maruthamuthu Ramasamy; John Sanjeev Kumar Athisayam

    2016-01-01

    A novel content based image retrieval (CBIR) algorithm using relevant feedback is presented. The proposed framework has three major contributions: a novel feature descriptor cal ed color spectral histogram (CSH) to measure the similarity between images; two-dimensional matrix based indexing approach pro-posed for short-term learning (STL);and long-term learning (LTL). In general, image similarities are measured from feature repre-sentation which includes color quantization, texture, color, shape and edges. However, CSH can describe the image feature only with the histogram. Typical y the image retrieval process starts by finding the similarity between the query image and the images in the database; the major computation involved here is that the selection of top ranking images requires a sorting algorithm to be employed at least with the lower bound of O(n log n). A 2D ma-trix based indexing of images can enormously reduce the search time in STL. The same structure is used for LTL with an aim to reduce the amount of log to be maintained. The performance of the proposed framework is analyzed and compared with the exist-ing approaches, the quantified results indicates that the proposed feature descriptor is more effectual than the existing feature de-scriptors that were original y developed for CBIR. In terms of STL, the proposed 2D matrix based indexing minimizes the computation effort for retrieving similar images and for LTL, the proposed algo-rithm takes minimum log information than the existing approaches.

  11. Students' Misconceptions in Interpreting Center and Variability of Data Represented via Histograms and Stem-and-Leaf Plots

    Science.gov (United States)

    Cooper, Linda L.; Shore, Felice S.

    2008-01-01

    This paper identifies and discusses misconceptions that students have in making judgments of center and variability when data are presented graphically. An assessment addressing interpreting center and variability in histograms and stem-and-leaf plots was administered to, and follow-up interviews were conducted with, undergraduates enrolled in…

  12. TaBoo SeArch Algorithm with a Modified Inverse Histogram for Reproducing Biologically Relevant Rare Events of Proteins.

    Science.gov (United States)

    Harada, Ryuhei; Takano, Yu; Shigeta, Yasuteru

    2016-05-10

    The TaBoo SeArch (TBSA) algorithm [ Harada et al. J. Comput. Chem. 2015 , 36 , 763 - 772 and Harada et al. Chem. Phys. Lett. 2015 , 630 , 68 - 75 ] was recently proposed as an enhanced conformational sampling method for reproducing biologically relevant rare events of a given protein. In TBSA, an inverse histogram of the original distribution, mapped onto a set of reaction coordinates, is constructed from trajectories obtained by multiple short-time molecular dynamics (MD) simulations. Rarely occurring states of a given protein are statistically selected as new initial states based on the inverse histogram, and resampling is performed by restarting the MD simulations from the new initial states to promote the conformational transition. In this process, the definition of the inverse histogram, which characterizes the rarely occurring states, is crucial for the efficiency of TBSA. In this study, we propose a simple modification of the inverse histogram to further accelerate the convergence of TBSA. As demonstrations of the modified TBSA, we applied it to (a) hydrogen bonding rearrangements of Met-enkephalin, (b) large-amplitude domain motions of Glutamine-Binding Protein, and (c) folding processes of the B domain of Staphylococcus aureus Protein A. All demonstrations numerically proved that the modified TBSA reproduced these biologically relevant rare events with nanosecond-order simulation times, although a set of microsecond-order, canonical MD simulations failed to reproduce the rare events, indicating the high efficiency of the modified TBSA.

  13. Studying the time histogram of a terrestrial electron beam detected from the opposite hemisphere of its associated TGF

    Science.gov (United States)

    Sarria, D.; Blelly, P.-L.; Briggs, M. S.; Forme, F.

    2016-05-01

    Terrestrial gamma-ray flashes are bursts of X/gamma photons, correlated to thunderstorms. By interacting with the atmosphere, the photons produce a substantial number of electrons and positrons. Some of these reach a sufficiently high altitude that their interactions with the atmosphere become negligible, and they are then guided by geomagnetic field lines, forming a Terrestrial Electron Beam. On 9 December 2009, the Gamma-Ray Burst Monitor (GBM) instrument on board the Fermi Space Telescope made a particularly interesting measurement of such an event. To study this type of event in detail, we perform Monte-Carlo simulations and focus on the resulting time histograms. In agreement with previous work, we show that the histogram measured by Fermi GBM is reproducible from a simulation. We then show that the time histogram resulting from this simulation is only weakly dependent on the production altitude, duration, beaming angle, and spectral shape of the associated terrestrial gamma-ray flash. Finally, we show that the time histogram can be decomposed into three populations of leptons, coming from the opposite hemisphere, and mirroring back to the satellite with or without interacting with the atmosphere, and that these populations can be clearly distinguished by their pitch angles.

  14. Measurable inhomogeneities in stock trading volume flow

    Science.gov (United States)

    Cortines, A. A. G.; Riera, R.; Anteneodo, C.

    2008-08-01

    We investigate the statistics of volumes of shares traded in stock markets. We show that the stochastic process of trading volumes can be understood on the basis of a mixed Poisson process at the microscopic time level. The beta distribution of the second kind (also known as q-gamma distribution), that has been proposed to describe empirical volume histograms, naturally results from our analysis. In particular, the shape of the distribution at small volumes is governed by the degree of granularity in the trading process, while the exponent controlling the tail is a measure of the inhomogeneities in market activity. Furthermore, the present case furnishes empirical evidence of how power law probability distributions can arise as a consequence of a fluctuating intrinsic parameter.

  15. BI-LEVEL CLASSIFICATION OF COLOR INDEXED IMAGE HISTOGRAMS FOR CONTENT BASED IMAGE RETRIEVAL

    Directory of Open Access Journals (Sweden)

    Karpagam Vilvanathan

    2013-01-01

    Full Text Available This dissertation proposes content based image classification and retrieval with Classification and Regression Tree (CART. A simple CBIR system (WH is designed and proved to be efficient even in the presence of distorted and noisy images. WH exhibits good performance in terms of precision, without using any intensive image processing feature extraction techniques. Unique indexed color histogram and wavelet decomposition based horizontal, vertical and diagonal image attributes have been chosen as the primary attributes in the design of the retrieval system. The output feature vectors of the WH method serve as input to the proposed decision tree based image classification and retrieval system. The performance of the proposed content based image classification and retrieval system is evaluated with the standard SIMPLIcity dataset which has been used in several previous works. The performance of the system is measured with precision as the metric. Holdout validation and k-fold cross validation are used to validate the results. The proposed system performs obviously better than SIMPLIcity and all the other compared methods.

  16. Parameters of proteome evolution from histograms of amino-acid sequence identities of paralogous proteins

    Directory of Open Access Journals (Sweden)

    Yan Koon-Kiu

    2007-11-01

    Full Text Available Abstract Background The evolution of the full repertoire of proteins encoded in a given genome is mostly driven by gene duplications, deletions, and sequence modifications of existing proteins. Indirect information about relative rates and other intrinsic parameters of these three basic processes is contained in the proteome-wide distribution of sequence identities of pairs of paralogous proteins. Results We introduce a simple mathematical framework based on a stochastic birth-and-death model that allows one to extract some of this information and apply it to the set of all pairs of paralogous proteins in H. pylori, E. coli, S. cerevisiae, C. elegans, D. melanogaster, and H. sapiens. It was found that the histogram of sequence identities p generated by an all-to-all alignment of all protein sequences encoded in a genome is well fitted with a power-law form ~ p-γ with the value of the exponent γ around 4 for the majority of organisms used in this study. This implies that the intra-protein variability of substitution rates is best described by the Gamma-distribution with the exponent α ≈ 0.33. Different features of the shape of such histograms allow us to quantify the ratio between the genome-wide average deletion/duplication rates and the amino-acid substitution rate. Conclusion We separately measure the short-term ("raw" duplication and deletion rates rdup∗ MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGacaGaaiaabeqaaeqabiWaaaGcbaGaemOCai3aa0baaSqaaiabbsgaKjabbwha1jabbchaWbqaaiabgEHiQaaaaaa@3283@, rdel∗ MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacPC6xNi=xH8viVGI8Gi=hEeeu0xXdbba9frFj0xb9qqpG0dXdb9aspeI8k8fiI+fsY=rqGqVepae9pg0db9vqaiVgFr0xfr=xfr=xc9adbaqaaeGacaGaaiaabeqaaeqabiWaaaGcbaGaemOCai3aa0baaSqaaiabbsga

  17. Application of detector precision characteristics and histogram packing for compression of biological fluorescence micrographs.

    Science.gov (United States)

    Bernas, Tytus; Starosolski, Roman; Robinson, J Paul; Rajwa, Bartlomiej

    2012-11-01

    Modern applications of biological microscopy such as high-content screening (HCS), 4D imaging, and multispectral imaging may involve collection of thousands of images in every experiment making efficient image-compression techniques necessary. Reversible compression algorithms, when used with biological micrographs, provide only a moderate compression ratio, while irreversible techniques obtain better ratios at the cost of removing some information from images and introducing artifacts. We construct a model of noise, which is a function of signal in the imaging system. In the next step insignificant intensity levels are discarded using intensity binning. The resultant images, characterized by sparse intensity histograms, are coded reversibly. We evaluate compression efficiency of combined reversible coding and intensity depth-reduction using single-channel 12-bit light micrographs of several subcellular structures. We apply local and global measures of intensity distribution to estimate maximum distortions introduced by the proposed algorithm. We demonstrate that the algorithm provides efficient compression and does not introduce significant changes to biological micrographs. The algorithm preserves information content of these images and therefore offers better fidelity than standard irreversible compression method JPEG2000. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  18. A Histogram-Based Static-Error Correction Technique for Flash ADCs

    Institute of Scientific and Technical Information of China (English)

    Armin Jalili; J Jacob Wikner; Sayed Masoud Sayedi; Rasoul Dehghani

    2011-01-01

    High-speed, high-accuracy data converters are attractive for use in most RF applications. Such converters allow direct conversion to occur between the digital baseband and the antenna. However, high speed and high accuracy make the analog components in a converter more complex, and this complexity causes more power to be dissipated than if a traditional approach were taken. A static calibration technique for flash analog-to-digital converters (ADCs) is discussed in this paper. The calibration is based onhistogram test methods, and equivalent errors in the flash ADC comparators are estimated in the digital domain without any significant changes being made to the ADC comparators. In the trimming process, reference voltages are adjusted to compensate for static errors. Behavioral-level simulations of a moderate-resolution 8-bit flash ADC show that, for typical errors, ADC performance is considerably improved by the proposed technique. As a result of calibration, the differential no.nlinearities (DNLs) are reduced on average from 4 LSB to 0.5 LSB, and the integral nonlinearities (INLs) are reduced on average from 4.2 LSB to 0.35 LSB. Implementation issues for this proposed technique are discussed in our subsequent paper, “A Histogram-Based Static-Error Correction Technique for Flash ADCs: Implementation Aspects. ”

  19. Facial expression recognition and histograms of oriented gradients: a comprehensive study.

    Science.gov (United States)

    Carcagnì, Pierluigi; Del Coco, Marco; Leo, Marco; Distante, Cosimo

    2015-01-01

    Automatic facial expression recognition (FER) is a topic of growing interest mainly due to the rapid spread of assistive technology applications, as human-robot interaction, where a robust emotional awareness is a key point to best accomplish the assistive task. This paper proposes a comprehensive study on the application of histogram of oriented gradients (HOG) descriptor in the FER problem, highlighting as this powerful technique could be effectively exploited for this purpose. In particular, this paper highlights that a proper set of the HOG parameters can make this descriptor one of the most suitable to characterize facial expression peculiarities. A large experimental session, that can be divided into three different phases, was carried out exploiting a consolidated algorithmic pipeline. The first experimental phase was aimed at proving the suitability of the HOG descriptor to characterize facial expression traits and, to do this, a successful comparison with most commonly used FER frameworks was carried out. In the second experimental phase, different publicly available facial datasets were used to test the system on images acquired in different conditions (e.g. image resolution, lighting conditions, etc.). As a final phase, a test on continuous data streams was carried out on-line in order to validate the system in real-world operating conditions that simulated a real-time human-machine interaction.

  20. Computationally efficient multidimensional analysis of complex flow cytometry data using second order polynomial histograms.

    Science.gov (United States)

    Zaunders, John; Jing, Junmei; Leipold, Michael; Maecker, Holden; Kelleher, Anthony D; Koch, Inge

    2016-01-01

    Many methods have been described for automated clustering analysis of complex flow cytometry data, but so far the goal to efficiently estimate multivariate densities and their modes for a moderate number of dimensions and potentially millions of data points has not been attained. We have devised a novel approach to describing modes using second order polynomial histogram estimators (SOPHE). The method divides the data into multivariate bins and determines the shape of the data in each bin based on second order polynomials, which is an efficient computation. These calculations yield local maxima and allow joining of adjacent bins to identify clusters. The use of second order polynomials also optimally uses wide bins, such that in most cases each parameter (dimension) need only be divided into 4-8 bins, again reducing computational load. We have validated this method using defined mixtures of up to 17 fluorescent beads in 16 dimensions, correctly identifying all populations in data files of 100,000 beads in analysis, and up to 65 subpopulations of PBMC in 33-dimensional CyTOF data, showing its usefulness in discovery research. SOPHE has the potential to greatly increase efficiency of analysing complex mixtures of cells in higher dimensions.

  1. Assessing the hydrologic alteration of the Yangtze River using the histogram matching approach

    Science.gov (United States)

    Huang, F.; Zhang, N.; Guo, L. D.; Xia, Z. Q.

    2016-08-01

    Hydrologic changes of the Yangtze River, an important river with abundant water resources in China, were investigated using the Histogram Matching Approach. Daily streamflow data spanning the time interval from 1955 to 2013 was collected from Yichang and Datong stations, which monitor the hydrologic processes of the upper and lower reach of the Yangtze River, respectively. The Gezhouba Dam, the first dam constructed at the main stream of the Yangtze River, started operations in 1981. 1981 was used to differentiate the pre-dam (1955-1980) and post-dam (1981-2013) hydrologic regimes. The hydrologic regime was quantified by the Indicators of Hydrologic Alteration. The overall alteration degree of the upper Yangtze River was 31% and the alteration degree of every hydrologic indicator ranged from 10% to 81%. Only 1, 5 and 26 hydrologic indicators were altered at high, moderate and low degrees, respectively. The overall alteration degree of the lower Yangtze River was 30%, and the alteration degree of every hydrologic indicator ranged from 8% to 49%. No high alteration degree was detected at the Datong station. Ten hydrologic indicators were altered at moderate degrees and 22 hydrologic indicators were altered at low degrees. Significant increases could be observed for the low-flow relevant indicators, including the monthly flow from January-March, the annual minimum 1, 3, 7, 30 and 90-day flows, and the base flow index.

  2. Multicomponent adsorption in mesoporous flexible materials with flat-histogram Monte Carlo methods

    Science.gov (United States)

    Mahynski, Nathan A.; Shen, Vincent K.

    2016-11-01

    We demonstrate an extensible flat-histogram Monte Carlo simulation methodology for studying the adsorption of multicomponent fluids in flexible porous solids. This methodology allows us to easily obtain the complete free energy landscape for the confined fluid-solid system in equilibrium with a bulk fluid of any arbitrary composition. We use this approach to study the adsorption of a prototypical coarse-grained binary fluid in "Hookean" solids, where the free energy of the solid may be described as a simple spring. However, our approach is fully extensible to solids with arbitrarily complex free energy profiles. We demonstrate that by tuning the fluid-solid interaction ranges, the inhomogeneous fluid structure inside the pore can give rise to enhanced selective capture of a larger species through cooperative adsorption with a smaller one. The maximum enhancement in selectivity is observed at low to intermediate pressures and is especially pronounced when the larger species is very dilute in the bulk. This suggest a mechanism by which the selective capture of a minor component from a bulk fluid may be enhanced.

  3. Intravoxel incoherent motion (IVIM) histogram biomarkers for prediction of neoadjuvant treatment response in breast cancer patients.

    Science.gov (United States)

    Cho, Gene Y; Gennaro, Lucas; Sutton, Elizabeth J; Zabor, Emily C; Zhang, Zhigang; Giri, Dilip; Moy, Linda; Sodickson, Daniel K; Morris, Elizabeth A; Sigmund, Eric E; Thakur, Sunitha B

    2017-01-01

    To examine the prognostic capabilities of intravoxel incoherent motion (IVIM) metrics and their ability to predict response to neoadjuvant treatment (NAT). Additionally, to observe changes in IVIM metrics between pre- and post-treatment MRI. This IRB-approved, HIPAA-compliant retrospective study observed 31 breast cancer patients (32 lesions). Patients underwent standard bilateral breast MRI along with diffusion-weighted imaging before and after NAT. Six patients underwent an additional IVIM-MRI scan 12-14 weeks after initial scan and 2 cycles of treatment. In addition to apparent diffusion coefficients (ADC) from monoexponential decay, IVIM mean values (tissue diffusivity Dt, perfusion fraction fp, and pseudodiffusivity Dp) and histogram metrics were derived using a biexponential model. An additional filter identified voxels of highly vascular tumor tissue (VTT), excluding necrotic or normal tissue. Clinical data include histology of biopsy and clinical response to treatment through RECIST assessment. Comparisons of treatment response were made using Wilcoxon rank-sum tests. Average, kurtosis, and skewness of pseudodiffusion Dp significantly differentiated RECIST responders from nonresponders. ADC and Dt values generally increased (∼70%) and VTT% values generally decreased (∼20%) post-treatment. Dp metrics showed prognostic capabilities; slow and heterogeneous pseudodiffusion offer poor prognosis. Baseline ADC/Dt parameters were not significant predictors of response. This work suggests that IVIM mean values and heterogeneity metrics may have prognostic value in the setting of breast cancer NAT.

  4. Face Recognition Performance Improvement using a Similarity Score of Feature Vectors based on Probabilistic Histograms

    Directory of Open Access Journals (Sweden)

    SRIKOTE, G.

    2016-08-01

    Full Text Available This paper proposes an improved performance algorithm of face recognition to identify two face mismatch pairs in cases of incorrect decisions. The primary feature of this method is to deploy the similarity score with respect to Gaussian components between two previously unseen faces. Unlike the conventional classical vector distance measurement, our algorithms also consider the plot of summation of the similarity index versus face feature vector distance. A mixture of Gaussian models of labeled faces is also widely applicable to different biometric system parameters. By comparative evaluations, it has been shown that the efficiency of the proposed algorithm is superior to that of the conventional algorithm by an average accuracy of up to 1.15% and 16.87% when compared with 3x3 Multi-Region Histogram (MRH direct-bag-of-features and Principal Component Analysis (PCA-based face recognition systems, respectively. The experimental results show that similarity score consideration is more discriminative for face recognition compared to feature distance. Experimental results of Labeled Face in the Wild (LFW data set demonstrate that our algorithms are suitable for real applications probe-to-gallery identification of face recognition systems. Moreover, this proposed method can also be applied to other recognition systems and therefore additionally improves recognition scores.

  5. Bladder dose accumulation based on a biomechanical deformable image registration algorithm in volumetric modulated arc therapy for prostate cancer

    DEFF Research Database (Denmark)

    Andersen, E S; Muren, L P; Sørensen, T S

    2012-01-01

    ) to improve the accuracy of bladder dose assessment. For each of nine prostate cancer patients, the initial treatment plan was re-calculated on eight to nine repeat computed tomography (CT) scans. The planned bladder dose–volume histogram (DVH) parameters were compared to corresponding parameters derived from...... DIR-based accumulations and DVH summation were small and well within 1 Gy. For the investigated treatment scenario, DIR- based bladder dose accumulation did not result in substantial improvement of dose estimation as compared to the straightforward DVH summation. Large variations were found...... in individual patients between the doses from the initial treatment plan and the accumulated bladder doses. Hence, the use of repeat imaging has a potential for improved accuracy in treatment dose reporting....

  6. Dosimetric comparison of different radiation treatment modalities for acoustic neuromas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Wook; Chung, Weon Kuu [Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of); Shin, Dong Oh [Kyung Hee Medical Center, Seoul (Korea, Republic of); Shin, Dongho [National Cancer Center, Goyang (Korea, Republic of)

    2014-11-15

    The dosimetric differences for intensity-modulatedradiotherapy (IMRT), volumetric modulated arc therapy (VMAT), proton therapy(PROTON) and stereotactic radiosurgery (SRS) in patient with acoustic neuroma (AN) were compared by using the dose-volume histogram (DVH). In the present study, we estimated the dosimetric differences for patient with AN who received different treatment modalities. In this study, we found proton therapy is relatively effective treatment techniques than the other.

  7. Curve Evolution in Subspaces and Exploring the Metameric Class of Histogram of Gradient Orientation based Features using Nonlinear Projection Methods

    DEFF Research Database (Denmark)

    Tatu, Aditya Jayant

    defined subspace, the N-links bicycle chain space, i.e. the space of curves with equidistant neighboring landmark points. This in itself is a useful shape space for medical image analysis applications. The Histogram of Gradient orientation based features are many in number and are widely used......This thesis deals with two unrelated issues, restricting curve evolution to subspaces and computing image patches in the equivalence class of Histogram of Gradient orientation based features using nonlinear projection methods. Curve evolution is a well known method used in various applications like...... specific requirements like shape priors or a given data model, and due to limitations of the computer, the computed curve evolution forms a path in some finite dimensional subspace of the space of curves. We give methods to restrict the curve evolution to a finite dimensional linear or implicitly defined...

  8. Histogramming in the LATOME-firmware for the Phase-1 upgrade of the ATLAS LAr calorimeter readout

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Philipp; Hentges, Rainer; Straessner, Arno [Institut fuer Kern- und Teilchenphysik, Dresden (Germany)

    2016-07-01

    Due to the increased luminosity and the higher effective event rate after the phase 1 upgrade the ATLAS LAr detector needs new trigger electronics. The so-called LATOME-Board was designed as a LAr Digital Processing Blade (LPDB) to reconstruct the energy deposited by the particles and is an important part of the read out system. A prototype has already been build and the firmware for the on-board FPGA is under development. The insertion of a histogram-builder in this device gives the unique opportunity to look at untriggered data. This talk provides an insight in the LATOME-firmware and shows the different possibilities to implement the histogram-builder.

  9. 基于自投影和灰度检索的视频帧中异常行为检测%Anomalous Behavior Detection in Video Sequence Based on Self-Casting Histogram and Gray Histogram

    Institute of Scientific and Technical Information of China (English)

    郭迎春; 吴鹏; 袁浩杰

    2012-01-01

    针对智能监控系统,提出了一种基于运动目标灰度直方图和自身投影直方图的检索匹配方法,能够快速实现视频序列中行人的运动方向异常检测.该方法结合目标的灰度直方图和自身投影直方图在人群中快速检索匹配目标,采用目标质心运动历史记录表连续记录目标质心和运动方向,通过比较各个目标的运动方向找出运动人群中的异常目标.实验结果表明,引入目标的自身投影直方图,比只利用灰度图的灰度信息有更高的检测准确性,同时历史移动记录表可完全胜任运动目标信息记录的任务.该方法计算量小,同时利用记录质心的移动速度能实时对目标的运动情况进行预测,对运动目标的相互遮藏有一定的鲁棒性.%For the intelligent video surveillance system, a motion object retrieval match approach is proposed, combining with the gray histogram and the self-casting histogram. It can rapidly detect an object with abnormal direction of motion. The method uses the feature combined with the gray and self-casting histograms to detect and match the object among crowds. And it uses the motion history record list of object centroid to continuously record the centroid of object and its motion direction. Besides, it compares the motion direction to find the abnormal object among moving crowds. The experiment result shows that compared with the method only employing the information of gray histogram, the accuracy of detection is improved after introducing object self-casting histogram, and the motion history record list is fully qualified to record the motion information of moving objects. The method has small amount of calculation and good robustness against objects covered by each other during their movement by recording the speeds of centroid motion.

