WorldWideScience
 
 
1

Dynamic reconstruction and rendering of 3D tomosynthesis images  

Science.gov (United States)

Dynamic Reconstruction and Rendering (DRR) is a fast and flexible tomosynthesis image reconstruction and display implementation. By leveraging the computational efficiency gains afforded by off-the-shelf GPU hardware, tomosynthesis reconstruction can be performed on demand at real-time, user-interactive frame rates. Dynamic multiplanar reconstructions allow the user to adjust reconstruction and display parameters interactively, including axial sampling, slice location, plane tilt, magnification, and filter selection. Reconstruction on-demand allows tomosynthesis images to be viewed as true three-dimensional data rather than just a stack of two-dimensional images. The speed and dynamic rendering capabilities of DRR can improve diagnostic accuracy and lead to more efficient clinical workflows.

Kuo, Johnny; Ringer, Peter A.; Fallows, Steven G.; Bakic, Predrag R.; Maidment, Andrew D. A.; Ng, Susan

2011-03-01

2

Inter-plane artifact suppression in tomosynthesis using 3D CT image data  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Despite its superb lateral resolution, flat-panel-detector (FPD) based tomosynthesis suffers from low contrast and inter-plane artifacts caused by incomplete cancellation of the projection components stemming from outside the focal plane. The incomplete cancellation of the projection components, mostly due to the limited scan angle in the conventional tomosynthesis scan geometry, often makes the image contrast too low to differentiate the malignant tissues from the background tissues with confidence. Methods In this paper, we propose a new method to suppress the inter-plane artifacts in FPD-based tomosynthesis. If 3D whole volume CT images are available before the tomosynthesis scan, the CT image data can be incorporated into the tomosynthesis image reconstruction to suppress the inter-plane artifacts, hence, improving the image contrast. In the proposed technique, the projection components stemming from outside the region-of-interest (ROI) are subtracted from the measured tomosynthesis projection data to suppress the inter-plane artifacts. The projection components stemming from outside the ROI are calculated from the 3D whole volume CT images which usually have lower lateral resolution than the tomosynthesis images. The tomosynthesis images are reconstructed from the subtracted projection data which account for the x-ray attenuation through the ROI. After verifying the proposed method by simulation, we have performed both CT scan and tomosynthesis scan on a phantom and a sacrificed rat using a FPD-based micro-CT. Results We have measured contrast-to-noise ratio (CNR) from the tomosynthesis images which is an indicator of the residual inter-plane artifacts on the focal-plane image. In both cases of the simulation and experimental imaging studies of the contrast evaluating phantom, CNRs have been significantly improved by the proposed method. In the rat imaging also, we have observed better visual contrast from the tomosynthesis images reconstructed by the proposed method. Conclusions The proposed tomosynthesis technique can improve image contrast with aids of 3D whole volume CT images. Even though local tomosynthesis needs extra 3D CT scanning, it may find clinical applications in special situations in which extra 3D CT scan is already available or allowed.

Kim Jae G; Jin Seung O; Cho Min H; Lee Soo Y

2011-01-01

3

Fast reconstruction of digital tomosynthesis using on-board images  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Digital tomosynthesis (DTS) is a method to reconstruct pseudo three-dimensional (3D) volume images from two-dimensional x-ray projections acquired over limited scan angles. Compared with cone-beam computed tomography, which is frequently used for 3D image guided radiation therapy, DTS requires less ...

Yan, Hui; Godfrey, Devon J.; Yin, Fang-Fang

4

Introductory pictorial atlas of 3D tomosynthesis.  

UK PubMed Central (United Kingdom)

Mammography is an essential tool for early detection of breast cancer. Breast imaging based on three-dimensional digital breast tomosynthesis (DBT) is a new method for breast cancer screening and diagnosis that uses three-dimensional digital images to allow separation of overlapping breast structures, which may allow for improved visualization of potentially significant findings. This article will highlight the utility of DBT as a tool for the detection of breast pathology; it will demonstrate normal findings as well as breast pathology on DBT and two-dimensional conventional mammography. DBT is a very promising modality, which may decrease the false-positive rate of mammography and find additional abnormalities not seen on two-dimensional mammography.

Cohen SL; Margolies LR; Szabo JR; Patel NS; Hermann G

2013-10-01

5

The simulation of 3D microcalcification clusters in 2D digital mammography and breast tomosynthesis  

International Nuclear Information System (INIS)

Purpose: This work proposes a new method of building 3D models of microcalcification clusters and describes the validation of their realistic appearance when simulated into 2D digital mammograms and into breast tomosynthesis images. Methods: A micro-CT unit was used to scan 23 breast biopsy specimens of microcalcification clusters with malignant and benign characteristics and their 3D reconstructed datasets were segmented to obtain 3D models of microcalcification clusters. These models were then adjusted for the x-ray spectrum used and for the system resolution and simulated into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. Six radiologists were asked to distinguish between 40 real and 40 simulated clusters of microcalcifications in two separate studies on 2D mammography and tomosynthesis datasets. Receiver operating characteristic (ROC) analysis was used to test the ability of each observer to distinguish between simulated and real microcalcification clusters. The kappa statistic was applied to assess how often the individual simulated and real microcalcification clusters had received similar scores (''agreement'') on their realistic appearance in both modalities. This analysis was performed for all readers and for the real and the simulated group of microcalcification clusters separately. ''Poor'' agreement would reflect radiologists' confusion between simulated and real clusters, i.e., lesions not systematically evaluated in both modalities as either simulated or real, and would therefore be interpreted as a success of the present models. Results: The area under the ROC curve, averaged over the observers, was 0.55 (95% confidence interval [0.44, 0.66]) for the 2D study, and 0.46 (95% confidence interval [0.29, 0.64]) for the tomosynthesis study, indicating no statistically significant difference between real and simulated lesions (p > 0.05). Agreement between allocated lesion scores for 2D mammography and those for the tomosynthesis series was poor. Conclusions: The realistic appearance of the 3D models of microcalcification clusters, whether malignant or benign clusters, was confirmed for 2D digital mammography images and the breast tomosynthesis datasets; this database of clusters is suitable for use in future observer performance studies related to the detectability of microcalcification clusters. Such studies include comparing 2D digital mammography to breast tomosynthesis and comparing different reconstruction algorithms.

2011-01-01

6

The simulation of 3D microcalcification clusters in 2D digital mammography and breast tomosynthesis  

Energy Technology Data Exchange (ETDEWEB)

Purpose: This work proposes a new method of building 3D models of microcalcification clusters and describes the validation of their realistic appearance when simulated into 2D digital mammograms and into breast tomosynthesis images. Methods: A micro-CT unit was used to scan 23 breast biopsy specimens of microcalcification clusters with malignant and benign characteristics and their 3D reconstructed datasets were segmented to obtain 3D models of microcalcification clusters. These models were then adjusted for the x-ray spectrum used and for the system resolution and simulated into 2D projection images to obtain mammograms after image processing and into tomographic sequences of projection images, which were then reconstructed to form 3D tomosynthesis datasets. Six radiologists were asked to distinguish between 40 real and 40 simulated clusters of microcalcifications in two separate studies on 2D mammography and tomosynthesis datasets. Receiver operating characteristic (ROC) analysis was used to test the ability of each observer to distinguish between simulated and real microcalcification clusters. The kappa statistic was applied to assess how often the individual simulated and real microcalcification clusters had received similar scores (''agreement'') on their realistic appearance in both modalities. This analysis was performed for all readers and for the real and the simulated group of microcalcification clusters separately. ''Poor'' agreement would reflect radiologists' confusion between simulated and real clusters, i.e., lesions not systematically evaluated in both modalities as either simulated or real, and would therefore be interpreted as a success of the present models. Results: The area under the ROC curve, averaged over the observers, was 0.55 (95% confidence interval [0.44, 0.66]) for the 2D study, and 0.46 (95% confidence interval [0.29, 0.64]) for the tomosynthesis study, indicating no statistically significant difference between real and simulated lesions (p > 0.05). Agreement between allocated lesion scores for 2D mammography and those for the tomosynthesis series was poor. Conclusions: The realistic appearance of the 3D models of microcalcification clusters, whether malignant or benign clusters, was confirmed for 2D digital mammography images and the breast tomosynthesis datasets; this database of clusters is suitable for use in future observer performance studies related to the detectability of microcalcification clusters. Such studies include comparing 2D digital mammography to breast tomosynthesis and comparing different reconstruction algorithms.

Shaheen, Eman; Van Ongeval, Chantal; Zanca, Federica; Cockmartin, Lesley; Marshall, Nicholas; Jacobs, Jurgen; Young, Kenneth C.; Dance, David R.; Bosmans, Hilde [Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); National Coordinating Centre for the Physics of Mammography, Royal Surrey County Hospital, Guildford, GU2 7XX (United Kingdom); Department of Radiology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium)

2011-12-15

7

3D heart reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The purpose of this thesis was to achieve a 3D reconstruction of the four heart chambers using 2D echocardiographic images. A level set algorithm based on the phase symmetry approach and on a new logarithmic based stopping function was used to extract simultaneously the four heart cavities from thes...

Roxo, Diogo

8

Application of boundary detection information in breast tomosynthesis reconstruction  

International Nuclear Information System (INIS)

Digital tomosynthesis mammography (DTM) is one of the most promising techniques that can potentially improve early detection of breast cancers. DTM can provide three-dimensional (3D) structural information by reconstructing the whole imaged volume from a sequence of projection-view (PV) mammograms that are acquired at a small number of projection angles over a limited angular range. Our previous study showed that simultaneous algebraic reconstruction technique (SART) can produce satisfactory tomosynthesized image quality compared to maximum likelihood-type algorithms. To improve the efficiency of DTM reconstruction and address the problem of boundary artifacts, we have developed methods to incorporate both two-dimensional (2D) and 3D breast boundary information within the SART reconstruction algorithm in this study. A second generation GE prototype tomosynthesis mammography system with a stationary digital detector was used for PV image acquisition from 21 angles in 3 deg. increments over a ±30 deg. angular range. The 2D breast boundary curves on all PV images were obtained by automated segmentation and were used to restrict the SART reconstruction to be performed only within the breast volume. The computation time of SART reconstruction was reduced by 76.3% and 69.9% for cranio-caudal and mediolateral oblique views, respectively, for the chosen example. In addition, a 3D conical trimming method was developed in which the 2D breast boundary curves from all PVs were back projected to generate the 3D breast surface. This 3D surface was then used to eliminate the multiple breast shadows outside the breast volume due to reconstruction by setting these voxels to a constant background value. Our study demonstrates that, by using the 2D and 3D breast boundary information, all breast boundary and most detector boundary artifacts can be effectively removed on all tomosynthesized slices.

2007-01-01

9

Segmentation of adipose and glandular tissue for breast tomosynthesis imaging using a 3D hidden-Markov model trained on breast MRIs  

Science.gov (United States)

Breast tomosynthesis involves a restricted number of images acquired in an arc in conventional mammography projection geometry. Despite its angular undersampling, tomosynthesis projections are reconstructed into a volume at a dose comparable to mammography. Tomosynthesis thus provides depth information, which is especially beneficial to patients with dense breasts. Because the device can be based on an existing FFDM unit, tomosynthesis may be used to accurately assess breast tissue composition, which would greatly benefit high-risk patients with less access to costly imaging modalities such as MRI. This study plans to extract quantitative 3D breast tissue density information using a fully automatic probabilistic model trained on segmented MRIs. The MRI ground truth was obtained for 293 breasts by iterative threshold-based fatty / glandular tissue segmentation. After training a 3D hidden Markov model (HMM) on 10 MR volumes, our model was validated by segmenting 214 of the 293 breasts. After the tomosynthesis value optimization, the same trained HMM was tested to segment breast tomosynthesis volumes of subjects whose MRIs were used for validation. Initial training / testing of the HMM on MRIs matched density to thresholding within 5% for 70/214 breasts and 10% for 127/214 breasts. HMM segmentation was qualitatively superior at the cranial/caudal end slices in MRIs and quantitatively superior for most tested tomosynthesis volumes. Its robustness and ease of modification give the HMM great promise and potential for expansion in this multi-modality study.

Shafer, Christina M.; Seewaldt, Victoria L.; Lo, Joseph Y.

2011-03-01

10

Fast reconstruction of digital tomosynthesis using on-board images  

International Nuclear Information System (INIS)

Digital tomosynthesis (DTS) is a method to reconstruct pseudo three-dimensional (3D) volume images from two-dimensional x-ray projections acquired over limited scan angles. Compared with cone-beam computed tomography, which is frequently used for 3D image guided radiation therapy, DTS requires less imaging time and dose. Successful implementation of DTS for fast target localization requires the reconstruction process to be accomplished within tight clinical time constraints (usually within 2 min). To achieve this goal, substantial improvement of reconstruction efficiency is necessary. In this study, a reconstruction process based upon the algorithm proposed by Feldkamp, Davis, and Kress was implemented on graphics hardware for the purpose of acceleration. The performance of the novel reconstruction implementation was tested for phantom and real patient cases. The efficiency of DTS reconstruction was improved by a factor of 13 on average, without compromising image quality. With acceleration of the reconstruction algorithm, the whole DTS generation process including data preprocessing, reconstruction, and DICOM conversion is accomplished within 1.5 min, which ultimately meets clinical requirement for on-line target localization.

2008-01-01

11

[Application of algebraic reconstruction technique of multi-source tomosynthesis in dynamic reconstruction].  

UK PubMed Central (United Kingdom)

To reduce the motion artifacts, a new scanning configuration is proposed for tomosynthesis in dynamic reconstruction. In this new configuration, multiple x-ray sources are uniformly distributed on the circular scanning trajectory and moving simultaneously. Numerical experiments are performed using two dynamic digital phantoms and algebraic reconstruction technique. The reconstruction images of single-source tomosynthesis and multi-source tomosynthesis are compared and evaluated. The results show that multi-source tomosynthesis could reduce artifacts effectively, thus improving image quality. The advantages of multi-source tomosynthesis in dynamic reconstruction are important to cardiac imaging and respiratory imaging.

Peng J; Zhao J

2011-07-01

12

Optimized image acquisition for breast tomosynthesis in projection and reconstruction space  

International Nuclear Information System (INIS)

[en] Breast tomosynthesis has been an exciting new development in the field of breast imaging. While the diagnostic improvement via tomosynthesis is notable, the full potential of tomosynthesis has not yet been realized. This may be attributed to the dependency of the diagnostic quality of tomosynthesis on multiple variables, each of which needs to be optimized. Those include dose, number of angular projections, and the total angular span of those projections. In this study, the authors investigated the effects of these acquisition parameters on the overall diagnostic image quality of breast tomosynthesis in both the projection and reconstruction space. Five mastectomy specimens were imaged using a prototype tomosynthesis system. 25 angular projections of each specimen were acquired at 6.2 times typical single-view clinical dose level. Images at lower dose levels were then simulated using a noise modification routine. Each projection image was supplemented with 84 simulated 3 mm 3D lesions embedded at the center of 84 nonoverlapping ROIs. The projection images were then reconstructed using a filtered backprojection algorithm at different combinations of acquisition parameters to investigate which of the many possible combinations maximizes the performance. Performance was evaluated in terms of a Laguerre-Gauss channelized Hotelling observer model-based measure of lesion detectability. The analysis was also performed without reconstruction by combining the model results from projection images using Bayesian decision fusion algorithm. The effect of acquisition parameters on projection images and reconstructed slices were then compared to derive an optimization rule for tomosynthesis. The results indicated that projection images yield comparable but higher performance than reconstructed images. Both modes, however, offered similar trends: Performance improved with an increase in the total acquisition dose level and the angular span. Using a constant dose level and angular span, the performance rolled off beyond a certain number of projections, indicating that simply increasing the number of projections in tomosynthesis may not necessarily improve its performance. The best performance for both projection images and tomosynthesis slices was obtained for 15-17 projections spanning an angular arc of ?45 deg. - the maximum tested in our study, and for an acquisition dose equal to single-view mammography. The optimization framework developed in this framework is applicable to other reconstruction techniques and other multiprojection systems.

2009-01-01

13

Optimized image acquisition for breast tomosynthesis in projection and reconstruction space  

Energy Technology Data Exchange (ETDEWEB)

Breast tomosynthesis has been an exciting new development in the field of breast imaging. While the diagnostic improvement via tomosynthesis is notable, the full potential of tomosynthesis has not yet been realized. This may be attributed to the dependency of the diagnostic quality of tomosynthesis on multiple variables, each of which needs to be optimized. Those include dose, number of angular projections, and the total angular span of those projections. In this study, the authors investigated the effects of these acquisition parameters on the overall diagnostic image quality of breast tomosynthesis in both the projection and reconstruction space. Five mastectomy specimens were imaged using a prototype tomosynthesis system. 25 angular projections of each specimen were acquired at 6.2 times typical single-view clinical dose level. Images at lower dose levels were then simulated using a noise modification routine. Each projection image was supplemented with 84 simulated 3 mm 3D lesions embedded at the center of 84 nonoverlapping ROIs. The projection images were then reconstructed using a filtered backprojection algorithm at different combinations of acquisition parameters to investigate which of the many possible combinations maximizes the performance. Performance was evaluated in terms of a Laguerre-Gauss channelized Hotelling observer model-based measure of lesion detectability. The analysis was also performed without reconstruction by combining the model results from projection images using Bayesian decision fusion algorithm. The effect of acquisition parameters on projection images and reconstructed slices were then compared to derive an optimization rule for tomosynthesis. The results indicated that projection images yield comparable but higher performance than reconstructed images. Both modes, however, offered similar trends: Performance improved with an increase in the total acquisition dose level and the angular span. Using a constant dose level and angular span, the performance rolled off beyond a certain number of projections, indicating that simply increasing the number of projections in tomosynthesis may not necessarily improve its performance. The best performance for both projection images and tomosynthesis slices was obtained for 15-17 projections spanning an angular arc of {approx}45 deg. - the maximum tested in our study, and for an acquisition dose equal to single-view mammography. The optimization framework developed in this framework is applicable to other reconstruction techniques and other multiprojection systems.

Chawla, Amarpreet S.; Lo, Joseph Y.; Baker, Jay A.; Samei, Ehsan [Department of Radiology and Department of Biomedical Engineering, Duke Advanced Imaging Laboratories, Duke University, Durham, North Carolina 27705 (United States); Department of Radiology, Department of Medical Physics, and Department of Biomedical Engineering, Duke Advanced Imaging Laboratories, Duke University Durham, North Carolina 27705 (United States); Department of Radiology, Duke Advanced Imaging Laboratories, Duke University Durham, North Carolina 27705 (United States); Department of Radiology, Department of Medical Physics, and Department of Biomedical Engineering, Duke Advanced Imaging Laboratories, Duke University Durham, North Carolina 27705 (United States)

2009-11-15

14

Optimized image acquisition for breast tomosynthesis in projection and reconstruction space.  

Science.gov (United States)

Breast tomosynthesis has been an exciting new development in the field of breast imaging. While the diagnostic improvement via tomosynthesis is notable, the full potential of tomosynthesis has not yet been realized. This may be attributed to the dependency of the diagnostic quality of tomosynthesis on multiple variables, each of which needs to be optimized. Those include dose, number of angular projections, and the total angular span of those projections. In this study, the authors investigated the effects of these acquisition parameters on the overall diagnostic image quality of breast tomosynthesis in both the projection and reconstruction space. Five mastectomy specimens were imaged using a prototype tomosynthesis system. 25 angular projections of each specimen were acquired at 6.2 times typical single-view clinical dose level. Images at lower dose levels were then simulated using a noise modification routine. Each projection image was supplemented with 84 simulated 3 mm 3D lesions embedded at the center of 84 nonoverlapping ROIs. The projection images were then reconstructed using a filtered backprojection algorithm at different combinations of acquisition parameters to investigate which of the many possible combinations maximizes the performance. Performance was evaluated in terms of a Laguerre-Gauss channelized Hotelling observer model-based measure of lesion detectability. The analysis was also performed without reconstruction by combining the model results from projection images using Bayesian decision fusion algorithm. The effect of acquisition parameters on projection images and reconstructed slices were then compared to derive an optimization rule for tomosynthesis. The results indicated that projection images yield comparable but higher performance than reconstructed images. Both modes, however, offered similar trends: Performance improved with an increase in the total acquisition dose level and the angular span. Using a constant dose level and angular span, the performance rolled off beyond a certain number of projections, indicating that simply increasing the number of projections in tomosynthesis may not necessarily improve its performance. The best performance for both projection images and tomosynthesis slices was obtained for 15-17 projections spanning an angular are of approximately 45 degrees--the maximum tested in our study, and for an acquisition dose equal to single-view mammography. The optimization framework developed in this framework is applicable to other reconstruction techniques and other multiprojection systems. PMID:19994493

Chawla, Amarpreet S; Lo, Joseph Y; Baker, Jay A; Samei, Ehsan

2009-11-01

15

Generating synthetic mammograms from reconstructed tomosynthesis volumes.  

UK PubMed Central (United Kingdom)

Digital breast tomosynthesis (DBT) is a promising 3D modality that may replace mammography in the future. However, lesion search is likely to require more time in DBT volumes, while comparisons between views from different projections and prior exams might be harder to make. This may make screening with DBT cumbersome. A solution may be provided by synthesizing 2D mammograms from DBT, which may then be used to guide the search for abnormalities. In this work we focus on synthesizing mammograms in which masses and architectural distortions are optimally visualized. Our approach first determines relevant points in a DBT volume with a computer-aided detection system and then renders a mammogram from the intersection of a surface fitted through these points and the DBT volume. The method was evaluated in a pilot observer study where three readers reported mass findings in 87 patients (25 malignant, 62 normal) for which both DBT and digital mammograms were available. We found that on average, diagnostic accuracy in the synthetic mammograms was higher (Az=0.85) than in conventional mammograms (Az=0.81), although the difference was not statistically significant. Preliminary results suggest that the synthesized mammograms are an acceptable alternative for real mammograms regarding the detection of mass lesions.

Van Schie G; Mann R; Imhof-Tas M; Karssemeijer N

2013-09-01

16

A novel approach to digital breast tomosynthesis for simultaneous acquisition of 2D and 3D images  

Energy Technology Data Exchange (ETDEWEB)

The complexity of anatomical structure within the breast represents the ultimate limit to signal detection on a mammogram. To increase lesion conspicuity Digital Breast Tomosynthesis (DBT) has been recently proposed and several manufacturers are currently performing clinical trials. In this study we investigate the potential of DBT with variable dose distribution by using a phantom in which details of interest are within a heterogeneous background. To compare the performance of a commercial digital mammography unit and a DBT prototype, 2D and 3D images of the breast phantom were obtained at similar dose levels. As expected, DBT showed superior performance over digital mammography. Although certain details of interest are not detectable with digital mammography, DBT can reveal their signal by reducing the complexity of tissue structures. Additionally, the potential of the central projection in variable dose DBT is similar to the standard projection obtained with digital mammography. Finally, the uniform and variable dose approaches provided almost identical reconstructed slices. This preliminary investigation demonstrates that breast tomosynthesis acquired with variable dose distribution exhibits inherent 3D reconstruction advantages for structure noise removal and provides a 2D projection with a physical image quality close to that of standard mammography. (orig.)

Vecchio, Sara [University of Bologna, Department of Physics, Bologna (Italy); Albanese, Achille; Vignoli, Paolo [Internazionale Medico Scientifica S.r.l., Pontecchio Marconi, BO (Italy); Taibi, Angelo [University of Ferrara, Department of Physics, Ferrara (Italy)

2011-06-15

17

A novel approach to digital breast tomosynthesis for simultaneous acquisition of 2D and 3D images  

International Nuclear Information System (INIS)

The complexity of anatomical structure within the breast represents the ultimate limit to signal detection on a mammogram. To increase lesion conspicuity Digital Breast Tomosynthesis (DBT) has been recently proposed and several manufacturers are currently performing clinical trials. In this study we investigate the potential of DBT with variable dose distribution by using a phantom in which details of interest are within a heterogeneous background. To compare the performance of a commercial digital mammography unit and a DBT prototype, 2D and 3D images of the breast phantom were obtained at similar dose levels. As expected, DBT showed superior performance over digital mammography. Although certain details of interest are not detectable with digital mammography, DBT can reveal their signal by reducing the complexity of tissue structures. Additionally, the potential of the central projection in variable dose DBT is similar to the standard projection obtained with digital mammography. Finally, the uniform and variable dose approaches provided almost identical reconstructed slices. This preliminary investigation demonstrates that breast tomosynthesis acquired with variable dose distribution exhibits inherent 3D reconstruction advantages for structure noise removal and provides a 2D projection with a physical image quality close to that of standard mammography. (orig.)

2011-01-01

18

Stereotactic vacuum-assisted biopsies on a digital breast 3D-tomosynthesis system.  

UK PubMed Central (United Kingdom)

The purpose of this study was to describe our operating process and to report results of 118 stereotactic vacuum-assisted biopsies performed on a digital breast 3D-tomosynthesis system. From October 2009 to December 2010, 118 stereotactic vacuum assisted biopsies have been performed on a digital breast 3D-tomosynthesis system. Informed consent was obtained for all patients. A total of 106 patients had a lesion, six had two lesions. Sixty-one lesions were clusters of micro-calcifications, 54 were masses and three were architectural distortions. Patients were in lateral decubitus position to allow shortest skin-target approach (or sitting). Specific compression paddle, adapted on the system, performed, and graduated, allowing localization in X-Y. Tomosynthesis views define the depth of lesion. Graduated Coaxial localization kit determines the beginning of the biopsy window. Biopsies were performed with an ATEC-Suros, 9 Gauge handpiece. All biopsies, except one, have reached the lesions. Five hemorrhages were incurred in the process, but no interruption was needed. Eight breast hematomas, were all spontaneously resolved. One was an infection. About 40% of patients had a skin ecchymosis. Processing is fast, easy, and requires lower irradiation dose than with classical stereotactic biopsies. Histology analysis reported 45 benign clusters of micro-calcifications, 16 malignant clusters of micro-calcifications, 24 benign masses, and 33 malignant masses. Of 13 malignant lesions, digital 2D-mammography failed to detect eight lesions and underestimated the classification of five lesions. Digital breast 3D-tomosynthesis depicts malignant lesions not visualized on digital 2D-mammography. Development of tomosynthesis biopsy unit integrated to stereotactic system will permit histology analysis for suspicious lesions.

Viala J; Gignier P; Perret B; Hovasse C; Hovasse D; Chancelier-Galan MD; Bornet G; Hamrouni A; Lasry JL; Convard JP

2013-01-01

19

Development of model observers applied to 3D breast tomosynthesis microcalcifications and masses  

Science.gov (United States)

The development of model observers for mimicking human detection strategies has followed from symmetric signals in simple noise to increasingly complex backgrounds. In this study we implement different model observers for the complex task of detecting a signal in a 3D image stack. The backgrounds come from real breast tomosynthesis acquisitions and the signals were simulated and reconstructed within the volume. Two different tasks relevant to the early detection of breast cancer were considered: detecting an 8 mm mass and detecting a cluster of microcalcifications. The model observers were calculated using a channelized Hotelling observer (CHO) with dense difference-of-Gaussian channels, and a modified (Partial prewhitening [PPW]) observer which was adapted to realistic signals which are not circularly symmetric. The sustained temporal sensitivity function was used to filter the images before applying the spatial templates. For a frame rate of five frames per second, the only CHO that we calculated performed worse than the humans in a 4-AFC experiment. The other observers were variations of PPW and outperformed human observers in every single case. This initial frame rate was a rather low speed and the temporal filtering did not affect the results compared to a data set with no human temporal effects taken into account. We subsequently investigated two higher speeds at 5, 15 and 30 frames per second. We observed that for large masses, the two types of model observers investigated outperformed the human observers and would be suitable with the appropriate addition of internal noise. However, for microcalcifications both only the PPW observer consistently outperformed the humans. The study demonstrated the possibility of using a model observer which takes into account the temporal effects of scrolling through an image stack while being able to effectively detect a range of mass sizes and distributions.