  10. SU-E-T-471: Improvement of Gamma Knife Treatment Planning Through Tumor Control Probability for Metastatic Brain Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z [East Carolina University, Greenville, NC (United States); Feng, Y [East Carolina Univ, Rockville, MD (United States); Lo, S [Case Western Reserve University, Cleveland, OH (United States); Grecula, J [Ohio State University, Columbus, OH (United States); Mayr, N; Yuh, W [University of Washington, Seattle, WA (United States)

    2015-06-15

    Purpose: The dose–volume histogram (DVH) has been normally accepted as a tool for treatment plan evaluation. However, spatial information is lacking in DVH. As a supplement to the DVH in three-dimensional treatment planning, the differential DVH (DDVH) provides the spatial variation, the size and magnitude of the different dose regions within a region of interest, which can be incorporated into tumor control probability model. This study was to provide a method in evaluating and improving Gamma Knife treatment planning. Methods: 10 patients with brain metastases from different primary tumors including melanoma (#1,#4,#5, #10), breast cancer (#2), prostate cancer (#3) and lung cancer (#6–9) were analyzed. By using Leksell GammaPlan software, two plans were prepared for each patient. Special attention was given to the DDVHs that were different for different plans and were used for a comparison between two plans. Dose distribution inside target and tumor control probability (TCP) based on DDVH were calculated, where cell density and radiobiological parameters were adopted from literature. The plans were compared based on DVH, DDVH and TCP. Results: Using DVH, the coverage and selectivity were the same between plans for 10 patients. DDVH were different between two plans for each patient. The paired t-test showed no significant difference in TCP between the two plans. For brain metastases from melanoma (#1, #4–5), breast cancer (#2) and lung cancer (#6–8), the difference in TCP was less than 5%. But the difference in TCP was about 6.5% for patient #3 with the metastasis from prostate cancer, 10.1% and 178.7% for two patients (#9–10) with metastasis from lung cancer. Conclusion: Although DVH provides average dose–volume information, DDVH provides differential dose– volume information with respect to different regions inside the tumor. TCP provides radiobiological information and adds additional information on improving treatment planning as well as adaptive

  11. Nanothermodynamics of large iron clusters by means of a flat histogram Monte Carlo method

    Science.gov (United States)

    Basire, M.; Soudan, J.-M.; Angelié, C.

    2014-09-01

    The thermodynamics of iron clusters of various sizes, from 76 to 2452 atoms, typical of the catalyst particles used for carbon nanotubes growth, has been explored by a flat histogram Monte Carlo (MC) algorithm (called the σ-mapping), developed by Soudan et al. [J. Chem. Phys. 135, 144109 (2011), Paper I]. This method provides the classical density of states, gp(Ep) in the configurational space, in terms of the potential energy of the system, with good and well controlled convergence properties, particularly in the melting phase transition zone which is of interest in this work. To describe the system, an iron potential has been implemented, called "corrected EAM" (cEAM), which approximates the MEAM potential of Lee et al. [Phys. Rev. B 64, 184102 (2001)] with an accuracy better than 3 meV/at, and a five times larger computational speed. The main simplification concerns the angular dependence of the potential, with a small impact on accuracy, while the screening coefficients Sij are exactly computed with a fast algorithm. With this potential, ergodic explorations of the clusters can be performed efficiently in a reasonable computing time, at least in the upper half of the solid zone and above. Problems of ergodicity exist in the lower half of the solid zone but routes to overcome them are discussed. The solid-liquid (melting) phase transition temperature Tm is plotted in terms of the cluster atom number Nat. The standard N_{at}^{-1/3} linear dependence (Pawlow law) is observed for Nat >300, allowing an extrapolation up to the bulk metal at 1940 ±50 K. For Nat potential clusters studied in Paper I.

  12. Coding and decoding with adapting neurons: a population approach to the peri-stimulus time histogram.

    Science.gov (United States)

    Naud, Richard; Gerstner, Wulfram

    2012-01-01

    The response of a neuron to a time-dependent stimulus, as measured in a Peri-Stimulus-Time-Histogram (PSTH), exhibits an intricate temporal structure that reflects potential temporal coding principles. Here we analyze the encoding and decoding of PSTHs for spiking neurons with arbitrary refractoriness and adaptation. As a modeling framework, we use the spike response model, also known as the generalized linear neuron model. Because of refractoriness, the effect of the most recent spike on the spiking probability a few milliseconds later is very strong. The influence of the last spike needs therefore to be described with high precision, while the rest of the neuronal spiking history merely introduces an average self-inhibition or adaptation that depends on the expected number of past spikes but not on the exact spike timings. Based on these insights, we derive a 'quasi-renewal equation' which is shown to yield an excellent description of the firing rate of adapting neurons. We explore the domain of validity of the quasi-renewal equation and compare it with other rate equations for populations of spiking neurons. The problem of decoding the stimulus from the population response (or PSTH) is addressed analogously. We find that for small levels of activity and weak adaptation, a simple accumulator of the past activity is sufficient to decode the original input, but when refractory effects become large decoding becomes a non-linear function of the past activity. The results presented here can be applied to the mean-field analysis of coupled neuron networks, but also to arbitrary point processes with negative self-interaction.

  13. Assessment of Autonomic Function by Phase Rectification of RRInterval Histogram Analysis in Chagas Disease

    Directory of Open Access Journals (Sweden)

    Olivassé Nasari Junior

    2015-06-01

    Full Text Available Background: In chronic Chagas disease (ChD, impairment of cardiac autonomic function bears prognostic implications. Phase‑rectification of RR-interval series isolates the sympathetic, acceleration phase (AC and parasympathetic, deceleration phase (DC influences on cardiac autonomic modulation. Objective: This study investigated heart rate variability (HRV as a function of RR-interval to assess autonomic function in healthy and ChD subjects. Methods: Control (n = 20 and ChD (n = 20 groups were studied. All underwent 60-min head-up tilt table test under ECG recording. Histogram of RR-interval series was calculated, with 100 ms class, ranging from 600–1100 ms. In each class, mean RR-intervals (MNN and root-mean-squared difference (RMSNN of consecutive normal RR-intervals that suited a particular class were calculated. Average of all RMSNN values in each class was analyzed as function of MNN, in the whole series (RMSNNT, and in AC (RMSNNAC and DC (RMSNNDC phases. Slopes of linear regression lines were compared between groups using Student t-test. Correlation coefficients were tested before comparisons. RMSNN was log-transformed. (α < 0.05. Results: Correlation coefficient was significant in all regressions (p < 0.05. In the control group, RMSNNT, RMSNNAC, and RMSNNDC significantly increased linearly with MNN (p < 0.05. In ChD, only RMSNNAC showed significant increase as a function of MNN, whereas RMSNNT and RMSNNDC did not. Conclusion: HRV increases in proportion with the RR-interval in healthy subjects. This behavior is lost in ChD, particularly in the DC phase, indicating cardiac vagal incompetence.

  14. Combining a modified vector field histogram algorithm and real-time image processing for unknown environment navigation

    Science.gov (United States)

    Nepal, Kumud; Fine, Adam; Imam, Nabil; Pietrocola, David; Robertson, Neil; Ahlgren, David J.

    2009-01-01

    Q is an unmanned ground vehicle designed to compete in the Autonomous and Navigation Challenges of the AUVSI Intelligent Ground Vehicle Competition (IGVC). Built on a base platform of a modified PerMobil Trax off-road wheel chair frame, and running off a Dell Inspiron D820 laptop with an Intel t7400 Core 2 Duo Processor, Q gathers information from a SICK laser range finder (LRF), video cameras, differential GPS, and digital compass to localize its behavior and map out its navigational path. This behavior is handled by intelligent closed loop speed control and robust sensor data processing algorithms. In the Autonomous challenge, data taken from two IEEE 1394 cameras and the LRF are integrated and plotted on a custom-defined occupancy grid and converted into a histogram which is analyzed for openings between obstacles. The image processing algorithm consists of a series of steps involving plane extraction, normalizing of the image histogram for an effective dynamic thresholding, texture and morphological analysis and particle filtering to allow optimum operation at varying ambient conditions. In the Navigation Challenge, a modified Vector Field Histogram (VFH) algorithm is combined with an auto-regressive path planning model for obstacle avoidance and better localization. Also, Q features the Joint Architecture for Unmanned Systems (JAUS) Level 3 compliance. All algorithms are developed and implemented using National Instruments (NI) hardware and LabVIEW software. The paper will focus on explaining the various algorithms that make up Q's intelligence and the different ways and modes of their implementation.

  15. RelMon: A general approach to QA, validation and physics analysis through comparison of large sets of histograms

    CERN Document Server

    Piparo, Danilo

    2012-01-01

    The estimation of the compatibility of large amounts of histogram pairs is a recurrent problem in high energy physics. The issue is common to several different areas, from software quality monitoring to data certification, preservation and analysis. Given two sets of histograms, it is very important to be able to scrutinize the outcome of several goodness of fit tests, obtain a clear answer about the overall compatibility, easily spot the single anomalies and directly access the concerned histogram pairs. This procedure must be automated in order to reduce the human workload, therefore improving the process of identification of differences which is usually carried out by a trained human mind. Some solutions to this problem have been proposed, but they are experiment specific. RelMon depends only on ROOT and offers several goodness of fit tests (e.g. chi-squared or Kolmogorov-Smirnov). It produces highly readable web reports, in which aggregations of the comparisons rankings are available as well as all the pl...

  16. Automatic detection of atrial fibrillation using the coefficient of variation and density histograms of RR and deltaRR intervals.

    Science.gov (United States)

    Tateno, K; Glass, L

    2001-11-01

    The paper describes a method for the automatic detection of atrial fibrillation, an abnormal heart rhythm, based on the sequence of intervals between heartbeats. The RR interval is the interbeat interval, and deltaRR is the difference between two successive RR intervals. Standard density histograms of the RR and deltaRR intervals were prepared as templates for atrial fibrillation detection. As the coefficients of variation of the RR and deltaRR intervals were approximately constant during atrial fibrillation, the coefficients of variation in the test data could be compared with the standard coefficients of variation (CV test). Further, the similarities between the density histograms of the test data and the standard density histograms were estimated using the Kolmogorov-Smirnov test. The CV test based on the RR intervals showed a sensitivity of 86.6% and a specificity of 84.3%. The CV test based on the deltaRR intervals showed that the sensitivity and the specificity are both approximately 84%. The Kolmogorov-Smirnov test based on the RR intervals did not improve on the result of the CV test. In contrast, the Kolmogorov-Smirnov test based on the ARR intervals showed a sensitivity of 94.4% and a specificity of 97.2%.

  17. Visual vs Fully Automatic Histogram-Based Assessment of Idiopathic Pulmonary Fibrosis (IPF Progression Using Sequential Multidetector Computed Tomography (MDCT.

    Directory of Open Access Journals (Sweden)

    Davide Colombi

    Full Text Available To describe changes over time in extent of idiopathic pulmonary fibrosis (IPF at multidetector computed tomography (MDCT assessed by semi-quantitative visual scores (VSs and fully automatic histogram-based quantitative evaluation and to test the relationship between these two methods of quantification.Forty IPF patients (median age: 70 y, interquartile: 62-75 years; M:F, 33:7 that underwent 2 MDCT at different time points with a median interval of 13 months (interquartile: 10-17 months were retrospectively evaluated. In-house software YACTA quantified automatically lung density histogram (10th-90th percentile in 5th percentile steps. Longitudinal changes in VSs and in the percentiles of attenuation histogram were obtained in 20 untreated patients and 20 patients treated with pirfenidone. Pearson correlation analysis was used to test the relationship between VSs and selected percentiles.In follow-up MDCT, visual overall extent of parenchymal abnormalities (OE increased in median by 5%/year (interquartile: 0%/y; +11%/y. Substantial difference was found between treated and untreated patients in HU changes of the 40th and of the 80th percentiles of density histogram. Correlation analysis between VSs and selected percentiles showed higher correlation between the changes (Δ in OE and Δ 40th percentile (r=0.69; p<0.001 as compared to Δ 80th percentile (r=0.58; p<0.001; closer correlation was found between Δ ground-glass extent and Δ 40th percentile (r=0.66, p<0.001 as compared to Δ 80th percentile (r=0.47, p=0.002, while the Δ reticulations correlated better with the Δ 80th percentile (r=0.56, p<0.001 in comparison to Δ 40th percentile (r=0.43, p=0.003.There is a relevant and fully automatically measurable difference at MDCT in VSs and in histogram analysis at one year follow-up of IPF patients, whether treated or untreated: Δ 40th percentile might reflect the change in overall extent of lung abnormalities, notably of ground-glass pattern

  18. [Forms of histograms constructed from measurements of alpha-decay of 228Ra in Lindau (Germany) and neutron fluxes in Moscow change synchronously according to the local time].

    Science.gov (United States)

    Zenchenko, K I; Zenchenko, T A; Kuzhevskiĭ, B M; Vilken, B; Axford, Y; Shnol', S E

    2001-01-01

    In joint experiments performed at Max Plank Institute of Aeronomy (Germany) and the Institute of Theoretical and Experimental Biophysics in Pushchino, the main manifestations of the phenomenon of macroscopic fluctuations were confirmed. An increased probability of the similarity in synchronous histograms in independent measurements performed by two installations in one laboratory and in two laboratories separated by a distance of 2000 km was shown. In the latter case, the similarity of histograms is most probable at the same local time.

  19. Nanothermodynamics of large iron clusters by means of a flat histogram Monte Carlo method

    Energy Technology Data Exchange (ETDEWEB)

    Basire, M.; Soudan, J.-M.; Angelié, C., E-mail: christian.angelie@cea.fr [Laboratoire Francis Perrin, CNRS-URA 2453, CEA/DSM/IRAMIS/LIDyL, F-91191 Gif-sur-Yvette Cedex (France)

    2014-09-14

    The thermodynamics of iron clusters of various sizes, from 76 to 2452 atoms, typical of the catalyst particles used for carbon nanotubes growth, has been explored by a flat histogram Monte Carlo (MC) algorithm (called the σ-mapping), developed by Soudan et al. [J. Chem. Phys. 135, 144109 (2011), Paper I]. This method provides the classical density of states, g{sub p}(E{sub p}) in the configurational space, in terms of the potential energy of the system, with good and well controlled convergence properties, particularly in the melting phase transition zone which is of interest in this work. To describe the system, an iron potential has been implemented, called “corrected EAM” (cEAM), which approximates the MEAM potential of Lee et al. [Phys. Rev. B 64, 184102 (2001)] with an accuracy better than 3 meV/at, and a five times larger computational speed. The main simplification concerns the angular dependence of the potential, with a small impact on accuracy, while the screening coefficients S{sub ij} are exactly computed with a fast algorithm. With this potential, ergodic explorations of the clusters can be performed efficiently in a reasonable computing time, at least in the upper half of the solid zone and above. Problems of ergodicity exist in the lower half of the solid zone but routes to overcome them are discussed. The solid-liquid (melting) phase transition temperature T{sub m} is plotted in terms of the cluster atom number N{sub at}. The standard N{sub at}{sup −1/3} linear dependence (Pawlow law) is observed for N{sub at} >300, allowing an extrapolation up to the bulk metal at 1940 ±50 K. For N{sub at} <150, a strong divergence is observed compared to the Pawlow law. The melting transition, which begins at the surface, is stated by a Lindemann-Berry index and an atomic density analysis. Several new features are obtained for the thermodynamics of cEAM clusters, compared to the Rydberg pair potential clusters studied in Paper I.

  20. Apparent diffusion coefficient histogram analysis of neonatal hypoxic-ischemic encephalopathy

    Energy Technology Data Exchange (ETDEWEB)

    Cauley, Keith A. [University of Massachusetts Medical School, Department of Radiology, Worcester, MA (United States); New York Presbyterian Hospital, Columbia University Medical Center, Department of Radiology, New York, NY (United States); Filippi, Christopher G. [New York Presbyterian Hospital, Columbia University Medical Center, Department of Radiology, New York, NY (United States)

    2014-06-15

    Diffusion-weighted imaging is a valuable tool in the assessment of the neonatal brain, and changes in diffusion are seen in normal development as well as in pathological states such as hypoxic-ischemic encephalopathy (HIE). Various methods of quantitative assessment of diffusion values have been reported. Global ischemic injury occurring during the time of rapid developmental changes in brain myelination can complicate the imaging diagnosis of neonatal HIE. To compare a quantitative method of histographic analysis of brain apparent coefficient (ADC) maps to the qualitative interpretation of routine brain MR imaging studies. We correlate changes in diffusion values with gestational age in radiographically normal neonates, and we investigate the sensitivity of the method as a quantitative measure of hypoxic-ischemic encephalopathy. We reviewed all brain MRI studies from the neonatal intensive care unit (NICU) at our university medical center over a 4-year period to identify cases that were radiographically normal (23 cases) and those with diffuse, global hypoxic-ischemic encephalopathy (12 cases). We histographically displayed ADC values of a single brain slice at the level of the basal ganglia and correlated peak (s-sD{sub av}) and lowest histogram values (s-sD{sub lowest}) with gestational age. Normative s-sD{sub av} values correlated significantly with gestational age and declined linearly through the neonatal period (r {sup 2} = 0.477, P < 0.01). Six of 12 cases of known HIE demonstrated significantly lower s-sD{sub av} and s-sD{sub lowest} ADC values than were reflected in the normative distribution; several cases of HIE fell within a 95% confidence interval for normative studies, and one case demonstrated higher-than-normal s-sD{sub av}. Single-slice histographic display of ADC values is a rapid and clinically feasible method of quantitative analysis of diffusion. In this study normative values derived from consecutive neonates without radiographic evidence of

  1. Volume Entropy

    CERN Document Server

    Astuti, Valerio; Rovelli, Carlo

    2016-01-01

    Building on a technical result by Brunnemann and Rideout on the spectrum of the Volume operator in Loop Quantum Gravity, we show that the dimension of the space of the quadrivalent states --with finite-volume individual nodes-- describing a region with total volume smaller than $V$, has \\emph{finite} dimension, bounded by $V \\log V$. This allows us to introduce the notion of "volume entropy": the von Neumann entropy associated to the measurement of volume.

  2. Whole-lesion histogram analysis of the apparent diffusion coefficient: Evaluation of the correlation with subtypes of mucinous breast carcinoma.

    Science.gov (United States)

    Guo, Yuan; Kong, Qing-Cong; Zhu, Ye-Qing; Liu, Zhen-Zhen; Peng, Ling-Rong; Tang, Wen-Jie; Yang, Rui-Meng; Xie, Jia-Jun; Liu, Chun-Ling

    2017-06-22

    To evaluate the utility of the whole-lesion histogram apparent diffusion coefficient (ADC) for characterizing the heterogeneity of mucinous breast carcinoma (MBC) and to determine which ADC metrics may help to best differentiate subtypes of MBC. This retrospective study involved 52 MBC patients, including 37 pure MBC (PMBC) and 15 mixed MBC (MMBC). The PMBC patients were subtyped into PMBC-A (20 cases) and PMBC-B (17 cases) groups. All patients underwent preoperative diffusion-weighted imaging (DWI) at 1.5T and the whole-lesion ADC assessments were generated. Histogram-derived ADC parameters were compared between PMBC vs. MMBC and PMBC-A vs. PMBC-B, and receiver operating characteristic (ROC) curve analysis was used to determine optimal histogram parameters for differentiating these groups. The PMBC group exhibited significantly higher ADC values for the mean (P = 0.004), 25(th) (P = 0.004), 50(th) (P = 0.004), 75(th) (P = 0.006), and 90(th) percentiles (P = 0.013) and skewness (P = 0.021) than did the MMBC group. The 25(th) percentile of ADC values achieved the highest area under the curve (AUC) (0.792), with a cutoff value of 1.345 × 10(-3) mm(2) /s, in distinguishing PMBC and MMBC. The PMBC-A group showed significantly higher ADC values for the mean (P = 0.049), 25(th) (P = 0.015), and 50(th) (P = 0.026) percentiles and skewness (P = 0.004) than did the PMBC-B group. The 25(th) percentile of the ADC cutoff value (1.476 × 10(-3) mm(2) /s) demonstrated the best AUC (0.837) among the ADC values for distinguishing PMBC-A and PMBC-B. Whole-lesion ADC histogram analysis enables comprehensive evaluation of an MBC in its entirety and differentiating subtypes of MBC. Thus, it may be a helpful and supportive tool for conventional MRI. 4 TECHNICAL EFFICACY: Stage 2 J. Magn. Reson. Imaging 2017. © 2017 International Society for Magnetic Resonance in Medicine.

  3. Volume adjustment of lung density by computed tomography scans in patients with emphysema

    DEFF Research Database (Denmark)

    Shaker, S B; Dirksen, A; Laursen, Lars Christian

    2004-01-01

    package that detected the lung in contiguous images and subsequently generated a histogram of the pixel attenuation values. The total lung volume (TLV), lung weight, percentile density (PD), and relative area of emphysema (RA) were calculated from this histogram. RA and PD are commonly applied measures......PURPOSE: To determine how to adjust lung density measurements for the volume of the lung calculated from computed tomography (CT) scans in patients with emphysema. MATERIAL AND METHODS: Fifty patients with emphysema underwent 3 CT scans at 2-week intervals. The scans were analyzed with a software...... of pulmonary emphysema derived from CT scans. These parameters are markedly influenced by changes in the level of inspiration. The variability of lung density due to within-subject variation in TLV was explored by plotting TLV against PD and RA. RESULTS: The coefficients for volume adjustment for PD were...

  4. Survey of fish impingement at power plants in the United States. Volume I. The Great Lakes

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Rajendra K.; Freeman, III, Richard F.

    1977-03-01

    Impingement of fish at cooling-water intakes of 20 power plants located on the Great Lakes has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV.

  5. Survey of fish impingement at power plants in the United States. Volume II. Inland waters

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, III, Richard F.; Sharma, Rajendra K.

    1977-03-01

    Impingement of fish at cooling-water intakes of 33 power plants located on inland waters other than the Great Lakes has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV.

  6. Late swallowing dysfunction and dysphagia after radiotherapy for pharynx cancer: frequency, intensity and correlation with dose and volume parameters

    DEFF Research Database (Denmark)

    Jensen, Kenneth; Lambertsen, Karin; Grau, Cai

    2007-01-01

    sphincter resulted in a low risk of aspiration. DISCUSSION: Both subjective and objective swallowing problems were frequent and severe after radiotherapy for pharynx cancer. Swallowing dysfunction was correlated with dose and volume parameters of the upper aerodigestive tract. Udgivelsesdato: 2007-Oct...... function after radiotherapy and examine its correlation with irradiated volume and dose. PATIENTS AND METHODS: All recurrence free patients treated for pharynx cancer with radical radiotherapy at our institution, between 1998 and 2002, were invited to participate, 35 (55% of eligible) agreed. Patients were...... in 88%, penetration in 59% and aspiration in 18% of patients. Several significant correlations were found between both subjective and objective swallowing problems and DVH parameters of the upper aerodigestive tract. Doses less than 60 Gy to the supraglottic region, the larynx and upper esophageal...

  7. Quantifying kinetics from time series of single-molecule Förster resonance energy transfer efficiency histograms.

    Science.gov (United States)

    Benke, Stephan; Nettels, Daniel; Hofmann, Hagen; Schuler, Benjamin

    2017-03-17

    Single-molecule fluorescence spectroscopy is a powerful approach for probing biomolecular structure and dynamics, including protein folding. For the investigation of nonequilibrium kinetics, Förster resonance energy transfer combined with confocal multiparameter detection has proven particularly versatile, owing to the large number of observables and the broad range of accessible timescales, especially in combination with rapid microfluidic mixing. However, a comprehensive kinetic analysis of the resulting time series of transfer efficiency histograms and complementary observables can be challenging owing to the complexity of the data. Here we present and compare three different methods for the analysis of such kinetic data: singular value decomposition, multivariate curve resolution with alternating least square fitting, and model-based peak fitting, where an explicit model of both the transfer efficiency histogram of each species and the kinetic mechanism of the process is employed. While each of these methods has its merits for specific applications, we conclude that model-based peak fitting is most suitable for a quantitative analysis and comparison of kinetic mechanisms.

  8. Experimental assessment of an automatic breast density classification algorithm based on principal component analysis applied to histogram data

    Science.gov (United States)

    Angulo, Antonio; Ferrer, Jose; Pinto, Joseph; Lavarello, Roberto; Guerrero, Jorge; Castaneda, Benjamín.