Diaz, Ivan; Timberg, Pontus; Zhang, Sheng; Abbey, Craig; Verdun, Francis; Bochud, François O.

2011-03-01

20

Numerical Methods for Coupled Reconstruction and Registration in Digital Breast Tomosynthesis  

CERN Multimedia

Digital Breast Tomosynthesis (DBT) provides an insight into the fine details of normal fibroglandular tissues and abnormal lesions by reconstructing a pseudo-3D image of the breast. In this respect, DBT overcomes a major limitation of conventional X-ray mammography by reducing the confounding effects caused by the superposition of breast tissue. In a breast cancer screening or diagnostic context, a radiologist is interested in detecting change, which might be indicative of malignant disease. To help automate this task image registration is required to establish spatial correspondence between time points. Typically, images, such as MRI or CT, are first reconstructed and then registered. This approach can be effective if reconstructing using a complete set of data. However, for ill-posed, limited-angle problems such as DBT, estimating the deformation is complicated by the significant artefacts associated with the reconstruction, leading to severe inaccuracies in the registration. This paper presents a mathemati...

Yang, Guang; Hawkes, David J; Arridge, Simon R

2013-01-01

 
 
 
 
21

Forensic 3D Scene Reconstruction  

Energy Technology Data Exchange (ETDEWEB)

Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

1999-10-12

22

Thin slice three dimentional (3D) reconstruction versus CT 3D reconstruction of human breast cancer.  

UK PubMed Central (United Kingdom)

BACKGROUND & OBJECTIVES: With improvement in the early diagnosis of breast cancer, breast conserving therapy (BCT) is being increasingly used. Precise preoperative evaluation of the incision margin is, therefore, very important. Utilizing three dimentional (3D) images in a preoperative evaluation for breast conserving surgery has considerable significance, but the currently 3D CT scan reconstruction commonly used has problems in accurately displaying breast cancer. Thin slice 3D reconstruction is also widely used now to delineate organs and tissues of breast cancers. This study was aimed to compare 3D CT with thin slice 3D reconstruction in breast cancer patients to find a better technique for accurate evaluation of breast cancer. METHODS: A total of 16-slice spiral CT scans and 3D reconstructions were performed on 15 breast cancer patients. All patients had been treated with modified radical mastectomy; 2D and 3D images of breast and tumours were obtained. The specimens were fixed and sliced at 2 mm thickness to obtain serial thin slice images, and reconstructed using 3D DOCTOR software to gain 3D images. RESULTS: Compared with 2D CT images, thin slice images showed more clearly the morphological characteristics of tumour, breast tissues and the margins of different tissues in each slice. After 3D reconstruction, the tumour shapes obtained by the two reconstruction methods were basically the same, but the thin slice 3D reconstruction showed the tumour margins more clearly. INTERPRETATION & CONCLUSIONS: Compared with 3D CT reconstruction, thin slice 3D reconstruction of breast tumour gave clearer images, which could provide guidance for the observation and application of CT 3D reconstructed images and contribute to the accurate evaluation of tumours using CT imaging technology.

Zhang Y; Zhou Y; Yang X; Tang P; Qiu Q; Liang Y; Jiang J

2013-01-01

23

3-D image reconstruction in radiology  

International Nuclear Information System (INIS)

In this course, we present highlights on fully 3-D image reconstruction algorithms used in 3-D X-ray Computed Tomography (3-D-CT) and 3-D Rotational Radiography (3-D-RR). We first consider the case of spiral CT with a one-row detector. Starting from the 2-D fan-beam inversion formula for a circular trajectory, we introduce spiral CT 3-D image reconstruction algorithm using axial interpolation for each transverse slice. In order to improve the X-ray detection efficiency and to speed the acquisition process, the future is to use multi-row detectors associated with small angle cone-beam geometry. The generalization of the 2-D fan-beam image reconstruction algorithm to cone beam defined direct inversion formula referred as Feldkamp's algorithm for a circular trajectory and Wang's algorithm for a spiral trajectory. However, large area detectors does exist such as Radiological Image Intensifiers or in a near future solid state detectors. To get a larger zoom effect, it defines a cone-beam geometry associated with a large aperture angle. For this case, we introduce indirect image reconstruction algorithm by plane re-binning in the Radon domain. We will present some results from a prototype MORPHOMETER device using the RADON reconstruction software. Lastly, we consider the special case of 3-D Rotational Digital Subtraction Angiography with a restricted number of views. We introduce constraint optimization algorithm using quadratic, entropic or half-quadratic constraints. Generalized ART (Algebraic Reconstruction Technique) iterative reconstruction algorithm can be derived from the Bregman algorithm. We present reconstructed vascular trees from a prototype MORPHOMETER device. (author)

1999-01-01

24

Convergence of iterative image reconstruction algorithms for Digital Breast Tomosynthesis  

DEFF Research Database (Denmark)

Most iterative image reconstruction algorithms are based on some form of optimization, such as minimization of a data-fidelity term plus an image regularizing penalty term. While achieving the solution of these optimization problems may not directly be clinically relevant, accurate optimization solutions can aid in iterative image reconstruction algorithm design. This issue is particularly acute for iterative image reconstruction in Digital Breast Tomosynthesis (DBT), where the corresponding data model IS particularly poorly conditioned. The impact of this poor conditioning is that iterative algorithms applied to this system can be slow to converge. Recent developments in first-order algorithms are now beginning to allow for accurate solutions to optimization problems of interest to tomographic imaging in general. In particular, we investigate an algorithm developed by Chambolle and Pock (2011 J. Math. Imag. Vol. 40, pgs 120-145) and apply it to iterative image reconstruction in DBT.

Sidky, Emil; JØrgensen, Jakob Heide

2012-01-01

25

Stratified Approach to 3D Reconstruction  

Directory of Open Access Journals (Sweden)

Full Text Available 3D reconstruction problem from images can be classified into three strata each of which is equivalent to the estimation of a specific geometry group. The simplest being projective, then affine, next metric and finally Euclidean structure. The advantage of stratification is that the images do not need to be from calibrated cameras in order to obtain reconstruction. In this paper results for both camera calibration and reconstruction are presented to verify that it is possible to obtain a 3D model directly from features in the images for man-made world.

Muhammad Arif; Huang Xinhan; Wang Min

2002-01-01

26

Accelerating reconstruction of reference digital tomosynthesis using graphics hardware  

International Nuclear Information System (INIS)

[en] The successful implementation of digital tomosynthesis (DTS) for on-board image guided radiation therapy (IGRT) requires fast DTS image reconstruction. Both target and reference DTS image sets are required to support an image registration application for IGRT. Target images are usually DTS image sets reconstructed from on-board projections, which can be accomplished quickly using the conventional filtered backprojection algorithm. Reference images are DTS image sets reconstructed from digitally reconstructed radiographs (DRRs) previously generated from conventional planning CT data. Generating a set of DRRs from planning CT is relatively slow using the conventional ray-casting algorithm. In order to facilitate DTS reconstruction within a clinically acceptable period of time, we implemented a high performance DRR reconstruction algorithm on a graphics processing unit of commercial PC graphics hardware. The performance of this new algorithm was evaluated and compared with that which is achieved using the conventional software-based ray-casting algorithm. DTS images were reconstructed from DRRs previously generated by both hardware and software algorithms. On average, the DRR reconstruction efficiency using the hardware method is improved by a factor of 67 over the software method. The image quality of the DRRs was comparable to those generated using the software-based ray-casting algorithm. Accelerated DRR reconstruction significantly reduces the overall time required to produce a set of reference DTS images from planning CT and makes this technique clinically practical for target localization for radiation therapy

2007-01-01

27

A review of breast tomosynthesis. Part II. Image reconstruction, processing and analysis, and advanced applications.  

UK PubMed Central (United Kingdom)

Many important post-acquisition aspects of breast tomosynthesis imaging can impact its clinical performance. Chief among them is the reconstruction algorithm that generates the representation of the three-dimensional breast volume from the acquired projections. But even after reconstruction, additional processes, such as artifact reduction algorithms, computer aided detection and diagnosis, among others, can also impact the performance of breast tomosynthesis in the clinical realm. In this two part paper, a review of breast tomosynthesis research is performed, with an emphasis on its medical physics aspects. In the companion paper, the first part of this review, the research performed relevant to the image acquisition process is examined. This second part will review the research on the post-acquisition aspects, including reconstruction, image processing, and analysis, as well as the advanced applications being investigated for breast tomosynthesis.

Sechopoulos I

2013-01-01

28

Multichannel algorithm for fast 3D reconstruction  

International Nuclear Information System (INIS)

Some recent medical imaging applications such as functional imaging (PET and SPECT) or interventional imaging (CT fluoroscopy) involve increasing amounts of data. In order to reduce the image reconstruction time, we develop a new fast 3D reconstruction algorithm based on a divide and conquer approach. The proposed multichannel algorithm performs an indirect frequential subband decomposition of the image f to be reconstructed (f=?fj) through the filtering of the projections Rf. The subband images fj are reconstructed on a downsampled grid without information suppression. In order to reduce the computation time, we do not backproject the null filtered projections and we downsample the number of projections according to the Shannon conditions associated with the subband image. Our algorithm is based on filtering and backprojection operators. Using the same algorithms for these basic operators, our approach is three and a half times faster than a classical FBP algorithm for a 2D image 512x512 and six times faster for a 3D image 32x512x512. (author)

2002-08-07

29

3-D image reconstruction in radiology; Reconstruction d'image 3D en radiologie  

Energy Technology Data Exchange (ETDEWEB)

In this course, we present highlights on fully 3-D image reconstruction algorithms used in 3-D X-ray Computed Tomography (3-D-CT) and 3-D Rotational Radiography (3-D-RR). We first consider the case of spiral CT with a one-row detector. Starting from the 2-D fan-beam inversion formula for a circular trajectory, we introduce spiral CT 3-D image reconstruction algorithm using axial interpolation for each transverse slice. In order to improve the X-ray detection efficiency and to speed the acquisition process, the future is to use multi-row detectors associated with small angle cone-beam geometry. The generalization of the 2-D fan-beam image reconstruction algorithm to cone beam defined direct inversion formula referred as Feldkamp's algorithm for a circular trajectory and Wang's algorithm for a spiral trajectory. However, large area detectors does exist such as Radiological Image Intensifiers or in a near future solid state detectors. To get a larger zoom effect, it defines a cone-beam geometry associated with a large aperture angle. For this case, we introduce indirect image reconstruction algorithm by plane re-binning in the Radon domain. We will present some results from a prototype MORPHOMETER device using the RADON reconstruction software. Lastly, we consider the special case of 3-D Rotational Digital Subtraction Angiography with a restricted number of views. We introduce constraint optimization algorithm using quadratic, entropic or half-quadratic constraints. Generalized ART (Algebraic Reconstruction Technique) iterative reconstruction algorithm can be derived from the Bregman algorithm. We present reconstructed vascular trees from a prototype MORPHOMETER device. (author)

Grangeat, P

1999-07-01

30

3D reconstruction of tensors and vectors  

International Nuclear Information System (INIS)

Here we have developed formulations for the reconstruction of 3D tensor fields from planar (Radon) and line-integral (X-ray) projections of 3D vector and tensor fields. Much of the motivation for this work is the potential application of MRI to perform diffusion tensor tomography. The goal is to develop a theory for the reconstruction of both Radon planar and X-ray or line-integral projections because of the flexibility of MRI to obtain both of these type of projections in 3D. The development presented here for the linear tensor tomography problem provides insight into the structure of the nonlinear MRI diffusion tensor inverse problem. A particular application of tensor imaging in MRI is the potential application of cardiac diffusion tensor tomography for determining in vivo cardiac fiber structure. One difficulty in the cardiac application is the motion of the heart. This presents a need for developing future theory for tensor tomography in a motion field. This means developing a better understanding of the MRI signal for diffusion processes in a deforming media. The techniques developed may allow the application of MRI tensor tomography for the study of structure of fiber tracts in the brain, atherosclerotic plaque, and spine in addition to fiber structure in the heart. However, the relations presented are also applicable to other fields in medical imaging such as diffraction tomography using ultrasound. The mathematics presented can also be extended to exponential Radon transform of tensor fields and to other geometric acquisitions such as cone beam tomography of tensor fields.

2005-01-01

31

3D reconstruction of tensors and vectors  

Energy Technology Data Exchange (ETDEWEB)

Here we have developed formulations for the reconstruction of 3D tensor fields from planar (Radon) and line-integral (X-ray) projections of 3D vector and tensor fields. Much of the motivation for this work is the potential application of MRI to perform diffusion tensor tomography. The goal is to develop a theory for the reconstruction of both Radon planar and X-ray or line-integral projections because of the flexibility of MRI to obtain both of these type of projections in 3D. The development presented here for the linear tensor tomography problem provides insight into the structure of the nonlinear MRI diffusion tensor inverse problem. A particular application of tensor imaging in MRI is the potential application of cardiac diffusion tensor tomography for determining in vivo cardiac fiber structure. One difficulty in the cardiac application is the motion of the heart. This presents a need for developing future theory for tensor tomography in a motion field. This means developing a better understanding of the MRI signal for diffusion processes in a deforming media. The techniques developed may allow the application of MRI tensor tomography for the study of structure of fiber tracts in the brain, atherosclerotic plaque, and spine in addition to fiber structure in the heart. However, the relations presented are also applicable to other fields in medical imaging such as diffraction tomography using ultrasound. The mathematics presented can also be extended to exponential Radon transform of tensor fields and to other geometric acquisitions such as cone beam tomography of tensor fields.

Defrise, Michel; Gullberg, Grant T.

2005-02-17

32

Patchwork reconstruction with resolution modeling for digital breast tomosynthesis.  

UK PubMed Central (United Kingdom)

PURPOSE: Digital breast tomosynthesis is a relatively new diagnostic x-ray modality that allows high resolution breast imaging while suppressing interference from overlapping anatomical structures. However, proper visualization of microcalcifications remains a challenge. For the subset of systems considered by the authors, the main cause of deterioration is movement of the x-ray source during exposures. They propose a modified grouped coordinate ascent algorithm that includes a specific acquisition model to compensate for this deterioration. METHODS: A resolution model based on the movement of the x-ray source during image acquisition is created and combined with a grouped coordinate ascent algorithm. Choosing planes parallel to the detector surface as the groups enables efficient implementation of the position dependent resolution model. In the current implementation, the resolution model is approximated by a Gaussian smoothing kernel. The effect of the resolution model on the iterative reconstruction is evaluated by measuring contrast to noise ratio (CNR) of spherical microcalcifications in a homogeneous background. After this, the new reconstruction method is compared to the optimized filtered backprojection method for the considered system, by performing two observer studies: the first study simulates clusters of spherical microcalcifications in a power law background for a free search task; the second study simulates smooth or irregular microcalcifications in the same type of backgrounds for a classification task. RESULTS: Including the resolution model in the iterative reconstruction methods increases the CNR of microcalcifications. The first observer study shows a significant improvement in detection of microcalcifications (p = 0.029), while the second study shows that performance on a classification task remains the same (p = 0.935) compared to the filtered backprojection method. CONCLUSIONS: The new method shows higher CNR and improved visualization of microcalcifications in an observer experiment on synthetic data. Further study of the negative results of the classification task showed performance variations throughout the volume linked to the changing noise structure introduced by the combination of the resolution model and the smoothing prior.

Michielsen K; Van Slambrouck K; Jerebko A; Nuyts J

2013-03-01

33

Prostate implant reconstruction from C-arm images with motion-compensated tomosynthesis  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Accurate localization of prostate implants from several C-arm images is necessary for ultrasound-fluoroscopy fusion and intraoperative dosimetry. The authors propose a computational motion compensation method for tomosynthesis-based reconstruction that enables 3D localization of prostate implants from C-arm images despite C-arm oscillation and sagging. Methods: Five C-arm images are captured by rotating the C-arm around its primary axis, while measuring its rotation angle using a protractor or the C-arm joint encoder. The C-arm images are processed to obtain binary seed-only images from which a volume of interest is reconstructed. The motion compensation algorithm, iteratively, compensates for 2D translational motion of the C-arm by maximizing the number of voxels that project on a seed projection in all of the images. This obviates the need for C-arm full pose tracking traditionally implemented using radio-opaque fiducials or external trackers. The proposed reconstruction method is tested in simulations, in a phantom study and on ten patient data sets. Results: In a phantom implanted with 136 dummy seeds, the seed detection rate was 100% with a localization error of 0.86 {+-} 0.44 mm (Mean {+-} STD) compared to CT. For patient data sets, a detection rate of 99.5% was achieved in approximately 1 min per patient. The reconstruction results for patient data sets were compared against an available matching-based reconstruction method and showed relative localization difference of 0.5 {+-} 0.4 mm. Conclusions: The motion compensation method can successfully compensate for large C-arm motion without using radio-opaque fiducial or external trackers. Considering the efficacy of the algorithm, its successful reconstruction rate and low computational burden, the algorithm is feasible for clinical use.

Dehghan, Ehsan; Moradi, Mehdi; Wen, Xu; French, Danny; Lobo, Julio; Morris, W. James; Salcudean, Septimiu E.; Fichtinger, Gabor [School of Computing, Queen' s University, Kingston, Ontario K7L-3N6 (Canada); Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, British Columbia V6T-1Z4 (Canada); Vancouver Cancer Centre, Vancouver, British Columbia V5Z-1E6 (Canada); Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, British Columbia V6T-1Z4 (Canada); School of Computing, Queen' s University, Kingston, Ontario K7L-3N6 (Canada)

2011-10-15

34

A novel digital tomosynthesis (DTS) reconstruction method using a deformation field map  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We developed a novel digital tomosynthesis (DTS) reconstruction method using a deformation field map to optimally estimate volumetric information in DTS images. The deformation field map is solved by using prior information, a deformation model, and new projection data. Patients’ previous cone-beam ...

Ren, Lei; Zhang, Junan; Thongphiew, Danthai; Godfrey, Devon J.; Wu, Q. Jackie; Zhou, Su-Min; Yin, Fang-Fang

35

A novel digital tomosynthesis (DTS) reconstruction method using a deformation field map  

International Nuclear Information System (INIS)

We developed a novel digital tomosynthesis (DTS) reconstruction method using a deformation field map to optimally estimate volumetric information in DTS images. The deformation field map is solved by using prior information, a deformation model, and new projection data. Patients' previous cone-beam CT (CBCT) or planning CT data are used as the prior information, and the new patient volume to be reconstructed is considered as a deformation of the prior patient volume. The deformation field is solved by minimizing bending energy and maintaining new projection data fidelity using a nonlinear conjugate gradient method. The new patient DTS volume is then obtained by deforming the prior patient CBCT or CT volume according to the solution to the deformation field. This method is novel because it is the first method to combine deformable registration with limited angle image reconstruction. The method was tested in 2D cases using simulated projections of a Shepp-Logan phantom, liver, and head-and-neck patient data. The accuracy of the reconstruction was evaluated by comparing both organ volume and pixel value differences between DTS and CBCT images. In the Shepp-Logan phantom study, the reconstructed pixel signal-to-noise ratio (PSNR) for the 60 deg. DTS image reached 34.3 dB. In the liver patient study, the relative error of the liver volume reconstructed using 60 deg. projections was 3.4%. The reconstructed PSNR for the 60 deg. DTS image reached 23.5 dB. In the head-and-neck patient study, the new method using 60 deg. projections was able to reconstruct the 8.1 deg. rotation of the bony structure with 0.0 deg. error. The reconstructed PSNR for the 60 deg. DTS image reached 24.2 dB. In summary, the new reconstruction method can optimally estimate the volumetric information in DTS images using 60 deg. projections. Preliminary validation of the algorithm showed that it is both technically and clinically feasible for image guidance in radiation therapy.

2008-01-01

36

Fast iterative image reconstruction of 3D PET data  

International Nuclear Information System (INIS)

For count-limited PET imaging protocols, two different approaches to reducing statistical noise are volume, or 3D, imaging to increase sensitivity, and statistical reconstruction methods to reduce noise propagation. These two approaches have largely been developed independently, likely due to the perception of the large computational demands of iterative 3D reconstruction methods. We present results of combining the sensitivity of 3D PET imaging with the noise reduction and reconstruction speed of 2D iterative image reconstruction methods. This combination is made possible by using the recently-developed Fourier rebinning technique (FORE), which accurately and noiselessly rebins 3D PET data into a 2D data set. The resulting 2D sinograms are then reconstructed independently by the ordered-subset EM (OSEM) iterative reconstruction method, although any other 2D reconstruction algorithm could be used. We demonstrate significant improvements in image quality for whole-body 3D PET scans by using the FORE+OSEM approach compared with the standard 3D Reprojection (3DRP) algorithm. In addition, the FORE+OSEM approach involves only 2D reconstruction and it therefore requires considerably less reconstruction time than the 3DRP algorithm, or any fully 3D statistical reconstruction algorithm

1996-01-01

37

Fast iterative image reconstruction of 3D PET data  

Energy Technology Data Exchange (ETDEWEB)

For count-limited PET imaging protocols, two different approaches to reducing statistical noise are volume, or 3D, imaging to increase sensitivity, and statistical reconstruction methods to reduce noise propagation. These two approaches have largely been developed independently, likely due to the perception of the large computational demands of iterative 3D reconstruction methods. We present results of combining the sensitivity of 3D PET imaging with the noise reduction and reconstruction speed of 2D iterative image reconstruction methods. This combination is made possible by using the recently-developed Fourier rebinning technique (FORE), which accurately and noiselessly rebins 3D PET data into a 2D data set. The resulting 2D sinograms are then reconstructed independently by the ordered-subset EM (OSEM) iterative reconstruction method, although any other 2D reconstruction algorithm could be used. We demonstrate significant improvements in image quality for whole-body 3D PET scans by using the FORE+OSEM approach compared with the standard 3D Reprojection (3DRP) algorithm. In addition, the FORE+OSEM approach involves only 2D reconstruction and it therefore requires considerably less reconstruction time than the 3DRP algorithm, or any fully 3D statistical reconstruction algorithm.

Kinahan, P.E.; Townsend, D.W. [Univ. of Pittsburgh, PA (United States); Michel, C. [Catholic Univ. of Louvain (Belgium)] [and others

1996-12-31

38

Assessing the Value of 3D Reconstruction in Building Construction  

CERN Document Server

3-dimensional (3D) reconstruction is an emerging field in image processing and computer vision that aims to create 3D visualizations/ models of objects/ scenes from image sets. However, its commercial applications and benefits are yet to be fully explored. In this paper, we describe ongoing work towards assessing the value of 3D reconstruction in the building construction domain. We present preliminary results from a user study, where our objective is to understand the use of visual information in building construction in order to determine problems with the use of visual information and identify potential benefits and scenarios for the use of 3D reconstruction.

Murthy, Uma; Dib, Hazar; Garg, Chirag

2012-01-01

39

Reconstruction and analysis of shapes from 3D scans  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this thesis we use 3D laser range scans for the acquisition, reconstruction, and analysis of 3D shapes. 3D laser range scanning has proven to be a fast and effective way to capture the surface of an object in a computer. Thousands of depth measurements represent a part of the surface geometry as ...

Haar, F.B. ter

40

Integration of 3D digital mammography with tomosynthesis for population breast-cancer screening (STORM): a prospective comparison study.  

UK PubMed Central (United Kingdom)

BACKGROUND: Digital breast tomosynthesis with 3D images might overcome some of the limitations of conventional 2D mammography for detection of breast cancer. We investigated the effect of integrated 2D and 3D mammography in population breast-cancer screening. METHODS: Screening with Tomosynthesis OR standard Mammography (STORM) was a prospective comparative study. We recruited asymptomatic women aged 48 years or older who attended population-based breast-cancer screening through the Trento and Verona screening services (Italy) from August, 2011, to June, 2012. We did screen-reading in two sequential phases-2D only and integrated 2D and 3D mammography-yielding paired data for each screen. Standard double-reading by breast radiologists determined whether to recall the participant based on positive mammography at either screen read. Outcomes were measured from final assessment or excision histology. Primary outcome measures were the number of detected cancers, the number of detected cancers per 1000 screens, the number and proportion of false positive recalls, and incremental cancer detection attributable to integrated 2D and 3D mammography. We compared paired binary data with McNemar's test. FINDINGS: 7292 women were screened (median age 58 years [IQR 54-63]). We detected 59 breast cancers (including 52 invasive cancers) in 57 women. Both 2D and integrated 2D and 3D screening detected 39 cancers. We detected 20 cancers with integrated 2D and 3D only versus none with 2D screening only (p<0.0001). Cancer detection rates were 5.3 cancers per 1000 screens (95% CI 3.8-7.3) for 2D only, and 8.1 cancers per 1000 screens (6.2-10.4) for integrated 2D and 3D screening. The incremental cancer detection rate attributable to integrated 2D and 3D mammography was 2.7 cancers per 1000 screens (1.7-4.2). 395 screens (5.5%; 95% CI 5.0-6.0) resulted in false positive recalls: 181 at both screen reads, and 141 with 2D only versus 73 with integrated 2D and 3D screening (p<0.0001). We estimated that conditional recall (positive integrated 2D and 3D mammography as a condition to recall) could have reduced false positive recalls by 17.2% (95% CI 13.6-21.3) without missing any of the cancers detected in the study population. INTERPRETATION: Integrated 2D and 3D mammography improves breast-cancer detection and has the potential to reduce false positive recalls. Randomised controlled trials are needed to compare integrated 2D and 3D mammography with 2D mammography for breast cancer screening. FUNDING: National Breast Cancer Foundation, Australia; National Health and Medical Research Council, Australia; Hologic, USA; Technologic, Italy.

Ciatto S; Houssami N; Bernardi D; Caumo F; Pellegrini M; Brunelli S; Tuttobene P; Bricolo P; Fantò C; Valentini M; Montemezzi S; Macaskill P

2013-06-01

 
 
 
 
41

Fully Automatic 3D Reconstruction of Histological Images  

CERN Document Server

In this paper, we propose a computational framework for 3D volume reconstruction from 2D histological slices using registration algorithms in feature space. To improve the quality of reconstructed 3D volume, first, intensity variations in images are corrected by an intensity standardization process which maps image intensity scale to a standard scale where similar intensities correspond to similar tissues. Second, a subvolume approach is proposed for 3D reconstruction by dividing standardized slices into groups. Third, in order to improve the quality of the reconstruction process, an automatic best reference slice selection algorithm is developed based on an iterative assessment of image entropy and mean square error of the registration process. Finally, we demonstrate that the choice of the reference slice has a significant impact on registration quality and subsequent 3D reconstruction.

Bagci, Ulas

2009-01-01

42

Background Modeling Method Based on 3D Shape Reconstruction Technology  

Directory of Open Access Journals (Sweden)

Full Text Available In this research, we present a novel dynamic background modeling method based on reconstructed 3D shapes, which can solve background modeling problems of multi-camera in real-time. While 3D shape reconstruction is a popular technology widely used for detecting, tracking or identifying various objects, little effort has been made in applying this useful method to background subtraction. In this work we propose an approach to using 3D shape reconstruction technology to develop a novel decision making mechanism for background image updating. This 3D shape reconstruction based background subtraction method is adaptive to changes in illumination, capable of handling sudden illumination changes as well as complex dynamic scenes efficiently.