    2015-01-01

    Breast parenchymal density is considered a strong indicator of cancer risk. However, measures of breast density are often qualitative and require the subjective judgment of radiologists. This work proposes a supervised algorithm to automatically assign a BI-RADS breast density score to a digital mammogram. The algorithm applies principal component analysis to the histograms of a training dataset of digital mammograms to create four different spaces, one for each BI-RADS category. Scoring is achieved by projecting the histogram of the image to be classified onto the four spaces and assigning it to the closest class. In order to validate the algorithm, a training set of 86 images and a separate testing database of 964 images were built. All mammograms were acquired in the craniocaudal view from female patients without any visible pathology. Eight experienced radiologists categorized the mammograms according to a BIRADS score and the mode of their evaluations was considered as ground truth. Results show better agreement between the algorithm and ground truth for the training set (kappa=0.74) than for the test set (kappa=0.44) which suggests the method may be used for BI-RADS classification but a better training is required.

  9. ANALYSE DATA IN THE FORM OF HISTOGRAM WITH COMPARISON BETWEEN KOLMOGOROV-SMIRNOV TEST AND CHI SQUARE TEST

    CERN Document Server

    Pg Haji Mohd Ariffin, Ak Muhamad Amirul Irfan

    2015-01-01

    This paper presents the project that I have been tasked while attending a three-month Summer Programme at CERN. The Project specification is to analyse the result of a weekly data produced by Compact Muon Solenoid (CMS) in the form of histograms. CMS is a detector which is a multi-purpose apparatus use to operate at the Large Hadron Collider (LHC) at CERN. It will yield head-on collisions of two proton (ion) beams of 7 TeV (2.75 TeV per nucleon) each, with a design luminosity of 10 34 cm -2s-1. A comparison of the results is then made using two methods namely Kolmogorov Smirnov Statistic Test and Chi-Squared Test. These tests will be further elaborated in the subsequent paragraphs. To execute this project, I have to firstly study the entire basic computer programming in particular C++ and the ROOT Basic Programmes. This is important to ensure the tasks given can be resolved within the given time. A program is subsequently written to provide output of histogram and calculation of Kolmogorov-Smirnov Test and Ch...

  10. Quantifying kinetics from time series of single-molecule Förster resonance energy transfer efficiency histograms

    Science.gov (United States)

    Benke, Stephan; Nettels, Daniel; Hofmann, Hagen; Schuler, Benjamin

    2017-03-01

    Single-molecule fluorescence spectroscopy is a powerful approach for probing biomolecular structure and dynamics, including protein folding. For the investigation of nonequilibrium kinetics, Förster resonance energy transfer combined with confocal multiparameter detection has proven particularly versatile, owing to the large number of observables and the broad range of accessible timescales, especially in combination with rapid microfluidic mixing. However, a comprehensive kinetic analysis of the resulting time series of transfer efficiency histograms and complementary observables can be challenging owing to the complexity of the data. Here we present and compare three different methods for the analysis of such kinetic data: singular value decomposition, multivariate curve resolution with alternating least square fitting, and model-based peak fitting, where an explicit model of both the transfer efficiency histogram of each species and the kinetic mechanism of the process is employed. While each of these methods has its merits for specific applications, we conclude that model-based peak fitting is most suitable for a quantitative analysis and comparison of kinetic mechanisms.

  11. Properties of the histogram location approach and the extent and change of downward nominal wage rigidity in the EU

    Directory of Open Access Journals (Sweden)

    Andreas Behr

    2006-06-01

    Full Text Available The histogram location approach has been proposed by Kahn (1997 to estimate the fraction of wage cuts prevented by downward nominal wage rigidity. In this paper, we analyze the validity of the approach by means of a simulation study which yielded evidence of unbiasedness but also of potential underestimation of rigidity parameter uncertainty and therefore of potential anticonservative inference. We apply the histogram location approach to estimate the extent of downward nominal wage rigidity across the EU for 1995-2001. Our data base is the User Data Base (UDB of the European Community Household Panel (ECHP. The results show wide variation in the fraction of wage cuts prevented by nominal wage rigidity across the EU. The lowest rigidity parameters are found for the UK, Spain and Ireland, the largest for Portugal and Italy. Analyzing the change of rigidity between sub periods 1995-1997 and 1999-2001 even shows an widening of the differences in nominal wage rigidity. Due to the finding of large differences across the EU, the results imply that the costs of low inflation policies across the EU differ substantially.

  12. Screening for EDTA-dependent deviations in platelet counts and abnormalities in platelet distribution histograms in pseudothrombocytopenia.

    Science.gov (United States)

    Bartels, P C; Schoorl, M; Lombarts, A J

    1997-11-01

    Screening for pseudothrombocytopenia caused by in vitro platelet clumping has been performed in 45,000 subjects attending a general hospital. In our region, the observed prevalence of EDTA-induced pseudothrombocytopenia in blood samples with an initial platelet count below 150 x 10(9)/l was estimated to amount to 0.1%. EDTA-induced pseudothrombocytopenia was confirmed by detection of platelet aggregates by means of microscopic evaluation from the blood smear. In routine investigations, pseudothrombocytopenia could be highly suspected when the Sysmex NE 8000 showed characteristic peculiarities in the white blood cell (WBC) scattergram and histogram. Platelet aggregation is avoided in such cases by the use of citrate as an anticoagulant instead of EDTA. Pseudothrombocytopenia was detected in 46 subjects. As a screening test for pseudothrombocytopenia, increased cut-off values derived from the WBC histogram demonstrated 90% sensitivity and 100% specificity. Automated flagging for platelet clumps, deviations reflecting MPV, or PDW abnormalities revealed lower scores with respect to sensitivity.

  13. Modeling the dark current histogram induced by gold contamination in complementary-metal-oxide-semiconductor image sensors

    Science.gov (United States)

    Domengie, F.; Morin, P.; Bauza, D.

    2015-07-01

    We propose a model for dark current induced by metallic contamination in a CMOS image sensor. Based on Shockley-Read-Hall kinetics, the expression of dark current proposed accounts for the electric field enhanced emission factor due to the Poole-Frenkel barrier lowering and phonon-assisted tunneling mechanisms. To that aim, we considered the distribution of the electric field magnitude and metal atoms in the depth of the pixel. Poisson statistics were used to estimate the random distribution of metal atoms in each pixel for a given contamination dose. Then, we performed a Monte-Carlo-based simulation for each pixel to set the number of metal atoms the pixel contained and the enhancement factor each atom underwent, and obtained a histogram of the number of pixels versus dark current for the full sensor. Excellent agreement with the dark current histogram measured on an ion-implanted gold-contaminated imager has been achieved, in particular, for the description of the distribution tails due to the pixel regions in which the contaminant atoms undergo a large electric field. The agreement remains very good when increasing the temperature by 15 °C. We demonstrated that the amplification of the dark current generated for the typical electric fields encountered in the CMOS image sensors, which depends on the nature of the metal contaminant, may become very large at high electric field. The electron and hole emissions and the resulting enhancement factor are described as a function of the trap characteristics, electric field, and temperature.

  14. 胸上段食管癌螺旋断层放疗和容积旋转调强放疗的剂量学比较%Dosimetric comparison of helical tomotherapy and volume-modulated arc therapy for upper thoracic esophageal carcinoma

    Institute of Scientific and Technical Information of China (English)

    戴相昆; 蔡博宁; 葛瑞刚; 王小深; 王运来

    2016-01-01

    Objective To compare the dosimetric differences between helical tomotherapy (HT) and volume-modulated arc therapy (VMAT) in the treatment of upper thoracic esophageal carcinoma (UTEC).Methods A total of 10 patients with UTEC were randomly selected.HT plan and double-arc VMAT plan were designed and optimized for each patient.The prescription dose was 50 Gy/30 fractions for gross target volume (GTV), 66 Gy/30 fractions for planned target volume (PTV).The dose distribution and conformal index (CI), homogeneity index (HI) of target volume, the D1%, D5%, Dg5%, D99%, and dose of organ at risk (OAR) were analyzed by using the dose volume histogram (DVH).The monitor units and delivery time were also evaluated.Results For GTV and PTV, the D99% of HT plans were slightly higher than those of VMAT plans (t =4.476, 3.756, P < 0.05) , but no significant differences in D1% , D5% , D95% , HI and CI (P > 0.05) were found.The V10, V15, V20 and mean lung dose (MLD) to the total-lung of HT plans were all significantly lower than those of VMAT plans (t =-3.369,-4.824, -4.869,-3.657, P < 0.05).There were no significant differences for V5, V30 and Dmax of cord (P > 0.05).The monitor units and delivery time of VMAT plans were significantly lower than those of HT plans (t =13.970, 7.982, P < 0.05).Conclusions Both HT and VMAT are appropriate for esophageal cancer radiotherapy.HT significantly reduces the radiation dose of the total-lung, while VMAT has obvious advantages in efficiency.%目的 比较胸上段食管癌螺旋断层(HT)与容积旋转调强放疗(VMAT)计划的剂量学差异.方法 随机抽样法选取10例胸上段食管癌患者,分别设计HT和VMAT双弧照射调强放疗计划,肿瘤靶区体积(GTV)给予66 Gy/30次,计划靶区体积(PTV)给予50 Gy/30次.根据剂量体积直方图(DVH)评价靶区的D1%、D5%、D95%、D99%、适形指数(CI)、均匀性指数(HI)和危及器官(OAR)受量,比较治疗时间和

  15. 用于弱目标检测的形态滤波和小波变换图像增强算法%Morphological Filters and Wavelet-based Histogram Equalization Image Enhancement for Weak Target Detection

    Institute of Scientific and Technical Information of China (English)

    吉书鹏; 丁小青

    2003-01-01

    Image enhancement methods are typically aimed at improvement of the overall visibility of features. Though histogram equalization can enhance the contrast by redistributing the gray levels, it has the drawback that it reduces the information in the processed image. In this paper, we present a new image enhancement algorithm. After histogram equalization is carried out, morphological filters and wavelet-based enhancement algorithm is used to clean out the unwanted details and further enhance the image and compensate for the information loss during histogram equalization. Experimental results show that the morphological filters and wavelet-based histogram equalization algorithm can significantly enhance the contrast and increase the information entropy of the image.

  16. Fine structure of histograms of alpha-activity measurements depends on direction of alpha particles flow and the Earth rotation: experiments with collimators

    CERN Document Server

    Shnoll, S E; Berulis, I I; Udaltsova, N V; Rubinstein, I A; Shnoll, Simon E.; Zenchenko, Konstantin I.; Berulis, Iosas I.; Udaltsova, Natalia V.; Rubinstein, Ilia A.

    2004-01-01

    The fine structure of histograms of measurements of 239Pu alpha-activity varies periodically, and the period of these variations is equal to sidereal day (1436 minutes). The periodicity is not observed in the experiments with collimator that restricts the alpha particles flow to be oriented to the Polar Star. Based on this study and other independent data, such as measurements conducted by the Arctic expedition, and similarity of the histograms in processes observed at different locations at the same local time, the conclusion was made, that the fine structure of statistical distributions of the observed processes depends on the celestial sphere.

  17. Study about quantification and classification of biological tissues in tomographic images from histograms; Estudo sobre quantificacao e classificacao dos tecidos biologicos em imagens tomograficas a partir de histogramas

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Rafael T.F.; Lemke, Ney; Hormaza, Joel Mesa; Alvarez, Matheus, E-mail: rafael@ibb.unesp.b [Universidade Estadual Paulista Julio de Mesquisa Filho (DFB/IB/UNESP), Botucatu, SP (Brazil). Inst. de Biociencias. Dept. de Fisica e Biofisica; Pina, Diana R.; Teixeira, Altamir S. [Universidade Estadual Paulista Julio de Mesquisa Filho (HC/FM/UNESP), Botucatu, SP (Brazil). Hospital de Clinicas. Dept. de Doencas Tropicais e Diagnostico por Imagem

    2010-06-15

    An algorithm for determining the equivalent thickness of biological tissue by the removal of Gaussian from the histograms was proposed. This algorithm classifies the different biological tissues using histograms, constructed from CT scans in DICOM format and calculates the average thickness of these tissues. The founded results show to be coherent with literature, with discrepancies of up to 21.6% on the bone, and analyzed for the anthropomorphic phantom (RANDO). These results allow the use of this method in living tissues for the construction of chest homogeneous phantoms of newborn and suckling patients, which are subsequently used in the optimization process of pediatric radiographic images. (author)

  18. Facial Expression Recognition from Video Sequences Based on Spatial-Temporal Motion Local Binary Pattern and Gabor Multiorientation Fusion Histogram

    Directory of Open Access Journals (Sweden)

    Lei Zhao

    2017-01-01

    Full Text Available This paper proposes novel framework for facial expressions analysis using dynamic and static information in video sequences. First, based on incremental formulation, discriminative deformable face alignment method is adapted to locate facial points to correct in-plane head rotation and break up facial region from background. Then, spatial-temporal motion local binary pattern (LBP feature is extracted and integrated with Gabor multiorientation fusion histogram to give descriptors, which reflect static and dynamic texture information of facial expressions. Finally, a one-versus-one strategy based multiclass support vector machine (SVM classifier is applied to classify facial expressions. Experiments on Cohn-Kanade (CK + facial expression dataset illustrate that integrated framework outperforms methods using single descriptors. Compared with other state-of-the-art methods on CK+, MMI, and Oulu-CASIA VIS datasets, our proposed framework performs better.

  19. Detection of acute lymphocyte leukemia using k-nearest neighbor algorithm based on shape and histogram features

    Science.gov (United States)

    Purwanti, Endah; Calista, Evelyn

    2017-05-01

    Leukemia is a type of cancer which is caused by malignant neoplasms in leukocyte cells. Leukemia disease which can cause death quickly enough for the sufferer is a type of acute lymphocyte leukemia (ALL). In this study, we propose automatic detection of lymphocyte leukemia through classification of lymphocyte cell images obtained from peripheral blood smear single cell. There are two main objectives in this study. The first is to extract featuring cells. The second objective is to classify the lymphocyte cells into two classes, namely normal and abnormal lymphocytes. In conducting this study, we use combination of shape feature and histogram feature, and the classification algorithm is k-nearest Neighbour with k variation is 1, 3, 5, 7, 9, 11, 13, and 15. The best level of accuracy, sensitivity, and specificity in this study are 90%, 90%, and 90%, and they were obtained from combined features of area-perimeter-mean-standard deviation with k=7.

  20. An Implementation of Document Image Reconstruction System on a Smart Device Using a 1D Histogram Calibration Algorithm

    Directory of Open Access Journals (Sweden)

    Lifeng Zhang

    2014-01-01

    Full Text Available In recent years, the smart devices equipped with imaging functions are widely spreading for consumer application. It is very convenient for people to record information using these devices. For example, people can photo one page of a book in a library or they can capture an interesting piece of news on the bulletin board when walking on the street. But sometimes, one shot full area image cannot give a sufficient resolution for OCR soft or for human visual recognition. Therefore, people would prefer to take several partial character images of a readable size and then stitch them together in an efficient way. In this study, we propose a print document acquisition method using a device with a video camera. A one-dimensional histogram based self-calibration algorithm is developed for calibration. Because the calculation cost is low, it can be installed on a smartphone. The simulation result shows that the calibration and stitching are well performed.

  1. The combination of a histogram-based clustering algorithm and support vector machine for the diagnosis of osteoporosis

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Min Suk; Kavitha, Muthu Subash [Dept. of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul (Korea, Republic of); Asano, Akira [Graduate School of Engineering, Hiroshima University, Hiroshima (Japan); Taguchi, Akira [Dept. of Oral and Maxillofacial Radiology, Matsumoto Dental University, Nagano (Japan)

    2013-09-15

    To prevent low bone mineral density (BMD), that is, osteoporosis, in postmenopausal women, it is essential to diagnose osteoporosis more precisely. This study presented an automatic approach utilizing a histogram-based automatic clustering (HAC) algorithm with a support vector machine (SVM) to analyse dental panoramic radiographs (DPRs) and thus improve diagnostic accuracy by identifying postmenopausal women with low BMD or osteoporosis. We integrated our newly-proposed histogram-based automatic clustering (HAC) algorithm with our previously-designed computer-aided diagnosis system. The extracted moment-based features (mean, variance, skewness, and kurtosis) of the mandibular cortical width for the radial basis function (RBF) SVM classifier were employed. We also compared the diagnostic efficacy of the SVM model with the back propagation (BP) neural network model. In this study, DPRs and BMD measurements of 100 postmenopausal women patients (aged >50 years), with no previous record of osteoporosis, were randomly selected for inclusion. The accuracy, sensitivity, and specificity of the BMD measurements using our HAC-SVM model to identify women with low BMD were 93.0% (88.0%-98.0%), 95.8% (91.9%-99.7%) and 86.6% (79.9%-93.3%), respectively, at the lumbar spine; and 89.0% (82.9%-95.1%), 96.0% (92.2%-99.8%) and 84.0% (76.8%-91.2%), respectively, at the femoral neck. Our experimental results predict that the proposed HAC-SVM model combination applied on DPRs could be useful to assist dentists in early diagnosis and help to reduce the morbidity and mortality associated with low BMD and osteoporosis.

  2. Quantization Selection of Colour Histogram Bins to Categorize the Colour Appearance of Landscape Paintings for Image Retrieval

    Directory of Open Access Journals (Sweden)

    Aniza Othman

    2016-12-01

    Full Text Available In the world of today, most images are digitized and kept in digital libraries for better organization and management. With the growth of information and communication technology, collection holders such as museums or cultural institutions have been increasingly interested in making their collections available anytime and anywhere for any Image Retrieval (IR activities such as browsing and searching. In a colour image retrieval application, images retrieved by users are accomplished according to their specifications on what they want or acquire, which could be based upon so many concepts. We suggest an  approach to categorize the colour appearances of whole scene landscape painting images based on human colour perception. The colour features in the image are represented using a colour histogram. We then find  the suitable quantization bins that can be used to generate optimum colour histograms for all categories of colour appearances, which is selected based on theHarmonic Mean of the precision and recall,  also known as F-Score percentage higher saturated value. Colour appearance attributes in the CIELab colour model (L-Lightness, a and b are colour-opponent dimension are used to generate colour appearance feature vectors namely the saturation metric, lightness metric and multicoloured metric. For the categorizations, we use the Nearest Neighbour (NN method to detect the classes by using the predefined colour appearance descriptor measures and the pre-set thresholds.  The experimental results show that the quantization of CIELab colour model into 11 uniformly bins for each component had achieved the optimum result for all colour appearances categories.

  3. Modeling the dark current histogram induced by gold contamination in complementary-metal-oxide-semiconductor image sensors

    Energy Technology Data Exchange (ETDEWEB)

    Domengie, F., E-mail: florian.domengie@st.com; Morin, P. [STMicroelectronics Crolles 2 (SAS), 850 Rue Jean Monnet, 38926 Crolles Cedex (France); Bauza, D. [CNRS, IMEP-LAHC - Grenoble INP, Minatec: 3, rue Parvis Louis Néel, CS 50257, 38016 Grenoble Cedex 1 (France)

    2015-07-14

    We propose a model for dark current induced by metallic contamination in a CMOS image sensor. Based on Shockley-Read-Hall kinetics, the expression of dark current proposed accounts for the electric field enhanced emission factor due to the Poole-Frenkel barrier lowering and phonon-assisted tunneling mechanisms. To that aim, we considered the distribution of the electric field magnitude and metal atoms in the depth of the pixel. Poisson statistics were used to estimate the random distribution of metal atoms in each pixel for a given contamination dose. Then, we performed a Monte-Carlo-based simulation for each pixel to set the number of metal atoms the pixel contained and the enhancement factor each atom underwent, and obtained a histogram of the number of pixels versus dark current for the full sensor. Excellent agreement with the dark current histogram measured on an ion-implanted gold-contaminated imager has been achieved, in particular, for the description of the distribution tails due to the pixel regions in which the contaminant atoms undergo a large electric field. The agreement remains very good when increasing the temperature by 15 °C. We demonstrated that the amplification of the dark current generated for the typical electric fields encountered in the CMOS image sensors, which depends on the nature of the metal contaminant, may become very large at high electric field. The electron and hole emissions and the resulting enhancement factor are described as a function of the trap characteristics, electric field, and temperature.

  4. Distinct effects of rectum delineation methods in 3D-confromal vs. IMRT treatment planning of prostate cancer

    Directory of Open Access Journals (Sweden)

    Vordermark Dirk

    2006-09-01

    Full Text Available Abstract Background The dose distribution to the rectum, delineated as solid organ, rectal wall and rectal surface, in 3D conformal (3D-CRT and intensity-modulated radiotherapy treatment (IMRT planning for localized prostate cancer was evaluated. Materials and methods In a retrospective planning study 3-field, 4-field and IMRT treatment plans were analyzed for ten patients with localized prostate cancer. The dose to the rectum was evaluated based on dose-volume histograms of 1 the entire rectal volume (DVH 2 manually delineated rectal wall (DWH 3 rectal wall with 3 mm wall thickness (DWH3 4 and the rectal surface (DSH. The influence of the rectal filling and of the seminal vesicles' anatomy on these dose parameters was investigated. A literature review of the dose-volume relationship for late rectal toxicity was conducted. Results In 3D-CRT (3-field and 4-field the dose parameters differed most in the mid-dose region: the DWH showed significantly lower doses to the rectum (8.7% ± 4.2% compared to the DWH3 and the DSH. In IMRT the differences between dose parameters were larger in comparison with 3D-CRT. Differences were statistically significant between DVH and all other dose parameters and between DWH and DSH. Mean doses were increased by 23.6% ± 8.7% in the DSH compared to the DVH in the mid-dose region. Furthermore, both the rectal filling and the anatomy of the seminal vesicles influenced the relationship between the dose parameters: a significant correlation of the difference between DVH and DWH and the rectal volume was seen in IMRT treatment. Discussion The method of delineating the rectum significantly influenced the dose representation in the dose-volume histogram. This effect was pronounced in IMRT treatment planning compared to 3D-CRT. For integration of dose-volume parameters from the literature into clinical practice these results have to be considered.

  5. Dose volume analysis in brachytherapy and stereotactic radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Tozer-Loft, S.M

    2000-12-01

    A brief introduction to three branches of radiotherapy is given: interstitial brachytherapy, external beam megavoltage radiotherapy, and stereotactic radiosurgery. The current interest in issues around conformity, uniformity and optimisation is explained in the light of technical developments in these fields. A novel method of displaying dose-volume information, which mathematically suppresses the inverse-square law, as first suggested by L.L. Anderson for use in brachytherapy is explained in detail, and some improvements proposed. These 'natural' histograms are extended to show the effects of real point sources which do not exactly follow the inverse-square law, and to demonstrate the in-target dose-volume distribution, previously unpublished. The histograms are used as a way of mathematically analysing the properties of theoretical mono-energetic radionuclides, and for demonstrating the dosimetric properties of a potential new brachytherapy source (Ytterbium-169). A new modification of the Anderson formalism is then described for producing Anderson Inverse-Square Shifted (AISS) histograms for the Gamma Knife, which are shown to be useful for demonstrating the quality of stereotactic radiosurgery dose distributions. A study is performed analysing the results of Gamma Knife treatments on 44 patients suffering from a benign brain tumour (acoustic neuroma). Follow-up data is used to estimate the volume shrinkage or growth of each tumour, and this measure of outcome is compared with a range of figures of merit which express different aspects of the quality of each dose distributions. The results are analysed in an attempt to answer the question: What are the important features of the dose distribution (conformality, uniformity, etc) which show a definite relationship with the outcome of the treatment? Initial results show positively that, when Gamma Knife radiosurgery is used to treat acoustic neuroma, some measures of conformality seem to have a surprising

  6. Survey of fish impingement at power plants in the United States. Volume III. Estuaries and coastal waters

    Energy Technology Data Exchange (ETDEWEB)

    Stupka, Richard C.; Sharma, Rajendra K.

    1977-03-01

    Impingement of fish at cooling-water intakes of 32 power plants, located on estuaries and coastal waters has been surveyed and data are presented. Descriptions of site, plant, and intake design and operation are provided. Reports in this volume summarize impingement data for individual plants in tabular and histogram formats. Information was available from differing sources such as the utilities themselves, public documents, regulatory agencies, and others. Thus, the extent of detail in the reports varies greatly from plant to plant. Histogram preparation involved an extrapolation procedure that has inadequacies. The reader is cautioned in the use of information presented in this volume to determine intake-design acceptability or intensity of impacts on ecosystems. No conclusions are presented herein; data comparisons are made in Volume IV.