Xue Yuan; Xiaoli Hao; Houjin Chen; Xueye Wei

2013-01-01

43

Spatial transformation during 3D reconstruction in positron emission tomography  

International Nuclear Information System (INIS)

Spatial transformations of positron emission tomographic data for aligning images or transforming to standard anatomical space are usually performed with reconstructed images. However, they can also be performed during the reconstruction process, thereby interpolating the raw data fewer times. We investigated the performance of spatial transformations during reconstruction, implemented it in a standard 3D reconstruction algorithm, and tested it on phantom and patient H215O activation studies for the application of aligning both transmission and emission scans. Performing the transformations during reconstruction was shown to be equivalent to performing the transformations with reconstructed images for this particular application. (orig.).

1997-01-01

44

3D Beam Reconstruction by Fluorescence Imaging  

CERN Document Server

We present a technique for mapping the complete 3D spatial intensity profile of a laser beam from its fluorescence in an atomic vapour. We propagate shaped light through a rubidium vapour cell and record the resonant scattering from the side. From a single measurement we obtain a camera limited resolution of 200 x 200 transverse points and 659 longitudinal points. In constrast to invasive methods in which the camera is placed in the beam path, our method is capable of measuring patterns formed by counterpropagating laser beams. It has high resolution in all 3 dimensions, is fast and can be completely automated. The technique has applications in areas which require complex beam shapes, such as optical tweezers, atom trapping and pattern formation.

Radwell, Neal; Franke-Arnold, Sonja

2013-01-01

45

3D fast reconstruction in positron emission tomography  

International Nuclear Information System (INIS)

The issue of long reconstruction times in positron emission tomography (PET) has been addressed from several points of view, resulting in an affordable dedicated system capable of handling routine 3D reconstructions in a few minutes per frame : on the hardware side using fast processors and a parallel architecture, and on the software side, using efficient implementation of computationally less intensive algorithms

1996-01-01

46

An analytical statistical approach to the 3D reconstruction problem  

Energy Technology Data Exchange (ETDEWEB)

The presented here approach is concerned with the reconstruction problem for 3D spiral X-ray tomography. The reconstruction problem is formulated taking into considerations the statistical properties of signals obtained in X-ray CT. Additinally, image processing performed in our approach is involved in analytical methodology. This conception significantly improves quality of the obtained after reconstruction images and decreases the complexity of the reconstruction problem in comparison with other approaches. Computer simulations proved that schematically described here reconstruction algorithm outperforms conventional analytical methods in obtained image quality. (orig.)

Cierniak, Robert [Czestochowa Univ. of Technology (Poland). Inst. of Computer Engineering

2011-07-01

47

Use of Ultrasound and Computer Vision for 3D Reconstruction  

Science.gov (United States)

The main result of this work is an approach for reconstructing the 3D shape and pose of tumors for applications in laparoscopy from stereo endoscopic ultrasound images using Conformal Geometric Algebra. We record simultaneously stereo endoscopic and ultrasonic images and then the 3D pose of the ultrasound probe is calculated using conformal geometric algebra. When the position in 3D of the ultrasound probe is calculated, we compound multiple 2D ultrasound images into a 3D volume. To segment 2D ultrasound images we have used morphological operators and compared its performance versus the obtained with segmentation using level set methods.

Machucho-Cadena, Ruben; Moya-Sánchez, Eduardo; de La Cruz-Rodríguez, Sergio; Bayro-Corrochano, Eduardo

48

Scattering computation for 3D laser imagery and reconstruction algorithms  

Science.gov (United States)

This paper addresses non-conventional three-dimensional imaging with laser systems which explores the advantages of laser imagery to form a three-dimensional image of the scene. In this paper, we present the 3D laser scattering simulation of objects hidden behind porous occluders, such as foliage or camouflage. The physics based model presented in this paper is designed to provide accurate results but also to include all the electromagnetic interaction mechanisms with the different elements of the scene. A 3D laser cross-section computer model is used to develop reconstruction algorithms to obtain a high-resolved three-dimensional image. Synthetic images of three-dimensional objects are based on extraction of laser backscattered signals. But 3D reconstruction must take into account sparse collected data and reconstruction algorithms must solve a complex multi-parameter inverse problem. The objective of our paper is also to present new algorithmic approaches for the generation of 3D surface data from 3D sparse point clouds corresponding to our reconstruction algorithm. The role of this type of algorithmic process is to complete the 3D image at satisfactory levels for reliable identification of concealed objects. Identifying targets or objects concealed by foliage or camouflage is a critical requirement for operations in public safety, law enforcement and defense.

Berechet, Ion; Berginc, Gérard; Berechet, Stefan

2012-10-01

49

3D reconstruction for the detection of cranial anomalies  

International Nuclear Information System (INIS)

There is a growing interest in the use of three-dimensional (3D) cranial reconstruction from CT scans for surgical planning. A low-cost imaging system has been developed, which provides pseudo-3D images which may be manipulated to reveal the craniofacial skeleton as a whole or any particular component region. The contrast between congenital (hydrocephalic), normocephalic and acquired (carcinoma of the maxillary sinus) anomalous cranial forms demonstrates the potential of this system.

1986-01-01

50

Clinical implementation of a digital tomosynthesis-based seed reconstruction algorithm for intraoperative postimplant dose evaluation in low dose rate prostate brachytherapy  

Energy Technology Data Exchange (ETDEWEB)

Purpose: The low dose rate brachytherapy procedure would benefit from an intraoperative postimplant dosimetry verification technique to identify possible suboptimal dose coverage and suggest a potential reimplantation. The main objective of this project is to develop an efficient, operator-free, intraoperative seed detection technique using the imaging modalities available in a low dose rate brachytherapy treatment room. Methods: This intraoperative detection allows a complete dosimetry calculation that can be performed right after an I-125 prostate seed implantation, while the patient is still under anesthesia. To accomplish this, a digital tomosynthesis-based algorithm was developed. This automatic filtered reconstruction of the 3D volume requires seven projections acquired over a total angle of 60 deg. with an isocentric imaging system. Results: A phantom study was performed to validate the technique that was used in a retrospective clinical study involving 23 patients. In the patient study, the automatic tomosynthesis-based reconstruction yielded seed detection rates of 96.7% and 2.6% false positives. The seed localization error obtained with a phantom study is 0.4{+-}0.4 mm. The average time needed for reconstruction is below 1 min. The reconstruction algorithm also provides the seed orientation with an uncertainty of 10 deg. {+-}8 deg. The seed detection algorithm presented here is reliable and was efficiently used in the clinic. Conclusions: When combined with an appropriate coregistration technique to identify the organs in the seed coordinate system, this algorithm will offer new possibilities for a next generation of clinical brachytherapy systems.

Brunet-Benkhoucha, Malik; Verhaegen, Frank; Lassalle, Stephanie; Beliveau-Nadeau, Dominic; Reniers, Brigitte; Donath, David; Taussky, Daniel; Carrier, Jean-Francois [Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Medical Physics Unit, McGill University, Montreal General Hospital, 1650 Cedar Avenue, Montreal, Quebec H3G 1A4 (Canada) and Department of Radiation Oncology (MAASTRO), GROW Research Institute, University Medical Centre Maastricht, Maastricht (Netherlands); Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada); Departement de Radio-Oncologie, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada) and CRCHUM, Centre Hospitalier de l' Universite de Montreal, 1560 rue Sherbrooke Est, Quebec, Montreal, Quebec H2L 4M1 (Canada)

2009-11-15

51

3D reconstruction for endoscopic environment based on optical tracker  

Science.gov (United States)

3D reconstruction, an important point in computer vision, has a promising application potential in endoscopic-assisted minimally invasive surgery. In this paper, a 3D reconstruction method based on image sequences is proposed, in which the improved SIFT feature is applied for point extraction and matching, as well as an optical tracker is used to get the orientation of the camera in real time. The proposed approach is evaluated on sequence digital images gotten from an 1394 camera and the experimental results show that the proposed approach is effective.

Yang, Bo; Zhou, Ya; Hu, Xiaoming; Lin, Junqin; Xing, Qiaona

2012-12-01

52

3D surface reconstruction multi-scale hierarchical approaches  

CERN Multimedia

3D Surface Reconstruction: Multi-Scale Hierarchical Approaches presents methods to model 3D objects in an incremental way so as to capture more finer details at each step. The configuration of the model parameters, the rationale and solutions are described and discussed in detail so the reader has a strong understanding of the methodology. Modeling starts from data captured by 3D digitizers and makes the process even more clear and engaging. Innovative approaches, based on two popular machine learning paradigms, namely Radial Basis Functions and the Support Vector Machines, are also introduced

Bellocchio, Francesco; Ferrari, Stefano; Piuri, Vincenzo

2012-01-01

53

NeuralNetwork Based 3D Surface Reconstruction  

CERN Multimedia

This paper proposes a novel neural-network-based adaptive hybrid-reflectance three-dimensional (3-D) surface reconstruction model. The neural network combines the diffuse and specular components into a hybrid model. The proposed model considers the characteristics of each point and the variant albedo to prevent the reconstructed surface from being distorted. The neural network inputs are the pixel values of the two-dimensional images to be reconstructed. The normal vectors of the surface can then be obtained from the output of the neural network after supervised learning, where the illuminant direction does not have to be known in advance. Finally, the obtained normal vectors can be applied to integration method when reconstructing 3-D objects. Facial images were used for training in the proposed approach

Joseph, Vincy

2009-01-01

54

Using simulated annealing for 3D reconstruction of orthopedic fracture  

International Nuclear Information System (INIS)

Three-dimensional (3D) reconstruction from two orthogonal images has been realized, and a Monte Carlo program MCNP4B has been applied to simulate the x-ray images. These two approaches can be applied to reconstruction of orthopedic fractures, using computed radiography images. The purpose of this paper is to utilize the information from pairs of orthogonal images at different stages of healing to generate a 3D reconstruction of the callus which builds up during the treatment, thus facilitating understanding and enabling assessment of the process of fracture healing. The reconstruction from Monte Carlo simulated images and x-ray images shows that this approach may be feasible in clinical practice.

2004-01-01

55

Propagated Photoconsistency and Convexity in Variational Multiview 3D Reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we make two contributions. Firstly, we replace the generic balloon constraints widely used in 3D reconstruction by a more sophisticated data-dependent regional term. The key idea is to propagate classical photoconsistency along visual rays into regional values describing voxel probabi...

Kolev, Kalin; Klodt, Maria; Brox, Thomas; Cremers, Daniel

56

Use of a model for 3D image reconstruction  

International Nuclear Information System (INIS)

We propose a software for 3D image reconstruction in transmission tomography. This software is based on the use of a model and of the RADON algorithm developed at LETI. The introduction of a markovian model helps us to enhance contrast and straitened the natural transitions existing in the objects studied, whereas standard transform methods smoothe them

1991-01-01

57

CT with 3D-Image Reconstructions in Preoperative Planning  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Computed tomography is one of the most evolving fields of modern radiology. The current CT applications permit among other things angiography, 3D image reconstructions, material decomposition and tissue characterization. CT is an important tool in the assessment of specific patient populations prior...

Dimopoulou, Angeliki

58

3D reconstruction based on a complex constrain matching algorithm  

Science.gov (United States)

The precision of stereo matching directly influence the result of 3D reconstruction from images. a matching method is proposed to increase matching accuracy. Two pictures are taken for an object in different angle using a digital camera, then the feature points are extracted from the two images. After that, the initial matching is firstly done for the image feature points, then accurate matching is performed by use of affine transformation constrain, epipolar geometry constrain and gray scale relativity constrain comprehensively. Finally the accurate matching points are utilized to reconstruct the 3D points, which are filtered, smoothed, triangulated and textured to get a true 3D model Experimental results show that this algorithm converges fast and can increase matching accuracy effectively.

Li, Qiongyan; Ma, Feng

2010-08-01

59

3D video sequence reconstruction algorithms implemented on a DSP  

Science.gov (United States)

A novel approach for 3D image and video reconstruction is proposed and implemented. This is based on the wavelet atomic functions (WAF) that have demonstrated better approximation properties in different processing problems in comparison with classical wavelets. Disparity maps using WAF are formed, and then they are employed in order to present 3D visualization using color anaglyphs. Additionally, the compression via Pth law is performed to improve the disparity map quality. Other approaches such as optical flow and stereo matching algorithm are also implemented as the comparative approaches. Numerous simulation results have justified the efficiency of the novel framework. The implementation of the proposed algorithm on the Texas Instruments DSP TMS320DM642 permits to demonstrate possible real time processing mode during 3D video reconstruction for images and video sequences.

Ponomaryov, V. I.; Ramos-Diaz, E.

2011-02-01

60

QUANTITATIVE 3D RECONSTRUCTIONS AS IDENTIFICATION TOOL IN HEART DEVELOPMENT  

Directory of Open Access Journals (Sweden)

Full Text Available A method for displaying quantitative information in 3D reconstructions of the embryonic heart was developed to investigate spatial distributions of cell division and cell density. The method utilizes serial sections to extract morphological as well as quantitative data. The morphological data are used to reconstruct the embryonic heart and the quantitative data are classified and superimposed on the resulting reconstruction. The bias, which would result from size differences between cell populations, was investigated. If present, it would influence the absolute number of particles (nuclei) per volume, although the classification applied on the reconstruction displaying the mitotic fraction remains unchanged. Although the reconstruction displaying the local densities is influenced by the bias, less than 2.5% of the regions is misclassified.

Alexandre T Soufan; Jan M Ruijter; Maurice JB Van Den Hoff; Antoon FM Moorman

2001-01-01

 
 
 
 
61

Improvement of geometrical measurements from 3D-SEM reconstructions  

DEFF Research Database (Denmark)

The quantification of 3D geometry at the nanometric scale is a major metrological challenge. In this work geometrical measurements on cylindrical items obtained with a 3D-SEM were investigated. Two items were measured: a wire gauge having a 0.25 mm nominal diameter and a hypodermic needle having an external diameter of 0.26mm. A series of measurements were performed to determine the accuracy of 3D reconstructions obtained using stereo-photogrammetry methods, finding a procedure to determine the optimum number of rotations of the object for an acceptable measuring uncertainty. It was determined that the diameter estimation performed using the 3D-SEM leads to an overestimation of approx. 7% compared to the reference values obtained using a 1-D length measuring machine. Standard deviation of SEM measurements performed on the wire gauge is approx. 1.5 times lower than the one performed on the hypodermic needle.

Carli, Lorenzo Technical University of Denmark,

2009-01-01

62

3D surface reconstruction using optical flow for medical imaging  

International Nuclear Information System (INIS)

The recovery of a 3D model from a sequence of 2D images is very useful in medical image analysis. Image sequences obtained from the relative motion between the object and the camera or the scanner contain more 3D information than a single image. Methods to visualize the computed tomograms can be divided into two approaches: the surface rendering approach and the volume rendering approach. A new surface rendering method using optical flow is proposed. Optical flow is the apparent motion in the image plane produced by the projection of the real 3D motion onto 2D image. In this paper, the object remains stationary while the scanner undergoes translational motion. The 3D motion of an object can be recovered from the optical flow field using additional constraints. By extracting the surface information from 3D motion, it is possible to get an accurate 3D model of the object. Both synthetic and real image sequences have been used to illustrate the feasibility of the proposed method. The experimental results suggest that the proposed method is suitable for the reconstruction of 3D models from ultrasound medical images as well as other computed tomograms

1996-01-01

63

3D surface reconstruction using optical flow for medical imaging  

Energy Technology Data Exchange (ETDEWEB)

The recovery of a 3D model from a sequence of 2D images is very useful in medical image analysis. Image sequences obtained from the relative motion between the object and the camera or the scanner contain more 3D information than a single image. Methods to visualize the computed tomograms can be divided into two approaches: the surface rendering approach and the volume rendering approach. A new surface rendering method using optical flow is proposed. Optical flow is the apparent motion in the image plane produced by the projection of the real 3D motion onto 2D image. In this paper, the object remains stationary while the scanner undergoes translational motion. The 3D motion of an object can be recovered from the optical flow field using additional constraints. By extracting the surface information from 3D motion, it is possible to get an accurate 3D model of the object. Both synthetic and real image sequences have been used to illustrate the feasibility of the proposed method. The experimental results suggest that the proposed method is suitable for the reconstruction of 3D models from ultrasound medical images as well as other computed tomograms.

Weng, Nan; Yang, Yee-Hong; Pierson, R. [Univ. of Saskatchewan, Saskatoon (Canada)

1996-12-31

64

Reconstruction and 3D visualisation based on objective real 3D based documentation.  

UK PubMed Central (United Kingdom)

Reconstructions based directly upon forensic evidence alone are called primary information. Historically this consists of documentation of findings by verbal protocols, photographs and other visual means. Currently modern imaging techniques such as 3D surface scanning and radiological methods (computer tomography, magnetic resonance imaging) are also applied. Secondary interpretation is based on facts and the examiner's experience. Usually such reconstructive expertises are given in written form, and are often enhanced by sketches. However, narrative interpretations can, especially in complex courses of action, be difficult to present and can be misunderstood. In this report we demonstrate the use of graphic reconstruction of secondary interpretation with supporting pictorial evidence, applying digital visualisation (using 'Poser') or scientific animation (using '3D Studio Max', 'Maya') and present methods of clearly distinguishing between factual documentation and examiners' interpretation based on three cases. The first case involved a pedestrian who was initially struck by a car on a motorway and was then run over by a second car. The second case involved a suicidal gunshot to the head with a rifle, in which the trigger was pushed with a rod. The third case dealt with a collision between two motorcycles. Pictorial reconstruction of the secondary interpretation of these cases has several advantages. The images enable an immediate overview, give rise to enhanced clarity, and compel the examiner to look at all details if he or she is to create a complete image.

Bolliger MJ; Buck U; Thali MJ; Bolliger SA

2012-09-01

65

3D reconstruction of multiple stained histology images.  

UK PubMed Central (United Kingdom)

CONTEXT: Three dimensional (3D) tissue reconstructions from the histology images with different stains allows the spatial alignment of structural and functional elements highlighted by different stains for quantitative study of many physiological and pathological phenomena. This has significant potential to improve the understanding of the growth patterns and the spatial arrangement of diseased cells, and enhance the study of biomechanical behavior of the tissue structures towards better treatments (e.g. tissue-engineering applications). METHODS: This paper evaluates three strategies for 3D reconstruction from sets of two dimensional (2D) histological sections with different stains, by combining methods of 2D multi-stain registration and 3D volumetric reconstruction from same stain sections. SETTING AND DESIGN: The different strategies have been evaluated on two liver specimens (80 sections in total) stained with Hematoxylin and Eosin (H and E), Sirius Red, and Cytokeratin (CK) 7. RESULTS AND CONCLUSION: A strategy of using multi-stain registration to align images of a second stain to a volume reconstructed by same-stain registration results in the lowest overall error, although an interlaced image registration approach may be more robust to poor section quality.

Song Y; Treanor D; Bulpitt AJ; Magee DR

2013-01-01

66

Deformable Surface 3D Reconstruction from Monocular Images  

CERN Multimedia

Being able to recover the shape of 3D deformable surfaces from a single video stream would make it possible to field reconstruction systems that run on widely available hardware without requiring specialized devices. However, because many different 3D shapes can have virtually the same projection, such monocular shape recovery is inherently ambiguous. In this survey, we will review the two main classes of techniques that have proved most effective so far: The template-based methods that rely on establishing correspondences with a reference image in which the shape is already known, and non-rig

Salzmann, Matthieu

2010-01-01

67

Twenty-fold acceleration of 3D projection reconstruction MPI.  

UK PubMed Central (United Kingdom)

Abstract We experimentally demonstrate a 20-fold improvement in acquisition time in projection reconstruction (PR) magnetic particle imaging (MPI) relative to the state-of-the-art PR MPI imaging results. We achieve this acceleration in our imaging system by introducing an additional Helmholtz electromagnet pair, which creates a slow shift (focus) field. Because of magnetostimulation limits in humans, we show that scan time with three-dimensional (3D) PR MPI is theoretically within the same order of magnitude as 3D MPI with a field free point; however, PR MPI has an order of magnitude signal-to-noise ratio gain.

Konkle JJ; Goodwill PW; Saritas EU; Zheng B; Lu K; Conolly SM

2013-08-01

68

Digital tomosynthesis of hands using simultaneous algebraic reconstruction technique with distance driven projector  

Energy Technology Data Exchange (ETDEWEB)

Digital tomosynthesis (DT) is an X-ray tomographic technique for producing a three-dimensional stack of crosssectional images, based on a limited number of low-dose two-dimensional projections, acquired over a limited angular range. Currently, DT has mainly been investigated for the breast and chest imaging. Another application of DT may be an orthopaedic imaging of hands. A three-dimensional reconstruction with a high in-plane resolution, a low dose and potentially low costs make DT attractive for hand imaging comparing with the planar radiography or computed tomography. However, it should be noted that an accurate image reconstruction in DT is a challenging task due to the high degree of data incompleteness. Images are affected by the residual blur of structures that are located above and below the plane of interest. A human hand consists of 27 bones and therefore the artifact problem becomes even more acute in this case, since the magnitude of artifacts is related not only to the chosen reconstruction type but also to the size and contrast of the artifact-generating object. The study presented in the current work has been performed to show a capability of Simultaneous Algebraic Reconstruction Technique (SART) for hand visualization in tomosynthesis. A distance-driven type for the projector and backprojector operator has been used to make the calculation fast and accurate. Studies have been carried out on a phantom with an uniform background and millimeter-sized balls, a dried finger bone and an in toto hand phantom. A Siemens Mammomat Inspiration device has been used to acquire the projection data. Experimental results show that SART is able to reduce out-of-plane artifacts caused by bone tissue. It provides reconstruction with acceptable quality in only one iteration with the recovered visibility of the obscured trabecular structures as well as the joint spaces and the margins. (orig.)

Levakhina, Y.M. [Luebeck Univ. (Germany). Graduate School for Computing in Medicine and Life Sciences; Luebeck Univ. (Germany). Inst. of Medical Engineering; Duschka, R.L.; Barkhausen, J. [Universitaetsklinikum Schleswig-Holstein, Luebeck (Germany). Klinik fuer Radiologie und Nuklearmedizin; Buzug, T.M. [Luebeck Univ. (Germany). Inst. of Medical Engineering

2011-07-01

69

Oromandibular reconstruction using 3D planned triple template method.  

UK PubMed Central (United Kingdom)

PURPOSE: Reconstruction of an oromandibular defect remains one of the most formidable surgical challenges faced by the reconstructive head and neck surgeon. The purpose of this study was to illustrate the added value of 3D imaging and planning in oromandibular reconstruction. MATERIALS AND METHODS: A 41-year-old dentate male patient with T2N0M0 osteosarcoma of the mandible required segmental resection of the lateral mandible. In a virtual environment, the bony resection and reconstruction were planned preoperatively based on computed tomographic data of the head and neck and lower leg. Three custom-made templates designed in a computer-assisted design and manufacturing software package and materialized by a selective laser sintering process (DuraForm PA, 3D Worknet, Ede, Netherlands) were used to transfer this planning to the operating theater. RESULTS: During the operative procedure, the 3 templates allowed for a rapid and accurate execution of the different surgical steps, ie, establishing the bony surgical margins and resection of the mandible (first template), cutting of the fibula while being pedicled to the leg (second template), and placement of the fibula to the donor site (third template). CONCLUSION: Computer-aided surgery and planning using the 3-template method lead to an accurate and oncologically safe reconstruction of the mandibular geometry by eliminating intraoperative decision making, shortening ischemic time of the fibular graft, and shortening overall operative time.

Coppen C; Weijs W; Bergé SJ; Maal TJ

2013-08-01

70

Reconstruction of 3D scenes from sequences of images  

Science.gov (United States)

Reconstruction of three-dimensional (3D) scenes is an active research topic in the field of computer vision and 3D display. It's a challenge to model 3D objects rapidly and effectively. A 3D model can be extracted from multiple images. The system only requires a sequence of images taken with cameras without knowing the parameters of camera, which provide flexibility to a high degree. We focus on quickly merging point cloud of the object from depth map sequences. The whole system combines algorithms of different areas in computer vision, such as camera calibration, stereo correspondence, point cloud splicing and surface reconstruction. The procedure of 3D reconstruction is decomposed into a number of successive steps. Firstly, image sequences are received by the camera freely moving around the object. Secondly, the scene depth is obtained by a non-local stereo matching algorithm. The pairwise is realized with the Scale Invariant Feature Transform (SIFT) algorithm. An initial matching is then made for the first two images of the sequence. For the subsequent image that is processed with previous image, the point of interest corresponding to ones in previous images are refined or corrected. The vertical parallax between the images is eliminated. The next step is to calibrate camera, and intrinsic parameters and external parameters of the camera are calculated. Therefore, The relative position and orientation of camera are gotten. A sequence of depth maps are acquired by using a non-local cost aggregation method for stereo matching. Then point cloud sequence is achieved by the scene depths, which consists of point cloud model using the external parameters of camera and the point cloud sequence. The point cloud model is then approximated by a triangular wire-frame mesh to reduce geometric complexity and to tailor the model to the requirements of computer graphics visualization systems. Finally, the texture is mapped onto the wire-frame model, which can also be used for 3D display. According to the experimental results, we can reconstruct a 3D point cloud model more quickly and efficiently than other methods.

Niu, Bei; Sang, Xinzhu; Chen, Duo; Cai, Yuanfa

2013-08-01

71

3D liver volume reconstructed for palpation training.  

UK PubMed Central (United Kingdom)

Virtual Reality systems for medical procedures such as the palpation of different organs, requires fast, robust, accurate and reliable computational methods for providing realism during interaction with the 3D biological models. This paper presents the segmentation, reconstruction and palpation simulation of a healthy liver volume as a tool for training. The chosen method considers the mechanical characteristics and liver properties for correctly simulating palpation interactions, which results appropriate as a complementary tool for training medical students in familiarizing with the liver anatomy.

Tibamoso G; Perez-Gutierrez B; Uribe-Quevedo A

2013-01-01

72

High Resolution 3d Reconstructions of Rocks and Composites Reconstructions 3D haute résolution de roches et de composites  

Directory of Open Access Journals (Sweden)

Full Text Available Ten micrometers resolution 3D representations of different media, were obtained with a laboratory computer microtomograph developed from an electron microprobe column. From the original electron microprobe, only minor modifications have been required, indeed several of the utilities of the microprobe have been used to ensure high resolution radiography (2 micrometers). The impact of the electron beam focused onto a thin film is used to form a pointX-ray source and the radiographic image of the sample is acquired on a CCD camera. A specimen rotation mechanism allows multiple radiograph acquisition and reconstruction of the X-ray attenuation 3D cartography. Since X-ray attenuation is directly related to density and atomic number, the microscanner provides 3D cartographs of the different phases present in the sample. System performances have been evaluated on various samples, mainly rocks and composites. Comparison with scanning electron micrographs was used when possible to validate the reconstructions. Results are mostly qualitative but already show the potential of the technique in describing 3D connectivity and topology of pore networks or 3D orientation of fibres in composites. Des représentations tridimensionnelles de différents milieux ont été obtenues avec une résolution de 10 micromètres en utilisant un microscanner développé au laboratoire à partir d'une microsonde électronique. Peu de modifications ont été nécessaires. Certains éléments de la microsonde ont même été conservés pour assurer la stabilité de l'acquisition et permettre l'obtention de radiographies haute résolution (2 micromètres). L'impact d'un faisceau d'électrons focalisé sur un film mince constitue la source X et l'image radiographiée de l'échantillon est acquise à l'aide d'une caméra CCD. Un mécanisme de rotation de l'échantillon permet l'acquisition de radiographies à différentes positions angulaires ainsi que la reconstruction de la cartographie 3D des coefficients d'atténuation. L'atténuation des rayons X étant directement reliée à la densité et au numéro atomique du matériau irradié, le microscanner fournit une cartographie 3D des différentes phases présentes dans l'échantillon. Les performances du système ont été testées sur divers échantillons, principalement des roches et des matériaux composites. La comparaison avec des images de microscopie électronique à balayage a été utilisée pour valider les reconstructions. Les résultats sont pour la plupart qualitatifs mais montrent déjà le potentiel de cette technique pour décrire la topologie et la connectivité 3D de milieux poreux ou l'orientation des fibres dans des composites renforcés de fibres de verre.