  7. Efficient Method for Histogram Generation on GPU%一种高效直方图生成算法在GPU上的实现

    Institute of Scientific and Technical Information of China (English)

    狄鹏; 胡长军; 李建江

    2012-01-01

    Histogram generation is an inherently sequential loop computation with irregular data-dependence, which has a full range of applications in diverse fields. However, the presence of irregular memory access in histogram loop nest poses an obstacle to its paralleled execution using a massive number of fine-grained threads due to access latency leaded by bank conflicts. It is non-trivial to accelerate histogram generation algorithm on parallel platform, particularly on the state-of-the-art parallel platform, graphics processing unit (GPU). For reducing bank conflicts, utilization of padding technique can evenly distribute shared memory access of multiple threads to different banks and largely exploit GPU's potential on accelerating histogram generation. Moreover, efficient near-optimal configuration search model can guide programmers choosing appropriate GPU execution parameters for higher performance. Experimental result demonstrates the improved histogram generation algorithm has approximate 42% to 88% speedups than traditional histogram generation algorithm on GPU.%直方图生成算法(Histogram Generation)是一种顺序的非规则数据依赖的循环运算,已在许多领域被广泛应用.但是,由于非规则的内存访问,使得多线程对共享内存访问会产生很多存储体冲突(Bank Conflict),从而阻碍并行效率.如何在并行处理器平台,特别是当前最先进的图像处理单元(Graphic Processing Unit,GPU)实现高效的直方图生成算法是很有研究价值的.为了减少直方图生成过程中的存储体冲突,通过内存填充技术,将多线程的共享内存访问均匀地分散到各个存储体,可以大幅减少直方图生成算法在GPU上的内存访问延时.同时,通过提出有效可靠的近似最优配置搜索模型,可以指导用户配置GPU执行参数,以获得更高的性能.经实验验证,在实际应用中,改良后的算法比原有算法性能提高了42%~88%.

  8. Insight on AV-45 binding in white and grey matter from histogram analysis: a study on early Alzheimer's disease patients and healthy subjects

    Energy Technology Data Exchange (ETDEWEB)

    Nemmi, Federico; Saint-Aubert, Laure; Peran, Patrice [Inserm, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse (France); Universite de Toulouse, UPS, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Adel, Djilali; Salabert, Anne-Sophie; Payoux, Pierre [Inserm, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse (France); Universite de Toulouse, UPS, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Centre Hospitalier Universitaire de Toulouse, Service de Medecine Nucleaire, Pole Imagerie, Toulouse (France); Pariente, Jeremie [Inserm, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse (France); Universite de Toulouse, UPS, Imagerie Cerebrale et Handicaps Neurologiques UMR 825, Centre Hospitalier Universitaire de Toulouse, Toulouse (France); Centre Hospitalier Universitaire de Toulouse, Service de Neurologie, Pole Neurosciences, Toulouse (France); Barbeau, Emmanuel J. [Centre Hospitalier Universitaire de Toulouse, Service de Neurologie, Pole Neurosciences, Toulouse (France); Universite de Toulouse, UPS, Centre de Recherche Cerveau et Cognition, CNRS, CerCo, Toulouse (France)

    2014-07-15

    AV-45 amyloid biomarker is known to show uptake in white matter in patients with Alzheimer's disease (AD), but also in the healthy population. This binding, thought to be of a non-specific lipophilic nature, has not yet been investigated. The aim of this study was to determine the differential pattern of AV-45 binding in white matter in healthy and pathological populations. We recruited 24 patients presenting with AD at an early stage and 17 matched, healthy subjects. We used an optimized positron emission tomography-magnetic resonance imaging (PET-MRI) registration method and an approach based on an intensity histogram using several indices. We compared the results of the intensity histogram analyses with a more canonical approach based on target-to-cerebellum Standard Uptake Value (SUVr) in white and grey matter using MANOVA and discriminant analyses. A cluster analysis on white and grey matter histograms was also performed. White matter histogram analysis revealed significant differences between AD and healthy subjects, which were not revealed by SUVr analysis. However, white matter histograms were not decisive to discriminate groups, and indices based on grey matter only showed better discriminative power than SUVr. The cluster analysis divided our sample into two clusters, showing different uptakes in grey, but also in white matter. These results demonstrate that AV-45 binding in white matter conveys subtle information not detectable using the SUVr approach. Although it is not more efficient than standard SUVr in discriminating AD patients from healthy subjects, this information could reveal white matter modifications. (orig.)

  9. Variations in Rectal Volumes and Dosimetry Values Including NTCP due to Interfractional Variability When Administering 2D-Based IG-IMRT for Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Takashi Hanada

    2014-01-01

    Full Text Available We estimated variations in rectal volumes and dosimetry values including NTCP with interfractional motion during prostate IG-IMRT. Rectal volumes, DVH parameters, and NTCPs of 20 patients were analyzed. For this patient population, the median (range volume on the initial plan for the rectum was 45.6 cc (31.3–82.0, showing on-treatment spread around the initial prediction based on the initial plan. DVH parameters of on-treatment CBCT analyses showed systematic regularity shift from the prediction based on the initial plan. Using the Lyman-Kutcher-Burman model, NTCPs of predicted late rectal bleeding toxicity of rectal grade ≥ 2 (RTOG and the QUANTEC update rectal toxicity for the prediction based on the initial plan were 0.09% (0.02–0.24 and 0.02% (0.00–0.07, respectively, with NTCPs from on-treatment CBCT analyses being 0.35% (0.01–6.16 and 0.12% (0.00–4.11, respectively. Using the relative seriality model, for grade ≥ 2 bleeding rectal toxicity, NTCP of the prediction based on the initial plan was 0.64% (0.15–1.22 versus 1.48% (0.18–7.66 for on-treatment CBCT analysis. Interfraction variations in rectal volumes occur in all patients due to physiological changes. Thus, rectal assessment during 2D-based IG-IMRT using NTCP models has the potential to provide useful and practical dosimetric verification.

  10. SU-E-T-157: Evaluation and Comparison of Doses to Pelvic Lymph Nodes and to Point B with 3D Image Guided Treatment Planning for High Dose Brachytherapy for Treatment of Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bhandare, N. [University of Florida (United States)

    2014-06-01

    Purpose: To estimate and compare the doses received by the obturator, external and internal iliac lymph nodes and point Methods: CT-MR fused image sets of 15 patients obtained for each of 5 fractions of HDR brachytherapy using tandem and ring applicator, were used to generate treatment plans optimized to deliver a prescription dose to HRCTV-D90 and to minimize the doses to organs at risk (OARs). For each set of image, target volume (GTV, HRCTV) OARs (Bladder, Rectum, Sigmoid), and both left and right pelvic lymph nodes (obturator, external and internal iliac lymph nodes) were delineated. Dose-volume histograms (DVH) were generated for pelvic nodal groups (left and right obturator group, internal and external iliac chains) Per fraction DVH parameters used for dose comparison included dose to 100% volume (D100), and dose received by 2cc (D2cc), 1cc (D1cc) and 0.1 cc (D0.1cc) of nodal volume. Dose to point B was compared with each DVH parameter using 2 sided t-test. Pearson correlation were determined to examine relationship of point B dose with nodal DVH parameters. Results: FIGO clinical stage varied from 1B1 to IIIB. The median pretreatment tumor diameter measured on MRI was 4.5 cm (2.7– 6.4cm).The median dose to bilateral point B was 1.20 Gy ± 0.12 or 20% of the prescription dose. The correlation coefficients were all <0.60 for all nodal DVH parameters indicating low degree of correlation. Only 2 cc of obturator nodes was not significantly different from point B dose on t-test. Conclusion: Dose to point B does not adequately represent the dose to any specific pelvic nodal group. When using image guided 3D dose-volume optimized treatment nodal groups should be individually identified and delineated to obtain the doses received by pelvic nodes.

  11. Evaluation of parameters of the HDV (V20 and dose average) in radiotherapy of lung cancer with lung volumes design adapted compounds (ITV); Evaluacion de parametros del HDV (V20 Y Dmed) en radioterapia adaptada de cancer de pulmon con diseno de volumenes pulmonares compuestos (ITV)

    Energy Technology Data Exchange (ETDEWEB)

    Monroy Anton, J. L.; Solar Tortosa, M.; Lopez Munoz, M.; Navarro Bergada, A.; Estornell Gualde, M. A.; Melchor Iniguez, M.

    2013-07-01

    Our objective was to evaluate the V20 parameters and dose average compared to a single lung volume designed with a CT study in normal breathing of the patient and the corresponding to a lung volume composed, designed from three studies of CT in different phases of the respiratory cycle. Check if there are important differences in these cases that determine the necessity of creating a composite lung volume to evaluate dose volume histogram. (Author)

  12. Applications of tissue heterogeneity corrections and biologically effective dose volume histograms in assessing the doses for accelerated partial breast irradiation using an electronic brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Shi Chengyu; Guo Bingqi; Eng, Tony; Papanikolaou, Nikos [Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, TX 78229 (United States); Cheng, Chih-Yao, E-mail: shic@uthscsa.ed [Radiation Oncology Department, Oklahoma University Health Science Center, Oklahoma, OK 73104 (United States)

    2010-09-21

    A low-energy electronic brachytherapy source (EBS), the model S700 Axxent(TM) x-ray device developed by Xoft Inc., has been used in high dose rate (HDR) intracavitary accelerated partial breast irradiation (APBI) as an alternative to an Ir-192 source. The prescription dose and delivery schema of the electronic brachytherapy APBI plan are the same as the Ir-192 plan. However, due to its lower mean energy than the Ir-192 source, an EBS plan has dosimetric and biological features different from an Ir-192 source plan. Current brachytherapy treatment planning methods may have large errors in treatment outcome prediction for an EBS plan. Two main factors contribute to the errors: the dosimetric influence of tissue heterogeneities and the enhancement of relative biological effectiveness (RBE) of electronic brachytherapy. This study quantified the effects of these two factors and revisited the plan quality of electronic brachytherapy APBI. The influence of tissue heterogeneities is studied by a Monte Carlo method and heterogeneous 'virtual patient' phantoms created from CT images and structure contours; the effect of RBE enhancement in the treatment outcome was estimated by biologically effective dose (BED) distribution. Ten electronic brachytherapy APBI cases were studied. The results showed that, for electronic brachytherapy cases, tissue heterogeneities and patient boundary effect decreased dose to the target and skin but increased dose to the bones. On average, the target dose coverage PTV V{sub 100} reduced from 95.0% in water phantoms (planned) to only 66.7% in virtual patient phantoms (actual). The actual maximum dose to the ribs is 3.3 times higher than the planned dose; the actual mean dose to the ipsilateral breast and maximum dose to the skin were reduced by 22% and 17%, respectively. Combining the effect of tissue heterogeneities and RBE enhancement, BED coverage of the target was 89.9% in virtual patient phantoms with RBE enhancement (actual BED) as compared to 95.2% in water phantoms without RBE enhancement (planned BED). About 10% increase in the source output is required to raise BED PTV V{sub 100} to 95%. As a conclusion, the composite effect of dose reduction in the target due to heterogeneities and RBE enhancement results in a net effect of 5.3% target BED coverage loss for electronic brachytherapy. Therefore, it is suggested that about 10% increase in the source output may be necessary to achieve sufficient target coverage higher than 95%.

  13. Cardiac function after chemoradiation for esophageal cancer : comparison of heart dose-volume histogram parameters to multiple gated acquisition scan changes

    NARCIS (Netherlands)

    Tripp, P; Malhotra, H K; Javle, M; Shaukat, A; Russo, R; de Boer, Sietse; Podgorsak, M; Nava, H; Yang, G Y

    2005-01-01

    In this paper we determine if preoperative chemoradiation for locally advanced esophageal cancer leads to changes in cardiac ejection fraction. This is a retrospective review of 20 patients treated at our institution for esophageal cancer between 2000 and 2002. Multiple gated acquisition cardiac sca

  14. Safety surrogate histograms (SSH): A novel real-time safety assessment of dilemma zone related conflicts at signalized intersections.

    Science.gov (United States)

    Ghanipoor Machiani, Sahar; Abbas, Montasir

    2016-11-01

    Drivers' indecisiveness in dilemma zones (DZ) could result in crash-prone situations at signalized intersections. DZ is to the area ahead of an intersection in which drivers encounter a dilemma regarding whether to stop or proceed through the intersection when the signal turns yellow. An improper decision to stop by the leading driver, combined with the following driver deciding to go, can result in a rear-end collision, unless the following driver recognizes a collision is imminent and adjusts his or her behavior at or shortly after the onset of yellow. Considering the significance of DZ-related crashes, a comprehensive safety measure is needed to characterize the level of safety at signalized intersections. In this study, a novel safety surrogate measure was developed utilizing real-time radar field data. This new measure, called safety surrogate histogram (SSH), captures the degree and frequency of DZ-related conflicts at each intersection approach. SSH includes detailed information regarding the possibility of crashes, because it is calculated based on the vehicles conflicts. An example illustrating the application of the new methodology at two study sites in Virginia is presented and discussed, and a comparison is provided between SSH and other DZ-related safety surrogate measures mentioned in the literature. The results of the study reveal the efficacy of the SSH as complementary to existing surrogate measures.

  15. Characterization of stroke lesions using a histogram-based data analysis including diffusion- and perfusion-weighted imaging

    Science.gov (United States)

    Grzesik, Alexander; Bernarding, Johannes; Braun, Juergen; Koennecke, Hans-Christian; Wolf, Karl J.; Tolxdorff, Thomas

    2000-04-01

    Diffusion- and perfusion-weighted magnetic resonance imaging (DWI, PWI) allows the diagnosis of ischemic brain injury at a time when ischemic lesions may not yet be detectable in computer tomography or T2-weighted (T2w) MRI. However, regions with pathologic apparent diffusion coefficients (ADC) do not necessarily match with regions of prolonged mean transit times (MTT) or pathologic relative cerebral blood flow (rCBF). Mismatching parts are thought to correlate with tissues that can be saved by appropriate treatment. Ten patients with cerebral ischemia underwent standard T1w and T2w imaging as well as single-shot echo planar imaging (EPI) DWI, and PWI. Multidimensional histograms were constructed from T2w images, DWI, ADC, rCBF, and MTT maps. After segmenting different tissues, signal changes of ischemic tissues relative to unaffected parenchyma were calculated. Combining different information allowed the segmentation of lesions and unaffected tissues. Acute infarcts exhibited decreased ADC values as well as hypo- and hyperperfused areas. Correlating ADC, T2w, and rCBF with clinical symptoms allowed the estimation of age and perfusion state of the lesions. Combining DWI, PWI, and standard imaging overcomes strongly fluctuating parameters such as ADC values. A multidimensional parameter-set characterizes unaffected and pathologic tissues which may help in the evaluation of new therapeutic strategies.

  16. Segmentation and Recognition of Handwritten Kannada Text Using Relevance Feedback and Histogram of Oriented Gradients – A Novel Approach

    Directory of Open Access Journals (Sweden)

    Karthik S

    2016-01-01

    Full Text Available India is a multilingual country with 22 official languages and more than 1600 languages in existence. Kannada is one of the official languages and widely used in the state of Karnataka whose population is over 65 million. Kannada is one of the south Indian languages and it stands in the 33rd position among the list of widely spoken languages across the world. However, the survey reveals that much more effort is required to develop a complete Optical Character Recognition (OCR system. In this direction the present research work throws light on the development of suitable methodology to achieve the goal of developing an OCR. It is noted that the overall accuracy of the OCR system largely depends on the accuracy of the segmentation phase. So it is desirable to have a robust and efficient segmentation method. In this paper, a method has been proposed for proper segmentation of the text to improve the performance of OCR at the later stages. In the proposed method, the segmentation has been done using horizontal projection profile and windowing. The result obtained is passed to the recognition module. The Histogram of Oriented Gradient (HoG is used for the recognition in combination with the support vector machine (SVM. The result is taken as the feedback and fed to the segmentation module to improve the accuracy. The experimentation is delivered promising results.

  17. Adaptive block-wise alphabet reduction scheme for lossless compression of images with sparse and locally sparse histograms

    Science.gov (United States)

    Masmoudi, Atef; Zouari, Sonia; Ghribi, Abdelaziz

    2015-11-01

    We propose a new adaptive block-wise lossless image compression algorithm, which is based on the so-called alphabet reduction scheme combined with an adaptive arithmetic coding (AC). This new encoding algorithm is particularly efficient for lossless compression of images with sparse and locally sparse histograms. AC is a very efficient technique for lossless data compression and produces a rate that is close to the entropy; however, a compression performance loss occurs when encoding images or blocks with a limited number of active symbols by comparison with the number of symbols in the nominal alphabet, which consists in the amplification of the zero frequency problem. Generally, most methods add one to the frequency count of each symbol from the nominal alphabet, which leads to a statistical model distortion, and therefore reduces the efficiency of the AC. The aim of this work is to overcome this drawback by assigning to each image block the smallest possible set including all the existing symbols called active symbols. This is an alternative of using the nominal alphabet when applying the conventional arithmetic encoders. We show experimentally that the proposed method outperforms several lossless image compression encoders and standards including the conventional arithmetic encoders, JPEG2000, and JPEG-LS.

  18. Renormalized Volume

    Science.gov (United States)

    Gover, A. Rod; Waldron, Andrew

    2017-09-01

    We develop a universal distributional calculus for regulated volumes of metrics that are suitably singular along hypersurfaces. When the hypersurface is a conformal infinity we give simple integrated distribution expressions for the divergences and anomaly of the regulated volume functional valid for any choice of regulator. For closed hypersurfaces or conformally compact geometries, methods from a previously developed boundary calculus for conformally compact manifolds can be applied to give explicit holographic formulæ for the divergences and anomaly expressed as hypersurface integrals over local quantities (the method also extends to non-closed hypersurfaces). The resulting anomaly does not depend on any particular choice of regulator, while the regulator dependence of the divergences is precisely captured by these formulæ. Conformal hypersurface invariants can be studied by demanding that the singular metric obey, smoothly and formally to a suitable order, a Yamabe type problem with boundary data along the conformal infinity. We prove that the volume anomaly for these singular Yamabe solutions is a conformally invariant integral of a local Q-curvature that generalizes the Branson Q-curvature by including data of the embedding. In each dimension this canonically defines a higher dimensional generalization of the Willmore energy/rigid string action. Recently, Graham proved that the first variation of the volume anomaly recovers the density obstructing smooth solutions to this singular Yamabe problem; we give a new proof of this result employing our boundary calculus. Physical applications of our results include studies of quantum corrections to entanglement entropies.

  19. A Clustering-Based Automatic Transfer Function Design for Volume Visualization

    Directory of Open Access Journals (Sweden)

    Tianjin Zhang

    2016-01-01

    Full Text Available The two-dimensional transfer functions (TFs designed based on intensity-gradient magnitude (IGM histogram are effective tools for the visualization and exploration of 3D volume data. However, traditional design methods usually depend on multiple times of trial-and-error. We propose a novel method for the automatic generation of transfer functions by performing the affinity propagation (AP clustering algorithm on the IGM histogram. Compared with previous clustering algorithms that were employed in volume visualization, the AP clustering algorithm has much faster convergence speed and can achieve more accurate clustering results. In order to obtain meaningful clustering results, we introduce two similarity measurements: IGM similarity and spatial similarity. These two similarity measurements can effectively bring the voxels of the same tissue together and differentiate the voxels of different tissues so that the generated TFs can assign different optical properties to different tissues. Before performing the clustering algorithm on the IGM histogram, we propose to remove noisy voxels based on the spatial information of voxels. Our method does not require users to input the number of clusters, and the classification and visualization process is automatic and efficient. Experiments on various datasets demonstrate the effectiveness of the proposed method.

  20. An extension of digital volume correlation for multimodality image registration

    Science.gov (United States)

    Tudisco, E.; Jailin, C.; Mendoza, A.; Tengattini, A.; Andò, E.; Hall, Stephen A.; Viggiani, Gioacchino; Hild, F.; Roux, S.

    2017-09-01

    The question of registering two images (or image volumes) acquired with different modalities, and thus exhibiting different contrast, at different positions is addressed based on an extension of global digital image (or volume) correlation. A specific comparison metric is introduced allowing the signature of the different phases to be related. A first solution consists of a Gaussian mixture to describe the joint distribution of gray levels, which not only provides a matching of both images, but also offers a natural segmentation indicator. A second ‘self-adapting’ solution does not include any postulated a priori model for the joint histogram and leads to a registration of the images based on their initial histograms. The algorithm is implemented with a pyramidal multiscale framework for the sake of robustness. The proposed multiscale technique is tested on two 3D images obtained from x-ray and neutron tomography respectively. The proposed approach brings the two images to coincidence with a sub-pixel accuracy and allows for a ‘natural’ segmentation of the different phases.

  1. 基于直方图规定化的图像去雾算法%Image Haze Removal Algorithm Based on Histogram Specification

    Institute of Scientific and Technical Information of China (English)

    王万国; 王滨海; 张晶晶; 李丽

    2014-01-01

    直方图规定化是图像增强领域一个常用的算法,文中提出一种通过高斯函数加权的直方图规定化的图像去雾算法。首先通过分析晴天与雾霾天气下图像的直方图的特点,提出一种通过对高斯函数中方差的改变和高斯函数的加权的方式,解决了原有的单纯高斯函数直方图规定化图像偏暗的问题。通过实验图像的对比可以看出,文中提出的算法可有效去除雾霾天气的影响,其处理效果明显优于直方图规定化算法,而且计算量小、处理速度快、不需要人工干预。%Histogram specification is a commonly used algorithm in image enhancement field. Propose an image haze removal algorithm of histogram specification based on the weighted Gaussian probability density function ( Gaussian PDF) in this paper. Firstly,analyzing the characteristics of image histogram that captured in sunny,fogging and haze weather. Then,solve the weak intensity problem of image specification of the single Gaussian function through changing the variance and weighted Gaussian PDF. The experimental results show the algorithm is able to remove the fog effectively,which is superior to the some existing algorithms of histogram specification about effi-ciency. It also has many advantages such as low computation,fast processing speed,no manual intervention.

  2. 基于颜色/形状直方图的图像检索方法%The Color/Shape Histogram-based Image Retrieval Method

    Institute of Scientific and Technical Information of China (English)

    王晓红; 杨玲

    2003-01-01

    Content-based retrieval technology is widely used in multimedia databases.Some image databases use the color of image as the main retrieving content feature.Shape feature is also used to query image, such as moment variant,rotating angle, etc. In this article, a new approach is presented to retrieve image using the color and shape histogram in-formation. The color/shape-based retrieval technology has the advantages of accelerating the retrieving speed and resisting the image noise.

  3. A hybrid phase-space and histogram source model for GPU-based Monte Carlo radiotherapy dose calculation

    Science.gov (United States)

    Townson, Reid W.; Zavgorodni, Sergei

    2014-12-01

    In GPU-based Monte Carlo simulations for radiotherapy dose calculation, source modelling from a phase-space source can be an efficiency bottleneck. Previously, this has been addressed using phase-space-let (PSL) sources, which provided significant efficiency enhancement. We propose that additional speed-up can be achieved through the use of a hybrid primary photon point source model combined with a secondary PSL source. A novel phase-space derived and histogram-based implementation of this model has been integrated into gDPM v3.0. Additionally, a simple method for approximately deriving target photon source characteristics from a phase-space that does not contain inheritable particle history variables (LATCH) has been demonstrated to succeed in selecting over 99% of the true target photons with only ~0.3% contamination (for a Varian 21EX 18 MV machine). The hybrid source model was tested using an array of open fields for various Varian 21EX and TrueBeam energies, and all cases achieved greater than 97% chi-test agreement (the mean was 99%) above the 2% isodose with 1% / 1 mm criteria. The root mean square deviations (RMSDs) were less than 1%, with a mean of 0.5%, and the source generation time was 4-5 times faster. A seven-field intensity modulated radiation therapy patient treatment achieved 95% chi-test agreement above the 10% isodose with 1% / 1 mm criteria, 99.8% for 2% / 2 mm, a RMSD of 0.8%, and source generation speed-up factor of 2.5. Presented as part of the International Workshop on Monte Carlo Techniques in Medical Physics

  4. Osteoarthritis classification using self organizing map based on gabor kernel and contrast-limited adaptive histogram equalization.

    Science.gov (United States)

    Anifah, Lilik; Purnama, I Ketut Eddy; Hariadi, Mochamad; Purnomo, Mauridhi Hery

    2013-01-01

    Localization is the first step in osteoarthritis (OA) classification. Manual classification, however, is time-consuming, tedious, and expensive. The proposed system is designed as decision support system for medical doctors to classify the severity of knee OA. A method has been proposed here to localize a joint space area for OA and then classify it in 4 steps to classify OA into KL-Grade 0, KL-Grade 1, KL-Grade 2, KL-Grade 3 and KL-Grade 4, which are preprocessing, segmentation, feature extraction, and classification. In this proposed system, right and left knee detection was performed by employing the Contrast-Limited Adaptive Histogram Equalization (CLAHE) and the template matching. The Gabor kernel, row sum graph and moment methods were used to localize the junction space area of knee. CLAHE is used for preprocessing step, i.e.to normalize the varied intensities. The segmentation process was conducted using the Gabor kernel, template matching, row sum graph and gray level center of mass method. Here GLCM (contrast, correlation, energy, and homogeinity) features were employed as training data. Overall, 50 data were evaluated for training and 258 data for testing. Experimental results showed the best performance by using gabor kernel with parameters α=8, θ=0, Ψ=[0 π/2], γ=0,8, N=4 and with number of iterations being 5000, momentum value 0.5 and α0=0.6 for the classification process. The run gave classification accuracy rate of 93.8% for KL-Grade 0, 70% for KL-Grade 1, 4% for KL-Grade 2, 10% for KL-Grade 3 and 88.9% for KL-Grade 4.

  5. Optimizing a machine learning based glioma grading system using multi-parametric MRI histogram and texture features.

    Science.gov (United States)

    Zhang, Xin; Yan, Lin-Feng; Hu, Yu-Chuan; Li, Gang; Yang, Yang; Han, Yu; Sun, Ying-Zhi; Liu, Zhi-Cheng; Tian, Qiang; Han, Zi-Yang; Liu, Le-De; Hu, Bin-Quan; Qiu, Zi-Yu; Wang, Wen; Cui, Guang-Bin

    2017-07-18

    Current machine learning techniques provide the opportunity to develop noninvasive and automated glioma grading tools, by utilizing quantitative parameters derived from multi-modal magnetic resonance imaging (MRI) data. However, the efficacies of different machine learning methods in glioma grading have not been investigated.A comprehensive comparison of varied machine learning methods in differentiating low-grade gliomas (LGGs) and high-grade gliomas (HGGs) as well as WHO grade II, III and IV gliomas based on multi-parametric MRI images was proposed in the current study. The parametric histogram and image texture attributes of 120 glioma patients were extracted from the perfusion, diffusion and permeability parametric maps of preoperative MRI. Then, 25 commonly used machine learning classifiers combined with 8 independent attribute selection methods were applied and evaluated using leave-one-out cross validation (LOOCV) strategy. Besides, the influences of parameter selection on the classifying performances were investigated. We found that support vector machine (SVM) exhibited superior performance to other classifiers. By combining all tumor attributes with synthetic minority over-sampling technique (SMOTE), the highest classifying accuracy of 0.945 or 0.961 for LGG and HGG or grade II, III and IV gliomas was achieved. Application of Recursive Feature Elimination (RFE) attribute selection strategy further improved the classifying accuracies. Besides, the performances of LibSVM, SMO, IBk classifiers were influenced by some key parameters such as kernel type, c, gama, K, etc. SVM is a promising tool in developing automated preoperative glioma grading system, especially when being combined with RFE strategy. Model parameters should be considered in glioma grading model optimization.

  6. Repeatability of derived parameters from histograms following non-Gaussian diffusion modelling of diffusion-weighted imaging in a paediatric oncological cohort

    Energy Technology Data Exchange (ETDEWEB)

    Jerome, Neil P.; Miyazaki, Keiko; Collins, David J.; Orton, Matthew R.; D' Arcy, James A.; Leach, Martin O. [Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research, London (United Kingdom); Wallace, Toni; Koh, Dow-Mu [Royal Marsden NHS Foundation Trust, Department of Radiology, Sutton, Surrey (United Kingdom); Moreno, Lucas [The Institute of Cancer Research, Paediatric Drug Development Team, Division of Cancer Therapeutics and Clinical Studies, London (United Kingdom); Hospital Nino Jesus, Madrid (Spain); Royal Marsden NHS Foundation Trust, Paediatric Drug Development Unit, Children and Young People' s Unit, Sutton, Surrey (United Kingdom); Pearson, Andrew D.J.; Marshall, Lynley V.; Carceller, Fernando; Zacharoulis, Stergios [The Institute of Cancer Research, Paediatric Drug Development Team, Division of Cancer Therapeutics and Clinical Studies, London (United Kingdom); Royal Marsden NHS Foundation Trust, Paediatric Drug Development Unit, Children and Young People' s Unit, Sutton, Surrey (United Kingdom)

    2017-01-15

    To examine repeatability of parameters derived from non-Gaussian diffusion models in data acquired in children with solid tumours. Paediatric patients (<16 years, n = 17) were scanned twice, 24 h apart, using DWI (6 b-values, 0-1000 mm{sup -2} s) at 1.5 T in a prospective study. Tumour ROIs were drawn (3 slices) and all data fitted using IVIM, stretched exponential, and kurtosis models; percentage coefficients of variation (CV) calculated for each parameter at all ROI histogram centiles, including the medians. The values for ADC, D, DDC{sub α}, α, and DDC{sub K} gave CV < 10 % down to the 5th centile, with sharp CV increases below 5th and above 95th centile. K, f, and D* showed increased CV (>30 %) over the histogram. ADC, D, DDC{sub α}, and DDC{sub K} were strongly correlated (ρ > 0.9), DDC{sub α} and α were not correlated (ρ = 0.083). Perfusion- and kurtosis-related parameters displayed larger, more variable CV across the histogram, indicating observed clinical changes outside of D/DDC in these models should be interpreted with caution. Centiles below 5th for all parameters show high CV and are unreliable as diffusion metrics. The stretched exponential model behaved well for both DDC{sub α} and α, making it a strong candidate for modelling multiple-b-value diffusion imaging data. (orig.)

  7. Synchronous Changes of the Shape of Histograms Constructed from the Results of Measurements of 90-Sr Beta-Decay and 239-Pu Alpha-Decay Observed in More than 3000 km Distant Laboratories

    Directory of Open Access Journals (Sweden)

    Filin E. Y.

    2015-07-01

    Full Text Available It was discovered many years ago that histograms constructed from the results of mea- surements of various natural processes are not random. The histogram shape was demonstrated to be determined by the diurnal rotation and circumsolar movement of the Earth and to be independent of the nature of the process considered [1-17]. The results of those works change our basic views about stochasticity of natural processes. When the time series of physical measurements, which are traditionally considered stochastic, are transformed into the series of histograms constructed for an optimally small num- ber of the results (i.e., optimally short segment of the time series, one can see regular changes in the histogram shape. The paper illustrates the main manifestations of this phenomenon by comparing the results of 90 Sr -radioactivity and 239 Pu -decay mea- surements, with the distance between the laboratories in which the data were collected being about 3000 km.

  8. Visibility Histogram Based Transfer Function for 3D Visualization of Heart%基于可见性直方图的传递函数在心脏三维显示中的应用

    Institute of Scientific and Technical Information of China (English)

    顾翀; 杨新; 姚莉萍; 薛海虹; 孙锟

    2013-01-01

    Transfer function is an important tool for direct volume rendering of 3D visualization of heart. However, the complexity of heart structure makes the design of transfer function a difficult task. In this paper, we introduce visibility histogram based transfer function to display the cardiac dual source CT data. We first preprocess the cardiac dual source CT volume data and afterwards explore the transfer function based on visibility histogram. Furthermore, we propose the automatic method to design the transfer function. With these methods, users can highlight the region of interested and even observe more details of cardiac chamber. Finally, we accelerate the calculation and 3D rendering using the technology of CUD A, thus leading to the real-time dynamic display of three-dimensional volume data. The experiments show that the proposed method can effectively remove the ribs, pulmonary veins in cardiac dual source CT data, enhance the myocardial tissue, blood and some internal structures such as the aortic valve, which is of great importance for cardiologists in clinical diagnosis.%在心脏的三维可视化的研究中,传递函数是一个十分重要的工具.然而,心脏复杂的结构使传递函数的设计十分困难.本文介绍了基于可见性直方图的传递函数设计以用来显示心脏双源CT数据.先对心脏双源CT体数据做预处理,提出在视线投射算法中利用基于可见性直方图的心脏传递函数对心脏数据进行三维显示,并且提出半自动方法来确定传递函数.通过这些方法,用户可以通过调节传递函数突出显示感兴趣的部分,甚至可以观察到心腔的许多细节.最后,利用CUDA技术对计算及显示进行加速,对三维体数据进行实时动态显示.实验表明,利用本文提出的方法可以有效地去掉心脏双源CT中的肋骨,肺静脉等数据,突出显示心肌组织及血液,并且通过传递函数可以看到主动脉瓣等心脏内部结构,对于心外

  9. Renormalized Volume

    CERN Document Server

    Gover, A Rod

    2016-01-01

    For any conformally compact manifold with hypersurface boundary we define a canonical renormalized volume functional and compute an explicit, holographic formula for the corresponding anomaly. For the special case of asymptotically Einstein manifolds, our method recovers the known results. The anomaly does not depend on any particular choice of regulator, but the coefficients of divergences do. We give explicit formulae for these divergences valid for any choice of regulating hypersurface; these should be relevant to recent studies of quantum corrections to entanglement entropies. The anomaly is expressed as a conformally invariant integral of a local Q-curvature that generalizes the Branson Q-curvature by including data of the embedding. In each dimension this canonically defines a higher dimensional generalization of the Willmore energy/rigid string action. We show that the variation of these energy functionals is exactly the obstruction to solving a singular Yamabe type problem with boundary data along the...

  10. 原发性肝癌诊断中CT值直方图的应用解析%Application of CT histogram in diagnosis of primary liver cancer

    Institute of Scientific and Technical Information of China (English)

    冯雷

    2015-01-01

    Objectiveto study the value of ct histogram in the diagnosis of primary hepatic carcinoma by analyzing the ct histogram in different character of the liver lesions of the liver.Methodsthe data of 486 patients with imaging data were analyzed, according to the type of disease will the into 3 groups, a group of hepatic cyst, a group of hepatic hemangioma, a group for primary liver cancer, through ct histogram analysis of the different groups of patients in the lfat scanning phase, arterial phase, portal venous phase and delayed phase data and analysis within the group and between groups.Results most accounted for ct value histograms for the normal distribution curve and within the tumor appeared calciifcation for positive skewness distribution curve, necrosis and liquefaction was negative skewness distribution curve in the tumor; ct value histogram in different nature of space occupying lesions between mean value (the average ct value), max value (max), min value (minimum) and sd values (standard deviation) and r value (range) have their own characteristics.Conclusion in the diagnosis of primary liver cancer, the speciifcity of the partial distribution curve is high, and the ct value of Mean histogram is signiifcantly lower, and the r value is signiifcantly higher, which shows that it is likely to be the primary liver cancer.%目的:通过分析ct值直方图在不同性质肝脏占位性病变中的表现,研究原发性肝癌诊断中ct值直方图的价值。方法选取486例患者影像学资料进行研究分析,根据患者疾病类型将其分为3组,一组为肝囊肿,一组为肝血管瘤,一组为原发性肝癌,通过ct值直方图分析不同组别患者在平扫期、动脉期、门脉期和延迟期的数据,并分析组内和组间数据。结果多数占位ct值直方图为正态分布曲线,在癌肿内出现大范围钙化时为正偏态分布曲线,在癌肿内出现坏死并液化时为负偏态分布曲线;ct值直方图在

  11. An innovative technique for contrast enhancement of computed tomography images using normalized gamma-corrected contrast-limited adaptive histogram equalization

    Science.gov (United States)

    Al-Ameen, Zohair; Sulong, Ghazali; Rehman, Amjad; Al-Dhelaan, Abdullah; Saba, Tanzila; Al-Rodhaan, Mznah

    2015-12-01

    Image contrast is an essential visual feature that determines whether an image is of good quality. In computed tomography (CT), captured images tend to be low contrast, which is a prevalent artifact that reduces the image quality and hampers the process of extracting its useful information. A common tactic to process such artifact is by using histogram-based techniques. However, although these techniques may improve the contrast for different grayscale imaging applications, the results are mostly unacceptable for CT images due to the presentation of various faults, noise amplification, excess brightness, and imperfect contrast. Therefore, an ameliorated version of the contrast-limited adaptive histogram equalization (CLAHE) is introduced in this article to provide a good brightness with decent contrast for CT images. The novel modification to the aforesaid technique is done by adding an initial phase of a normalized gamma correction function that helps in adjusting the gamma of the processed image to avoid the common errors of the basic CLAHE of the excess brightness and imperfect contrast it produces. The newly developed technique is tested with synthetic and real-degraded low-contrast CT images, in which it highly contributed in producing better quality results. Moreover, a low intricacy technique for contrast enhancement is proposed, and its performance is also exhibited against various versions of histogram-based enhancement technique using three advanced image quality assessment metrics of Universal Image Quality Index (UIQI), Structural Similarity Index (SSIM), and Feature Similarity Index (FSIM). Finally, the proposed technique provided acceptable results with no visible artifacts and outperformed all the comparable techniques.

  12. Histogram analysis of apparent diffusion coefficient maps for the differentiation between lymphoma and metastatic lymph nodes of squamous cell carcinoma in head and neck region.

    Science.gov (United States)

    Wang, Yan-Jun; Xu, Xiao-Quan; Hu, Hao; Su, Guo-Yi; Shen, Jie; Shi, Hai-Bin; Wu, Fei-Yun

    2017-01-01

    Background To clarify the nature of cervical malignant lymphadenopathy is highly important for the diagnosis and differential diagnosis of head and neck tumors. Purpose To investigate the role of first-order apparent diffusion coefficient (ADC) histogram analysis for differentiating lymphoma from metastatic lymph nodes of squamous cell carcinoma (SCC) in the head and neck region. Material and Methods Diffusion-weighted imaging (DWI) data of 67 patients (lymphoma, n = 20; SCC, n = 47) with malignant lymphadenopathy were retrospectively analyzed. The SCC group was divided into nasopharyngeal SCC and non-nasopharyngeal SCC groups. The ADC histogram features (ADC10, ADC25, ADCmean, ADCmedian, ADC75, ADC90, skewness, and kurtosis) were derived and then compared by independent-samples t-test and one-way analysis of variance test, respectively. Receiver operating characteristic curve analyses were employed to investigate diagnostic performance of the significant parameters. Results Lymphoma showed significantly lower ADCmean, ADCmedian, ADC75, and ADC90 than SCC (all P  0.05). Lymphoma showed significantly lower ADC25, ADCmean, ADCmedian, ADC75, and ADC90 than non-nasopharyngeal SCC (all P < 0.05). Optimal diagnostic performance (AUC = 0.847, sensitivity = 86.7%, specificity = 80.0%) could be achieved when setting ADC90 = 0.943 × 10(-3 )mm(2)/s as the threshold value. Conclusion Given its limitations, our study has shown that first-order ADC histogram analysis is capable of differentiating lymphoma from metastatic lymph nodes of SCC, especially those of non-nasopharyngeal SCC.

  13. 一种视觉词软直方图的图像表示方法%Visual Word Soft-Histogram for Image Representation

    Institute of Scientific and Technical Information of China (English)

    王彦杰; 刘峡壁; 贾云得

    2012-01-01

    基于视觉词的统计建模和判别学习,提出一种视觉词软直方图的图像表示方法.假设属于同一视觉词的图像局部特征服从高斯混合分布,利用最大-最小后验伪概率判别学习方法从样本中估计该分布,计算局部特征与视觉词的相似度.累加图像中每个视觉词与对应局部特征的相似度,在全部视觉词集合上进行结果的归一化,得到图像的视觉词软直方图.讨论了两种具体实现方法:一种是基于分类的软直方图方法,该方法根据相似度最大原则建立局部特征与视觉词的对应关系;另一种是完全软直方图方法,该方法将每个局部特征匹配到所有视觉词,在数据库Caltech-4和PASCAL VOC 2006上的实验结果表明,该方法是有效的.%This paper proposes a visual word soft-histogram for image representation based on statistical modeling and discriminative learning of visual words. This type of learning uses Gaussian mixture models (GMM) to reflect the appearance variation of each visual word and employs the max-min posterior pseudo-probabilities discriminative learning method to estimate GMMs of visual words. The similarities between each visual word and corresponding local features are computed, summed, and normalized to construct a soft-histogram, This paper also discusses the implementation of two representation methods. The first one is called classification-based soft histogram, in which each local feature is assigned to only one visual word with maximum similarity. The second one is called completely soft histogram, in which each local feature is assigned to all the visual words. The experimental results of Caltech-4 and PASCAL VOC 2006 confirm the effectiveness of this method.

  14. Development of DQM software infrastructure: storing and reading the monitoring information from the histograms filled by online client applications into relational tables.

    CERN Document Server

    Andrzejczak, Adam

    2015-01-01

    In CMS the online DQM stores the monitoring information from several heterogeneous data sources into histograms, which are later sent to the DQMGUI for visualization. System for the handling of monitoring data is crucial for operating the detector and realizing whether or not it is undergoing failures: in particular, relational databases are the current best option for hosting such data. In this context a new DQM plugin DQMDatabaseWriter was developed, it provides interface which can be used in other DQM modules to drop desired data into the relational database. In addition, a python script provides possibility to read and visualize already saved records.

  15. International Spine Radiosurgery Consortium Consensus Guidelines for Target Volume Definition in Spinal Stereotactic Radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Cox, Brett W., E-mail: coxb@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Spratt, Daniel E. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Lovelock, Michael [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Bilsky, Mark H. [Department of Surgery, Division of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Lis, Eric [Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Ryu, Samuel [Department of Radiation Oncology, Henry Ford Hospital, Detroit, Michigan (United States); Sheehan, Jason [Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, Virginia (United States); Gerszten, Peter C. [Department of Neurological Surgery and Radiation Oncology, University of Pittsburgh Medical Center, UPMC Presbyterian, Pittsburgh, Pennsylvania (United States); Chang, Eric [Department of Radiation Oncology, University of Southern California Keck School of Medicine, Health Sciences Campus, Los Angeles, California (United States); Gibbs, Iris; Soltys, Scott [Department of Radiation Oncology, Stanford University School of Medicine, Stanford, California (United States); Sahgal, Arjun [Department of Radiation Oncology, Princess Margaret Hospital and the Sunnybrook Health Sciences Center, University of Toronto, Toronto, Ontario (Canada); Deasy, Joe [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Flickinger, John; Quader, Mubina [Department of Radiation Oncology, University of Pittsburgh Medical Center, UPMC Presbyterian, Pittsburgh, Pennsylvania (United States); Mindea, Stefan [Department of Neurosurgery, Stanford University School of Medicine, Stanford, California (United States); and others

    2012-08-01

    Purpose: Spinal stereotactic radiosurgery (SRS) is increasingly used to manage spinal metastases. However, target volume definition varies considerably and no consensus target volume guidelines exist. This study proposes consensus target volume definitions using common scenarios in metastatic spine radiosurgery. Methods and Materials: Seven radiation oncologists and 3 neurological surgeons with spinal radiosurgery expertise independently contoured target and critical normal structures for 10 cases representing common scenarios in metastatic spine radiosurgery. Each set of volumes was imported into the Computational Environment for Radiotherapy Research. Quantitative analysis was performed using an expectation maximization algorithm for Simultaneous Truth and Performance Level Estimation (STAPLE) with kappa statistics calculating agreement between physicians. Optimized confidence level consensus contours were identified using histogram agreement analysis and characterized to create target volume definition guidelines. Results: Mean STAPLE agreement sensitivity and specificity was 0.76 (range, 0.67-0.84) and 0.97 (range, 0.94-0.99), respectively, for gross tumor volume (GTV) and 0.79 (range, 0.66-0.91) and 0.96 (range, 0.92-0.98), respectively, for clinical target volume (CTV). Mean kappa agreement was 0.65 (range, 0.54-0.79) for GTV and 0.64 (range, 0.54-0.82) for CTV (P<.01 for GTV and CTV in all cases). STAPLE histogram agreement analysis identified optimal consensus contours (80% confidence limit). Consensus recommendations include that the CTV should include abnormal marrow signal suspicious for microscopic invasion and an adjacent normal bony expansion to account for subclinical tumor spread in the marrow space. No epidural CTV expansion is recommended without epidural disease, and circumferential CTVs encircling the cord should be used only when the vertebral body, bilateral pedicles/lamina, and spinous process are all involved or there is extensive metastatic

  16. Contrast Enhancement Method Based on Gray and Its Distance Double-Weighting Histogram Equalization for 3D CT Images of PCBs

    Directory of Open Access Journals (Sweden)

    Lei Zeng

    2016-01-01

    Full Text Available Cone beam computed tomography (CBCT is a new detection method for 3D nondestructive testing of printed circuit boards (PCBs. However, the obtained 3D image of PCBs exhibits low contrast because of several factors, such as the occurrence of metal artifacts and beam hardening, during the process of CBCT imaging. Histogram equalization (HE algorithms cannot effectively extend the gray difference between a substrate and a metal in 3D CT images of PCBs, and the reinforcing effects are insignificant. To address this shortcoming, this study proposes an image enhancement algorithm based on gray and its distance double-weighting HE. Considering the characteristics of 3D CT images of PCBs, the proposed algorithm uses gray and its distance double-weighting strategy to change the form of the original image histogram distribution, suppresses the grayscale of a nonmetallic substrate, and expands the grayscale of wires and other metals. The proposed algorithm also enhances the gray difference between a substrate and a metal and highlights metallic materials. The proposed algorithm can enhance the gray value of wires and other metals in 3D CT images of PCBs. It applies enhancement strategies of changing gray and its distance double-weighting mechanism to adapt to this particular purpose. The flexibility and advantages of the proposed algorithm are confirmed by analyses and experimental results.

  17. Preliminary evaluation of a fully automated quantitative framework for characterizing general breast tissue histology via color histogram and color texture analysis

    Science.gov (United States)

    Keller, Brad M.; Gastounioti, Aimilia; Batiste, Rebecca C.; Kontos, Despina; Feldman, Michael D.

    2016-03-01

    Visual characterization of histologic specimens is known to suffer from intra- and inter-observer variability. To help address this, we developed an automated framework for characterizing digitized histology specimens based on a novel application of color histogram and color texture analysis. We perform a preliminary evaluation of this framework using a set of 73 trichrome-stained, digitized slides of normal breast tissue which were visually assessed by an expert pathologist in terms of the percentage of collagenous stroma, stromal collagen density, duct-lobular unit density and the presence of elastosis. For each slide, our algorithm automatically segments the tissue region based on the lightness channel in CIELAB colorspace. Within each tissue region, a color histogram feature vector is extracted using a common color palette for trichrome images generated with a previously described method. Then, using a whole-slide, lattice-based methodology, color texture maps are generated using a set of color co-occurrence matrix statistics: contrast, correlation, energy and homogeneity. The extracted features sets are compared to the visually assessed tissue characteristics. Overall, the extracted texture features have high correlations to both the percentage of collagenous stroma (r=0.95, phistological processes in digitized histology specimens.

  18. Quantitative characterization of brain β-amyloid in 718 normal subjects using a joint PiB/FDG PET image histogram

    Science.gov (United States)

    Camp, Jon J.; Hanson, Dennis P.; Lowe, Val J.; Kemp, Bradley J.; Senjem, Matthew L.; Murray, Melissa E.; Dickson, Dennis W.; Parisi, Joseph E.; Petersen, Ronald C.; Robb, Richard A.; Holmes, David R.

    2016-03-01

    We have previously described an automated system for the co-registration of PiB and FDG PET images with structural MRI and a neurological anatomy atlas to produce region-specific quantization of cortical activity and amyloid burden. We also reported a global joint PiB/FDG histogram-based measure (FDG-Associated PiB Uptake Ratio - FAPUR) that performed as well as regional PiB ratio in stratifying Alzheimer's disease (AD) and Lewy Body Dementia (LBD) patients from normal subjects in an autopsy-verified cohort of 31. In this paper we examine results of this analysis on a clinically-verified cohort of 718 normal volunteers. We found that the global FDG ratio correlated negatively with age (r2 = 0.044) and global PiB ratio correlated positively with age (r2=0.038). FAPUR also correlated negatively with age (r2-.025), and in addition, we introduce a new metric - the Pearson's correlation coefficient (r2) of the joint PiB/FDG histogram which correlates positively (r2=0.014) with age. We then used these measurements to construct age-weighted Z-scores for all measurements made on the original autopsy cohort. We found similar stratification using Z-scores compared to raw values; however, the joint PiB/FDG r2 Z-score showed the greatest stratification ability.