Rosenberg E.; Lynch J.; Gueroult P.; Bisiaux M.; Ferreira De Paiva R.

2006-01-01

73

Event-based 3D reconstruction from neuromorphic retinas.  

UK PubMed Central (United Kingdom)

This paper presents a novel N-ocular 3D reconstruction algorithm for event-based vision data from bio-inspired artificial retina sensors. Artificial retinas capture visual information asynchronously and encode it into streams of asynchronous spike-like pulse signals carrying information on, e.g., temporal contrast events in the scene. The precise time of the occurrence of these visual features are implicitly encoded in the spike timings. Due to the high temporal resolution of the asynchronous visual information acquisition, the output of these sensors is ideally suited for dynamic 3D reconstruction. The presented technique takes full benefit of the event-driven operation, i.e. events are processed individually at the moment they arrive. This strategy allows us to preserve the original dynamics of the scene, hence allowing for more robust 3D reconstructions. As opposed to existing techniques, this algorithm is based on geometric and time constraints alone, making it particularly simple to implement and largely linear.

Carneiro J; Ieng SH; Posch C; Benosman R

2013-09-01

74

Evaluation of digital breast tomosynthesis reconstruction algorithms using synchrotron radiation in standard geometry  

International Nuclear Information System (INIS)

Purpose: In this article, the image quality of reconstructed volumes by four algorithms for digital tomosynthesis, applied in the case of breast, is investigated using synchrotron radiation. Methods: An angular data set of 21 images of a complex phantom with heterogeneous tissue-mimicking background was obtained using the SYRMEP beamline at ELETTRA Synchrotron Light Laboratory, Trieste, Italy. The irradiated part was reconstructed using the multiple projection algorithm (MPA) and the filtered backprojection with ramp followed by hamming windows (FBR-RH) and filtered backprojection with ramp (FBP-R). Additionally, an algorithm for reducing the noise in reconstructed planes based on noise mask subtraction from the planes of the originally reconstructed volume using MPA (MPA-NM) has been further developed. The reconstruction techniques were evaluated in terms of calculations and comparison of the contrast-to-noise ratio (CNR) and artifact spread function. Results: It was found that the MPA-NM resulted in higher CNR, comparable with the CNR of FBP-RH for high contrast details. Low contrast objects are well visualized and characterized by high CNR using the simple MPA and the MPA-NM. In addition, the image quality of the reconstructed features in terms of CNR and visual appearance as a function of the initial number of projection images and the reconstruction arc was carried out. Slices reconstructed with more input projection images result in less reconstruction artifacts and higher detail CNR, while those reconstructed from projection images acquired in reduced angular range causes pronounced streak artifacts. Conclusions: Of the reconstruction algorithms implemented, the MPA-NM and MPA are a good choice for detecting low contrast objects, while the FBP-RH, FBP-R, and MPA-NM provide high CNR and well outlined edges in case of microcalcifications.

2010-01-01

75

Evaluation of digital breast tomosynthesis reconstruction algorithms using synchrotron radiation in standard geometry  

Energy Technology Data Exchange (ETDEWEB)

Purpose: In this article, the image quality of reconstructed volumes by four algorithms for digital tomosynthesis, applied in the case of breast, is investigated using synchrotron radiation. Methods: An angular data set of 21 images of a complex phantom with heterogeneous tissue-mimicking background was obtained using the SYRMEP beamline at ELETTRA Synchrotron Light Laboratory, Trieste, Italy. The irradiated part was reconstructed using the multiple projection algorithm (MPA) and the filtered backprojection with ramp followed by hamming windows (FBR-RH) and filtered backprojection with ramp (FBP-R). Additionally, an algorithm for reducing the noise in reconstructed planes based on noise mask subtraction from the planes of the originally reconstructed volume using MPA (MPA-NM) has been further developed. The reconstruction techniques were evaluated in terms of calculations and comparison of the contrast-to-noise ratio (CNR) and artifact spread function. Results: It was found that the MPA-NM resulted in higher CNR, comparable with the CNR of FBP-RH for high contrast details. Low contrast objects are well visualized and characterized by high CNR using the simple MPA and the MPA-NM. In addition, the image quality of the reconstructed features in terms of CNR and visual appearance as a function of the initial number of projection images and the reconstruction arc was carried out. Slices reconstructed with more input projection images result in less reconstruction artifacts and higher detail CNR, while those reconstructed from projection images acquired in reduced angular range causes pronounced streak artifacts. Conclusions: Of the reconstruction algorithms implemented, the MPA-NM and MPA are a good choice for detecting low contrast objects, while the FBP-RH, FBP-R, and MPA-NM provide high CNR and well outlined edges in case of microcalcifications.

Bliznakova, K.; Kolitsi, Z.; Speller, R. D.; Horrocks, J. A.; Tromba, G.; Pallikarakis, N. [Department of Medical Physics, School of Medicine, University of Patras, Rio, Patras GR-26500 (Greece); Department of Medical Physics and Bioengineering, University College London, London WC1E 6BT (United Kingdom); Clinical Physics Group, St. Bartholomew' s Hospital, Barts and the London NHS Trust, London EC1A 7BE (United Kingdom); ELETTRA, Basovizza, Trieste I-34012 (Italy); Department of Medical Physics, School of Medicine, University of Patras, Rio, Patras GR-26500 (Greece)

2010-04-15

76

Dose fractionation theorem in 3-D reconstruction (tomography)  

Energy Technology Data Exchange (ETDEWEB)

It is commonly assumed that the large number of projections for single-axis tomography precludes its application to most beam-labile specimens. However, Hegerl and Hoppe have pointed out that the total dose required to achieve statistical significance for each voxel of a computed 3-D reconstruction is the same as that required to obtain a single 2-D image of that isolated voxel, at the same level of statistical significance. Thus a statistically significant 3-D image can be computed from statistically insignificant projections, as along as the total dosage that is distributed among these projections is high enough that it would have resulted in a statistically significant projection, if applied to only one image. We have tested this critical theorem by simulating the tomographic reconstruction of a realistic 3-D model created from an electron micrograph. The simulations verify the basic conclusions of high absorption, signal-dependent noise, varying specimen contrast and missing angular range. Furthermore, the simulations demonstrate that individual projections in the series of fractionated-dose images can be aligned by cross-correlation because they contain significant information derived from the summation of features from different depths in the structure. This latter information is generally not useful for structural interpretation prior to 3-D reconstruction, owing to the complexity of most specimens investigated by single-axis tomography. These results, in combination with dose estimates for imaging single voxels and measurements of radiation damage in the electron microscope, demonstrate that it is feasible to use single-axis tomography with soft X-ray microscopy of frozen-hydrated specimens.

Glaeser, R.M. [Lawrence Berkeley National Lab., CA (United States)

1997-02-01

77

A comparison of reconstruction algorithms for C-arm mammography tomosynthesis  

International Nuclear Information System (INIS)

Digital tomosynthesis is an imaging technique to produce a tomographic image from a series of angular digital images in a manner similar to conventional focal plane tomography. Unlike film focal plane tomography, the acquisition of the data in a C-arm geometry causes the image receptor to be positioned at various angles to the reconstruction tomogram. The digital nature of the data allows for input images to be combined into the desired plane with the flexibility of generating tomograms of many separate planes from a single set of input data. Angular datasets were obtained of a low contrast detectability (LCD) phantom and cadaver breast utilizing a Lorad stereotactic biopsy unit with a coupled source and digital detector in a C-arm configuration. Datasets of 9 and 41 low-dose projections were collected over a 30 deg. angular range. Tomographic images were reconstructed using a Backprojection (BP) algorithm, an Iterative Subtraction (IS) algorithm that allows the partial subtraction of out-of-focus planes, and an Algebraic Reconstruction (AR) algorithm. These were compared with single view digital radiographs. The methods' effectiveness at enhancing visibility of an obscured LCD phantom was quantified in terms of the Signal to Noise Ratio (SNR), and Signal to Background Ratio (SBR), all normalized to the metric value for the single projection image. The methods' effectiveness at removing ghosting artifacts in a cadaver breast was quantified in terms of the Artifact Spread Function (ASF). The technology proved effective at partially removing out of focus structures and enhancing SNR and SBR. The normalized SNR was highest at 4.85 for the obscured LCD phantom, using nine projections and IS algorithm. The normalized SBR was highest at 23.2 for the obscured LCD phantom, using 41 projections and an AR algorithm. The highest normalized metric values occurred with the obscured phantom. This supports the assertion that the greatest value of tomosynthesis is in imaging fibroglandular breasts. The ASF performance was best with the AR technique and nine projections.

2006-01-01

78

A comparative study of limited-angle cone-beam reconstruction methods for breast tomosynthesis  

International Nuclear Information System (INIS)

Digital tomosynthesis mammography (DTM) is a promising new modality for breast cancer detection. In DTM, projection-view images are acquired at a limited number of angles over a limited angular range and the imaged volume is reconstructed from the two-dimensional projections, thus providing three-dimensional structural information of the breast tissue. In this work, we investigated three representative reconstruction methods for this limited-angle cone-beam tomographic problem, including the backprojection (BP) method, the simultaneous algebraic reconstruction technique (SART) and the maximum likelihood method with the convex algorithm (ML-convex). The SART and ML-convex methods were both initialized with BP results to achieve efficient reconstruction. A second generation GE prototype tomosynthesis mammography system with a stationary digital detector was used for image acquisition. Projection-view images were acquired from 21 angles in 3 deg. increments over a ±30 deg. angular range. We used an American College of Radiology phantom and designed three additional phantoms to evaluate the image quality and reconstruction artifacts. In addition to visual comparison of the reconstructed images of different phantom sets, we employed the contrast-to-noise ratio (CNR), a line profile of features, an artifact spread function (ASF), a relative noise power spectrum (NPS), and a line object spread function (LOSF) to quantitatively evaluate the reconstruction results. It was found that for the phantoms with homogeneous background, the BP method resulted in less noisy tomosynthesized images and higher CNR values for masses than the SART and ML-convex methods. However, the two iterative methods provided greater contrast enhancement for both masses and calcification, sharper LOSF, and reduced interplane blurring and artifacts with better ASF behaviors for masses. For a contrast-detail phantom with heterogeneous tissue-mimicking background, the BP method had strong blurring artifacts along the x-ray source motion direction that obscured the contrast-detail objects, while the other two methods can remove the superimposed breast structures and significantly improve object conspicuity. With a properly selected relaxation parameter, the SART method with one iteration can provide tomosynthesized images comparable to those obtained from the ML-convex method with seven iterations, when BP results were used as initialization for both methods.

2006-01-01

79

Reconstruction of hidden 3D shapes using diffuse reflections  

CERN Multimedia

We analyze multi-bounce propagation of light in an unknown hidden volume and demonstrate that the reflected light contains sufficient information to recover the 3D structure of the hidden scene. We formulate the forward and inverse theory of secondary and tertiary scattering reflection using ideas from energy front propagation and tomography. We show that using careful choice of approximations, such as Fresnel approximation, greatly simplifies this problem and the inversion can be achieved via a backpropagation process. We provide a theoretical analysis of the invertibility, uniqueness and choices of space-time-angle dimensions using synthetic examples. We show that a 2D streak camera can be used to discover and reconstruct hidden geometry. Using a 1D high speed time of flight camera, we show that our method can be used recover 3D shapes of objects "around the corner".

Gupta, Otkrist; Willwacher, Thomas; Veeraraghavan, Ashok; Raskar, Ramesh

2012-01-01

80

Reconstruction of hidden 3D shapes using diffuse reflections.  

UK PubMed Central (United Kingdom)

We analyze multi-bounce propagation of light in an unknown hidden volume and demonstrate that the reflected light contains sufficient information to recover the 3D structure of the hidden scene. We formulate the forward and inverse theory of secondary scattering using ideas from energy front propagation and tomography. We show that using Fresnel approximation greatly simplifies this problem and the inversion can be achieved via a backpropagation process. We study the invertibility, uniqueness and choices of space-time-angle dimensions using synthetic examples. We show that a 2D streak camera can be used to discover and reconstruct hidden geometry. Using a 1D high speed time of flight camera, we show that our method can be used recover 3D shapes of objects "around the corner".

Gupta O; Willwacher T; Velten A; Veeraraghavan A; Raskar R

2012-08-01

 
 
 
 
81

Reconstruction of hidden 3D shapes using diffuse reflections.  

Science.gov (United States)

We analyze multi-bounce propagation of light in an unknown hidden volume and demonstrate that the reflected light contains sufficient information to recover the 3D structure of the hidden scene. We formulate the forward and inverse theory of secondary scattering using ideas from energy front propagation and tomography. We show that using Fresnel approximation greatly simplifies this problem and the inversion can be achieved via a backpropagation process. We study the invertibility, uniqueness and choices of space-time-angle dimensions using synthetic examples. We show that a 2D streak camera can be used to discover and reconstruct hidden geometry. Using a 1D high speed time of flight camera, we show that our method can be used recover 3D shapes of objects "around the corner". PMID:23038550

Gupta, Otkrist; Willwacher, Thomas; Velten, Andreas; Veeraraghavan, Ashok; Raskar, Ramesh

2012-08-13

82

Fast implementations of reconstruction-based scatter compensation in fully 3D SPECT image reconstruction  

International Nuclear Information System (INIS)

Accurate scatter compensation in SPECT can be performed by modelling the scatter response function during the reconstruction process. This method is called reconstruction-based scatter compensation (RBSC). It has been shown that RBSC has a number of advantages over other methods of compensating for scatter, but using RBSC for fully 3D compensation has resulted in prohibitively long reconstruction times. In this work we propose two new methods that can be used in conjunction with existing methods to achieve marked reductions in RBSC reconstruction times. The first method, coarse-grid scatter modelling, significantly accelerates the scatter model by exploiting the fact that scatter is dominated by low-frequency information. The second method, intermittent RBSC, further accelerates the reconstruction process by limiting the number of iterations during which scatter is modelled. The fast implementations were evaluated using a Monte Carlo simulated experiment of the 3D MCAT phantom with 99mTc tracer, and also using experimentally acquired data with 201Tl tracer. Results indicated that these fast methods can reconstruct, with fully 3D compensation, images very similar to those obtained using standard RBSC methods, and in reconstruction times that are an order of magnitude shorter. Using these methods, fully 3D iterative reconstruction with RBSC can be performed well within the realm of clinically realistic times (under 10 minutes for 64x64x24 image reconstruction). (author)

1998-01-01

83

3D Reconstruction in Spiral Multislice CT Scans  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction & Background: The rapid development of spiral (helical) computed tomography (CT) has resulted in exciting new applications for CT. One of these applications, three-dimensional (3D) CT with volume ren-dering, is now a major area of clinical and academic interest. One of the greatest advantages of spiral CT with 3D volume rendering is that it provides all the necessary information in a single radiologic study (and there-fore at the lowest possible price) in cases that previously required two or more studies. Three-dimensional vol-ume rendering generates clinically accurate and immediately available images from the full CT data set with-out extensive editing. It allows the radiologist and clinician to address specific questions concerning patient care by interactively exploring different aspects of the data set. Three-dimensional images integrate a series of axial CT sections into a form that is often easier to interpret than the sections themselves and can be made to appear similar to other more familiar images such as catheter angiograms. The data are organized into a 3D matrix of volume elements (voxels). The screen of the computer monitor is a 2D-surface composed of discrete picture elements (pixels). Presenting what is stored in memory (ie, floating within the monitor) on a 2D-screen is a challenge, but it is the very problem that 3D reconstruc-tion software has creatively solved. Voxel selection is usually accomplished by projecting lines (rays) through the data set that correspond to the pixel matrix of the desired 2D image. Differences in the images produced with various 3D rendering techniques are the result of variations in how voxels are selected and weighted. In this article, I compare 3D volume rendering of spiral CT data with other rendering techniques (shaded surface display, maximum intensity projection) and present a brief history of 3D volume rendering and discuss the im-plementation of this promising technology in terms of strategies for volume data management, selection of rendering parameters, and features of data display. In addition, I present recent research on the accuracy of the technique in specific medical applications and discuss a number of current clinical applications of 3D volume rendering of spiral CT data.

M. Ghafouri

2005-01-01

84

The Sinogram Polygonizer for Reconstructing 3D Shapes.  

Science.gov (United States)

This paper proposes a novel approach, the sinogram polygonizer, for directly reconstructing 3D shapes from sinograms (i.e., the primary output from X-ray computed tomography (CT) scanners consisting of projection image sequences of an object shown from different viewing angles). To obtain a polygon mesh approximating the surface of a scanned object, a grid-based isosurface polygonizer, such as Marching Cubes, has been conventionally applied to the CT volume reconstructed from a sinogram. In contrast, the proposed method treats CT values as a continuous function and directly extracts a triangle mesh based on tetrahedral mesh deformation. This deformation involves quadratic error metric minimization and optimal Delaunay triangulation for the generation of accurate, high-quality meshes. Thanks to the analytical gradient estimation of CT values, sharp features are well approximated, even though the generated mesh is very coarse. Moreover, this approach eliminates aliasing artifacts on triangle meshes. PMID:24029910

Yamanaka, Daiki; Ohtake, Yutaka; Suzuki, Hiromasa

2013-11-01

85

Digital 3D facial reconstruction of George Washington  

Science.gov (United States)

PRISM is a focal point of interdisciplinary research in geometric modeling, computer graphics and visualization at Arizona State University. Many projects in the last ten years have involved laser scanning, geometric modeling and feature extraction from such data as archaeological vessels, bones, human faces, etc. This paper gives a brief overview of a recently completed project on the 3D reconstruction of George Washington (GW). The project brought together forensic anthropologists, digital artists and computer scientists in the 3D digital reconstruction of GW at 57, 45 and 19 including detailed heads and bodies. Although many other scanning projects such as the Michelangelo project have successfully captured fine details via laser scanning, our project took it a step further, i.e. to predict what that individual (in the sculpture) might have looked like both in later and earlier years, specifically the process to account for reverse aging. Our base data was GWs face mask at Morgan Library and Hudons bust of GW at Mount Vernon, both done when GW was 53. Additionally, we scanned the statue at the Capitol in Richmond, VA; various dentures, and other items. Other measurements came from clothing and even portraits of GW. The digital GWs were then milled in high density foam for a studio to complete the work. These will be unveiled at the opening of the new education center at Mt Vernon in fall 2006.

Razdan, Anshuman; Schwartz, Jeff; Tocheri, Mathew; Hansford, Dianne

2006-02-01

86

The Role of Color Attributes and Similarity Grouping in 3-D Building Reconstruction  

UK PubMed Central (United Kingdom)

This paper addresses two major issues: 3-D building reconstruction and the role of colorattributes and similarity grouping. We present ARUBA, a general framework for automated3-D building reconstruction from multiple color aerial images. After highlighting the strategyand concisely describing the framework and its 2-D and 3-D processing modules, we evaluatethe reconstructed roofs with respect to accurate reference data.

Olof Henricsson

87

Enhanced imaging of microcalcifications in digital breast tomosynthesis through improved image-reconstruction algorithms  

Energy Technology Data Exchange (ETDEWEB)

Purpose: The authors develop a practical, iterative algorithm for image-reconstruction in undersampled tomographic systems, such as digital breast tomosynthesis (DBT). Methods: The algorithm controls image regularity by minimizing the image total p variation (TpV), a function that reduces to the total variation when p=1.0 or the image roughness when p=2.0. Constraints on the image, such as image positivity and estimated projection-data tolerance, are enforced by projection onto convex sets. The fact that the tomographic system is undersampled translates to the mathematical property that many widely varied resultant volumes may correspond to a given data tolerance. Thus the application of image regularity serves two purposes: (1) Reduction in the number of resultant volumes out of those allowed by fixing the data tolerance, finding the minimum image TpV for fixed data tolerance, and (2) traditional regularization, sacrificing data fidelity for higher image regularity. The present algorithm allows for this dual role of image regularity in undersampled tomography. Results: The proposed image-reconstruction algorithm is applied to three clinical DBT data sets. The DBT cases include one with microcalcifications and two with masses. Conclusions: Results indicate that there may be a substantial advantage in using the present image-reconstruction algorithm for microcalcification imaging.

Sidky, Emil Y.; Pan Xiaochuan; Reiser, Ingrid S.; Nishikawa, Robert M.; Moore, Richard H.; Kopans, Daniel B. [Department of Radiology, University of Chicago, 5841 S. Maryland Avenue Chicago, Illinois 60637 (United States); Massachusetts General Hospital, Boston, Massachusetts 02114 (United States)

2009-11-15

88

Enhanced imaging of microcalcifications in digital breast tomosynthesis through improved image-reconstruction algorithms  

International Nuclear Information System (INIS)

Purpose: The authors develop a practical, iterative algorithm for image-reconstruction in undersampled tomographic systems, such as digital breast tomosynthesis (DBT). Methods: The algorithm controls image regularity by minimizing the image total p variation (TpV), a function that reduces to the total variation when p=1.0 or the image roughness when p=2.0. Constraints on the image, such as image positivity and estimated projection-data tolerance, are enforced by projection onto convex sets. The fact that the tomographic system is undersampled translates to the mathematical property that many widely varied resultant volumes may correspond to a given data tolerance. Thus the application of image regularity serves two purposes: (1) Reduction in the number of resultant volumes out of those allowed by fixing the data tolerance, finding the minimum image TpV for fixed data tolerance, and (2) traditional regularization, sacrificing data fidelity for higher image regularity. The present algorithm allows for this dual role of image regularity in undersampled tomography. Results: The proposed image-reconstruction algorithm is applied to three clinical DBT data sets. The DBT cases include one with microcalcifications and two with masses. Conclusions: Results indicate that there may be a substantial advantage in using the present image-reconstruction algorithm for microcalcification imaging.

2009-01-01

89

Image artifacts in digital breast tomosynthesis: Investigation of the effects of system geometry and reconstruction parameters using a linear system approach  

Energy Technology Data Exchange (ETDEWEB)

Digital breast tomosynthesis (DBT) is a three-dimensional (3D) x-ray imaging modality that reconstructs image slices parallel to the detector plane. Image acquisition is performed using a limited angular range (less than 50 degrees) and a limited number of projection views (less than 50 views). Due to incomplete data sampling, image artifacts are unavoidable in DBT. In this preliminary study, the image artifacts in DBT were investigated systematically using a linear system approximation. A cascaded linear system model of DBT was developed to calculate the 3D presampling modulation transfer function (MTF) with different image acquisition geometries and reconstruction filters using a filtered backprojection (FBP) algorithm. A thin, slanted tungsten (W) wire was used to measure the presampling MTF of the DBT system in the cross-sectional plane defined by the thickness (z-) and tube travel (x-) directions. The measurement was in excellent agreement with the calculation using the model. A small steel bead was used to calculate the artifact spread function (ASF) of the DBT system. The ASF was correlated with the convolution of the two-dimensional (2D) point spread function (PSF) of the system and the object function of the bead. The results showed that the cascaded linear system model can be used to predict the magnitude of image artifacts of small, high-contrast objects with different image acquisition geometry and reconstruction filters.

Hu Yuehoung; Zhao Bo; Zhao Wei [Department of Radiology, State University of New York at Stony Brook, L-4 120 Health Sciences Center, Stony Brook, New York 11794-8460 (United States)

2008-12-15

90

Image artifacts in digital breast tomosynthesis: Investigation of the effects of system geometry and reconstruction parameters using a linear system approach  

International Nuclear Information System (INIS)

Digital breast tomosynthesis (DBT) is a three-dimensional (3D) x-ray imaging modality that reconstructs image slices parallel to the detector plane. Image acquisition is performed using a limited angular range (less than 50 degrees) and a limited number of projection views (less than 50 views). Due to incomplete data sampling, image artifacts are unavoidable in DBT. In this preliminary study, the image artifacts in DBT were investigated systematically using a linear system approximation. A cascaded linear system model of DBT was developed to calculate the 3D presampling modulation transfer function (MTF) with different image acquisition geometries and reconstruction filters using a filtered backprojection (FBP) algorithm. A thin, slanted tungsten (W) wire was used to measure the presampling MTF of the DBT system in the cross-sectional plane defined by the thickness (z-) and tube travel (x-) directions. The measurement was in excellent agreement with the calculation using the model. A small steel bead was used to calculate the artifact spread function (ASF) of the DBT system. The ASF was correlated with the convolution of the two-dimensional (2D) point spread function (PSF) of the system and the object function of the bead. The results showed that the cascaded linear system model can be used to predict the magnitude of image artifacts of small, high-contrast objects with different image acquisition geometry and reconstruction filters.

2008-01-01

91

A diffusion-based truncated projection artifact reduction method for iterative digital breast tomosynthesis reconstruction  

Science.gov (United States)

Digital breast tomosynthesis (DBT) has strong promise to improve sensitivity for detecting breast cancer. DBT reconstruction estimates the breast tissue attenuation using projection views (PVs) acquired in a limited angular range. Because of the limited field of view (FOV) of the detector, the PVs may not completely cover the breast in the x-ray source motion direction at large projection angles. The voxels in the imaged volume cannot be updated when they are outside the FOV, thus causing a discontinuity in intensity across the FOV boundaries in the reconstructed slices, which we refer to as the truncated projection artifact (TPA). Most existing TPA reduction methods were developed for the filtered backprojection method in the context of computed tomography. In this study, we developed a new diffusion-based method to reduce TPAs during DBT reconstruction using the simultaneous algebraic reconstruction technique (SART). Our TPA reduction method compensates for the discontinuity in background intensity outside the FOV of the current PV after each PV updating in SART. The difference in voxel values across the FOV boundary is smoothly diffused to the region beyond the FOV of the current PV. Diffusion-based background intensity estimation is performed iteratively to avoid structured artifacts. The method is applicable to TPA in both the forward and backward directions of the PVs and for any number of iterations during reconstruction. The effectiveness of the new method was evaluated by comparing the visual quality of the reconstructed slices and the measured discontinuities across the TPA with and without artifact correction at various iterations. The results demonstrated that the diffusion-based intensity compensation method reduced the TPA while preserving the detailed tissue structures. The visibility of breast lesions obscured by the TPA was improved after artifact reduction.

Lu, Yao; Chan, Heang-Ping; Wei, Jun; Hadjiiski, Lubomir M.

2013-02-01

92

A diffusion-based truncated projection artifact reduction method for iterative digital breast tomosynthesis reconstruction.  

UK PubMed Central (United Kingdom)

Digital breast tomosynthesis (DBT) has strong promise to improve sensitivity for detecting breast cancer. DBT reconstruction estimates the breast tissue attenuation using projection views (PVs) acquired in a limited angular range. Because of the limited field of view (FOV) of the detector, the PVs may not completely cover the breast in the x-ray source motion direction at large projection angles. The voxels in the imaged volume cannot be updated when they are outside the FOV, thus causing a discontinuity in intensity across the FOV boundaries in the reconstructed slices, which we refer to as the truncated projection artifact (TPA). Most existing TPA reduction methods were developed for the filtered backprojection method in the context of computed tomography. In this study, we developed a new diffusion-based method to reduce TPAs during DBT reconstruction using the simultaneous algebraic reconstruction technique (SART). Our TPA reduction method compensates for the discontinuity in background intensity outside the FOV of the current PV after each PV updating in SART. The difference in voxel values across the FOV boundary is smoothly diffused to the region beyond the FOV of the current PV. Diffusion-based background intensity estimation is performed iteratively to avoid structured artifacts. The method is applicable to TPA in both the forward and backward directions of the PVs and for any number of iterations during reconstruction. The effectiveness of the new method was evaluated by comparing the visual quality of the reconstructed slices and the measured discontinuities across the TPA with and without artifact correction at various iterations. The results demonstrated that the diffusion-based intensity compensation method reduced the TPA while preserving the detailed tissue structures. The visibility of breast lesions obscured by the TPA was improved after artifact reduction.

Lu Y; Chan HP; Wei J; Hadjiiski LM

2013-02-01

93

3D-MSCT imaging of bullet trajectory in 3D crime scene reconstruction: Two case reports.  

UK PubMed Central (United Kingdom)

Postmortem investigations are increasingly assisted by three-dimensional multi-slice computed tomography (3D-MSCT) and have become more available to forensic pathologists over the past 20years. In cases of ballistic wounds, 3D-MSCT can provide an accurate description of the bullet location, bone fractures and, more interestingly, a clear visual of the intracorporeal trajectory (bullet track). These forensic medical examinations can be combined with tridimensional bullet trajectory reconstructions created by forensic ballistic experts. These case reports present the implementation of tridimensional methods and the results of 3D crime scene reconstruction in two cases. The authors highlight the value of collaborations between police forensic experts and forensic medicine institutes through the incorporation of 3D-MSCT data in a crime scene reconstruction, which is of great interest in forensic science as a clear visual communication tool between experts and the court.

Colard T; Delannoy Y; Bresson F; Marechal C; Raul JS; Hedouin V

2013-08-01

94

Rapid reconstruction of 3D structure of fibrous media  

CERN Document Server

Characterization of transport properties of porous media is increasingly relying on computational methods that require reconstruction of the media structure. We present a simple method of constructing the 3D surface of fibrous porous media - the gas diffusion layer (GDL) used as the porous electrode in PEM fuel cells. The method is based on extending the depth-of-field on the whole attainable thickness of the GDL. A series of images of the GDL sample is recorded by the sequential movement of the sample with respect to the microscope focus. Different layers of the surface of the sample appear in focus in the different images in the series. The indexed series of the in-focus portions of the sample surface is combined into one sharp 2D image and interpolated into the 3D surface representing the surface of an original GDL sample. The method uses a conventional upright stage microscope that is operated manually, the inexpensive Helicon Focus software, and the open source MeshLab software. The accuracy of the recon...

Berejnov, Viatcheslav; Djilali, Ned

2009-01-01

95

3-D Reconstruction of Medical Image Using Wavelet Transform and Snake Model  

Directory of Open Access Journals (Sweden)

Full Text Available Medical image segmentation is an important step in 3-D reconstruction, and 3-D reconstruction from medical images is an important application of computer graphics and biomedicine image processing. An improved image segmentation method which is suitable for 3-D reconstruction is presented in this paper. A 3-D reconstruction algorithm is used to reconstruct the 3-D model from medical images. Rough edge is obtained by multi-scale wavelet transform at first. With the rough edge, improved gradient vector flow snake model is used and the object contour in the image is found. In the experiments, we reconstruct 3-D models of kidney, liver and brain putamen. The performances of the experiments indicate that the new algorithm can produce accurate 3-D reconstruction.

Jinyong Cheng; Yihui Liu

2009-01-01

96

Three-dimensional linear system analysis for breast tomosynthesis.  

UK PubMed Central (United Kingdom)

The optimization of digital breast tomosynthesis (DBT) geometry and reconstruction is crucial for the clinical translation of this exciting new imaging technique. In the present work, the authors developed a three-dimensional (3D) cascaded linear system model for DBT to investigate the effects of detector performance, imaging geometry, and image reconstruction algorithm on the reconstructed image quality. The characteristics of a prototype DBT system equipped with an amorphous selenium flat-panel detector and filtered backprojection reconstruction were used as an example in the implementation of the linear system model. The propagation of signal and noise in the frequency domain was divided into six cascaded stages incorporating the detector performance, imaging geometry, and reconstruction filters. The reconstructed tomosynthesis imaging quality was characterized by spatial frequency dependent presampling modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) in 3D. The results showed that both MTF and NPS were affected by the angular range of the tomosynthesis scan and the reconstruction filters. For image planes parallel to the detector (in-plane), MTF at low frequencies was improved with increase in angular range. The shape of the NPS was affected by the reconstruction filters. Noise aliasing in 3D could be introduced by insufficient voxel sampling, especially in the z (slice-thickness) direction where the sampling distance (slice thickness) could be more than ten times that for in-plane images. Aliasing increases the noise at high frequencies, which causes degradation in DQE. Application of a reconstruction filter that limits the frequency components beyond the Nyquist frequency in the z direction, referred to as the slice thickness filter, eliminates noise aliasing and improves 3D DQE. The focal spot blur, which arises from continuous tube travel during tomosynthesis acquisition, could degrade DQE significantly because it introduces correlation in signal only, not NPS.

Zhao B; Zhao W

2008-12-01

97

3D fast reconstruction in positron emission tomography; Reconstrucao 3D rapida em tomografia por emissao de positrons  

Energy Technology Data Exchange (ETDEWEB)

The issue of long reconstruction times in positron emission tomography (PET) has been addressed from several points of view, resulting in an affordable dedicated system capable of handling routine 3D reconstructions in a few minutes per frame : on the hardware side using fast processors and a parallel architecture, and on the software side, using efficient implementation of computationally less intensive algorithms 6 refs., 2 figs., 1 tab.

Egger, M.L. [Sao Paulo Univ., SP (Brazil). Instituto do Coracao. Div. de Informatica; Scheurer, A. Hermann; Joseph, C. [Lausanne Univ. (Switzerland). Inst. de Physique Nucleaire; Morel, C. [Geneva Univ. (Switzerland). Hospital. Div. of Nuclear Medicine

1996-12-31

98

3-D Building Reconstruction with ARUBA: A Qualitative and Quantitative Evaluation  

UK PubMed Central (United Kingdom)

Reliable and accurate 3-D reconstruction of man-made objects is essential for many applicationsusing digital 3-D city models. Manual reconstruction of buildings from aerial images is time consumingand requires skilled personnel, hence large efforts are being directed towards the automationof building detection and reconstruction. In this paper we present ARUBA--- a frameworkfor automated 3-D building reconstruction. After highlighting our strategy and concisely describingthe framework and its modules, we evaluate the reconstructed roofs relative to accurate referencedata based on three criteria: completeness, geometric accuracy and shape similarity. Finally,we interpret the results of the performance evaluation and make suggestions for improvements.

Olof Henricsson; Emmanuel Baltsavias

99

Advanced system for 3D dental anatomy reconstruction and 3D tooth movement simulation during orthodontic treatment  

Science.gov (United States)

This paper describes a new method for 3D orthodontics treatment simulation developed for an orthodontics planning system (MAGALLANES). We develop an original system for 3D capturing and reconstruction of dental anatomy that avoid use of dental casts in orthodontic treatments. Two original techniques are presented, one direct in which data are acquired directly form patient's mouth by mean of low cost 3D digitizers, and one mixed in which data are obtained by 3D digitizing of hydrocollids molds. FOr this purpose we have designed and manufactured an optimized optical measuring system based on laser structured light. We apply these 3D dental models to simulate 3D movement of teeth, including rotations, during orthodontic treatment. The proposed algorithms enable to quantify the effect of orthodontic appliance on tooth movement. The developed techniques has been integrated in a system named MAGALLANES. This original system present several tools for 3D simulation and planning of orthodontic treatments. The prototype system has been tested in several orthodontic clinic with very good results.

Monserrat, Carlos; Alcaniz, Mariano; Juan, M. Carmen; Grau Colomer, Vincente; Albalat, Salvador

1997-05-01

100

Selective-diffusion regularization for enhancement of microcalcifications in digital breast tomosynthesis reconstruction  

International Nuclear Information System (INIS)

Purpose: Digital breast tomosynthesis (DBT) has been shown to improve mass detection. Detection of microcalcifications is more challenging because of the large breast volume to be searched for subtle signals. The simultaneous algebraic reconstruction technique (SART) was found to provide good image quality for DBT, but the image noise is amplified with an increasing number of iterations. In this study, the authors developed a selective-diffusion (SD) method for noise regularization with SART to improve the contrast-to-noise ratio (CNR) of microcalcifications in the DBT slices for human or machine detection. Methods: The SD method regularizes SART reconstruction during updating with each projection view. Potential microcalcifications are differentiated from the noisy background by estimating the local gradient information. Different degrees of regularization are applied to the signal or noise classes, such that the microcalcifications will be enhanced while the noise is suppressed. The new SD method was compared to several current methods, including the quadratic Laplacian (QL) method, the total variation (TV) method, and the nonconvex total p-variation (TpV) method for noise regularization with SART. A GE GEN2 prototype DBT system with a stationary digital detector was used for the acquisition of DBT scans at 21 angles in 3 deg. increments over a ±30 deg. range. The reconstruction image quality without regularization and that with the different regularization methods were compared using the DBT scans of an American College of Radiology phantom and a human subject. The CNR and the full width at half maximum (FWHM) of the line profiles of microcalcifications within the in-focus DBT slices were used as image quality measures. Results: For the comparison of large microcalcifications in the DBT data of the subject, the SD method resulted in comparable CNR to the nonconvex TpV method. Both of them performed better than the other two methods. For subtle microcalcifications, the SD method was superior to other methods in terms of CNR. In both the subject and phantom DBT data, for large microcalcifications, the FWHM of the SD method was comparable to that without regularization, which was wider than that of the TV type methods. For subtle microcalcifications, the SD method had comparable FWHM values to the TV type methods. All three regularization methods were superior to the QL method in terms of FWHM. Conclusions: The SART regularized by the selective-diffusion method enhanced the CNR and preserved the sharpness of microcalcifications. In comparison with three existing regularization methods, the selective-diffusion regularization was superior to the other methods for subtle microcalcifications.

2010-01-01

 
 
 
 
101

Selective-diffusion regularization for enhancement of microcalcifications in digital breast tomosynthesis reconstruction  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Digital breast tomosynthesis (DBT) has been shown to improve mass detection. Detection of microcalcifications is more challenging because of the large breast volume to be searched for subtle signals. The simultaneous algebraic reconstruction technique (SART) was found to provide good image quality for DBT, but the image noise is amplified with an increasing number of iterations. In this study, the authors developed a selective-diffusion (SD) method for noise regularization with SART to improve the contrast-to-noise ratio (CNR) of microcalcifications in the DBT slices for human or machine detection. Methods: The SD method regularizes SART reconstruction during updating with each projection view. Potential microcalcifications are differentiated from the noisy background by estimating the local gradient information. Different degrees of regularization are applied to the signal or noise classes, such that the microcalcifications will be enhanced while the noise is suppressed. The new SD method was compared to several current methods, including the quadratic Laplacian (QL) method, the total variation (TV) method, and the nonconvex total p-variation (TpV) method for noise regularization with SART. A GE GEN2 prototype DBT system with a stationary digital detector was used for the acquisition of DBT scans at 21 angles in 3 deg. increments over a {+-}30 deg. range. The reconstruction image quality without regularization and that with the different regularization methods were compared using the DBT scans of an American College of Radiology phantom and a human subject. The CNR and the full width at half maximum (FWHM) of the line profiles of microcalcifications within the in-focus DBT slices were used as image quality measures. Results: For the comparison of large microcalcifications in the DBT data of the subject, the SD method resulted in comparable CNR to the nonconvex TpV method. Both of them performed better than the other two methods. For subtle microcalcifications, the SD method was superior to other methods in terms of CNR. In both the subject and phantom DBT data, for large microcalcifications, the FWHM of the SD method was comparable to that without regularization, which was wider than that of the TV type methods. For subtle microcalcifications, the SD method had comparable FWHM values to the TV type methods. All three regularization methods were superior to the QL method in terms of FWHM. Conclusions: The SART regularized by the selective-diffusion method enhanced the CNR and preserved the sharpness of microcalcifications. In comparison with three existing regularization methods, the selective-diffusion regularization was superior to the other methods for subtle microcalcifications.

Lu Yao; Chan, Heang-Ping; Wei Jun; Hadjiiski, Lubomir M. [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2010-11-15

102

Techniques, clinical applications and limitations of 3D reconstruction in CT of the abdomen  

International Nuclear Information System (INIS)

Enhanced z-axis coverage with thin overlapping slices in breath-hold acquisitions with multidetector CT (MDCT) has considerably enhanced the quality of multiplanar 3D reconstruction. This pictorial essay describes the improvements in 3D reconstruction and technical aspects of 3D reconstruction and rendering techniques available for abdominal imaging. Clinical applications of 3D imaging in abdomen including liver, pancreaticobiliary system, urinary and gastrointestinal tracts and imaging before and after transplantation are discussed. In addition, this article briefly discusses the disadvantages of this-slice acquisitions including increasing numbers of transverse images, which must be reviewed by the radiologist.

2004-01-01

103

Techniques, clinical applications and limitations of 3D reconstruction in CT of the abdomen  

Energy Technology Data Exchange (ETDEWEB)

Enhanced z-axis coverage with thin overlapping slices in breath-hold acquisitions with multidetector CT (MDCT) has considerably enhanced the quality of multiplanar 3D reconstruction. This pictorial essay describes the improvements in 3D reconstruction and technical aspects of 3D reconstruction and rendering techniques available for abdominal imaging. Clinical applications of 3D imaging in abdomen including liver, pancreaticobiliary system, urinary and gastrointestinal tracts and imaging before and after transplantation are discussed. In addition, this article briefly discusses the disadvantages of this-slice acquisitions including increasing numbers of transverse images, which must be reviewed by the radiologist.

Maher, Michael M.; Kalra, Mannudeep K.; Sahani, Dushyant V.; Perumpillichira, James J.; Rizzo, Stephania; Saini, Sanjay; Mueller, Peter R. [Massachusetts General Hospital and Harvard Medical School, Boston (United States)

2004-03-15

104

Methodology for 3D reconstruction of objects for teaching virtual restoration  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we propose a methodology for 3D virtual reconstruction of objects that can be applied to virtual restoration. The methodology is based on an image-based modelling technique and allows generating a textured 3D mesh from a set of images. The proposed methodology consists in the following actions: obtain images of the object, processing of the images, 3D reconstruction of the object, finishing and completing details, restoration of the 3D virtual model. First, we review several frameworks and toolkits that can be used for image-based modelling and then a detail example of 3D reconstruction is presented. The advantage of this methodology for 3D virtual reconstruction is the use of inexpensive equipment, because only common video and computing devices are needed.

Silviu Butnariu; Florin Gîrbacia; Alex Orman

2013-01-01

105

The use of a Computer Aided Design (CAD) environment in 3D reconstruction of anatomic surfaces.  

UK PubMed Central (United Kingdom)

Paper presents an evaluation and comparison of two different types of software for generating a 3D model from medical imaging data: first, a dedicated 3D reconstruction Mimics interface, by Materialise and second, an engineering CAD (a Solid Works and AutoCAD) interface. Advantages and limitations of both software types are outlined and there some observations for 3D reconstruction of anatomic surfaces are presented.

Ciobanu O

2006-01-01

106

Three dimensional (3D) reconstruction of the rat ventricles  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study is to investigate the normal three dimensional (3D) shape of the ventricular system of rat brain. The shape and volume of ventricles can be correlated with clinical or other characteristics of illness. Recently, many diagnostic imaging techniques allow to get the 3D images of anatomical structures easily. So it is possible to determine the correlation between subjects and pattern of the structures. In this study, we constructed a 3D model of the rat ventricles and their related structures. It is possible to say that, ventricular system of rat brain was similar to the human’s completely. Understanding such patterns may eventually help to improve rat experiments’ vision. Furthermore, these 3D models can be used for virtual animations and stereotaxic trials in further studies.

Ozdemir MB; Akdogan I; Adiguzel E; Yonguc N

2005-01-01

107

[Application of image correction in 3D reconstruction of mandible from CT slices].  

UK PubMed Central (United Kingdom)

Precision registration of serial sections is an important step for 3-D image reconstruction. It directly affects the accuracy of the reconstructed result and parameter computation. This problem has been studied and demonstrated by many investigators, but the whole process has not yet reached good performance. In this paper, we discussed the registration of serial sections image of mandible and put forward a method of the soft registration-based transformation on the basis of the hard registration in consideration of the speciality of 3-D image reconstruction for the serial sections of mandible. Employing control points and using Affine Transformation and Extended Hough Transformation, we solved the problem of displacement on 3-D image reconstruction for serial secons and paved the way for reconstructing the mandible microstructure with reality. The results of experiments indicate that the 3D image reconstructed after registration has only a little distortion.

Yang W; Liu J; Liao M

2004-06-01

108

Characterization of masses in digital breast tomosynthesis: Comparison of machine learning in projection views and reconstructed slices  

International Nuclear Information System (INIS)

Purpose: In digital breast tomosynthesis (DBT), quasi-three-dimensional (3D) structural information is reconstructed from a small number of 2D projection view (PV) mammograms acquired over a limited angular range. The authors developed preliminary computer-aided diagnosis (CADx) methods for classification of malignant and benign masses and compared the effectiveness of analyzing lesion characteristics in the reconstructed DBT slices and in the PVs. Methods: A data set of MLO view DBT of 99 patients containing 107 masses (56 malignant and 51 benign) was collected at the Massachusetts General Hospital with IRB approval. The DBTs were obtained with a GE prototype system which acquired 11 PVs over a 50 deg. arc. The authors reconstructed the DBTs at 1 mm slice interval using a simultaneous algebraic reconstruction technique. The region of interest (ROI) containing the mass was marked by a radiologist in the DBT volume and the corresponding ROIs on the PVs were derived based on the imaging geometry. The subsequent processes were fully automated. For classification of masses using the DBT-slice approach, the mass on each slice was segmented by an active contour model initialized with adaptive k-means clustering. A spiculation likelihood map was generated by analysis of the gradient directions around the mass margin and spiculation features were extracted from the map. The rubber band straightening transform (RBST) was applied to a band of pixels around the segmented mass boundary. The RBST image was enhanced by Sobel filtering in the horizontal and vertical directions, from which run-length statistics texture features were extracted. Morphological features including those from the normalized radial length were designed to describe the mass shape. A feature space composed of the spiculation features, texture features, and morphological features extracted from the central slice alone and seven feature spaces obtained by averaging the corresponding features from three to 19 slices centered at the central slice were compared. For classification of masses using the PV approach, a feature extraction process similar to that described above for the DBT approach was performed on the ROIs from the individual PVs. Six feature spaces obtained from the central PV alone and by averaging the corresponding features from three to 11 PVs were formed. In each feature space for either the DBT-slice or the PV approach, a linear discriminant analysis classifier with stepwise feature selection was trained and tested using a two-loop leave-one-case-out resampling procedure. Simplex optimization was used to guide feature selection automatically within the training set in each leave-one-case-out cycle. The performance of the classifiers was evaluated by the area (Az) under the receiver operating characteristic curve. Results: The test Az values from the DBT-slice approach ranged from 0.87±0.03 to 0.93±0.02, while those from the PV approach ranged from 0.78±0.04 to 0.84±0.04. The highest test Az of 0.93±0.02 from the nine-DBT-slice feature space was significantly (p=0.006) better than the highest test Az of 0.84±0.04 from the nine-PV feature space. Conclusion: The features of breast lesions extracted from the DBT slices consistently provided higher classification accuracy than those extracted from the PV images.

2010-01-01

109

Characterization of masses in digital breast tomosynthesis: Comparison of machine learning in projection views and reconstructed slices  

Energy Technology Data Exchange (ETDEWEB)

Purpose: In digital breast tomosynthesis (DBT), quasi-three-dimensional (3D) structural information is reconstructed from a small number of 2D projection view (PV) mammograms acquired over a limited angular range. The authors developed preliminary computer-aided diagnosis (CADx) methods for classification of malignant and benign masses and compared the effectiveness of analyzing lesion characteristics in the reconstructed DBT slices and in the PVs. Methods: A data set of MLO view DBT of 99 patients containing 107 masses (56 malignant and 51 benign) was collected at the Massachusetts General Hospital with IRB approval. The DBTs were obtained with a GE prototype system which acquired 11 PVs over a 50 deg. arc. The authors reconstructed the DBTs at 1 mm slice interval using a simultaneous algebraic reconstruction technique. The region of interest (ROI) containing the mass was marked by a radiologist in the DBT volume and the corresponding ROIs on the PVs were derived based on the imaging geometry. The subsequent processes were fully automated. For classification of masses using the DBT-slice approach, the mass on each slice was segmented by an active contour model initialized with adaptive k-means clustering. A spiculation likelihood map was generated by analysis of the gradient directions around the mass margin and spiculation features were extracted from the map. The rubber band straightening transform (RBST) was applied to a band of pixels around the segmented mass boundary. The RBST image was enhanced by Sobel filtering in the horizontal and vertical directions, from which run-length statistics texture features were extracted. Morphological features including those from the normalized radial length were designed to describe the mass shape. A feature space composed of the spiculation features, texture features, and morphological features extracted from the central slice alone and seven feature spaces obtained by averaging the corresponding features from three to 19 slices centered at the central slice were compared. For classification of masses using the PV approach, a feature extraction process similar to that described above for the DBT approach was performed on the ROIs from the individual PVs. Six feature spaces obtained from the central PV alone and by averaging the corresponding features from three to 11 PVs were formed. In each feature space for either the DBT-slice or the PV approach, a linear discriminant analysis classifier with stepwise feature selection was trained and tested using a two-loop leave-one-case-out resampling procedure. Simplex optimization was used to guide feature selection automatically within the training set in each leave-one-case-out cycle. The performance of the classifiers was evaluated by the area (A{sub z}) under the receiver operating characteristic curve. Results: The test A{sub z} values from the DBT-slice approach ranged from 0.87{+-}0.03 to 0.93{+-}0.02, while those from the PV approach ranged from 0.78{+-}0.04 to 0.84{+-}0.04. The highest test A{sub z} of 0.93{+-}0.02 from the nine-DBT-slice feature space was significantly (p=0.006) better than the highest test A{sub z} of 0.84{+-}0.04 from the nine-PV feature space. Conclusion: The features of breast lesions extracted from the DBT slices consistently provided higher classification accuracy than those extracted from the PV images.

Chan, Heang-Ping; Wu Yita; Sahiner, Berkman; Wei, Jun; Helvie, Mark A.; Zhang Yiheng; Moore, Richard H.; Kopans, Daniel B.; Hadjiiski, Lubomir; Way, Ted [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts 02114 (United States); Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2010-07-15

110

Left ventricle volume estimation from 3D SPECT reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Our approach describes the three-dimensional reconstruction of the internal and external surfaces of the human's left ventricle from actual SPECT data. The reconstruction is a first process fitting in a complete VR application that will serve as an important diagnosis tool for hospitals. Beginning w...

Garcia-Panyella, O.; Susín Sánchez, Antonio

111

3D Reconstruction and Visualization of Volume Data in Electrical Capacitance Tomography  

Directory of Open Access Journals (Sweden)

Full Text Available Electrical capacitance tomography (ECT) is a non-invasive imaging technique that aims at visualization the permittivity distribution of dielectric materials based on the measured capacitances. In this paper, the 3D finite element models of a direct 3D ECT sensor with or without dielectric spheres inside the sensor are set up by using finite element modeling. The sensitivity analysis of the sensor is carried out by means of electric field intensity. A Landweber iteration method with non-zero threshold is presented to reconstruct 3D permittivity distributions directly. 3D visualization of the reconstructed result (volume data) is achieved by iso-surface. 3D images reconstructed and error analysis show that the Landweber iteration method with non-zero threshold has much better reconstruction performance compared with the classic Landweber iteration method.

Hua Yan; Yang Lu; Yifan Wang

2013-01-01

112

3-D Reconstruction From 2-D Radiographic Images and Its Application to Clinical Veterinary Medicine  

Science.gov (United States)

3D imaging technique is very important and indispensable in diagnosis. The main stream of the technique is one in which 3D image is reconstructed from a set of slice images, such as X-ray CT and MRI. However, these systems require large space and high costs. On the other hand, a low cost and small size 3D imaging system is needed in clinical veterinary medicine, for example, in the case of diagnosis in X-ray car or pasture area. We propose a novel 3D imaging technique using 2-D X-ray radiographic images. This system can be realized by cheaper system than X-ray CT and enables to get 3D image in X-ray car or portable X-ray equipment. In this paper, a 3D visualization technique from 2-D radiographic images is proposed and several reconstructions are shown. These reconstructions are evaluated by veterinarians.

Hamamoto, Kazuhiko; Sato, Motoyoshi

113

A methodology for testing for statistically significant differences between fully 3D PET reconstruction algorithms  

International Nuclear Information System (INIS)

We present a practical methodology for evaluating 3D PET reconstruction methods. It includes generation of random samples from a statistically described ensemble of 3D images resembling those to which PET would be applied in a medical situation, generation of corresponding projection data with noise and detector point spread function simulating those of a 3D PET scanner, assignment of figures of merit appropriate for the intended medical applications, optimization of the reconstruction algorithms on a training set of data, and statistical testing of the validity of hypotheses that say that two reconstruction algorithms perform equally well (from the point of view of a particular figure of merit) as compared to the alternative hypotheses that say that one of the algorithms outperforms the other. Although the methodology was developed with the 3D PET in mind, it can be used, with minor changes, for other 3D data collection methods, such as fully 3D CT or SPECT. (Author)

1994-01-01

114

Enhanced imaging colonoscopy facilitates dense motion-based 3D reconstruction.  

UK PubMed Central (United Kingdom)

We propose a novel approach for estimating a dense 3D model of neoplasia in colonoscopy using enhanced imaging endoscopy modalities. Estimating a dense 3D model of neoplasia is important to make 3D measurements and to classify the superficial lesions in standard frameworks such as the Paris classification. However, it is challenging to obtain decent dense 3D models using computer vision techniques such as Structure-from-Motion due to the lack of texture in conventional (white light) colonoscopy. Therefore, we propose to use enhanced imaging endoscopy modalities such as Narrow Band Imaging and chromoendoscopy to facilitate the 3D reconstruction process. Thanks to the use of these enhanced endoscopy techniques, visualization is improved, resulting in more reliable feature tracks and 3D reconstruction results. We first build a sparse 3D model of neoplasia using Structure-from-Motion from enhanced endoscopy imagery. Then, the sparse reconstruction is densified using a Multi-View Stereo approach, and finally the dense 3D point cloud is transformed into a mesh by means of Poisson surface reconstruction. The obtained dense 3D models facilitate classification of neoplasia in the Paris classification, in which the 3D size and the shape of the neoplasia play a major role in the diagnosis.