  19. 基于ArcGIS Server的海岛管理平台设计与实现%Drawing of bore histogram based on MapInfo

    Institute of Scientific and Technical Information of China (English)

    崔伦辉; 金继业; 刘金

    2011-01-01

    This paper introduced an automatic mapping method based on MapInfo. Also, it discussed how to design bore database and lithological pattern library, and main idea of design, flow methods, key arithmetic of the bore histogram automatically mapping software. The software was developed by OLE technology based on utilizing Maplnfo, Visual Basic and SQL Server 2000. This software realized the management of bore data and automatic mapping with measured bore data. The application of this software could enhance the drawing efficiency and standardization level of bore histogram.%本文基于ArcGIS Server,结合时空数据模型和WebGIS理论,采用Flex技术,面向海岛管理,设计开发了集空间数据、属性信息和时态特性于一体的海岛管理支撑平台,对平台的体系结构、关键技术、数据组织和系统功能作了详细介绍,以期有效管理分布广泛的海岛,充分控制海洋、开发海洋资源.

  20. Histogram-based characterization of healthy and ischemic brain tissues using multiparametric MR imaging including apparent diffusion coefficient maps and relaxometry.

    Science.gov (United States)

    Bernarding, J; Braun, J; Hohmann, J; Mansmann, U; Hoehn-Berlage, M; Stapf, C; Wolf, K J; Tolxdorff, T

    2000-01-01

    Decreased, renormalized, or increased values of the calculated apparent diffusion coefficient (ADC) are observed in stroke models. A quantitative description of corresponding tissue states using ADC values may be extended to include true relaxation times. A histogram-based segmentation is well suited for characterizing tissues according to specific parameter combinations irrespective of the heterogeneity found for human healthy and ischemic brain tissues. In a new approach, navigated diffusion-weighted images and ADC maps were incorporated into voxel-based parameter sets of relaxation times (T1, T2), and T1- or T2-weighted images, followed by a supervised histogram-based analysis. Healthy tissues were segmented by incorporating T1 relaxation into the data set, ischemic regions by combining T2- or diffusion-weighted images with ADC maps. Mean values of healthy and pathologic tissues were determined, spatial distributions of the parameter vectors were visualized using color-encoded overlays. One to six days after stroke, ischemic regions exhibited reduced relative mean ADC values.

  1. Ear recognition with histogram of oriented gradient features%梯度方向直方图特征的人耳身份识别方法

    Institute of Scientific and Technical Information of China (English)

    封筠; 梁晓霞; 穆志纯

    2012-01-01

    人耳特征体具有普遍性、唯一性、稳定性和可采集性等作为生物特征识别必备的基本特性,易实现非打扰式识别.研究一类新型的基于梯度方向直方图的人耳身份识别方法,将人耳图像划分为不同子区域,分别提取各子区域梯度方向直方图特征,采用模糊隶属度匹配融合策略获取识别结果.重点讨论了局部遮挡时基于梯度方向直方图特征描述的人耳识别问题,定义并分析了人耳子区域识别贡献率,探讨累计遮挡问题,可为人耳图像有效鉴别子区域的确定提供参考.实验结果表明,基于梯度方向直方图的人耳身份识别方法是可行的与有效的.%Ear biometric has the basic characteristics, such as universality, distinctiveness, stability and collectibility. The non-disturbed recognition can be easily realized by ear biometric or fusion of ear and face biometrics. As a novel biometric identification, ear recognition is a very active research project in the field of pattern recognition. However, ear recognition result is usually affected by the head posture of image, illumination variations, occlusion and other factors, which makes the process of recognition more complicated and challenging. In this paper, a novel ear recognition approach based on histogram of oriented gradient feature extraction is studied. The ear recognition scheme by combining histogram of oriented gradient features with sub-region fuzzy fusion is presented. The ear image is divided into a number of sub-regions, histograms of oriented gradient features of different sub-regions are extracted separately, and the fuzzy membership matching fusion strategy is introduced to obtain the last classification label. Furthmore, the issue on ear recognition under local occlusion based on histogram of oriented gradient is discussed in detail. The recognition contribution rate for each sub-region is defined and analyzed, and the accumulated

  2. A novel four-dimensional radiotherapy planning strategy from a tumor-tracking beam's eye view

    Science.gov (United States)

    Li, Guang; Cohen, Patrice; Xie, Huchen; Low, Daniel; Li, Diana; Rimner, Andreas

    2012-11-01

    To investigate the feasibility of four-dimensional radiotherapy (4DRT) planning from a tumor-tracking beam's eye view (ttBEV) with reliable gross tumor volume (GTV) delineation, realistic normal tissue representation, high planning accuracy and low clinical workload, we propose and validate a novel 4D conformal planning strategy based on a synthesized 3.5D computed tomographic (3.5DCT) image with a motion-compensated tumor. To recreate patient anatomy from a ttBEV in the moving tumor coordinate system for 4DRT planning (or 4D planning), the centers of delineated GTVs in all phase CT images of 4DCT were aligned, and then the aligned CTs were averaged to produce a new 3.5DCT image. This GTV-motion-compensated CT contains a motionless target (with motion artifacts minimized) and motion-blurred normal tissues (with a realistic temporal density average). Semi-automatic threshold-based segmentation of the tumor, lung and body was applied, while manual delineation was used for other organs at risk (OARs). To validate this 3.5DCT-based 4D planning strategy, five patients with peripheral lung lesions of small size (<5 cm3) and large motion range (1.2-3.5 cm) were retrospectively studied for stereotactic body radiotherapy (SBRT) using 3D conformal radiotherapy planning tools. The 3.5DCT-based 4D plan (3.5DCT plan) with 9-10 conformal beams was compared with the 4DCT-based 4D plan (4DCT plan). The 4DCT plan was derived from multiple 3D plans based on all phase CT images, each of which used the same conformal beam configuration but with an isocenter shift to aim at the moving tumor and a minor beam aperture and weighting adjustment to maintain plan conformality. The dose-volume histogram (DVH) of the 4DCT plan was created with two methods: one is an integrated DVH (iDVH4D), which is defined as the temporal average of all 3D-phase-plan DVHs, and the other (DVH4D) is based on the dose distribution in a reference phase CT image by dose warping from all phase plans using the

  3. SU-E-T-621: Comprehensive Study of Head and Neck IMRT Parameters on Planning and Delivery Efficiency, Plan Quality, and Dose Accuracy.

    Science.gov (United States)

    Mittauer, K; Lu, B; Liu, C; Yan, G; Gopal, A

    2012-06-01

    To optimize planning and delivery efficiency, and quality of head and neck IMRT through the evaluation of planning parameters. This study also serves to identify the impact on dose accuracy due to calculation grid size. Eleven head and neck patients, 45 trials per patient (495 trials in total), were evaluated varying IMRT parameters of dose grid, minimum MU per segment, minimum segment area, and control point number. Plans were recomputed on Pinnacle Treatment Planning System (TPS), and scaled to the planning target volume (PTV) constraint of 95% volume. Differential dose volume histograms (DVHs) were exported, and a program was written to compile DVH results. Plans were delivered on an Elekta Synergy linear accelerator to assess delivery time. Plan quality, calculation time, and delivery time served as this study's endpoints. The 4 mm dose grid with 2 mm fluence grid in each direction, saving 1/3 the computation time, were most comparable by DVH results to the 2 mm dose and fluence grid. Dose uncertainty due to dose calculation grid effect was as high as 8.2%, 5.5 Gy for PTVs and 13.3%, 2.1 Gy for organs at risk. Smaller volumes and high gradient regions were more susceptible to uncertainties. Threshold values that maintained adequate plan quality were 5 cm(2) for minimum segment area and 5 MU for minimum MU. Minimum MU was more costly in terms of plan quality compared to the minimum segment area. DVH differences can be effectively used to quantify the dose grid calculation uncertainty. For minimum MU and segment area, the DVH differences are an effect of the intensity map, defined by MLC shape and the number of control points. Exceeding the adequate number of control points diminishes returns of plan quality and increases patient treatment time. © 2012 American Association of Physicists in Medicine.

  4. A plan quality classifier derived with overlap-wall-histogram of hollow organs for automatic IMRT plan quality control of prostate cancer cases

    Directory of Open Access Journals (Sweden)

    Ting Song

    2014-03-01

    Full Text Available Purpose: We developed a plan quality classification model to assess IMRT plan quality of prostate cancer patients for automatic plan quality control. Methods: For hollow organs such as rectum and bladder, dose-wall-histogram (DWH was used to evaluate OAR dose sparing in our institution. Correspondingly, we proposed a new descriptor called overlap-wall-histogram (OWH to describe the complex spatial relationship between PTV and a hollow organ. Two metrics calculated from the OWH and DWH are introduced to quantitatively evaluate the difficulty of patient geometry for planning and plan quality in terms of OAR sparing, respectively. A linear correlation between these two metrics was observed after plotting plan quality metric as a function of geometry difficulty metric studied from a database of prostate cases treated in our institution with acceptable plan quality. Thus, a fitting line was built acting as the boundary of high quality and poor quality plans. A query plan falling above the boundary is assessed as high quality, vice versa poor quality. Results: 15 prostate IMRT plans were used to test our model. One was identified as poor quality and the others were common-level. After re-planning all plans, the dose constraints for bladder wall W75 (percentage of wall receiving more than 75Gy, W70, W65 and W60 can be reduced by 3.34%, 3%, 6.99%, 6.54% for that poor quality plan and 1.11%, 0.95%, 1.45% and 1.81% averagely for the common-level quality group, without sacrificing PTV coverage and rectum dose sparing. Conclusion: An effective model was built to provide automatic IMRT plan quality control by evaluating hollow OAR dose sparing for prostate cancer patients. Furthermore, for the query plan with poor quality, potential improvement of plan quality can be estimated and a good reference plan with similar or harder geometry can be automatically chosen from our database to help guide the re-planning if necessary.---------------------------Cite this

  5. 彩色直方图估测前列腺血流的价值%Evaluation Prostatic Flow with Color Histogram

    Institute of Scientific and Technical Information of China (English)

    陈亚青; 周永昌; 黄慕民; 唐天雪; 张惠箴; 陈洁晴

    2001-01-01

    Objective:To set relative reference data of normal and abnormal prostatic color flow with color histogram and to discuss the role in the diagnosis of prostatic diseases.Methods:Twenty-five patients with benign prostatic hypertrophy(BPH)and twenty-five with prostatic carcinoma(PCa)were measured by color histogram with two types of transrectal probe(endfire and biplane),and twenty-two normal cases were as the control group.Results:There were significant differences in the mean BCR among three groups,and there was no significant difference between the two types of the probe.However,there was overlap on individuals in each group,the overlap range was 17%~26%,74%~83% with no overlap.Conclusions:Measurements of Prostatic blood flow with color histogram can become one of the objective parameters for diagnosis of prostatic diseases.%目的:本文利用彩色直方图对正常和异常前列腺彩色血流给出定量参考值并探讨其对前列腺疾病诊断的价值。方法:分别用端射式和双平面二种探头对经穿刺活检证实的前列腺增生症和前列腺癌各25例用彩色直方图软件测得前列腺内彩色血流面积占前列腺面积的百分比(BCR),并有22例正常对照。结果:正常组、前列腺增生症组、前列腺癌组之间BCR的均值在统计学上有显著意义(端射式P<0.05;双平面P<0.01),二种探头之间无统计学意义(P>0.05)。但对个体而言各组间存在一定交叉,其交叉范围为17%~26%,不交叉范围为74%~83%。结论:彩色直方图测定前列腺血流方法可作为前列腺疾病诊断中客观的参考依据。

  6. A Neural Network Classifier of Volume Datasets

    CERN Document Server

    Zukić, Dženan; Kolb, Andreas

    2009-01-01

    Many state-of-the art visualization techniques must be tailored to the specific type of dataset, its modality (CT, MRI, etc.), the recorded object or anatomical region (head, spine, abdomen, etc.) and other parameters related to the data acquisition process. While parts of the information (imaging modality and acquisition sequence) may be obtained from the meta-data stored with the volume scan, there is important information which is not stored explicitly (anatomical region, tracing compound). Also, meta-data might be incomplete, inappropriate or simply missing. This paper presents a novel and simple method of determining the type of dataset from previously defined categories. 2D histograms based on intensity and gradient magnitude of datasets are used as input to a neural network, which classifies it into one of several categories it was trained with. The proposed method is an important building block for visualization systems to be used autonomously by non-experts. The method has been tested on 80 datasets,...

  7. Uncertainties in the Standard Moments, the Derivation of the Y1 to Y8 parameters, and the Derivation of w1 to w8 for Feynman Histograms

    Energy Technology Data Exchange (ETDEWEB)

    Smith-Nelson, Mark A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cutler, Theresa Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hutchinson, Jesson D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-02

    Momentum is a neutron multiplicity analysis software package that calculates a variety of parameters associated with Feynman histograms. While most of these parameters are documented in Cifarelli and Smith-Nelson, there are some parameters which are not. Most prominent of these are the uncertainties in the standard moments, and this paper will explicitly document these parameters. This paper will also document the higher-order Yn parameters and their associated ωn functions because they may be useful for future applications. The generation of what is referred to as Feynman histograms is not explained here.

  8. Nonlinear dimensionality reduction of CT histogram based feature space for predicting recurrence-free survival in non-small-cell lung cancer

    Science.gov (United States)

    Kawata, Y.; Niki, N.; Ohmatsu, H.; Aokage, K.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, M.

    2015-03-01

    Advantages of CT scanners with high resolution have allowed the improved detection of lung cancers. In the recent release of positive results from the National Lung Screening Trial (NLST) in the US showing that CT screening does in fact have a positive impact on the reduction of lung cancer related mortality. While this study does show the efficacy of CT based screening, physicians often face the problems of deciding appropriate management strategies for maximizing patient survival and for preserving lung function. Several key manifold-learning approaches efficiently reveal intrinsic low-dimensional structures latent in high-dimensional data spaces. This study was performed to investigate whether the dimensionality reduction can identify embedded structures from the CT histogram feature of non-small-cell lung cancer (NSCLC) space to improve the performance in predicting the likelihood of RFS for patients with NSCLC.

  9. Infrared target segmentation algorithm based on partial histogram%基于局部直方图的红外目标分割算法

    Institute of Scientific and Technical Information of China (English)

    冯帅; 赵金博

    2014-01-01

    In infrared remote target detection system,the sky-background changes slowly,but the target shows the par-tial corner. It has a broad gray range and is brighter than the background. According to these characteristics,a target segmentation algorithm based on partial histogram is presented. The distribution characteristics of multi-target histo-gram are analyzed. According to gray level distribution rule and the image pixels restriction,the image segmentation is realized. Experiment results show that this method can segment flying targets rapidly and effectively,and it has strong practicability.%在远程红外探测系统中,背景为缓慢变化的天空,而目标则表现为局部奇异点。目标灰度分布范围大,局部较亮,边缘与背景对比度低。根据这一特性,提出了一种基于局部直方图的目标分割算法。文中分析了多个目标的直方图分布特性,根据其灰度分布规律和像素个数判决条件实现了目标的有效分割。该算法适用于空域背景下的飞行目标分割。经过仿真验证表明,本文所提出的算法能快速有效地分割出红外飞行目标,有很强的实用性。

  10. Pre-treatment diffusion-weighted MR imaging for predicting tumor recurrence in uterine cervical cancer treated with concurrent chemoradiation: Value of histogram analysis of apparent diffusion coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Suk Hee; Kim, Jin Woong; Lim, Hyo Soon; Jeong, Yong Yeon; Kang, Woo Dae; KIm, Seok Mo; Kang, Heong Keun [Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Hwasun (Korea, Republic of); Shin, Sang Soo [Chonnam National University Hospital, Chonnam National University Medical School, Gwangju (Korea, Republic of)

    2013-08-15

    To evaluate the value of apparent diffusion coefficient (ADC) histogram analysis for predicting tumor recurrence in patients with uterine cervical cancer treated with chemoradiation therapy (CRT). Our institutional review board approved this retrospective study and waived informed consent from each patient. Forty-two patients (mean age, 56 ± 14 years) with biopsy-proven uterine cervical squamous cell carcinoma who underwent both pre-treatment pelvic magnetic resonance imaging with a 3.0 T magnetic resonance scanner and concurrent CRT were included. All patients were followed-up for more than 6 months (mean, 36.4 ± 11.9 months; range 9.0-52.8 months) after completion of CRT. Baseline ADC parameters (mean ADC, 25th percentile, 50th percentile, and 75th percentile ADC values) of tumors were calculated and compared between the recurrence and no recurrence groups. In the recurrence group, the mean ADC and 75th percentile ADC values of tumors were significantly higher than those of the no recurrence group (p = 0.043 and p = 0.008, respectively). In multivariate analysis, the 75th percentile ADC value of tumors was a significant predictor for tumor recurrence (p = 0.009; hazard ratio, 1.319). When the cut-off value of the 75th percentile ADC (0.936 x 10{sup -3} mm{sup 2}/sec) was used, the overall recurrence free survival rate above the cut-off value was significantly lower than that below the cut-off value (51.9% vs. 91.7%, p = 0.003, log-rank test). Pre-CRT ADC histogram analysis may serve as a biomarker for predicting tumor recurrence in patients with uterine cervical cancer treated with CRT.

  11. 基于直方图统计分类隐写检测算法设计%THE STEGANOGRAPHY DETECTION ALGORITHM DESIGN BASED ON HISTOGRAM STATISTICAL CLASSIFICATION

    Institute of Scientific and Technical Information of China (English)

    邱志宏

    2013-01-01

    In order to improve the detection performance of steganography detection algorithm,in this paper we put forward a steganography detection algorithm which is based on histogram statistical classification.Through extracting the histogram characteristic parameters of the image information and using the classification mode which is constructed based on artificial neural networks,this algorithm achieves accurate judgement on images embedded with steganography information.We analyse in detail the design,principle and process of this steganography algorithm,and at last construct the experimental test environment.Test results indicate that the detection success rate and the false alarm rate of the steganography detection algorithm designed in the paper are better than those of Ezstego detection tool.%为了提高隐写检测算法的检测性能,提出基于直方图统计分类的隐写检测算法.通过对图片信息的直方图特征参数的提取,使用构建基于人工神经网络的分类模式,实现对嵌入隐写信息的图片准确判定.详细分析基于直方图统计分类隐写算法的设计原理和过程,最后构建实验测试环境.测试结果表明,该隐写检测算法的检测成功率和误检率均优于Ezstego检测工具.

  12. Regular Changes in the Fine Structure of Histograms Revealed in the Experiments with Collimators which Isolate Beams of Alpha-Particles Flying at Certain Directions

    Directory of Open Access Journals (Sweden)

    Shnoll S. E.

    2009-04-01

    Full Text Available As was shown in the works of 1951–1983, the fine structure of distributions of the re- sults of measurements of processes of diverse nature is not casual. The changes in the shape of histograms corresponding to the distributions were called “macroscopic fluctu- ations”. The universal character of the phenomenon and its independence of the nature of the process studied were demonstrated for various processes: biochemical and chem- ical reactions, movement of latex particles in the electric field, proton transverse relax- ation in the inhomogeneous magnetic field, discharge in the neon-tube RC-generator and radioactive decay of various - and -isotopes. Since 1982, the main object chosen to study macroscopic fluctuations has been -decay. The choice was based on the pro- cess being a priori independent of trivial factors and the possibility to conduct continu- ous long-term automatic measurements while storing the results in a computer archive (database. Started in 1982, these measurements have been carrying on, as unceasingly as possible, until now. Since July 2000, the measurements are conducted using devices designed by one of the coauthors of this review, I. A. Rubinstein. Application of these devices (especially, detectors with collimators which isolate beams of -particles fly- ing at certain directions, along with the use of Edwin Pozharsky’s computer program, which eases histogram comparing by the expert, has allowed us to reveal a number of fundamentally new regularities. In the review, we describe these regularities, device constructions, and the methods of measurement and analysis of the results obtained.

  13. VolHOG: a volumetric object recognition approach based on bivariate histograms of oriented gradients for vertebra detection in cervical spine MRI.

    Science.gov (United States)

    Daenzer, Stefan; Freitag, Stefan; von Sachsen, Sandra; Steinke, Hanno; Groll, Mathias; Meixensberger, Jürgen; Leimert, Mario

    2014-08-01

    The automatic recognition of vertebrae in volumetric images is an important step toward automatic spinal diagnosis and therapy support systems. There are many applications such as the detection of pathologies and segmentation which would benefit from automatic initialization by the detection of vertebrae. One possible application is the initialization of local vertebral segmentation methods, eliminating the need for manual initialization by a human operator. Automating the initialization process would optimize the clinical workflow. However, automatic vertebra recognition in magnetic resonance (MR) images is a challenging task due to noise in images, pathological deformations of the spine, and image contrast variations. This work presents a fully automatic algorithm for 3D cervical vertebra detection in MR images. We propose a machine learning method for cervical vertebra detection based on new features combined with a linear support vector machine for classification. An algorithm for bivariate gradient orientation histogram generation from three-dimensional raster image data is introduced which allows us to describe three-dimensional objects using the authors' proposed bivariate histograms. A detailed performance evaluation on 21 T2-weighted MR images of the cervical vertebral region is given. A single model for cervical vertebrae C3-C7 is generated and evaluated. The results show that the generic model performs equally well for each of the cervical vertebrae C3-C7. The algorithm's performance is also evaluated on images containing various levels of artificial noise. The results indicate that the proposed algorithm achieves good results despite the presence of severe image noise. The proposed detection method delivers accurate locations of cervical vertebrae in MR images which can be used in diagnosis and therapy. In order to achieve absolute comparability with the results of future work, the authors are following an open data approach by making the image dataset

  14. A planning quality evaluation tool for prostate adaptive IMRT based on machine learning

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Xiaofeng; Ge Yaorong; Li Taoran; Thongphiew, Danthai; Yin Fangfang; Wu, Q Jackie [Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27708 (United States); Department of Biomedical Engineering, Wake Forest University Health Sciences, Medical Center Boulevard, Winston-Salem, North Carolina 27106 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27708 (United States); Department of Radiation Oncology, Brody School of Medicine, East Carolina University, Greenville, North Carolina 27834 (United States); Department of Radiation Oncology, Duke University Medical Center, Durham, North Carolina 27708 (United States)

    2011-02-15

    Purpose: To ensure plan quality for adaptive IMRT of the prostate, we developed a quantitative evaluation tool using a machine learning approach. This tool generates dose volume histograms (DVHs) of organs-at-risk (OARs) based on prior plans as a reference, to be compared with the adaptive plan derived from fluence map deformation. Methods: Under the same configuration using seven-field 15 MV photon beams, DVHs of OARs (bladder and rectum) were estimated based on anatomical information of the patient and a model learned from a database of high quality prior plans. In this study, the anatomical information was characterized by the organ volumes and distance-to-target histogram (DTH). The database consists of 198 high quality prostate plans and was validated with 14 cases outside the training pool. Principal component analysis (PCA) was applied to DVHs and DTHs to quantify their salient features. Then, support vector regression (SVR) was implemented to establish the correlation between the features of the DVH and the anatomical information. Results: DVH/DTH curves could be characterized sufficiently just using only two or three truncated principal components, thus, patient anatomical information was quantified with reduced numbers of variables. The evaluation of the model using the test data set demonstrated its accuracy {approx}80% in prediction and effectiveness in improving ART planning quality. Conclusions: An adaptive IMRT plan quality evaluation tool based on machine learning has been developed, which estimates OAR sparing and provides reference in evaluating ART.

  15. Target volume definition and target conformal irradiation technique for breast cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Kiricuta, I.C.; Gotz, U.; Schwab, F.; Fehn, M.; Neumann, H.H. [St. Vincenz-Hospital, Limburg (Germany). Inst. of Radiation Oncology

    2000-07-01

    The aim of this study was to present the target volume and irradiation technique in the most complex situation where the breast or chest wall and the locoregional lymphatics (mammarial internal lymph nodes, axillary and supraclavicular lymph nodes) have to be irradiated. The study comprised 125 breast cancer patients treated with curative intent after primary surgery in the last two years at our institute. In 62 cases the target volume included the breast or chest wall and the locoregional lymphatics, which were treated using our irradiation technique. The target conformal irradiation technique is a multiple non-opposed beams one isocenter technique developed to protect the heart and lungs. This technique, consisting of several rotation beams modulated with wedge filters and individual lung absorbers as well as additional fixed beams, was used in our study to apply a homogeneous dose of 46 to 56 Gy to the target volume; the irradiation technique was optimized by means of dose-volume histograms. After pre-localization, the patients underwent computerized tomographic scanning, with sections at 1.0 cm intervals. Contouring of target volume and organs at risk was carried out with a MULTIDATA workstation for regions of interest (mammarial internal and/or axillary and/or supraclavicular lymphatics and the breast or chest wall) as well as the organs at risk, such as heart and lung parenchyma. Planning target volume coverage was examined by three-dimensional isodose visualization for all CT axial sections for each patient. To determine the incidence of acute or late side effects on the lung parenchyma, conventional chest x-rays and CT studies were carried out at 1 month, 3 months and 6 months after completion of radiotherapy. Dose-volume histogram analysis revealed that this irradiation technique permits the application of a homogeneous dose to the target volume, conforming to the ICRU norms. The maximum dose applied to the ipsilateral lung parenchyma was less than 50

  16. The specific form of histograms presenting the distribution of data of alpha-decay measurements appears simultaneously in the moment of New Moon in different points from Arctic to Antarctic

    CERN Document Server

    Zenchenko, S E S K I; Gorshkov, E S; Makarevich, A V; Troshichev, O A

    2004-01-01

    It is shown that fine structure of distributions of fluctuations in different processes depends on position of the Earth with respect of the Moon. The same form of histogram was observed at New Moon moment independently of geographic position of laboratory and local time. Possible origin of the phenomenon is discussed.

  17. Assessment of arterial wall enhancement for differentiation of parent artery disease from small artery disease: Comparison between histogram analysis and visual analysis on 3 dimensional contrast-enhanced T1-weighted turbo spin echo MR images at 3T

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Jin Hee; Kim, Tae Won; Hwang, Eo Jin; Choi, Hyun Seok; Koo, Ja Seung; Shin, Yong Sam; Jung, So Lyung; Ahn, Kook Jin; Kim, Bum Soo [College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2017-04-15

    The purpose of this study was to compare the histogram analysis and visual scores in 3T MRI assessment of middle cerebral arterial wall enhancement in patients with acute stroke, for the differentiation of parent artery disease (PAD) from small artery disease (SAD). Among the 82 consecutive patients in a tertiary hospital for one year, 25 patients with acute infarcts in middle cerebral artery (MCA) territory were included in this study including 15 patients with PAD and 10 patients with SAD. Three-dimensional contrast-enhanced T1-weighted turbo spin echo MR images with black-blood preparation at 3T were analyzed both qualitatively and quantitatively. The degree of MCA stenosis, and visual and histogram assessments on MCA wall enhancement were evaluated. A statistical analysis was performed to compare diagnostic accuracy between qualitative and quantitative metrics. The degree of stenosis, visual enhancement score, geometric mean (GM), and the 90th percentile (90P) value from the histogram analysis were significantly higher in PAD than in SAD (p = 0.006 for stenosis, < 0.001 for others). The receiver operating characteristic curve area of GM and 90P were 1 (95% confidence interval [CI], 0.86-1.00). A histogram analysis of a relevant arterial wall enhancement allows differentiation between PAD and SAD in patients with acute stroke within the MCA territory.

  18. Histograms Difference and Quantitative Steganalysis of JPEG SteganographyBased on Relative Entropy%基于相对熵的直方图差异与JPEG隐写的定量分析

    Institute of Scientific and Technical Information of China (English)

    杨春芳; 刘粉林; 罗向阳

    2011-01-01

    For the histogram features, which are usually used in image steganalysis, a category of algorithms based on relative entropy are given to measure the difference between the histograms of the given image and the estimated cover image. And a quantitative steganalysis method based on relative entropy is proposed for JPEG image steganography. Firstly, according to the likelihood ratio test, which is the optimum test for two hypotheses, the superiority of measuring the distance between the two histograms based on relative entropy is analyzed, and two algorithms are given to measure the difference between the two histograms based on relative entropy. Secondly, for the histogram-like features used in the blind steganalysis methods, the new histograms difference features are calculated by the given algorithms, and fed to the support vector regression to train the quantitative steganalyzers for JPEG image steganography. Finally, the proposed steganalysis methods are applied to the quantitative steganalysis of two categories of typical JPEG image steganography: Jsteg and the improved F5 steganography. Experimental results show that compared with the other typical algorithms, the steganalyzers based on the histograms difference features calculated by the proposed algorithms have higher accuracy and stability.%针对图像隐写分析中常用的直方图特征,给出了一类基于相对熵的直方图差异计算方法,并提出了一种基于相对熵的JPEG隐写的定量分析方法.首先根据两假设检验中的最优检验——似然比检验,分析了相对熵在衡量2个直方图间的距离时的优越性,并给出了2种基于相对熵的直方图差异计算方法.然后,以新的直方图差异特征为基础,训练支持向量回归分析器,以估计隐写对DCT系数的更改比率.针对JSteg和改进的F5隐写的实验结果表明:与其他的直方图差异特征相比,根据所提出的基于相对熵的直方图差异特征所训练的定量隐写

  19. Dose-volume relationships between enteritis and irradiated bowel volumes during 5-fluorouracil and oxaliplatin based chemoradiotherapy in locally advanced rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gunnlaugsson, Adalsteinn; Kjellen, Elisabeth; Bendahl, Paer-Ola; Johnsson, A nders [Dept. of Oncology, Lund Univ. Hospital, Lund (Sweden); Nilsson, Per [Dept. o f Radiation Physics, Lund Univ. Hospital, Lund (Sweden); Willner, Julian [Dept. of Radiology, Lund Univ. Hospital, Lund (Sweden)

    2007-10-15

    Purpose. Radiation enteritis is the main acute side-effect during pelvic irradiation. The aim of this study was to quantify the dose-volume relationship between irradiated bowel volumes and acute enteritis during combined chemoradiotherapy for rectal cancer. Material and methods. Twenty-eight patients with locally advanced rectal cancer received chemoradiotherapy. The radiation therapy was given with a traditional multi-field technique to a total dose of 50 Gy, with concurrent 5-Fluorouracil (5-FU) and oxaliplatin (OXA) based chemotherapy. All patients underwent three-dimensional CT-based treatment planning. Individual loops of small and large bowel as well as a volume defined as 'whole abdomen' were systematically contoured on each CT slice, and dose-volume histograms were generated. Diarrhea during treatment was scored retrospectively according to the NCI Common Toxicity Criteria scale. Results. There was a strong correlation between the occurrence of grade 2+diarrhea and irradiated small bowel volume, most notably at doses >15 Gy. Neither irradiated large bowel volume, nor irradiated 'whole abdomen' volume correlated significantly with diarrhea. Clinical or treatment related factors such as age, gender, hypertension, previous surgery, enterostomy, or dose fractionation (1.8 vs. 2.0 Gy/fraction) did not correlate with grade 2+diarrhea. Discussion. This study indicates a strong dose-volume relationship between small bowel volume and radiation enteritis during 5-FU-OXA-based chemoradiotherapy. These findings support the application of maneuvers to minimize small bowel irradiation, such as using a 'belly board' or the use of IMRT technique aiming at keeping the small bowel volume receiving more than 15 Gy under 150 cc.

  20. Ovarian volume throughout life

    DEFF Research Database (Denmark)

    Kelsey, Thomas W; Dodwell, Sarah K; Wilkinson, A Graham

    2013-01-01

    cancer. To date there is no normative model of ovarian volume throughout life. By searching the published literature for ovarian volume in healthy females, and using our own data from multiple sources (combined n=59,994) we have generated and robustly validated the first model of ovarian volume from...... to about 2.8 mL (95% CI 2.7-2.9 mL) at the menopause and smaller volumes thereafter. Our model allows us to generate normal values and ranges for ovarian volume throughout life. This is the first validated normative model of ovarian volume from conception to old age; it will be of use in the diagnosis...

  1. Methodology for commissioning a brachytherapy treatment planning system in the era of 3D planning.

    Science.gov (United States)

    Dempsey, Claire

    2010-12-01

    To describe the steps undertaken to commission a 3D high dose rate (HDR) brachytherapy treatment planning system (TPS). Emphasis was placed on validating previously published recommendations, in addition to checking 3D parameters such as treatment optimization and dose volume histogram (DVH) analysis. Commissioning was performed of the brachytherapy module of the Nucletron Oncentra MasterPlan treatment planning system (version 3.2). Commissioning test results were compared to an independent external beam TPS (Varian Eclipse v 8.6) and the previously commissioned Nucletron Plato (v 14.3.7) brachytherapy treatment planning system, with point doses also independently verified using the brachytherapy module in RadCalc (v 6.0) independent point dose calculation software. Tests were divided into eight categories: (i) Image import accuracy, (ii) Reconstruction accuracy, (iii) Source configuration data check, (iv) Dose calculation accuracy, (v) Treatment optimization validation, (vi) DVH reproducibility, (vii) Treatment export check and (viii) Printout consistency. Point dose agreement between Oncentra, Plato and RadCalc was better than 5% with source data and dose calculation protocols following the American Association of Physicists in Medicine (AAPM) guidelines. Testing of image accuracy (import and reconstruction), along with validation of automated treatment optimization and DVH analysis generated a more comprehensive set of testing procedures than previously listed in published recommendations.

  2. Influence of daily imaging on plan quality and normal tissue toxicity for prostate cancer radiotherapy.

    Science.gov (United States)

    Bell, Katharina; Heitfeld, Marina; Licht, Norbert; Rübe, Christian; Dzierma, Yvonne

    2017-01-10

    Modern radiotherapy offers various possibilities for image guided verification of patient positioning. Different clinically relevant IGRT (image guided radiotherapy) scenarios were considered with regard to their influence on dosimetric plan quality and normal tissue complication probability (NTCP). This study is based on treatment plans of 50 prostate patients. We evaluate the clinically performed IGRT and simulate the influence of different daily IGRT scenarios on plan quality. Imaging doses of planar and cone-beam-CT (CBCT) images for three different energies (6 MV, 1 MV and 121 kV) were added to the treatment plans. The plan quality of the different scenarios was assessed by a visual inspection of the dose distribution and dose-volume-histogram (DVH) and a statistical analysis of DVH criteria. In addition, an assessment of the normal tissue complication probability was performed. Daily 1MV-CBCTs result in undesirable high dose regions in the target volume. The DVH shows that the scenarios with actual imaging performed, daily kV-CBCT and daily 6MV imaging (1x CBCT, 4x planar images per week) do not differ exceedingly from the original plan; especially imaging with daily kV-CBCT has little influence to the sparing of organs at risk. In contrast, daily 1MV- CBCT entails an additional dose of up to two fraction doses. Due to the additional dose amount some DVH constraints for plan acceptability could no longer be satisfied, especially for the daily 1MV-CBCT scenario. This scenario also shows increased NTCP for the rectum. Daily kV-CBCT has negligible influence on plan quality and is commendable for the clinical routine. If no kV-modality is available, a daily IGRT scenario with one CBCT per week and planar axial images on the other days should be preferred over daily MV-CBCT.

  3. Coarse Iris Classification Using Histogram Statistics Features%基于直方图统计特征的虹膜粗分类

    Institute of Scientific and Technical Information of China (English)

    唐荣年; 翁绍捷; 王勇

    2011-01-01

    Aimed to improving the performance of iris matching, a new method for the coarse classification of iris images using Histogram statistics features is proposed. First, the iris image is segmented into eight blocks. Then, we calculate the Histogram ratio of these image blocks and take them as the class feature of iris image type. Finally, the iris images are classified into five categories in accordance with the similarity of blocks. The proposed method has been tested and evaluated on 500 iris cases from CASIA iris database. The experiment results shows that the proposed method classifies iris types with an accuracy of 98.2%. Compared with the initial Daugman iris matching method, a modified matching method, the proposed method with Daugman method, has lower equal error rate and decreases 29.47% matching time.%为改善大规模虹膜数据库中虹膜匹配算法的性能,本文提出了一种基于灰度统计特征的虹膜类型识别算法.该算法首先将虹膜纹理区域划分为8个子块,然后利用直方图比率提取虹膜类型的直方图统计特征.最后,根据对应子块特征的相似度将虹膜图像识别为五种类型.所提算法在CASIA虹膜库中挑选的500幅虹膜图像样本上进行了测试.仿真实验结果表明,所提算法对虹膜粗分类的准确率达到了98.2%.相对原有的Daugman虹膜匹配策略而言,所提算法结合Daugman算法的虹膜匹配策略不仅可以降低虹膜匹配的等错误率,而且使得匹配所用的时间下降了29.4%.

  4. Mean nuclear volume

    DEFF Research Database (Denmark)

    Mogensen, O.; Sørensen, Flemming Brandt; Bichel, P.

    1999-01-01

    We evaluated the following nine parameters with respect to their prognostic value in females with endometrial cancer: four stereologic parameters [mean nuclear volume (MNV), nuclear volume fraction, nuclear index and mitotic index], the immunohistochemical expression of cancer antigen (CA125...

  5. A Novel Method for Predicting Late Genitourinary Toxicity After Prostate Radiation Therapy and the Need for Age-Based Risk-Adapted Dose Constraints

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Awad A. [Temple University School of Medicine, Philadelphia, Pennsylvania (United States); Egleston, Brian [Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Alcantara, Pino [Department of Radiation Oncology, Hospital Universitario Clínico San Carlos, Madrid (Spain); Li, Linna [Department of Radiation Oncology, Bryn Mawr Hospital, Bryn Mawr, Pennsylvania (United States); Pollack, Alan [Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida (United States); Horwitz, Eric M. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Buyyounouski, Mark K., E-mail: mark.buyyounouski@fccc.edu [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States)

    2013-07-15

    Background: There are no well-established normal tissue sparing dose–volume histogram (DVH) criteria that limit the risk of urinary toxicity from prostate radiation therapy (RT). The aim of this study was to determine which criteria predict late toxicity among various DVH parameters when contouring the entire solid bladder and its contents versus the bladder wall. The area under the histogram curve (AUHC) was also analyzed. Methods and Materials: From 1993 to 2000, 503 men with prostate cancer received 3-dimensional conformal RT (median follow-up time, 71 months). The whole bladder and the bladder wall were contoured in all patients. The primary endpoint was grade ≥2 genitourinary (GU) toxicity occurring ≥3 months after completion of RT. Cox regressions of time to grade ≥2 toxicity were estimated separately for the entire bladder and bladder wall. Concordance probability estimates (CPE) assessed model discriminative ability. Before training the models, an external random test group of 100 men was set aside for testing. Separate analyses were performed based on the mean age (≤ 68 vs >68 years). Results: Age, pretreatment urinary symptoms, mean dose (entire bladder and bladder wall), and AUHC (entire bladder and bladder wall) were significant (P<.05) in multivariable analysis. Overall, bladder wall CPE values were higher than solid bladder values. The AUHC for bladder wall provided the greatest discrimination for late bladder toxicity when compared with alternative DVH points, with CPE values of 0.68 for age ≤68 years and 0.81 for age >68 years. Conclusion: The AUHC method based on bladder wall volumes was superior for predicting late GU toxicity. Age >68 years was associated with late grade ≥2 GU toxicity, which suggests that risk-adapted dose constraints based on age should be explored.

  6. Multicriteria optimization informed VMAT planning

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Huixiao; Craft, David L.; Gierga, David P., E-mail: dgierga@partners.org

    2014-04-01

    We developed a patient-specific volumetric-modulated arc therapy (VMAT) optimization procedure using dose-volume histogram (DVH) information from multicriteria optimization (MCO) of intensity-modulated radiotherapy (IMRT) plans. The study included 10 patients with prostate cancer undergoing standard fractionation treatment, 10 patients with prostate cancer undergoing hypofractionation treatment, and 5 patients with head/neck cancer. MCO-IMRT plans using 20 and 7 treatment fields were generated for each patient on the RayStation treatment planning system (clinical version 2.5, RaySearch Laboratories, Stockholm, Sweden). The resulting DVH of the 20-field MCO-IMRT plan for each patient was used as the reference DVH, and the extracted point values of the resulting DVH of the MCO-IMRT plan were used as objectives and constraints for VMAT optimization. Weights of objectives or constraints of VMAT optimization or both were further tuned to generate the best match with the reference DVH of the MCO-IMRT plan. The final optimal VMAT plan quality was evaluated by comparison with MCO-IMRT plans based on homogeneity index, conformity number of planning target volume, and organ at risk sparing. The influence of gantry spacing, arc number, and delivery time on VMAT plan quality for different tumor sites was also evaluated. The resulting VMAT plan quality essentially matched the 20-field MCO-IMRT plan but with a shorter delivery time and less monitor units. VMAT plan quality of head/neck cancer cases improved using dual arcs whereas prostate cases did not. VMAT plan quality was improved by fine gantry spacing of 2 for the head/neck cancer cases and the hypofractionation-treated prostate cancer cases but not for the standard fractionation–treated prostate cancer cases. MCO-informed VMAT optimization is a useful and valuable way to generate patient-specific optimal VMAT plans, though modification of the weights of objectives or constraints extracted from resulting DVH of MCO

  7. Multicriteria optimization informed VMAT planning.

    Science.gov (United States)

    Chen, Huixiao; Craft, David L; Gierga, David P

    2014-01-01

    We developed a patient-specific volumetric-modulated arc therapy (VMAT) optimization procedure using dose-volume histogram (DVH) information from multicriteria optimization (MCO) of intensity-modulated radiotherapy (IMRT) plans. The study included 10 patients with prostate cancer undergoing standard fractionation treatment, 10 patients with prostate cancer undergoing hypofractionation treatment, and 5 patients with head/neck cancer. MCO-IMRT plans using 20 and 7 treatment fields were generated for each patient on the RayStation treatment planning system (clinical version 2.5, RaySearch Laboratories, Stockholm, Sweden). The resulting DVH of the 20-field MCO-IMRT plan for each patient was used as the reference DVH, and the extracted point values of the resulting DVH of the MCO-IMRT plan were used as objectives and constraints for VMAT optimization. Weights of objectives or constraints of VMAT optimization or both were further tuned to generate the best match with the reference DVH of the MCO-IMRT plan. The final optimal VMAT plan quality was evaluated by comparison with MCO-IMRT plans based on homogeneity index, conformity number of planning target volume, and organ at risk sparing. The influence of gantry spacing, arc number, and delivery time on VMAT plan quality for different tumor sites was also evaluated. The resulting VMAT plan quality essentially matched the 20-field MCO-IMRT plan but with a shorter delivery time and less monitor units. VMAT plan quality of head/neck cancer cases improved using dual arcs whereas prostate cases did not. VMAT plan quality was improved by fine gantry spacing of 2 for the head/neck cancer cases and the hypofractionation-treated prostate cancer cases but not for the standard fractionation-treated prostate cancer cases. MCO-informed VMAT optimization is a useful and valuable way to generate patient-specific optimal VMAT plans, though modification of the weights of objectives or constraints extracted from resulting DVH of MCO-IMRT or

  8. Enhanced Gender Recognition System Using an Improved Histogram of Oriented Gradient (HOG) Feature from Quality Assessment of Visible Light and Thermal Images of the Human Body.

    Science.gov (United States)

    Nguyen, Dat Tien; Park, Kang Ryoung

    2016-07-21

    With higher demand from users, surveillance systems are currently being designed to provide more information about the observed scene, such as the appearance of objects, types of objects, and other information extracted from detected objects. Although the recognition of gender of an observed human can be easily performed using human perception, it remains a difficult task when using computer vision system images. In this paper, we propose a new human gender recognition method that can be applied to surveillance systems based on quality assessment of human areas in visible light and thermal camera images. Our research is novel in the following two ways: First, we utilize the combination of visible light and thermal images of the human body for a recognition task based on quality assessment. We propose a quality measurement method to assess the quality of image regions so as to remove the effects of background regions in the recognition system. Second, by combining the features extracted using the histogram of oriented gradient (HOG) method and the measured qualities of image regions, we form a new image features, called the weighted HOG (wHOG), which is used for efficient gender recognition. Experimental results show that our method produces more accurate estimation results than the state-of-the-art recognition method that uses human body images.

  9. Real -Time Histogram Statistics Design Based on FPGA%基于FPGA的实时直方图统计设计

    Institute of Scientific and Technical Information of China (English)

    张科; 徐书文; 葛珊

    2012-01-01

    A real - time histogram statistics design based on FPCA is introduced in this paper. Mealy state machine is used in this design which features with hierarchy and modularization. All software modules are programmed in VHDL Simulation is worked out with Modelsim and the integrated development environment is Quaitus II 9.0. Through the software simulation and hardware test,the results show that the design is correct and feasible.%介绍了一种采用基于FPGA状态机的设计方法,实现了对数字图像直方图实时统计功能.设计采用层次化、模块化的设计思想.所有模块用VHDL语言设计,由Modelsim仿真和集成开发环境QuartusⅡ9.0综合.通过软件仿真和实际硬件电路验证,该设计正确可行,具有较好的应用价值.

  10. 一种基于方向直方图的嵌入式手势识别系统%Embedded Gesture Recognition System Based on Orientation Histogram

    Institute of Scientific and Technical Information of China (English)

    王守磊; 朱民耀; 陆小锋; 张东升; 殷梦娇

    2012-01-01

    将手势识别算法在DSP嵌入式系统上实现,并将算法进行改进使其能适合嵌入式系统的特点,采用改进的边缘像素直方图的方法实现手势识别,最终用Bhattacharyya距离匹配模版,识别手势含义.该方法在嵌入式系统上实现,有实际应用的价值,并对前景的平移和尺寸变化不敏感.算法简单快速,稳健性好,有应用前景.%In this paper, gesture recognition is implemented on embedded system, and the algorithm to fit the embedded system is improved. Orientation histogram of edge pixels is used to feature extraction and Bhattacharyya distance is used for matching. This method has practical application value, and it has robustness to gesture translation. This method is fast and simple, and it has application prospects.

  11. WE-G-BRD-09: Prediction of Local Control/Failure by Using Feature Histogram Selection in Follow-Up T2-Weighted MR Image in Spinal Tumors After Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, J; Harb, J; Jawad, M; Yee, S; Schulze, D; Liang, J; Grills D, Yan [William Beaumont Hospital, Royal Oak, MI (United States)

    2014-06-15

    Purpose: In follow-up T2-weighted MR images of spinal tumor patients treated with stereotactic body radiation therapy (SBRT), high intensity features embedded in dark surroundings may suggest a local failure (LF). We investigated image intensity histogram in imaging features to predict LF and local control (LC). Methods: Sixty-seven spinal tumors were treated with SBRT at our institution with scheduled follow-up MR T2-weighted (TR 3200–6600ms; TE 75-132ms) imaging. The LF group included 10 tumors with 8.7 months median follow-up, while the LC group had 11 tumors with 24.1 months median follow-up. The follow-up images were fused to the planning CT. Image intensity histograms of the GTV were calculated. Voxels in greater than 90% (V90), 80% (V80), and peak (Vpeak) of the histogram were grouped into sub-ROIs to determine the best feature histogram. The intensity of each sub-ROI was evaluated using the mean T2-weighted signal ratio (intensity in sub-ROI / intensity in normal vertebrae). An ROC curve in predicting LF for each sub-ROI was calculated to determine the best feature histogram parameter for LF prediction. Results: Mean T2-weighted signal ratio in the LF group was significantly higher than that in the LC group for all sub-ROIs (1.1±0.4 vs. 0.7±0.2, 1.2±0.4 vs. 0.8±0.2, 1.4±0.5 vs. 0.8±0.2, for V90, V80, and Vpeak, p=0.02, 0.02, and 0.002, respectively). The corresponding areas-under-curve (AUC) of ROC were 0.78, 0.80, and 0.87, p=0.02, 0.03, 0.004, respectively. No correlation was found between T2-weighted signal ratio in Vpeak and follow-up time (Pearson's ρ=0.15). Conclusion: Increased T2-weighted signal can be used to identify local failure while decreased signal indicates local control after spinal SBRT. By choosing the best histogram parameter (here the Vpeak), the AUC of the ROC can be substantially improved, which implies reliable prediction of LC and LF. These results are being further studied and validated with large multi

  12. Histograms showing variations in oil yield, water yield, and specific gravity of oil from Fischer assay analyses of oil-shale drill cores and cuttings from the Piceance Basin, northwestern Colorado

    Science.gov (United States)

    Dietrich, John D.; Brownfield, Michael E.; Johnson, Ronald C.; Mercier, Tracey J.