Alcantarilla PF; Bartoli A; Chadebecq F; Tilmant C; Lepilliez V

2013-07-01

115

RECONSTRUCCIÓN DE OBJETO 3D A PARTIR DE IMÁGENES CALIBRADAS 3D OBJECT RECONSTRUCTION WITH CALIBRATED IMAGES  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabajo presenta el desarrollo de un sistema de reconstrucción de objeto 3D, a partir de una colección de vistas. El sistema se compone de dos módulos principales. El primero realiza el procesamiento de imagen, cuyo objetivo es determinar el mapa de profundidad en un par de vistas, donde cada par de vistas sucesivas sigue una secuencia de fases: detección de puntos de interés, correspondencia de puntos y reconstrucción de puntos; en el proceso de reconstrucción se determinan los parámetros que describen el movimiento (matriz de rotación R y el vector de traslación T) entre las dos vistas. Esta secuencia de pasos se repite para todos los pares de vista sucesivas del conjunto. El segundo módulo tiene como objetivo crear el modelo 3D del objeto, para lo cual debe determinar el mapa total de todos los puntos 3D generados; en cada iteración del módulo anterior, una vez obtenido el mapa de profundidad total, genera la malla 3D, aplicando el método de triangulación de Delaunay [28]. Los resultados obtenidos del proceso de reconstrucción son modelados en un ambiente virtual VRML para obtener una visualización más realista del objeto.The system is composed of two main modules. The first one, carries out the image prosecution, whose objective is to determine the depth map of a pair of views where each pair of successive views continues a sequence of phases: interest points detection, points correspondence and points reconstruction; in the reconstruction process, is determined the parameters that describe the movement (rotation matrix R and the translation vector T) between the two views. This an sequence of steps is repeated for all the peers of successive views of the set. The second module has as objective to create the 3D model of the object, for it should determine the total map of all the 3D points generated, by each iteration of the previous module, once obtained the map of total depth generates the 3D netting, applying the triangulation method of Delaunay [28]. The results obtained of the reconstruction process are shaped in a VRML virtual environment, to obtain a viewing more realist of the object.

Natividad Grandón-Pastén; Diego Aracena-Pizarro; Clésio Luis Tozzi

2007-01-01

116

A storage method of 3D CT image reconstruction system  

International Nuclear Information System (INIS)

In order to realize the miniaturization of three-dimensional cone-beam CT image reconstruction system to small-scale, A three-dimensional image reconstruction system based on FPGA is established. The memory bandwidth requirement of the FDK reconstruction algorithms and the data throughput of the storage system which is composed of SDRAM, SRAM and the internal RAM resource of FPGA is introduced. First, based on filtering algorithms and back projection algorithms the memory bandwidth requirement of a three-dimensional cone-beam CT image reconstruction system is studied. Then, a data access scheme is presented, which uses a SDRAM chip as its main storage a SRAM chip as its external cache and the SRAM resources of FPGA as its internal cache.Then, the process of the implementation and the testing methods of the storage scheme is introduced. Finally, data access capacity of the three-dimensional image reconstruction system was tested. Experimental results indicate that: the storage system can achieve a sequential access data rate of 151.9MB/s and a random access data rate of 100MB/s. It can satisfy the memory bandwidth requirement of a small-scale three-dimensional image reconstruction system. (authors)

2010-01-01

117

EKF-based 3D SLAM for Structured Environment Reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents the extension and experimental validation of the widely used EKF1-based SLAM2 algorithm to 3D space. It uses planar features extracted probabilistically from dense three-dimensional point clouds generated by a rotating 2D laser scanner. These features are represented in complianc...

Weingarten, J.; Siegwart, R.

118

Compressive sensing for improved depth discrimination in 3D holographic reconstruction  

Science.gov (United States)

Compressive holography has attracted significant interest since its introduction three about years ago. In this paper, we present an overview of our work on the ability to reconstruct a 3D volume from its 2D recorded compressive hologram. Using the single-exposure on-line (SEOL) setup, we show how CS applied to this naturally underdetermined problem enables the improved sectioning (or depth discrimination) of the reconstructed volume, when compared with standard in-line holography. We also present the mathematical guarantees for the reconstruction of the 3D volume features from its single 2D hologram and their physical implications for sectioning of 3D volume.

Rivenson, Yair; Stern, Adrian; Javidi, Bahram

2013-05-01

119

3D Hand Pose Reconstruction Using Specialized Mappings  

UK PubMed Central (United Kingdom)

A system for recovering 3D hand pose from monocular color sequences is proposed. The system employs a non-linear supervised learning framework, the specialized mappings architecture (SMA), to map image features to likely 3D hand poses. The SMA's fundamental components are a set of specialized forward mapping functions, and a single feedback matching function. The forward functions are estimated directly from training data, which in our case are examples of hand joint configurations and their corresponding visual features. The joint angle data in the training set is obtained via a CyberGlove, a glove with 22 sensors that monitor the angular motions of the palm and fingers. In training, the visual features are generated using a computer graphics module that renders the hand from arbitrary viewpoints given the 22 joint angles. We test our system both on synthetic sequences and on sequences taken with a color camera. The system automatically detects and tracks both hands of the user, calcu...

Romer Rosales; Vassilis Athitsos; Stan Sclaroff

120

3D Reconstruction of SPM Probes by Electron Tomography  

International Nuclear Information System (INIS)

Three-dimensional morphological and compositional structures of tungsten tips consisting of layered amorphous oxide shell and crystalline W core are reconstructed by electron tomography using both coherent and incoherent imaging modes. The fidelity of the reconstruction is dependent on three criteria, suppression of unwanted crystal orientation contrast in the crystalline core, nonlinear intensity-thickness relations above a certain thickness limit, and artefacts due to missing angular ranges when acquiring a tilt series of images. Annular dark field (ADF), and EDX chemical mapping are discussed as alternatives to standard bright field (BF) TEM imaging.

2006-08-04

 
 
 
 
121

A sensitivity analysis on 3D velocity reconstruction from multiple registered echo Doppler views.  

UK PubMed Central (United Kingdom)

We present a new method for reconstructing a 3D+t velocity field from multiple 3D+t colour Doppler images. Our technique reconstructs 3D velocity vectors from registered multiple standard 3D colour Doppler views, each of which contains a 1D projection of the blood velocity. Reconstruction is based on a scalable patch-wise Least Mean Squares approach, and a continuous velocity field is achieved by using a B-spline grid. We carry out a sensitivity analysis of clinically relevant parameters which affect the accuracy of the reconstruction, including the impact of noise, view angles and registration errors, using simulated data. A realistic simulation framework is achieved by a novel noise model to represent variations in colour Doppler images based on multiscale additive Gaussian noise. Simulations show that, if the Target Registration Error <2.5mm, view angles are >20° and the standard deviation of noise in the input data is <10 cm/s, the reconstructed velocity field presents visually plausible flow patterns and mean error in flow rate is approximately 10% compared to 2D+t Flow MRI. These results are verified by reconstructing 3D velocity on three healthy volunteers. The technique is applied to reconstruct 3D flow on three paediatric patients showing promising results for clinical application.

Gomez A; Pushparajah K; Simpson JM; Giese D; Schaeffter T; Penney G

2013-08-01

122

The clinical application of 3D CT reconstruction technique in bone tumor  

International Nuclear Information System (INIS)

Objective: To evaluate the clinical application of 3D CT reconstruction technique in bone tumor. Methods: In total 20 cases with bone tumor were scanned in 2-3 mm collimation and at pitch of 1 using Toshiba Xpress/SX CT scanner. After the scan was completed, 3D reconstruction including SSD and MPR was performed at Sun Sparc station 20 workstation with software Toshiba Xtension 2.01. Results: Quality 3D images were obtained in all 20 cases. The stereoscopy of the tumor and surrounding anatomical structure was well demonstrated in 3D images. Conclusion: Besides axial images, the 3D CT reconstruction including SSD and MPR provides extra information, and helps the qualitative diagnosis of bone tumor. (authors)

2005-01-01

123

Fast and Accurate 3D Edge Detection for Surface Reconstruction  

Science.gov (United States)

Although edge detection is a well investigated topic, 3D edge detectors mostly lack either accuracy or speed. We will show, how to build a highly accurate subvoxel edge detector, which is fast enough for practical applications. In contrast to other approaches we use a spline interpolation in order to have an efficient approximation of the theoretically ideal sinc interpolator. We give theoretical bounds for the accuracy and show experimentally that our approach reaches these bounds while the often-used subpixel-accurate parabola fit leads to much higher edge displacements.

Bähnisch, Christian; Stelldinger, Peer; Köthe, Ullrich

124

Assessing 3D tunnel position in ACL reconstruction using a novel single image 3D-2D registration  

Science.gov (United States)

The routinely used procedure for evaluating tunnel positions following anterior cruciate ligament (ACL) reconstructions based on standard X-ray images is known to pose difficulties in terms of obtaining accurate measures, especially in providing three-dimensional tunnel positions. This is largely due to the variability in individual knee joint pose relative to X-ray plates. Accurate results were reported using postoperative CT. However, its extensive usage in clinical routine is hampered by its major requirement of having CT scans of individual patients, which is not available for most ACL reconstructions. These difficulties are addressed through the proposed method, which aligns a knee model to X-ray images using our novel single-image 3D-2D registration method and then estimates the 3D tunnel position. In the proposed method, the alignment is achieved by using a novel contour-based 3D-2D registration method wherein image contours are treated as a set of oriented points. However, instead of using some form of orientation weighting function and multiplying it with a distance function, we formulate the 3D-2D registration as a probability density estimation using a mixture of von Mises-Fisher-Gaussian (vMFG) distributions and solve it through an expectation maximization (EM) algorithm. Compared with the ground-truth established from postoperative CT, our registration method in an experiment using a plastic phantom showed accurate results with errors of (-0.43°+/-1.19°, 0.45°+/-2.17°, 0.23°+/-1.05°) and (0.03+/-0.55, -0.03+/-0.54, -2.73+/-1.64) mm. As for the entry point of the ACL tunnel, one of the key measurements, it was obtained with high accuracy of 0.53+/-0.30 mm distance errors.

Kang, X.; Yau, W. P.; Otake, Y.; Cheung, P. Y. S.; Hu, Y.; Taylor, R. H.

2012-02-01

125

3D reconstruction of the hemocyanin subunit dimer from the chiton Acanthochiton fascicularis.  

UK PubMed Central (United Kingdom)

Procedures are presented for the purification of the subunit dimer from Acanthochiton fasicularis hemocyanin. Electron microscopy of negatively stained specimens revealed a uniform population of macromolecules possessing the characteristic "boat shape". A 3D reconstruction from this EM data generated a approximately 3 nm resolution model that correlates well with earlier data of the purported subunit dimer, extracted from the 3D reconstruction of the didecamer of Haliotis tuberculata hemocyanin type 1.

Harris JR; Meissner U; Gebauer W; Markl J

2004-01-01

126

3D reconstruction of the hemocyanin subunit dimer from the chiton Acanthochiton fascicularis.  

Science.gov (United States)

Procedures are presented for the purification of the subunit dimer from Acanthochiton fasicularis hemocyanin. Electron microscopy of negatively stained specimens revealed a uniform population of macromolecules possessing the characteristic "boat shape". A 3D reconstruction from this EM data generated a approximately 3 nm resolution model that correlates well with earlier data of the purported subunit dimer, extracted from the 3D reconstruction of the didecamer of Haliotis tuberculata hemocyanin type 1. PMID:15036283

Harris, J Robin; Meissner, Ulrich; Gebauer, Wolfgang; Markl, Jürgen

2004-01-01

127

Autonomous Planetary 3-D Reconstruction From Satellite Images  

DEFF Research Database (Denmark)

A common task for many deep space missions is autonomous generation of 3-D representations of planetary surfaces onboard unmanned spacecrafts. The basic problem for this class of missions is, that the closed loop time is far too long. The closed loop time is defined as the time from when a human operator detects an interesting object or feature on a, say, asteroid, to a command is issued to aim a science instrument at the feature. This delay may be in the range of hours for all except the objects closest to the Earth. Because the transit time of a typical interesting feature is in the range of seconds to a few minutes, the closed loop time effectively precludes active human control.The only way to circumvent this problem is to build an artificial feature extractor operating autonomously onboard the spacecraft.Different artificial feature extractors are presented and their efficiency is discussed.Based on such features, 3-D representations may be compiled from two or more 2-D satellite images. The main purposes of such a mapping system are extraction of landing sites, objects of scientific interest and general planetary surveying. All data processing is performed autonomously onboard in order to reduce data transfer to ground station and to eliminate the closed loop time delay.

Denver, Troelz

1999-01-01

128

The method of series expansion for 3-D vector tomography reconstruction  

Science.gov (United States)

The method of series expansion has been developed for the inversion of the X-ray transform of three-dimensional (3-D) vector fields, and the corresponding vector central-slice theorem derived. The simulation demonstrating the 3-D reconstruction of the model vector fields is presented.

Balandin, A. L.; Ono, Y.

2005-01-01

129

Knowledge-Based 3D Segmentation and Reconstruction of Coronary Arteries Using CT Images.  

Science.gov (United States)

An approach for the 3D segmentation and reconstruction of human left coronary arteries using angio-CT images is presented in this paper. Each voxel in the 3D dataset is assumed to belong to one of the three homogeneous regions: blood, myocardium, and lung...

Y. Yang A. Tannenbaum D. Giddens

2004-01-01

130

POD-based technique for 3D flow reconstruction using 2D data set  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We propose a technique, based on proper orthogonal decomposition, for reconstructing a fully developed 3D flow starting from spatially restricted measurement of the flow. The POD provides a basis of spatially coherent structures for the description of the 3D flow under study. We demonstrate that the...

Pastur, Luc; Lusseyran, François; Faure, Thierry; Podvin, Bérengère; Fraigneau, Yann

131

Efficient 3D porous microstructure reconstruction via Gaussian random field and hybrid optimization.  

UK PubMed Central (United Kingdom)

Obtaining an accurate three-dimensional (3D) structure of a porous microstructure is important for assessing the material properties based on finite element analysis. Whereas directly obtaining 3D images of the microstructure is impractical under many circumstances, two sets of methods have been developed in literature to generate (reconstruct) 3D microstructure from its 2D images: one characterizes the microstructure based on certain statistical descriptors, typically two-point correlation function and cluster correlation function, and then performs an optimization process to build a 3D structure that matches those statistical descriptors; the other method models the microstructure using stochastic models like a Gaussian random field and generates a 3D structure directly from the function. The former obtains a relatively accurate 3D microstructure, but computationally the optimization process can be very intensive, especially for problems with large image size; the latter generates a 3D microstructure quickly but sacrifices the accuracy due to issues in numerical implementations. A hybrid optimization approach of modelling the 3D porous microstructure of random isotropic two-phase materials is proposed in this paper, which combines the two sets of methods and hence maintains the accuracy of the correlation-based method with improved efficiency. The proposed technique is verified for 3D reconstructions based on silica polymer composite images with different volume fractions. A comparison of the reconstructed microstructures and the optimization histories for both the original correlation-based method and our hybrid approach demonstrates the improved efficiency of the approach.

Jiang Z; Chen W; Burkhart C

2013-11-01

132

Reconstruction of 3D morphology of polyhedral nanoparticles  

International Nuclear Information System (INIS)

The three-dimensional (3D) faceting morphology of ceria nanoparticles is analysed using transmission electron microscopy (TEM)-based computed tomography on the nanometre scale. A novel tomography mode of electron energy loss spectroscopic imaging using a single energy window for inelastically scattered electrons is introduced and found to be reliable and fast for freestanding nanoparticles. To compare the new tomographic method with other methods, we provide the first comprehensive application of three complementary TEM-based imaging techniques, including bright field TEM and annular dark field specific TEM (STEM). Traditional bright-field TEM tomography is found to be applicable, in spite of obvious artefacts, for crystalline particles of constant composition. However, the safest interpretation is achieved by a combined recording of bright field and spectroscopic images.

2007-06-06

133

Preoperative Planning Using 3D Reconstructions and Virtual Endoscopy for Location of the Frontal Sinus  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: Computed tomography (TC) generated tridimensional (3D) reconstructions allow the observation of cavities and anatomic structures of our body with detail. In our specialty there have been attempts to carry out virtual endoscopies and laryngoscopies. However, such application has been practically abandoned due to its complexity and need for computers with high power of graphic processing. Objective: To demonstrate the production of 3D reconstructions from CTs of patients in personal computers, with a free specific program and compare them to the surgery actual endoscopic images. Method: Prospective study in which the CTs proper files of 10 patients were reconstructed with the program Intage Realia, version 2009, 0, 0, 702 (KGT Inc., Japan). The reconstructions were carried out before the surgeries and a virtual endoscopy was made to assess the recess and frontal sinus region. After this study, the surgery was digitally performed and stored. The actual endoscopic images of the recess and frontal sinus region were compared to the virtual images. Results: The 3D reconstruction and virtual endoscopy were made in 10 patients submitted to the surgery. The virtual images had a large resemblance with the actual surgical images. Conclusion: With relatively simple tools and personal computer, we demonstrated the possibility to generate 3D reconstructions and virtual endoscopies. The preoperative knowledge of the frontal sinus natural draining path location may generate benefits during the performance of surgeries. However, more studies must be developed for the evaluation of the real roles of such 3D reconstructions and virtual endoscopies.

Martins, Marcos Jullian Barreto; Aguiar, Carolina Veras; Nogueira Júnior, João Flávio; Abreu, João Paulo Saraiva; Feijão, Moisés Ximenes; Jataí, Isabelle Oliveira; Bastos, Arthur Chaves Gomes

2011-01-01

134

Accelerated reconstruction of 3-D object images using estimated object area in backward computational integral imaging reconstruction  

Science.gov (United States)

In this paper, we propose a novel approach for fast reconstruction of three-dimensional (3-D) object images by using the depth data of 3-D objects in the backward computational integral imaging reconstruction (B-CIIR) method. In the conventional B-CIIR method, once a reconstruction plane is selected, every pixel value composed of the reconstruction plane has to be calculated by averaging the pixel values all of the corresponding elemental images. In the proposed method, however, a potential object area to be displayed on the reconstruction plane is estimated in advance by using the depth data of the 3-D object. Here, the object's depth data can be easily obtained by applying a stereo matching algorithm to subimages transformed from elemental images. Then, contrary to the conventional B-CIIR algorithm, the number of image pixels to be calculated for reconstruction of 3-D image on the output plane can be reduced to that of the pixels within the potential object area. This might result in a dramatic reduction of calculation time and finally achieve to the much faster reconstruction of the 3-D object image than the conventional B-CIIR method. To show the feasibility of the proposed method, experiments are carried out and the results are presented. [Figure not available: see fulltext.

Han, Peterbyunghoon; Piao, Yongri; Kim, Eun-Soo

2010-12-01

135

Stereoscopic imaging and reconstruction of the 3D geometry of flame surfaces  

Energy Technology Data Exchange (ETDEWEB)

Stereoscopic imaging and reconstruction of turbulent impinging diffusion flames have been demonstrated. The 3D geometry of the flame surface is reconstructed from any pair of stereo images through digital image processing and computer vision. Only one camera is required to capture the pair of stereo images due to the use of a stereo adapter. As a result the pair of flame images is captured on a single CCD chip. They are then post-processed to produce a 3D geometry of the flame. The 3D results and surface area calculations demonstrate the potential of stereo visualisation, data extraction and the validity of the proposed methodology. (orig.)

Ng, W.B.; Zhang, Y. [Thermodynamics and Fluid Mechanics Division, Mechanical, Aerospace and Manufacturing Engineering Department, UMIST, P. O. Box 88, M60 1QD, Manchester (United Kingdom)

2003-04-01

136

Neural Network Based Reconstruction of a 3D Object from a 2D Wireframe  

CERN Multimedia

We propose a new approach for constructing a 3D representation from a 2D wireframe drawing. A drawing is simply a parallel projection of a 3D object onto a 2D surface; humans are able to recreate mental 3D models from 2D representations very easily, yet the process is very difficult to emulate computationally. We hypothesize that our ability to perform this construction relies on the angles in the 2D scene, among other geometric properties. Being able to reproduce this reconstruction process automatically would allow for efficient and robust 3D sketch interfaces. Our research focuses on the relationship between 2D geometry observable in the sketch and 3D geometry derived from a potential 3D construction. We present a fully automated system that constructs 3D representations from 2D wireframes using a neural network in conjunction with a genetic search algorithm.

Johnson, Kyle; Lipson, Hod

2010-01-01

137

Two approaches to 3D reconstruction in NMR zeugmatography  

Energy Technology Data Exchange (ETDEWEB)

In nuclear magnetic resonance (NMR) zeugmatography, the primary data pertain to integrals of the unknown nuclear spin density f(x,y,z) over planes instead of lines in R/sup 3/. Two natural approaches to reconstructing f from such data are: (1) By numerical implementation of the inverse Radon transform in three dimensions (the direct approach), and (2) by application, in two successive stages, of existing well-known algorithms for inverting the two-dimensional Radon transform (the two-stage approach). These two approaches are discussed and compared, both from a theoretical standpoint and through computer results obtained with real NMR data. For the cases studied to date the two methods appear to produce qualitatively similar results.

Marr, R B; Chen, C N; Lauterbur, P C

1980-01-01

138

Two approaches to 3D reconstruction in NMR zeugmatography  

International Nuclear Information System (INIS)

In nuclear magnetic resonance (NMR) zeugmatography, the primary data pertain to integrals of the unknown nuclear spin density f(x,y,z) over planes instead of lines in R3. Two natural approaches to reconstructing f from such data are: (1) By numerical implementation of the inverse Radon transform in three dimensions (the direct approach), and (2) by application, in two successive stages, of existing well-known algorithms for inverting the two-dimensional Radon transform (the two-stage approach). These two approaches are discussed and compared, both from a theoretical standpoint and through computer results obtained with real NMR data. For the cases studied to date the two methods appear to produce qualitatively similar results

1980-02-16

139

Electrical Impedance Tomography: 3D Reconstructions using Scattering Transforms  

DEFF Research Database (Denmark)

In three dimensions the Calderon problem was addressed and solved in theory in the 1980s. The main ingredients in the solution of the problem are complex geometrical optics solutions to the conductivity equation and a (non-physical) scattering transform. The resulting reconstruction algorithm is in principle direct and addresses the full non-linear problem immediately. In this paper a new simplication of the algorithm is suggested. The method is based on solving a boundary integral equation for the complex geometrical optics solutions, and the method is implemented numerically using a Nystrom method. Convergence estimates are obtained using hyperinterpolation operators. We compare the method numerically to two other approximations by evaluation on two numerical examples. In addition a moment method for the numerical solution of the forward problem is given.

Delbary, Fabrice; Hansen, Per Christian

2012-01-01

140

Personalized 3D reconstruction of the rib cage for clinical assessment of trunk deformities.  

Science.gov (United States)

Scoliosis is a 3D deformity of the spine and rib cage. Extensive validation of 3D reconstruction methods of the spine from biplanar radiography has already been published. In this article, we propose a novel method to reconstruct the rib cage, using the same biplanar views as for the 3D reconstruction of the spine, to allow clinical assessment of whole trunk deformities. This technique uses a semi-automatic segmentation of the ribs in the postero-anterior X-ray view and an interactive segmentation of partial rib edges in the lateral view. The rib midlines are automatically extracted in 2D and reconstructed in 3D using the epipolar geometry. For the ribs not visible in the lateral view, the method predicts their 3D shape. The accuracy of the proposed method has been assessed using data obtained from a synthetic bone model as a gold standard and has also been evaluated using data of real patients with scoliotic deformities. Results show that the reconstructed ribs enable a reliable evaluation of the rib axial rotation, which will allow a 3D clinical assessment of the spine and rib cage deformities. PMID:23830740

Grenier, Sébastien; Parent, Stefan; Cheriet, Farida

2013-07-03

 
 
 
 
141

Personalized 3D reconstruction of the rib cage for clinical assessment of trunk deformities.  

UK PubMed Central (United Kingdom)

Scoliosis is a 3D deformity of the spine and rib cage. Extensive validation of 3D reconstruction methods of the spine from biplanar radiography has already been published. In this article, we propose a novel method to reconstruct the rib cage, using the same biplanar views as for the 3D reconstruction of the spine, to allow clinical assessment of whole trunk deformities. This technique uses a semi-automatic segmentation of the ribs in the postero-anterior X-ray view and an interactive segmentation of partial rib edges in the lateral view. The rib midlines are automatically extracted in 2D and reconstructed in 3D using the epipolar geometry. For the ribs not visible in the lateral view, the method predicts their 3D shape. The accuracy of the proposed method has been assessed using data obtained from a synthetic bone model as a gold standard and has also been evaluated using data of real patients with scoliotic deformities. Results show that the reconstructed ribs enable a reliable evaluation of the rib axial rotation, which will allow a 3D clinical assessment of the spine and rib cage deformities.

Grenier S; Parent S; Cheriet F

2013-11-01

142

Fully 3D PET image reconstruction with a 4D sinogram blurring kernel  

Energy Technology Data Exchange (ETDEWEB)

Accurately modeling PET system response is essential for high-resolution image reconstruction. Traditionally, sinogram blurring effects are modeled as a 2D blur in each sinogram plane. Such 2D blurring kernel is insufficient for fully 3D PET data, which has four dimensions. In this paper, we implement a fully 3D PET image reconstruction using a 4D sinogram blurring kernel estimated from point source scans and perform phantom experiments to evaluate the improvements in image quality over methods with existing 2D blurring kernels. The results show that the proposed reconstruction method can achieve better spatial resolution and contrast recovery than existing methods. (orig.)

Tohme, Michel S.; Qi, Jinyi [California Univ., Davis, CA (United States). Dept. of Biomedical Engineering; Zhou, Jian

2011-07-01

143

Stereoscopic reconstruction of 3D PIV data in T-junction with circular profile  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper experimental study of flow in T-junction using 3D PIV method is presented. Motion of seeding particles was recorded by a pair of suitably located cameras in precisely defined cross sections of the junction. Based on this information, three-dimensional model of flow in different sections of junction was reconstructed. The reconstruction results from the projection matrixes of each camera, which are obtained from positions of objects in the scene and their projection positions in the image plane. Standard 3D PIV reconstruction was rejected, because of optical distortion in T-Junction.

Kotek M.; Pavlík D.; Kopecký V.; Jašíková D.

2013-01-01

144

Stereoscopic reconstruction of 3D PIV data in T-junction with circular profile  

Science.gov (United States)

In this paper experimental study of flow in T-junction using 3D PIV method is presented. Motion of seeding particles was recorded by a pair of suitably located cameras in precisely defined cross sections of the junction. Based on this information, three-dimensional model of flow in different sections of junction was reconstructed. The reconstruction results from the projection matrixes of each camera, which are obtained from positions of objects in the scene and their projection positions in the image plane. Standard 3D PIV reconstruction was rejected, because of optical distortion in T-Junction.

Kotek, M.; Pavlík, D.; Kopecký, V.; Jašíková, D.

2013-04-01

145

Automatic Reconstruction of 3D Objects Using a Mobile Monoscopic Camera  

UK PubMed Central (United Kingdom)

A method for the automatic reconstruction of 3D objectsfrom multiple camera views for 3D multimediaapplications is presented. Conventional 3D reconstructiontechniques use equipment that restrict the flexibility ofthe user. In order to increase this flexibility, the presentedmethod is characterized by a simple measurement environment,that consists of a new calibration pattern placedbelow the object allowing object and pattern acquisitionsimultaneously. This ensures, that each view can be calibratedindividually. From these obtained calibrated cameraviews, a textured 3D wireframe model is estimatedusing a shape--from--silhouette approach and texture mappingof the original camera views. Experiments with thissystem have confirmed a significant gain of flexibility forthe user and a drastic reduction of costs for technicalequipment while ensuring comparable model quality asconventional reconstruction techniques at the same time.1 IntroductionNatural looking 3D models of re...

Wolfgang Niem

146

A Novel Method for Radio Propagation Simulation Based on Automatic 3D Environment Reconstruction  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, a novel method to simulate radio propagation is presented. The method consists of two steps: automatic 3D scenario reconstruction and propagation modeling. For 3D reconstruction, a machine learning algorithm is adopted and improved to automatically recognize objects in pictures taken from target regions, and 3D models are generated based on the recognized objects. The propagation model employs a ray tracing algorithm to compute signal strength for each point on the constructed 3D map. Our proposition reduces, or even eliminates, infrastructure cost and human efforts during the construction of realistic 3D scenes used in radio propagation modeling. In addition, the results obtained from our propagation model proves to be both accurate and efficient.

D. He; G. Liang; J. Portilla; T. Riesgo

2012-01-01

147

Data acquisition electronics and reconstruction software for real time 3D track reconstruction within the MIMAC project  

CERN Multimedia

Directional detection of non-baryonic Dark Matter requires 3D reconstruction of low energy nuclear recoils tracks. A gaseous micro-TPC matrix, filled with either 3He, CF4 or C4H10 has been developed within the MIMAC project. A dedicated acquisition electronics and a real time track reconstruction software have been developed to monitor a 512 channel prototype. This autotriggered electronic uses embedded processing to reduce the data transfer to its useful part only, i.e. decoded coordinates of hit tracks and corresponding energy measurements. An acquisition software with on-line monitoring and 3D track reconstruction is also presented.

Bourrion, O; Grignon, C; Bouly, J L; Richer, J P; Guillaudin, O; Mayet, F; Billard, J; Santos, D

2011-01-01

148

3D reconstruction methods using line-scanning microscopy with a linear sensor  

Science.gov (United States)

Line-scanning microscopy is a technique with ability to deliver images with an higher acquisition rate than confocal microscopy. But it is accomplished at expense of the degradation of resolution for details parallel to sensor if slit detectors are used. With a linear image sensor it is possible to attenuate or even cancel this effect through the use of information stored in each pixel / light distribution across line pixels of the sensor. In spite of its great potential the use of linear image sensors and in particular the development of three-dimensional (3D) reconstruction methods that take into account its specificity is scarce. This led to our motivation to build a laboratory prototype of a bench stage-scanning microscope using a linear image sensor. We aim at improving lateral resolution isotropy but also image visualization and 3D mesh reconstruction using different optical setups particularly illumination modes, e.g., widefield and line-illumination. The versatility of the laboratory prototype namely its software for image acquisition, processing and visualization is important to attain this goal in the sense that it provides excellent means to develop and test algorithms. Several algorithms for 3D reconstruction were developed and are presented and discussed in this paper. Results of the application of these 3D reconstruction methods show the improvements on lateral resolution isotropy and depth discrimination achieved using algorithms integrating sensor geometry or spatial sampling rate. Also it is evidenced the impact of an insufficient spatial sampling rate from 3D mesh reconstructions.

Macedo, Milton P.; Correia, C. M. B. A.

2013-06-01

149

A novel solid-angle tomosynthesis (SAT) scanning scheme  

International Nuclear Information System (INIS)

Purpose: Digital tomosynthesis (DTS) recently gained extensive research interests in both diagnostic and radiation therapy fields. Conventional DTS images are generated by scanning an x-ray source and flat-panel detector pair on opposite sides of an object, with the scanning trajectory on a one-dimensional curve. A novel tomosynthesis method named solid-angle tomosynthesis (SAT) is proposed, where the x-ray source scans on an arbitrary shaped two-dimensional surface. Methods: An iterative algorithm in the form of total variation regulated expectation maximization is developed for SAT image reconstruction. The feasibility and effectiveness of SAT is corroborated by computer simulation studies using three-dimensional (3D) numerical phantoms including a 3D Shepp-Logan phantom and a volumetric CT image set of a human breast. Results: SAT is able to cover more space in Fourier domain more uniformly than conventional DTS. Greater coverage and more isotropy in the frequency domain translate to fewer artifacts and more accurately restored features in the in-plane reconstruction. Conclusions: Comparing with conventional DTS, SAT allows cone-shaped x-ray beams to project from more solid angles, thus provides more coverage in the spatial-frequency domain, resulting in better quality of reconstructed image.

2010-01-01

150

A novel solid-angle tomosynthesis (SAT) scanning scheme  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Digital tomosynthesis (DTS) recently gained extensive research interests in both diagnostic and radiation therapy fields. Conventional DTS images are generated by scanning an x-ray source and flat-panel detector pair on opposite sides of an object, with the scanning trajectory on a one-dimensional curve. A novel tomosynthesis method named solid-angle tomosynthesis (SAT) is proposed, where the x-ray source scans on an arbitrary shaped two-dimensional surface. Methods: An iterative algorithm in the form of total variation regulated expectation maximization is developed for SAT image reconstruction. The feasibility and effectiveness of SAT is corroborated by computer simulation studies using three-dimensional (3D) numerical phantoms including a 3D Shepp-Logan phantom and a volumetric CT image set of a human breast. Results: SAT is able to cover more space in Fourier domain more uniformly than conventional DTS. Greater coverage and more isotropy in the frequency domain translate to fewer artifacts and more accurately restored features in the in-plane reconstruction. Conclusions: Comparing with conventional DTS, SAT allows cone-shaped x-ray beams to project from more solid angles, thus provides more coverage in the spatial-frequency domain, resulting in better quality of reconstructed image.

Zhang Jin; Yu, Cedric [Department of Radiation Oncology, University of Maryland School of Medicine, 22 S. Greene Street, Baltimore, Maryland 21201 and Xcision Medical System, LLC, 12707 Chapel Chase Drive, Clarksville, Maryland 21209 (United States)

2010-08-15

151

Optimization of PET image quality by means of 3D data acquisition and iterative image reconstruction  

International Nuclear Information System (INIS)

The experiments were performed at the latest-generation whole-body PET system ECAT EXACT HR+. For 2D data acquisition, a collimator of thin tungsten septa was positioned in the field-of-view. Prior to image reconstruction, the measured 3D data were sorted into 2D sinograms by using the Fourier rebinning (FORE) algorithm developed by M. Defrise. The standard filtered backprojection (FBP) method and an optimized ML/EM algorithm with overrelaxation for accelerated convergence were employed for image reconstruction. The spatial resolution of both methods as well as the convergence and noise properties of the ML/EM algorithm were studied in phantom measurements. Furthermore, patient data were acquired in the 2D mode as well as in the 3D mode and reconstructed with both techniques. At the same spatial resolution, the ML/EM-reconstructed images showed fewer and less prominent artefacts than the FBP-reconstructed images. The resulting improved detail conspicuously was achieved for the data acquired in the 2D mode as well as in the 3D mode. The best image quality was obtained by iterative 2D reconstruction of 3D data sets which were previously rebinned into 2D sinograms with help of the FORE algorithm. The phantom measurements revealed that 50 iteration steps with the otpimized ML/EM algorithm were sufficient to keep the relative quantitation error below 5%. (orig./MG).

1998-01-01

152

Effects of point configuration on the accuracy in 3D reconstruction from biplane images  

International Nuclear Information System (INIS)

Two or more angiograms are being used frequently in medical imaging to reconstruct locations in three-dimensional (3D) space, e.g., for reconstruction of 3D vascular trees, implanted electrodes, or patient positioning. A number of techniques have been proposed for this task. In this simulation study, we investigate the effect of the shape of the configuration of the points in 3D (the 'cloud' of points) on reconstruction errors for one of these techniques developed in our laboratory. Five types of configurations (a ball, an elongated ellipsoid (cigar), flattened ball (pancake), flattened cigar, and a flattened ball with a single distant point) are used in the evaluations. For each shape, 100 random configurations were generated, with point coordinates chosen from Gaussian distributions having a covariance matrix corresponding to the desired shape. The 3D data were projected into the image planes using a known imaging geometry. Gaussian distributed errors were introduced in the x and y coordinates of these projected points. Gaussian distributed errors were also introduced into the gantry information used to calculate the initial imaging geometry. The imaging geometries and 3D positions were iteratively refined using the enhanced-Metz-Fencil technique. The image data were also used to evaluate the feasible R-t solution volume. The 3D errors between the calculated and true positions were determined. The effects of the shape of the configuration, the number of points, the initial geometry error, and the input image error were evaluated. The results for the number of points, initial geometry error, and image error are in agreement with previously reported results, i.e., increasing the number of points and reducing initial geometry and/or image error, improves the accuracy of the reconstructed data. The shape of the 3D configuration of points also affects the error of reconstructed 3D configuration; specifically, errors decrease as the 'volume' of the 3D configuration increases, as would be intuitively expected, and shapes with larger spread, such as spherical shapes, yield more accurate reconstructions. These results are in agreement with an analysis of the solution volume of feasible geometries and could be used to guide selection of points for reconstruction of 3D configurations from two views

2005-01-01

153

Morphological evolution of a 3D CME cloud reconstructed from three viewpoints  

CERN Multimedia

The propagation properties of coronal mass ejections (CMEs) are crucial to predict its geomagnetic effect. A newly developed three dimensional (3D) mask fitting reconstruction method using coronagraph images from three viewpoints has been described and applied to the CME ejected on August 7, 2010. The CME's 3D localisation, real shape and morphological evolution are presented. Due to its interaction with the ambient solar wind, the morphology of this CME changed significantly in the early phase of evolution. Two hours after its initiation, it was expanding almost self-similarly. CME's 3D localisation is quite helpful to link remote sensing observations to in situ measurements. The investigated CME was propagating to Venus with its flank just touching STEREO B. Its corresponding ICME in the interplanetary space shows a possible signature of a magnetic cloud with a preceding shock in VEX observations, while from STEREO B only a shock is observed. We have calculated three principle axes for the reconstructed 3D ...

Feng, L; Wei, Y; Gan, W Q; Zhang, T L; Wang, M Y

2012-01-01

154

3D Reconstruction of Ultrasonic Images Based on Matlab/Simulink  

Directory of Open Access Journals (Sweden)

Full Text Available In this study we use Matlab/Simulink as a user friendly interface to examine three recent works on UT image processing; furthermore a new method based on morphological features is proposed. A series of simulated 2D UT images of two known cysts are processed by the 4 different methods. They will serve as the input for 3D surface reconstruction package. A novel comparison way related to 2D and 3D features of cysts is provided. The weakness, the advantages and the deficiencies of each method are explained for cyst 3D reconstruction. It is shown that our novel morphological based method has good performance for online reconstruction specially.

Asad Babakhani; Zhijiang Du; Lining Sun; Mianji Abdollah Fereidoon; Kardan Mohammad Reza

2006-01-01

155

Comparisons of CME morphological characteristics derived from five 3D reconstruction methods  

CERN Multimedia

We compare different methods to reconstruct the three-dimensional (3D) CME morphology. The explored methods include geometric localisation, mask fitting, forward modeling, polarisation ratio and local correlation tracking plus triangulation. The five methods are applied to the same CME event, which occurred on August 7 2010. Their corresponding results are presented and compared, especially in their propagation direction and spatial extent in 3D. We find that mask fitting and geometric localisation method produce consistent results. Reconstructions including three-view observations are more precise than reconstructions done with only two views. Compared to the forward modeling method, in which a-priori shape of the CME geometry is assumed, mask fitting has more flexibility. Polarisation ratio method makes use of the Thomson scattering geometry. We find spatially the 3D CME derived from mask fitting lies mostly in the overlap region obtained with the polarisation method from COR2 A and B. In addition, mask fit...

Feng, Li; Marilena, Mierla

2012-01-01

156

A Step Towards Reconstruction of 3-D CAD Models from Engineering Drawings  

UK PubMed Central (United Kingdom)

Among the different aspects of converting an engineering drawing to CAD, 3-D reconstruction fromseveral views has only been dealt with from a geometric perspective, although a lot of information isof symbolic nature and can be recognized as such directly on a single view. In this paper, we present afirst prototype of a system combining geometric reconstruction through the "fleshing out projections"paradigm with symbolic recognition and matching.KEYWORDSengineering drawings, 3-D reconstruction, fleshing out projections, CAD conversion1 IntroductionAt the previous ICDAR [5], we proposed an agenda for achieving real conversion of mechanical engineeringdrawings to 3-D CAD representations. The different points which we mentioned as having tobe worked on were:ffl primitive recognition, i.e. enhancing the existing state-of-the-art methodologies and developmentof additional tools for extracting geometric primitives;ffl syntax-based annotation analysis and layer separation, to...

Christian Ah-soon; Karl Tombre

157

Robust 3D reconstruction using LiDAR and N - visual image  

Science.gov (United States)

3D image reconstruction is desirable in many applications such as city planning, cartography and many vision applications. The accuracy of the 3D reconstruction plays a vital role in many real world applications. We introduce a method which uses one LiDAR image and N conventional visual images to reduce the error and to build a robust registration for 3D reconstruction. In this method we used lines as features in both the LiDAR and visual images. Our proposed system consists of two steps. In the first step, we extract lines from the LiDAR and visual images using Hough transform. In the second step, we estimate the camera matrices using a search algorithm combined with the fundamental matrices for the visual cameras. We demonstrate our method on a synthetic model which is an idealized representation of an urban environment.

Duraisamy, Prakash; Jackson, Stephen; Namuduri, Kamesh; Alam, Mohammed S.; Buckles, Bill

2013-03-01

158

A photogrammetry-based system for 3D surface reconstruction of prosthetics and orthotics.  

UK PubMed Central (United Kingdom)

The objective of this study is to develop an innovative close range digital photogrammetry (CRDP) system using the commercial digital SLR cameras to measure and reconstruct the 3D surface of prosthetics and orthotics. This paper describes the instrumentation, techniques and preliminary results of the proposed system. The technique works by taking pictures of the object from multiple view angles. The series of pictures were post-processed via feature point extraction, point match and 3D surface reconstruction. In comparison with the traditional method such as laser scanning, the major advantages of our instrument include the lower cost, compact and easy-to-use hardware, satisfactory measurement accuracy, and significantly less measurement time. Besides its potential applications in prosthetics and orthotics surface measurement, the simple setup and its ease of use will make it suitable for various 3D surface reconstructions.

Li GK; Gao F; Wang ZG

2011-01-01

159

GPU-Based 3D Cone-Beam CT Image Reconstruction for Large Data Volume  

Directory of Open Access Journals (Sweden)

Full Text Available Currently, 3D cone-beam CT image reconstruction speed is still a severe limitation for clinical application. The computational power of modern graphics processing units (GPUs) has been harnessed to provide impressive acceleration of 3D volume image reconstruction. For extra large data volume exceeding the physical graphic memory of GPU, a straightforward compromise is to divide data volume into blocks. Different from the conventional Octree partition method, a new partition scheme is proposed in this paper. This method divides both projection data and reconstructed image volume into subsets according to geometric symmetries in circular cone-beam projection layout, and a fast reconstruction for large data volume can be implemented by packing the subsets of projection data into the RGBA channels of GPU, performing the reconstruction chunk by chunk and combining the individual results in the end. The method is evaluated by reconstructing 3D images from computer-simulation data and real micro-CT data. Our results indicate that the GPU implementation can maintain original precision and speed up the reconstruction process by 110–120 times for circular cone-beam scan, as compared to traditional CPU implementation.

Xing Zhao; Jing-jing Hu; Peng Zhang

2009-01-01

160

3D reconstructions with pixel-based images are made possible by digitally clearing plant and animal tissue  

Science.gov (United States)

Reconstruction of 3D images from a series of 2D images has been restricted by the limited capacity to decrease the opacity of surrounding tissue. Commercial software that allows color-keying and manipulation of 2D images in true 3D space allowed us to produce 3D reconstructions from pixel based imag...

 
 
 
 
161

Toward real-time availability of 3D temperature maps created with temporally constrained reconstruction.  

Science.gov (United States)

PURPOSE: To extend the previously developed temporally constrained reconstruction (TCR) algorithm to allow for real-time availability of three-dimensional (3D) temperature maps capable of monitoring MR-guided high intensity focused ultrasound applications. METHODS: A real-time TCR (RT-TCR) algorithm is developed that only uses current and previously acquired undersampled k-space data from a 3D segmented EPI pulse sequence, with the image reconstruction done in a graphics processing unit implementation to overcome computation burden. Simulated and experimental data sets of HIFU heating are used to evaluate the performance of the RT-TCR algorithm. RESULTS: The simulation studies demonstrate that the RT-TCR algorithm has subsecond reconstruction time and can accurately measure HIFU-induced temperature rises of 20°C in 15 s for 3D volumes of 16 slices (RMSE = 0.1°C), 24 slices (RMSE = 0.2°C), and 32 slices (RMSE = 0.3°C). Experimental results in ex vivo porcine muscle demonstrate that the RT-TCR approach can reconstruct temperature maps with 192 × 162 × 66 mm 3D volume coverage, 1.5 × 1.5 × 3.0 mm resolution, and 1.2-s scan time with an accuracy of ±0.5°C. CONCLUSION: The RT-TCR algorithm offers an approach to obtaining large coverage 3D temperature maps in real-time for monitoring MR-guided high intensity focused ultrasound treatments. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc. PMID:23670981

Todd, Nick; Prakash, Jaya; Odéen, Henrik; de Bever, Josh; Payne, Allison; Yalavarthy, Phaneendra; Parker, Dennis L

2013-05-13

162

3D Reconstruction and Restoration Monitoring of Sculptural Artworks by a Multi-Sensor Framework  

Directory of Open Access Journals (Sweden)

Full Text Available Nowadays, optical sensors are used to digitize sculptural artworks by exploiting various contactless technologies. Cultural Heritage applications may concern 3D reconstructions of sculptural shapes distinguished by small details distributed over large surfaces. These applications require robust multi-view procedures based on aligning several high resolution 3D measurements. In this paper, the integration of a 3D structured light scanner and a stereo photogrammetric sensor is proposed with the aim of reliably reconstructing large free form artworks. The structured light scanner provides high resolution range maps captured from different views. The stereo photogrammetric sensor measures the spatial location of each view by tracking a marker frame integral to the optical scanner. This procedure allows the computation of the rotation-translation matrix to transpose the range maps from local view coordinate systems to a unique global reference system defined by the stereo photogrammetric sensor. The artwork reconstructions can be further augmented by referring metadata related to restoration processes. In this paper, a methodology has been developed to map metadata to 3D models by capturing spatial references using a passive stereo-photogrammetric sensor. The multi-sensor framework has been experienced through the 3D reconstruction of a Statue of Hope located at the English Cemetery in Florence. This sculptural artwork has been a severe test due to the non-cooperative environment and the complex shape features distributed over a large surface.

Sandro Barone; Alessandro Paoli; Armando Viviano Razionale

2012-01-01

163

3D reconstruction and restoration monitoring of sculptural artworks by a multi-sensor framework.  

UK PubMed Central (United Kingdom)

Nowadays, optical sensors are used to digitize sculptural artworks by exploiting various contactless technologies. Cultural Heritage applications may concern 3D reconstructions of sculptural shapes distinguished by small details distributed over large surfaces. These applications require robust multi-view procedures based on aligning several high resolution 3D measurements. In this paper, the integration of a 3D structured light scanner and a stereo photogrammetric sensor is proposed with the aim of reliably reconstructing large free form artworks. The structured light scanner provides high resolution range maps captured from different views. The stereo photogrammetric sensor measures the spatial location of each view by tracking a marker frame integral to the optical scanner. This procedure allows the computation of the rotation-translation matrix to transpose the range maps from local view coordinate systems to a unique global reference system defined by the stereo photogrammetric sensor. The artwork reconstructions can be further augmented by referring metadata related to restoration processes. In this paper, a methodology has been developed to map metadata to 3D models by capturing spatial references using a passive stereo-photogrammetric sensor. The multi-sensor framework has been experienced through the 3D reconstruction of a Statue of Hope located at the English Cemetery in Florence. This sculptural artwork has been a severe test due to the non-cooperative environment and the complex shape features distributed over a large surface.

Barone S; Paoli A; Razionale AV

2012-01-01

164

Clinical application of 3D reconstruction of tracheobronchial tree with electron beam CT  

International Nuclear Information System (INIS)

[en] Objective: To explore the clinical promise of CT 3D reconstruction of tracheobronchial tree (TBT) by analyzing 73 cases retrospectively. Methods: All the 73 cases were collected from October 1997 to February 2000, who were scanned by EBCT with 130 kV and 630 mA. The scanning method was continuous volume scan, the slice thickness were 3 mm or 1.5 mm. All cross-sectional images were transmitted to the INSIGHT workstation and reconstructed with SSD (shaded surface display), and the threshold setting were -500 to -300 HU. Results: 3D reconstruction of TBT with EBCT could reveal the abnormal changes of TBT by many kinds of diseases including central cancer, inflammation, bronchiectasis, saber-sheath trachea, trachea cancer, congenital disorders, post-surgical changes of lung cancer, and stenoses by adjacent benign or malignant diseases. It could be used to locate the stenoses and measure stenotic extent. Of the 35 central cancer cases with 3D reconstruction, 6 cases were pestle obstructed, 15 cases cone obstructed, 5 cases interrupted irregularly, 8 cases with eccentric stenoses, and 1 case with right stem destroyed and right upper lobe bronchus obstructed. Conclusion: 3D reconstruction of TBT has characteristic sign in the diagnosis or differential diagnosis of central airway's benign or malignant stenoses, and it is of instructional value in clinical use

2002-01-01

165

Reconstructing Plant Cells in 3D by Serial Section Electron Tomography.  

UK PubMed Central (United Kingdom)

In micrographs acquired with a transmission electron microscope, 3-dimensional (3D) objects are superimposed onto a 2D screen. This reduction in dimension necessarily leads to a degradation of image resolution. To overcome this problem, 3D microscopy techniques, such as tomography and single particle analysis, have been developed. Tomography has been used to visualize cells in 3D, and single particle analysis has been used to investigate macromolecules and viral particles. In this chapter we will describe how we have collected tilting series micrographs from plant cells and how we have reconstructed the cellular volumes using dual axis electron tomography.

Toyooka K; Kang BH

2014-01-01

166

Reconstructing Plant Cells in 3D by Serial Section Electron Tomography.  

Science.gov (United States)

In micrographs acquired with a transmission electron microscope, 3-dimensional (3D) objects are superimposed onto a 2D screen. This reduction in dimension necessarily leads to a degradation of image resolution. To overcome this problem, 3D microscopy techniques, such as tomography and single particle analysis, have been developed. Tomography has been used to visualize cells in 3D, and single particle analysis has been used to investigate macromolecules and viral particles. In this chapter we will describe how we have collected tilting series micrographs from plant cells and how we have reconstructed the cellular volumes using dual axis electron tomography. PMID:24132427

Toyooka, Kiminori; Kang, Byung-Ho

2014-01-01

167

Using flow information to support 3D vessel reconstruction from rotational angiography.  

UK PubMed Central (United Kingdom)

For the assessment of cerebrovascular diseases, it is beneficial to obtain three-dimensional (3D) morphologic and hemodynamic information about the vessel system. Rotational angiography is routinely used to image the 3D vascular geometry and we have shown previously that rotational subtraction angiography has the potential to also give quantitative information about blood flow. Flow information can be determined when the angiographic sequence shows inflow and possibly outflow of contrast agent. However, a standard volume reconstruction assumes that the vessel tree is uniformly filled with contrast agent during the whole acquisition. If this is not the case, the reconstruction exhibits artifacts. Here, we show how flow information can be used to support the reconstruction of the 3D vessel centerline and radii in this case. Our method uses the fast marching algorithm to determine the order in which voxels are analyzed. For every voxel, the rotational time intensity curve (R-TIC) is determined from the image intensities at the projection points of the current voxel. Next, the bolus arrival time of the contrast agent at the voxel is estimated from the R-TIC. Then, a measure of the intensity and duration of the enhancement is determined, from which a speed value is calculated that steers the propagation of the fast marching algorithm. The results of the fast marching algorithm are used to determine the 3D centerline by backtracking. The 3D radius is reconstructed from 2D radius estimates on the projection images. The proposed method was tested on computer simulated rotational angiography sequences with systematically varied x-ray acquisition, blood flow, and contrast agent injection parameters and on datasets from an experimental setup using an anthropomorphic cerebrovascular phantom. For the computer simulation, the mean absolute error of the 3D centerline and 3D radius estimation was 0.42 and 0.25 mm, respectively. For the experimental datasets, the mean absolute error of the 3D centerline was 0.45 mm. Under pulsatile and nonpulsatile conditions, flow information can be used to enable a 3D vessel reconstruction from rotational angiography with inflow and possibly outflow of contrast agent. We found that the most important parameter for the quality of the reconstruction of centerline and radii is the range through which the x-ray system rotates in the time span of the injection. Good results were obtained if this range was at least 135 degrees. As a standard c-arm can rotate 205 degrees, typically one third of the acquisition can show inflow or outflow of contrast agent, which is required for the quantification of blood flow from rotational angiography.

Waechter I; Bredno J; Weese J; Barratt DC; Hawkes DJ

2008-07-01

168

The role of 3D Helical CT in the reconstructive treatment of maxillofacial cancers  

International Nuclear Information System (INIS)

Purpose of this work is to investigate the role of Helical CT and the usefulness of three-dimensional (3D) imaging for pre-operative planning and follow-up of reconstructive maxillofacial surgery with alloplastic material in neoplastic disease involving this region. From 1996 to 1999 eleven patients were examined with Helical CT and 3D images for planning of maxillofacial plastic and reconstructive surgery for advanced cancer of this anatomically complex region. A 3D-modulated titanium mesh (100%) or micro nets was used to rebuild the anterior surface of maxillary bone and the orbital floor. The mesh was cut to the appropriate size and shape and curved where necessary. Within the residual sinusal cavity a siliconed filling was used surmounting an acrylic prosthesis with dental arch to rebuild the palate. A rehydrated bovine pericardium was affixed and moduled on the borders in two cases only. Three-dimensionally reconstructed CT images were obtained preoperatively and at least 6 months postoperatively in all patients. The images were generated on a computer workstation using the shaded surface display (SSD) software with threshold values ranging 425 to 630 HU, and a more closed window for the imaging of titanium mesh/bone interface in the post surgical follow-up. It was obtained an excellent complete spatial depiction of maxillo facial region both before and after surgery, with no artefacts so important as to affect the 3D reconstruction process and the image quality. Together with the head-neck surgical team it could be worked for preoperative planning through CT scans by different 3D points of view. The 3D reconstructed follow-up scans showed good filling of the defect in the area where the titanium mesh had been used. Then efficacious bone modelling and good biocompatibility of the alloplastic material were seen in all patients, with no inflammatory reactions. Titanium is a well-known material, which is widely used for cranioplasty. It is a radiolucent, non-ferrous metal of low atomic number that allows very clear CT and MR images to be obtained. Further Ti features are strength, biocompatibility and easy handling. 3D Helical CT scan has proven to be the most complete and accurate imaging technique for reconstructive plastic surgery with alloplastic material in advanced maxillofacial cancer, also considering the anatomic and functional complexity of his area. The prospect is provided to identify virtual 3D presurgical ablation planes. These may allow the surgeon to improve plastic reconstruction and shorten intervention time.