    2014-01-01

    Recent studies indicate that the Piceance Basin in northwestern Colorado contains over 1.5 trillion barrels of oil in place, making the basin the largest known oil-shale deposit in the world. Previously published histograms display oil-yield variations with depth and widely correlate rich and lean oil-shale beds and zones throughout the basin. Histograms in this report display oil-yield data plotted alongside either water-yield or oil specific-gravity data. Fischer assay analyses of core and cutting samples collected from exploration drill holes penetrating the Eocene Green River Formation in the Piceance Basin can aid in determining the origins of those deposits, as well as estimating the amount of organic matter, halite, nahcolite, and water-bearing minerals. This report focuses only on the oil yield plotted against water yield and oil specific gravity.

  13. Volume Regulated Channels

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjær

    - serves a multitude of functions in the mammalian cell, regulating the membrane potential (Em), cell volume, protein activity and the driving force for facilitated transporters giving Cl- and Cl- channels a major potential of regulating cellular function. These functions include control of the cell cycle...... of volume perturbations evolution have developed system of channels and transporters to tightly control volume homeostasis. In the past decades evidence has been mounting, that the importance of these volume regulated channels and transporters are not restricted to the defense of cellular volume......, controlled cell death and cellular migration. Volume regulatory mechanisms has long been in focus for regulating cellular proliferation and my thesis work have been focusing on the role of Cl- channels in proliferation with specific emphasis on ICl, swell. Pharmacological blockage of the ubiquitously...

  14. Factors Associated With Chest Wall Toxicity After Accelerated Partial Breast Irradiation Using High-Dose-Rate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Sheree, E-mail: shereedst32@hotmail.com [Department of Radiation Oncology, WellStar Kennestone Hospital, Marietta, Georgia (United States); Vicini, Frank [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan (United States); Vanapalli, Jyotsna R.; Whitaker, Thomas J.; Pope, D. Keith [Department of Radiation Oncology, WellStar Kennestone Hospital, Marietta, Georgia (United States); Lyden, Maureen [BioStat International, Inc., Tampa, Florida (United States); Bruggeman, Lisa; Haile, Kenneth L.; McLaughlin, Mark P. [Department of Radiation Oncology, WellStar Kennestone Hospital, Marietta, Georgia (United States)

    2012-07-01

    Purpose: The purpose of this analysis was to evaluate dose-volume relationships associated with a higher probability for developing chest wall toxicity (pain) after accelerated partial breast irradiation (APBI) by using both single-lumen and multilumen brachytherapy. Methods and Materials: Rib dose data were available for 89 patients treated with APBI and were correlated with the development of chest wall/rib pain at any point after treatment. Ribs were contoured on computed tomography planning scans, and rib dose-volume histograms (DVH) along with histograms for other structures were constructed. Rib DVH data for all patients were sampled at all volumes {>=}0.008 cubic centimeter (cc) (for maximum dose related to pain) and at volumes of 0.5, 1, 2, and 3 cc for analysis. Rib pain was evaluated at each follow-up visit. Patient responses were marked as yes or no. No attempt was made to grade responses. Eighty-nine responses were available for this analysis. Results: Nineteen patients (21.3%) complained of transient chest wall/rib pain at any point in follow-up. Analysis showed a direct correlation between total dose received and volume of rib irradiated with the probability of developing rib/chest wall pain at any point after follow-up. The median maximum dose at volumes {>=}0.008 cc of rib in patients who experienced chest wall pain was 132% of the prescribed dose versus 95% of the prescribed dose in those patients who did not experience pain (p = 0.0035). Conclusions: Although the incidence of chest wall/rib pain is quite low with APBI brachytherapy, attempts should be made to keep the volume of rib irradiated at a minimum and the maximum dose received by the chest wall as low as reasonably achievable.

  15. 基于到达时间差直方图的信号分选算法研究%A Signal Sorting Algorithm Based on Time Difference of Arrival.Histogram

    Institute of Scientific and Technical Information of China (English)

    杨翔; 顾洪宇

    2015-01-01

    The Time Difference Of Arrival (TDOA) histogram is effective for pulse train de-interleaving in radar detection. The performance of TDOA-histogram based pulse sorting algorithm depends on several parameters in the histogram, such as the Pulse Repetition Interval (PRI) detection threshold and the box length, which are set posteriorly in traditional TDOA-histogram based algorithm. In this paper, the explicit expressions of detection threshold for various PRI modes (i.e. stable, jitter, and stagger) are derived, and the relationship among these parameters are revealed. Consequently, a signal sorting algorithm is proposed, and its performance is validated by simulation in complex signal environment.%到达时间差(TDOA)直方图分析是电子支援侦察雷达信号主分选的基础;相关信号分选算法的性能与TDOA直方图脉冲重复间隔(PRI)检测门限的设定密切相关。为揭示PRI检测门限与TDOA直方图参数之间的关系,解决传统PRI检测门限依靠经验设定、无法灵活调整的问题,该文从分析TDOA直方图与脉冲序列的统计性质入手,推导了直方图稳定PRI、抖动PRI和参差PRI检测门限的解析表达式,提出了基于TDOA直方图PRI检测的信号分选算法,并通过仿真验证了算法的有效性。

  16. Particle Filter Object Tracking Based on Histograms of Oriented Grads and Colors%融合颜色和梯度方向直方图的粒子滤波跟踪算法

    Institute of Scientific and Technical Information of China (English)

    毛晓波; 朱东伟; 陈铁军

    2012-01-01

    针对基于单一颜色特征的粒子滤波跟踪算法在复杂环境下会导致跟踪失败的问题,提出了一种融合颜色直方图和梯度方向直方图,形成一种新的综合直方图特征的粒子滤波跟踪算法.颜色直方图是对目标在彩色图像中的全局描述,而梯度方向直方图包含了一定的结构信息,两者可以互为补充.实验结果表明,采用综合直方图特征能够在背景颜色干扰导致目标颜色特征鉴别能力丧失的情况下,仍能稳定可靠地跟踪目标,提高了跟踪精度,具有较强的鲁棒性.%Object tracking based on color feature often fails in a complex background. To deal with this problem , a particle filter object tracking approach is proposed in this paper based on the new histograms by the fusion of histograms of oriented grads and color. Color histogram is the global description of targets in color image , while histogram of oriented gradients contains some construction information. So they can complement each other. Experimental results show that the proposed method is able to track the object stably, when one of the features loses discrimination ability for tracking. It is simple and suitable to be applied to deal with tracking problems in complex scene.

  17. A MULTILEVEL REVERSIBLE WATERMARKING SCHEME BASED ON DIFFERENCE HISTOGRAM SHIFTING%一种基于差值直方图平移的多层可逆水印算法

    Institute of Scientific and Technical Information of China (English)

    刘芳; 汪玉凯

    2014-01-01

    A multilevel reversible watermarking scheme based on difference histogram shifting is proposed.First the image is divided into blocks,in each block there are two difference values generated,then the histogram of all difference values is built,which makes the genera-ted histogram steep and has higher chance to find the peak points.Finally with the idea of matrix encoding,the pixel value in each image block is modified no more than one,we reach the goal of embedding the watermark and shifting the histogram simultaneously.Experiments show that this algorithm can realise reversible watermark,furthermore,the invisibility of watermark is much better.The PSNR is greater than 52.90 db in the image with watermark embedded,the embedding capacity is higher,and the complexity of algorithm computation is lower as well.%提出一种基于差值直方图平移的多层可逆水印算法。首先划分图像块,每个图像块内产生两个差值;然后建立所有差值的直方图,使得产生的直方图陡峭,峰值点出现频率较大;最后利用矩阵编码的思想在每个图像块内至多修改一个像素的值,达到同时嵌入水印和平移直方图的目的。实验表明,该算法不仅可以实现可逆水印,而且水印不可见性较好,嵌入水印后图像的PSNR高于52.90 db,嵌入容量较高,算法复杂度较低。

  18. A comparison of inverse optimization algorithms for HDR/PDR prostate brachytherapy treatment planning.

    Science.gov (United States)

    Dinkla, Anna M; van der Laarse, Rob; Kaljouw, Emmie; Pieters, Bradley R; Koedooder, Kees; van Wieringen, Niek; Bel, Arjan

    2015-01-01

    Graphical optimization (GrO) is a common method for high-dose-rate/pulsed-dose-rate (PDR) prostate brachytherapy treatment planning. New methods performing inverse optimization of the dose distribution have been developed over the past years. The purpose is to compare GrO and two established inverse methods, inverse planning simulated annealing (IPSA) and hybrid inverse treatment planning and optimization (HIPO), and one new method, enhanced geometric optimization-interactive inverse planning (EGO-IIP), in terms of speed and dose-volume histogram (DVH) parameters. For 26 prostate cancer patients treated with a PDR brachytherapy boost, an experienced treatment planner optimized the dose distributions using four different methods: GrO, IPSA, HIPO, and EGO-IIP. Relevant DVH parameters (prostate-V100%, D90%, V150%; urethra-D(0.1cm3) and D(1.0cm3); rectum-D(0.1cm3) and D(2.0cm3); bladder-D(2.0cm3)) were evaluated and their compliance to the constraints. Treatment planning time was also recorded. All inverse methods resulted in shorter planning time (mean, 4-6.7 min), as compared with GrO (mean, 7.6 min). In terms of DVH parameters, none of the inverse methods outperformed the others. However, all inverse methods improved on compliance to the planning constraints as compared with GrO. On average, EGO-IIP and GrO resulted in highest D90%, and the IPSA plans resulted in lowest bladder D2.0cm3 and urethra D(1.0cm3). Inverse planning methods decrease planning time as compared with GrO for PDR/high-dose-rate prostate brachytherapy. DVH parameters are comparable for all methods. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  19. Precision volume measurement system.

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Erin E.; Shugard, Andrew D.

    2004-11-01

    A new precision volume measurement system based on a Kansas City Plant (KCP) design was built to support the volume measurement needs of the Gas Transfer Systems (GTS) department at Sandia National Labs (SNL) in California. An engineering study was undertaken to verify or refute KCP's claims of 0.5% accuracy. The study assesses the accuracy and precision of the system. The system uses the ideal gas law and precise pressure measurements (of low-pressure helium) in a temperature and computer controlled environment to ratio a known volume to an unknown volume.

  20. 基于方向直方图的Mean shift目标跟踪新算法%New Mean shift tracking algorithm based on orientation histogram

    Institute of Scientific and Technical Information of China (English)

    秦臻; 曹剑中

    2011-01-01

    Mean shift算法是一种非参数密度估计算法,可以实现快速的最优匹配.为了有效地将Mean shift算法应用到灰度图像中,使用空间分布和纹理信息作为匹配信息,提出了一种基于空间方向直方图的Mean shift跟踪新算法.利用卡尔曼滤波器来获得每帧目标的起始位置,再利用Mean shift算法得到跟踪位置.实验结果证明,该算法在目标运动较快,目标尺度变化的情况下仍能稳定、实时、高效地跟踪目标.%The Mean shift algorithm is a nonparametric density estimation method. The fast and optimal mode matching can be achieved by this method. In order to apply Mean shift algorithm on gray-level image effectively, a new tracking algorithm of Mean shift based on orientation histogram is proposed. It uses space spread and vein as matching information. The starting position of target is found with Kalman filter in every frame, and then Mean shift is utilized to track the target position. In the situation of target moving fast and changing of size, experiment results show that the object can be tracked steadily, effectively and real-time by using the proposed algorithm.

  1. A Robust Front-End Processor combining Mel Frequency Cepstral Coefficient and Sub-band Spectral Centroid Histogram methods for Automatic Speech Recognition

    Directory of Open Access Journals (Sweden)

    R. Thangarajan

    2009-06-01

    Full Text Available Environmental robustness is an important area of research in speech recognition. Mismatch between trained speech models and actual speech to be recognized is due to factors like background noise. It can cause severe degradation in the accuracy of recognizers whichare based on commonly used features like mel-frequency cepstral co-efficient (MFCC and linear predictive coding (LPC. It is well understood that all previous auditory based feature extraction methods perform extremely well in terms of robustness due to the dominantfrequency information present in them. But these methods suffer from high computational cost. Another method called sub-band spectral centroid histograms (SSCH integrates dominant-frequency information with sub-band power information. This method is based onsub-band spectral centroids (SSC which are closely related to spectral peaks for both clean and noisy speech. Since SSC can be computed efficiently from short-term speech power spectrum estimate, SSCH method is quite robust to background additive noise at a lowercomputational cost. It has been noted that MFCC method outperforms SSCH method in the case of clean speech. However in the case of speech with additive noise, MFCC method degrades substantially. In this paper, both MFCC and SSCH feature extraction have beenimplemented in Carnegie Melon University (CMU Sphinx 4.0 and trained and tested on AN4 database for clean and noisy speech. Finally, a robust speech recognizer which automatically employs either MFCC or SSCH feature extraction methods based on the variance of shortterm power of the input utterance is suggested.

  2. Bone mass density estimation: Archimede’s principle versus automatic X-ray histogram and edge detection technique in ovariectomized rats treated with germinated brown rice bioactives

    Science.gov (United States)

    Muhammad, Sani Ismaila; Maznah, Ismail; Mahmud, Rozi Binti; Esmaile, Maher Faik; Zuki, Abu Bakar Zakaria

    2013-01-01

    Background Bone mass density is an important parameter used in the estimation of the severity and depth of lesions in osteoporosis. Estimation of bone density using existing methods in experimental models has its advantages as well as drawbacks. Materials and methods In this study, the X-ray histogram edge detection technique was used to estimate the bone mass density in ovariectomized rats treated orally with germinated brown rice (GBR) bioactives, and the results were compared with estimated results obtained using Archimede’s principle. New bone cell proliferation was assessed by histology and immunohistochemical reaction using polyclonal nuclear antigen. Additionally, serum alkaline phosphatase activity, serum and bone calcium and zinc concentrations were detected using a chemistry analyzer and atomic absorption spectroscopy. Rats were divided into groups of six as follows: sham (nonovariectomized, nontreated); ovariectomized, nontreated; and ovariectomized and treated with estrogen, or Remifemin®, GBR-phenolics, acylated steryl glucosides, gamma oryzanol, and gamma amino-butyric acid extracted from GBR at different doses. Results Our results indicate a significant increase in alkaline phosphatase activity, serum and bone calcium, and zinc and ash content in the treated groups compared with the ovariectomized nontreated group (P Archimede’s principle and the edge detection technique between the treated groups (r2 = 0.737, P = 0.004). Conclusion Our study shows that GBR bioactives increase bone density, which might be via the activation of zinc formation and increased calcium content, and that X-ray edge detection technique is effective in the measurement of bone density and can be employed effectively in this respect. PMID:24187491

  3. 直方图均衡化技术在矢量等值填充图中的算法及实现%Algorithm and implementation of histogram equalization technology in the vector contour filling map

    Institute of Scientific and Technical Information of China (English)

    胥值礼; 崔志强

    2015-01-01

    Based on the study of histogram equalization algorithm for grid image,the histogram equalization algorithm for vector graphics is designed and the interface software of automatic histogram equalization on the MAPGIS platform is achieved. According to the different vector data and contour number,it can cut apart equivalence region and calculate level value automat-ically,and then can import the level values into MAPGIS DTM analysis module to complete graphics rendering.The quality and efficiency of mapping can be greatly improved.Practice has proved that it has good application effect.%在研究栅格图像直方图均衡化算法的基础上,提出了矢量图形直方图均衡化算法,并在MAPGIS 平台上实现了等值填充图的自动均衡化软件功能,能够根据不同的成图数据和等值层数,自动完成等值区分割和层值计算,并将层值自动导入到 MAPGIS DTM 分析模块中完成图形绘制,大大提高了成图质量和效率。实践证明,矢量图形直方图均衡化算法具有良好的应用效果。

  4. Influence of source batch Sk dispersion on dosimetry for prostate cancer treatment with permanent implants

    DEFF Research Database (Denmark)

    Nunez-Cumplido, Eduardo; Perez-Calatayud, J; Casares-Magaz, O;

    2015-01-01

    PURPOSE: In clinical practice, specific air kerma strength (SK) value is used in treatment planning system (TPS) permanent brachytherapy implant calculations with (125)I and (103)Pd sources; in fact, commercial TPS provide only one SK input value for all implanted sources and the certified shipment...... is to examine the impact of SK dispersion on typical implant parameters that are used to evaluate the dose volume histogram (DVH) for both planning target volume (PTV) and organs at risk (OARs). METHODS: The authors have developed a new algorithm to compute dose distributions with different SK values for each...... source. Three different prostate volumes (20, 30, and 40 cm(3)) were considered and two typical commercial sources of different radionuclides were used. Using a conventional TPS, clinically accepted calculations were made for (125)I sources; for the palladium, typical implants were simulated. To assess...

  5. Stereotactic Irradiation of Lung Cancer

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To investigate the best stereotactic irradiation (STI) technique in treatment of small lung tumors, using dose-volume statistics. Methods: Dose-volume histogram (DVH) of the study phantom consisting of CT using the software of FOCUS-3D planning system. The beam was a 6MV X-ray from a Varian 2300C. The analysis data of Dose-volume statistics was from the technique used for: (1) 2- 12 arcs; (2) 20° - 45° separation angle of arcs; (3) 80° - 160° of gantry rotation. Then we studied the difference of DVH with various irradiation techniques and the influence of target positions and field size by calculated to the distribution of dose from 20%- 90% of the six targets in the lung with 3×3 cm2, 4′ 4 cm2 and 5′ 5 cm2 field size. Results: The volume irradiated pulmonary tissue was the smallest using a six non-coplanar 120° arcs with 30° separation between arcs in the hypothetical set up, the non-coplanar SRI was superiority than conventional one's. The six targets were chosen in the right lung, the volume was the largest in geometric center and was decreased in hilus, bottom, anterior chest wall, lateral wall and apex of the lung in such an order. The DVH had significant change with an increasing field size. Conclusion: the irradiation damage of normal pulmonary tissue was the lowest using the six non-coplanar 120° arcs with a 30° separation between arcs by <5×5 cm2 field and the position of target was not a restricting factor.

  6. Comparing the dosimetric impact of interfractional anatomical changes in photon, proton and carbon ion radiotherapy for pancreatic cancer patients

    Science.gov (United States)

    Houweling, Antonetta C.; Crama, Koen; Visser, Jorrit; Fukata, Kyohei; Rasch, Coen R. N.; Ohno, Tatsuya; Bel, Arjan; van der Horst, Astrid

    2017-04-01

    Radiotherapy using charged particles is characterized by a low dose to the surrounding healthy organs, while delivering a high dose to the tumor. However, interfractional anatomical changes can greatly affect the robustness of particle therapy. Therefore, we compared the dosimetric impact of interfractional anatomical changes (i.e. body contour differences and gastrointestinal gas volume changes) in photon, proton and carbon ion therapy for pancreatic cancer patients. In this retrospective planning study, photon, proton and carbon ion treatment plans were created for 9 patients. Fraction dose calculations were performed using daily cone-beam CT (CBCT) images. To this end, the planning CT was deformably registered to each CBCT; gastrointestinal gas volumes were delineated on the CBCTs and copied to the deformed CT. Fraction doses were accumulated rigidly. To compare planned and accumulated dose, dose-volume histogram (DVH) parameters of the planned and accumulated dose of the different radiotherapy modalities were determined for the internal gross tumor volume, internal clinical target volume (iCTV) and organs-at-risk (OARs; duodenum, stomach, kidneys, liver and spinal cord). Photon plans were highly robust against interfractional anatomical changes. The difference between the planned and accumulated DVH parameters for the photon plans was less than 0.5% for the target and OARs. In both proton and carbon ion therapy, however, coverage of the iCTV was considerably reduced for the accumulated dose compared with the planned dose. The near-minimum dose ({{D}98 % } ) of the iCTV reduced with 8% for proton therapy and with 10% for carbon ion therapy. The DVH parameters of the OARs differed less than 3% for both particle modalities. Fractionated radiotherapy using photons is highly robust against interfractional anatomical changes. In proton and carbon ion therapy, such changes can severely reduce the dose coverage of the target.

  7. Dose-escalated simultaneous integrated-boost treatment of prostate cancer patients via helical tomotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Geier, M.; Astner, S.T.; Duma, M.N.; Putzhammer, J.; Winkler, C.; Molls, M.; Geinitz, H. [Technische Univ. Muenchen (Germany). Klinik und Poliklinik fuer Strahlentherapie und Radiologische Onkologie; Jacob, V. [Universitaetsklinikum Freiburg (Germany). Klinik fuer Strahlenheilkunde; Nieder, C. [Nordland Hospital, Bodoe (Norway). Dept. of Oncology and Palliative Care; Tromsoe Univ. (Norway). Inst. of Clinical Medicine

    2012-05-15

    The goal of this work was to assess the feasibility of moderately hypofractionated simultaneous integrated-boost intensity-modulated radiotherapy (SIB-IMRT) with helical tomotherapy in patients with localized prostate cancer regarding acute side effects and dose-volume histogram data (DVH data). Acute side effects and DVH data were evaluated of the first 40 intermediate risk prostate cancer patients treated with a definitive daily image-guided SIB-IMRT protocol via helical tomotherapy in our department. The planning target volume including the prostate and the base of the seminal vesicles with safety margins was treated with 70 Gy in 35 fractions. The boost volume containing the prostate and 3 mm safety margins (5 mm craniocaudal) was treated as SIB to a total dose of 76 Gy (2.17 Gy per fraction). Planning constraints for the anterior rectal wall were set in order not to exceed the dose of 76 Gy prescribed to the boost volume. Acute toxicity was evaluated prospectively using a modified CTCAE (Common Terminology Criteria for Adverse Events) score. SIB-IMRT allowed good rectal sparing, although the full boost dose was permitted to the anterior rectal wall. Median rectum dose was 38 Gy in all patients and the median volumes receiving at least 65 Gy (V65), 70 Gy (V70), and 75 Gy (V75) were 13.5%, 9%, and 3%, respectively. No grade 4 toxicity was observed. Acute grade 3 toxicity was observed in 20% of patients involving nocturia only. Grade 2 acute intestinal and urological side effects occurred in 25% and 57.5%, respectively. No correlation was found between acute toxicity and the DVH data. This institutional SIB-IMRT protocol using daily image guidance as a precondition for smaller safety margins allows dose escalation to the prostate without increasing acute toxicity. (orig.)

  8. Variable volume combustor

    Energy Technology Data Exchange (ETDEWEB)

    Ostebee, Heath Michael; Ziminsky, Willy Steve; Johnson, Thomas Edward; Keener, Christopher Paul

    2017-01-17

    The present application provides a variable volume combustor for use with a gas turbine engine. The variable volume combustor may include a liner, a number of micro-mixer fuel nozzles positioned within the liner, and a linear actuator so as to maneuver the micro-mixer fuel nozzles axially along the liner.

  9. Volume Regulated Channels

    DEFF Research Database (Denmark)

    Klausen, Thomas Kjær

    of volume perturbations evolution have developed system of channels and transporters to tightly control volume homeostasis. In the past decades evidence has been mounting, that the importance of these volume regulated channels and transporters are not restricted to the defense of cellular volume...... but are also essential for a number of physiological processes such as proliferation, controlled cell death, migration and endocrinology. The thesis have been focusing on two Channels, namely the swelling activated Cl- channel (ICl, swell) and the transient receptor potential Vanilloid (TRPV4) channel. I: Cl......- serves a multitude of functions in the mammalian cell, regulating the membrane potential (Em), cell volume, protein activity and the driving force for facilitated transporters giving Cl- and Cl- channels a major potential of regulating cellular function. These functions include control of the cell cycle...

  10. Rectal dose-volume constraints in high-dose radiotherapy of localized prostate cancer.

    Science.gov (United States)