2000-01-01

169

3D Reconstruction from X-ray Fluoroscopy for Clinical Veterinary Medicine using Differential Volume Rendering  

Science.gov (United States)

3D reconstruction from ordinary X-ray equipment which is not CT or MRI is required in clinical veterinary medicine. Authors have already proposed a 3D reconstruction technique from X-ray photograph to present bone structure. Although the reconstruction is useful for veterinary medicine, the thechnique has two problems. One is about exposure of X-ray and the other is about data acquisition process. An x-ray equipment which is not special one but can solve the problems is X-ray fluoroscopy. Therefore, in this paper, we propose a method for 3D-reconstruction from X-ray fluoroscopy for clinical veterinary medicine. Fluoroscopy is usually used to observe a movement of organ or to identify a position of organ for surgery by weak X-ray intensity. Since fluoroscopy can output a observed result as movie, the previous two problems which are caused by use of X-ray photograph can be solved. However, a new problem arises due to weak X-ray intensity. Although fluoroscopy can present information of not only bone structure but soft tissues, the contrast is very low and it is very difficult to recognize some soft tissues. It is very useful to be able to observe not only bone structure but soft tissues clearly by ordinary X-ray equipment in the field of clinical veterinary medicine. To solve this problem, this paper proposes a new method to determine opacity in volume rendering process. The opacity is determined according to 3D differential coefficient of 3D reconstruction. This differential volume rendering can present a 3D structure image of multiple organs volumetrically and clearly for clinical veterinary medicine. This paper shows results of simulation and experimental investigation of small dog and evaluation by veterinarians.

Khongsomboon, Khamphong; Hamamoto, Kazuhiko; Kondo, Shozo

170

3D reconstruction from X-ray fluoroscopy for clinical veterinary medicine using differential volume rendering  

International Nuclear Information System (INIS)

[en] 3D reconstruction from ordinary X-ray equipment which is not CT or MRI is required in clinical veterinary medicine. Authors have already proposed a 3D reconstruction technique from X-ray photograph to present bone structure. Although the reconstruction is useful for veterinary medicine, the technique has two problems. One is about exposure of X-ray and the other is about data acquisition process. An x-ray equipment which is not special one but can solve the problems is X-ray fluoroscopy. Therefore, in this paper, we propose a method for 3D-reconstruction from X-ray fluoroscopy for clinical veterinary medicine. Fluoroscopy is usually used to observe a movement of organ or to identify a position of organ for surgery by weak X-ray intensity. Since fluoroscopy can output a observed result as movie, the previous two problems which are caused by use of X-ray photograph can be solved. However, a new problem arises due to weak X-ray intensity. Although fluoroscopy can present information of not only bone structure but soft tissues, the contrast is very low and it is very difficult to recognize some soft tissues. It is very useful to be able to observe not only bone structure but soft tissues clearly by ordinary X-ray equipment in the field of clinical veterinary medicine. To solve this problem, this paper proposes a new method to determine opacity in volume rendering process. The opacity is determined according to 3D differential coefficient of 3D reconstruction. This differential volume rendering can present a 3D structure image of multiple organs volumetrically and clearly for clinical veterinary medicine. This paper shows results of simulation and experimental investigation of small dog and evaluation by veterinarians. (author)

2007-01-01

171

Error Evaluation in a Stereovision-Based 3D Reconstruction System  

Directory of Open Access Journals (Sweden)

Full Text Available The work presented in this paper deals with the performance analysis of the whole 3D reconstruction process of imaged objects, specifically of the set of geometric primitives describing their outline and extracted from a pair of images knowing their associated camera models. The proposed analysis focuses on error estimation for the edge detection process, the starting step for the whole reconstruction procedure. The fitting parameters describing the geometric features composing the workpiece to be evaluated are used as quality measures to determine error bounds and finally to estimate the edge detection errors. These error estimates are then propagated up to the final 3D reconstruction step. The suggested error analysis procedure for stereovision-based reconstruction tasks further allows evaluating the quality of the 3D reconstruction. The resulting final error estimates enable lastly to state if the reconstruction results fulfill a priori defined criteria, for example, fulfill dimensional constraints including tolerance information, for vision-based quality control applications for example.

Abdelkrim Belhaoua; Sophie Kohler; Ernest Hirsch

2010-01-01

172

Digital tomosynthesis in breast imaging.  

UK PubMed Central (United Kingdom)

PURPOSE: To describe and evaluate a method of tomosynthesis breast imaging with a full-field digital mammographic system. MATERIALS AND METHODS: In this tomosynthesis method, low-radiation-dose images were acquired as the x-ray source was moved in an arc above the stationary breast and digital detector. A step-and-expose method of imaging was used. Breast tomosynthesis and conventional images of two imaging phantoms and four mastectomy specimens were obtained. Three experienced readers scored the relative lesion visibility, lesion margin visibility, and confidence in the classification of six lesions. RESULTS: Tomosynthesis image-reconstruction algorithms allow tomographic imaging of the entire breast from a single arc of the x-ray source and at a radiation dose comparable with that in single-view mammography. Except for images of a large mass in a fatty breast, the tomosynthesis images were superior to the conventional images. CONCLUSION: Digital mammographic systems make breast tomosynthesis possible. Tomosynthesis may improve the specificity of mammography with improved lesion margin visibility and may improve early breast cancer detection, especially in women with radiographically dense breasts.

Niklason LT; Christian BT; Niklason LE; Kopans DB; Castleberry DE; Opsahl-Ong BH; Landberg CE; Slanetz PJ; Giardino AA; Moore R; Albagli D; DeJule MC; Fitzgerald PF; Fobare DF; Giambattista BW; Kwasnick RF; Liu J; Lubowski SJ; Possin GE; Richotte JF; Wei CY; Wirth RF

1997-11-01

173

A Smartphone Interface for a Wireless EEG Headset with Real-Time 3D Reconstruction  

DEFF Research Database (Denmark)

We demonstrate a fully functional handheld brain scanner consisting of a low-cost 14-channel EEG headset with a wireless connec- tion to a smartphone, enabling minimally invasive EEG monitoring in naturalistic settings. The smartphone provides a touch-based interface with real-time brain state decoding and 3D reconstruction.

Stopczynski, Arkadiusz; Larsen, Jakob Eg

2011-01-01

174

3D Reconstruction Using Interval Methods on The Kinect Device Coupled With an IMU  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The principle behind VSLAM applications like 3D object reconstruction or indoor mapping is to estimate the spatial transformation between two large clouds of points, which represent two poses of the same scene. They can further be processed to obtain detailed surfaces. Since its introduction in 1992...

Aymeric Bethencourt; Luc Jaulin

175

Modèles de formation d'image génériques : calibrage et algorithmes de reconstruction 3D  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Des applications en vision artificielle exploitent des caméras très variées : fish-eye, systèmes catadioptriques et multi-caméras, etc. Ces caméras ont des caractéristiques intéressantes, dont surtout un champ de vue étendu. Le calibrage et la reconstruction 3D sont deux problèmes fondamentaux en vi...

Ramalingam, Srikumar

176

3D Reconstruction: Novel Method for Finding of Corresponding Points using Pseudo Colors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper deals with the reconstruction of spatial coordinates of an arbitrary point in a scene using two images scanned by a 3D camera or two displaced cameras. Calculations are based on the perspective geom-etry. Accurate determination of corresponding points is a fundamental step in this process...

L. Bolecek; V. Ricny; M. Slanina

177

Technique for 3D shape reconstruction of spherical and aspheric surfaces using deflectometric principle  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We provide a description and analysis of a deflectometric technique for 3D measurements of optically smooth surfaces. It is presented that a surface reconstruction problem leads to a theoretical description by a nonlinear partial differential equation. Then, a surface shape can be calculated by...

Mikš A.; Novák J.; Novák P.

178

3D reconstruction techniques made easy: know-how and pictures  

Energy Technology Data Exchange (ETDEWEB)

Three-dimensional reconstructions represent a visual-based tool for illustrating the basis of three-dimensional post-processing such as interpolation, ray-casting, segmentation, percentage classification, gradient calculation, shading and illumination. The knowledge of the optimal scanning and reconstruction parameters facilitates the use of three-dimensional reconstruction techniques in clinical practise. The aim of this article is to explain the principles of multidimensional image processing in a pictorial way and the advantages and limitations of the different possibilities of 3D visualisation. (orig.)

Luccichenti, Giacomo; Sabatini, Umberto [IRCCS Fondazione Santa Lucia, Department of Radiology, Rome (Italy); Cademartiri, Filippo; Krestin, Gabriel P. [University of Rotterdam, Department of Radiology, Erasmus Medical Center, Rotterdam (Netherlands); Pezzella, Francesca Romana [University of Rome La Sapienza, Department of Neurological Sciences, Rome (Italy); Runza, Giuseppe; Midiri, Massimo [University of Palermo, Department of Radiology, Palermo (Italy); Belgrano, Manuel [University of Trieste, Deparment of Radiology, Trieste (Italy); Bastianello, Stefano [University of Pavia, Department of Neuroradiology, Institute of Neurology, IRCCS Fondazione C. Mondino, Pavia (Italy)

2005-10-01

179

3D reconstruction techniques made easy: know-how and pictures  

International Nuclear Information System (INIS)

Three-dimensional reconstructions represent a visual-based tool for illustrating the basis of three-dimensional post-processing such as interpolation, ray-casting, segmentation, percentage classification, gradient calculation, shading and illumination. The knowledge of the optimal scanning and reconstruction parameters facilitates the use of three-dimensional reconstruction techniques in clinical practise. The aim of this article is to explain the principles of multidimensional image processing in a pictorial way and the advantages and limitations of the different possibilities of 3D visualisation. (orig.)

2005-01-01

180

Array diagnostics, spatial resolution, and filtering of undesired radiation with the 3D reconstruction algorithm  

DEFF Research Database (Denmark)

This paper focuses on three important features of the 3D reconstruction algorithm of DIATOOL: the identification of array elements improper functioning and failure, the obtainable spatial resolution of the reconstructed fields and currents, and the filtering of undesired radiation and scattering to obtain a more accurate measured field. Results obtained by real measured data are presented. Special attention is given to the computational advantages given by the higher-order Method of Moments-based formulation of DIATOOL. Guidelines on the recommended measurement sampling and measured field truncation for achieving the best possible reconstruction results are also provided.

Cappellin, C.; Pivnenko, Sergey

2013-01-01

 
 
 
 
181

Evaluation of 3D reconstruction algorithms for a small animal PET camera  

International Nuclear Information System (INIS)

The use of paired, opposing position-sensitive phototube scintillation cameras (SCs) operating in coincidence for small animal imaging with positron emitters is currently under study. Because of the low sensitivity of the system even in 3D mode and the need to produce images with high resolution, it was postulated that a 3D expectation maximization (EM) reconstruction algorithm might be well suited for this application. We investigated four reconstruction algorithms for the 3D SC PET camera: 2D filtered back-projection (FBP), 2D ordered subset EM (OSEM), 3D reprojection (3DRP), and 3D OSEM. Noise was assessed for all slices by the coefficient of variation in a simulated uniform cylinder. Resolution was assessed from a simulation of 15 point sources in the warm background of the uniform cylinder. At comparable noise levels, the resolution achieved with OSEM (0.9-mm to 1.2-mm) is significantly better than that obtained with FBP or 3DRP (1.5-mm to 2.0-mm.) Images of a rat skull labeled with 18F-fluoride suggest that 3D OSEM can improve image quality of a small animal PET camera

1996-01-01

182

Non-periodic 3-D motion estimation and reconstruction of coronary stents  

Energy Technology Data Exchange (ETDEWEB)

C-arm CT enables 3-D imaging at high spatial resolution. Image quality would be sufficient for coronary artery stents at rest. However, spatial resolution is severely degraded by cardiac motion which needs to be considered in the reconstruction step. Existing approaches are based on detecting markers in the projection images. Based on the exact marker locations in all images, motion estimation and compensation is performed in the 2-D projection image domain and thus no 3-D motion information of the stent is available. In this paper a novel method for computing the non-periodic location of the stent markers in 3-D is proposed. The motion estimation step comprises marker detection in 2-D, computation of periodic 3-D motion and computation of non-periodic 3-D motion. For motion compensation the 3- D marker positions are used to compute an affine motion model as input for a motion compensated FDK reconstruction algorithm. First clinical results suggest a high image quality and the possibility to compute physiological parameters e.g. velocity curves. (orig.)

Rohkohl, Christopher [Siemens AG, Forchheim (Germany). Healthcare Sector; Erlangen-Nuernberg Univ., Erlangen (Germany). Pattern Recognition Lab; Lauritsch, Guenter [Siemens AG, Forchheim (Germany). Healthcare Sector; Hornegger, Joachim [Erlangen-Nuernberg Univ., Erlangen (Germany). Pattern Recognition Lab

2011-07-01

183

Pragmatic fully 3D image reconstruction for the MiCES mouse imaging PET scanner  

International Nuclear Information System (INIS)

We present a pragmatic approach to image reconstruction for data from the micro crystal elements system (MiCES) fully 3D mouse imaging positron emission tomography (PET) scanner under construction at the University of Washington. Our approach is modelled on fully 3D image reconstruction used in clinical PET scanners, which is based on Fourier rebinning (FORE) followed by 2D iterative image reconstruction using ordered-subsets expectation-maximization (OSEM). The use of iterative methods allows modelling of physical effects (e.g., statistical noise, detector blurring, attenuation, etc), while FORE accelerates the reconstruction process by reducing the fully 3D data to a stacked set of independent 2D sinograms. Previous investigations have indicated that non-stationary detector point-spread response effects, which are typically ignored for clinical imaging, significantly impact image quality for the MiCES scanner geometry. To model the effect of non-stationary detector blurring (DB) in the FORE+OSEM(DB) algorithm, we have added a factorized system matrix to the ASPIRE reconstruction library. Initial results indicate that the proposed approach produces an improvement in resolution without an undue increase in noise and without a significant increase in the computational burden. The impact on task performance, however, remains to be evaluated.

2004-10-07

184

Combined constraints for efficient algebraic regularized methods in fully 3D reconstruction  

International Nuclear Information System (INIS)

SPECT systems incorporate the use of one or more rotating gamma cameras which can be equipped with cone-beam collimators to improve the trade-off between spatial resolution and sensitivity. The geometry of the cone-beam collimators implies that a specific 3D reconstruction algorithm must be applied. Algebraic methods provide the possibility of including the physical characteristics, such as attenuation, Compton scatter and detector response, in the reconstruction process. However, the reconstruction problem is an ill-posed problem which should be regularized. This paper presents a 3D algebraic method that combines three regularizing constraints. These constraints deal respectively with penalizing negative voxels, local noise smoothing and missing data compensation. The results presented were obtained from imaging simulations, phantom data and from a thyroid clinical study of a normal volunteer. (author)

1998-01-01

185

Reconstructing a 3D-Model from an Unregistered Range Image  

UK PubMed Central (United Kingdom)

In this paper we present yet another reconstructiontechnique which generates a 3D closedtriangular mesh from an unregistered range imageby deforming discretely an initial triangular mesh.Combining the advantages of the previous workon a deformable model and on a function-graphmodel, our algorithm avoids not only holes in thereconstructed surfaces, but also self-intersections aswell.Keywords: Deformable models, range image, 3Dclosed mesh reconstruction.1 IntroductionDespite a variety of published work, the 3D reconstructionfrom a set of range images is still achallenging and important problem for visioncommunity. Since no single range image suf-ces to describe completely the surface of anobject, additional methods were devised eitherto register multiple range images before surfacemodel creation [10, 2] or to zipper" multiplemeshes reconstructed from unregisteredrange images [7]. In this context we may classifythe known reconstruction techniques intothree sche...

Shin Ting; Rosana Marques Da Silva

186

Recovery and Visualization of 3D Structure of Chromosomes from Tomographic Reconstruction Images  

Energy Technology Data Exchange (ETDEWEB)

The objectives of this work include automatic recovery and visualization of a 3D chromosome structure from a sequence of 2D tomographic reconstruction images taken through the nucleus of a cell. Structure is very important for biologists as it affects chromosome functions, behavior of the cell and its state. Chromosome analysis is significant in the detection of deceases and in monitoring environmental gene mutations. The algorithm incorporates thresholding based on a histogram analysis with a polyline splitting algorithm, contour extraction via active contours, and detection of the 3D chromosome structure by establishing corresponding regions throughout the slices. Visualization using point cloud meshing generates a 3D surface. The 3D triangular mesh of the chromosomes provides surface detail and allows a user to interactively analyze chromosomes using visualization software.

Babu, S; Liao, P; Shin, M C; Tsap, L V

2004-04-28

187

3D dose reconstruction for narrow beams using ion chamber array measurements  

International Nuclear Information System (INIS)

3D dose reconstruction is a verification of the delivered absorbed dose. Our aim was to describe and evaluate a 3D dose reconstruction method applied to phantoms in the context of narrow beams. A solid water phantom and a phantom containing a bone-equivalent material were irradiated on a 6 MV linac. The transmitted dose was measured by using one array of a 2D ion chamber detector. The dose reconstruction was obtained by an iterative algorithm. A phantom set-up error and organ interfraction motion were simulated to test the algorithm sensitivity. In all configurations convergence was obtained within three iterations. A local reconstructed dose agreement of at least 3% / 3 mm with respect to the planned dose was obtained, except in a few points of the penumbra. The reconstructed primary fluences were consistent with the planned ones, which validates the whole reconstruction process. The results validate our method in a simple geometry and for narrow beams. The method is sensitive to a set-up error of a heterogeneous phantom and interfraction heterogeneous organ motion. (orig.)

2012-01-01

188

3D dose reconstruction for narrow beams using ion chamber array measurements  

Energy Technology Data Exchange (ETDEWEB)

3D dose reconstruction is a verification of the delivered absorbed dose. Our aim was to describe and evaluate a 3D dose reconstruction method applied to phantoms in the context of narrow beams. A solid water phantom and a phantom containing a bone-equivalent material were irradiated on a 6 MV linac. The transmitted dose was measured by using one array of a 2D ion chamber detector. The dose reconstruction was obtained by an iterative algorithm. A phantom set-up error and organ interfraction motion were simulated to test the algorithm sensitivity. In all configurations convergence was obtained within three iterations. A local reconstructed dose agreement of at least 3% / 3 mm with respect to the planned dose was obtained, except in a few points of the penumbra. The reconstructed primary fluences were consistent with the planned ones, which validates the whole reconstruction process. The results validate our method in a simple geometry and for narrow beams. The method is sensitive to a set-up error of a heterogeneous phantom and interfraction heterogeneous organ motion. (orig.)

Schombourg, Karin; Bochud, Francois O.; Moeckli, Raphael [Lausanne Univ., University Hospital Centre (Switzerland). Inst. of Radiation Physics; Mirimanoff, Rene-Olivier [Lausanne Univ., University Hospital Centre (Switzerland). Radio-Oncology Dept.

2012-07-01

189

3D dose reconstruction for narrow beams using ion chamber array measurements.  

Science.gov (United States)

3D dose reconstruction is a verification of the delivered absorbed dose. Our aim was to describe and evaluate a 3D dose reconstruction method applied to phantoms in the context of narrow beams. A solid water phantom and a phantom containing a bone-equivalent material were irradiated on a 6 MV linac. The transmitted dose was measured by using one array of a 2D ion chamber detector. The dose reconstruction was obtained by an iterative algorithm. A phantom set-up error and organ interfraction motion were simulated to test the algorithm sensitivity. In all configurations convergence was obtained within three iterations. A local reconstructed dose agreement of at least 3% / 3mm with respect to the planned dose was obtained, except in a few points of the penumbra. The reconstructed primary fluences were consistent with the planned ones, which validates the whole reconstruction process. The results validate our method in a simple geometry and for narrow beams. The method is sensitive to a set-up error of a heterogeneous phantom and interfraction heterogeneous organ motion. PMID:22209700

Schombourg, Karin; Bochud, François O; Mirimanoff, René-Olivier; Moeckli, Raphaël

2011-12-30

190

3D dose reconstruction for narrow beams using ion chamber array measurements.  

UK PubMed Central (United Kingdom)

3D dose reconstruction is a verification of the delivered absorbed dose. Our aim was to describe and evaluate a 3D dose reconstruction method applied to phantoms in the context of narrow beams. A solid water phantom and a phantom containing a bone-equivalent material were irradiated on a 6 MV linac. The transmitted dose was measured by using one array of a 2D ion chamber detector. The dose reconstruction was obtained by an iterative algorithm. A phantom set-up error and organ interfraction motion were simulated to test the algorithm sensitivity. In all configurations convergence was obtained within three iterations. A local reconstructed dose agreement of at least 3% / 3mm with respect to the planned dose was obtained, except in a few points of the penumbra. The reconstructed primary fluences were consistent with the planned ones, which validates the whole reconstruction process. The results validate our method in a simple geometry and for narrow beams. The method is sensitive to a set-up error of a heterogeneous phantom and interfraction heterogeneous organ motion.

Schombourg K; Bochud FO; Mirimanoff RO; Moeckli R

2012-06-01

191

3D image reconstruction for PET by multi-slice rebinning and axial filtering  

Energy Technology Data Exchange (ETDEWEB)

Two different approaches are used at present to reconstruct from 3D coincidence data in PET. We refer to these approaches as the single-slice rebinning approach and the fully-3D approach. The single-slice rebinning approach involves geometrical approximations, but it requires the least possible amount of computation. Fully-3D reconstruction algorithms, both iterative and non-iterative, do not make such approximations, but require much more computation. Multi-slice rebinning with axial filtering is a new approach which attempts to achieve the geometrical accuracy of the fully-3D approach with the simplicity and modest amount of computation of the single-slice rebinning approach. The first step (multi-slice rebinning) involves rebinning of coincidence lines into a stack of 2D sinograms, where multiple sinograms are incremented for each oblique coincidence line. This operation is followed by an axial filtering operation, either before or after slice-by-slice reconstruction, to reduce the blurring in the axial direction. Tests with simulated and experimental data indicate that the new method has better geometrical accuracy than single-slice rebinning, at the cost of only a modest increase in computation. 11 refs.

Lewitt, R.M. [UGM Medical Systems, Inc., Philadelphia, PA (United States)]|[Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Radiology; Muehllehner, G. [UGM Medical Systems, Inc., Philadelphia, PA (United States); Karp, J.S. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Radiology

1991-12-01

192

Hybrid Reconstruction to Derive 3D Height-Time Evolution for Coronal Mass Ejections  

CERN Document Server

We present a hybrid combination of forward and inverse reconstruction methods using multiple observations of a coronal mass ejection (CME) to derive the 3D 'true' Height-Time plots for individual CME components. We apply this hybrid method to the components of the 31 Dec 2007 CME. This CME, observed clearly in both the STEREO A and STEREO B COR2 white light coronagraphs, evolves asymmetrically across the 15 solar radius field of view with in a span of three hours. The method has two reconstruction steps. We fit a boundary envelope for the potential 3D CME shape using a flux rope-type model oriented to best match the observations. Using this forward model as a constraining envelope, we then run an inverse reconstruction solving for the simplest underlying 3D electron density distribution that can, when rendered, reproduce the observed coronagraph data frames. We produce plots for each segment to establish the 3D or "true" Height-Time plots for each center of mass as well as for the bulk CME motion, and use the...

Antunes, Alex; Yahil, Amos

2009-01-01

193

Applicability of 3D-CT facial reconstruction for forensic individual identification  

Directory of Open Access Journals (Sweden)

Full Text Available Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) craniometric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution.

Rocha Sara dos Santos; Ramos Dalton Luiz de Paula; Cavalcanti Marcelo de Gusmão Paraíso

2003-01-01

194

Intuitive Terrain Reconstruction Using Height Observation-Based Ground Segmentation and 3D Object Boundary Estimation  

Directory of Open Access Journals (Sweden)

Full Text Available Mobile robot operators must make rapid decisions based on information about the robot’s surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot’s array of sensors, but some upper parts of objects are beyond the sensors’ measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances.

Wei Song; Kyungeun Cho; Kyhyun Um; Chee Sun Won; Sungdae Sim

2012-01-01

195

Detection and 3D reconstruction of traffic signs from multiple view color images  

Science.gov (United States)

3D reconstruction of traffic signs is of great interest in many applications such as image-based localization and navigation. In order to reflect the reality, the reconstruction process should meet both accuracy and precision. In order to reach such a valid reconstruction from calibrated multi-view images, accurate and precise extraction of signs in every individual view is a must. This paper presents first an automatic pipeline for identifying and extracting the silhouette of signs in every individual image. Then, a multi-view constrained 3D reconstruction algorithm provides an optimum 3D silhouette for the detected signs. The first step called detection, tackles with a color-based segmentation to generate ROIs (Region of Interests) in image. The shape of every ROI is estimated by fitting an ellipse, a quadrilateral or a triangle to edge points. A ROI is rejected if none of the three shapes can be fitted sufficiently precisely. Thanks to the estimated shape the remained candidates ROIs are rectified to remove the perspective distortion and then matched with a set of reference signs using textural information. Poor matches are rejected and the types of remained ones are identified. The output of the detection algorithm is a set of identified road signs whose silhouette in image plane is represented by and ellipse, a quadrilateral or a triangle. The 3D reconstruction process is based on a hypothesis generation and verification. Hypotheses are generated by a stereo matching approach taking into account epipolar geometry and also the similarity of the categories. The hypotheses that are plausibly correspond to the same 3D road sign are identified and grouped during this process. Finally, all the hypotheses of the same group are merged to generate a unique 3D road sign by a multi-view algorithm integrating a priori knowledges about 3D shape of road signs as constraints. The algorithm is assessed on real and synthetic images and reached and average accuracy of 3.5cm for position and 4.5° for orientation.

Soheilian, Bahman; Paparoditis, Nicolas; Vallet, Bruno

2013-03-01

196

A Monitoring Approach for Surface Reconstruction from 3D Point Cloud  

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes the surface reconstruction from 3D point cloud. The vertices of point cloud build a network of triangles using Delaunay Triangulation for 3D surface. DT plays an important role due to its guaranteed quality of triangular mesh generation. The process monitoring is emerging as a valuable tool and it is used to enhance operational efficiency. In this paper Delaunay algorithm monitors the various parameters of mesh generation and evaluates the performance of the algorithm by calculating parameters

Bharti Sood; Kamaldeep Kaur

2012-01-01

197

The 3D Doppler transform: elementary properties and computation of reconstruction kernels  

Science.gov (United States)

The 3D Doppler transform maps a vector field to its line integrals over that component of the field which is parallel to the line. In this paper we consider only lines aligned to the coordinate axes. Since the Doppler transform describes the mathematical model for the vector tomography, efficient inversion formulae are necessary in order to solve the reconstruction problem. The approximate inverse represents a numerical inversion scheme based on scalar products of the data with so-called reconstruction kernels. We characterize these reconstruction kernels as solutions of a normal equation connected with the Doppler transform and a mollifier. To solve this equation elementary properties of the underlying operator are investigated and a smoothing property is proved. We succeed in computing a reconstruction kernel for one special mollifier and give a representation with the help of the singular value decomposition of the 2D Radon transform.

Schuster, Thomas

2000-06-01

198

CAVAREV-an open platform for evaluating 3D and 4D cardiac vasculature reconstruction  

Energy Technology Data Exchange (ETDEWEB)

The 3D reconstruction of cardiac vasculature, e.g. the coronary arteries, using C-arm CT (rotational angiography) is an active and challenging field of research. There are numerous publications on different reconstruction techniques. However, there is still a lack of comparability of achieved results for several reasons: foremost, datasets used in publications are not open to public and thus experiments are not reproducible by other researchers. Further, the results highly depend on the vasculature motion, i.e. cardiac and breathing motion patterns which are also not comparable across publications. We aim to close this gap by providing an open platform, called Cavarev (CArdiac VAsculature Reconstruction EValuation). It features two simulated dynamic projection datasets based on the 4D XCAT phantom with contrasted coronary arteries which was derived from patient data. In the first dataset, the vasculature undergoes a continuous periodic motion. The second dataset contains aperiodic heart motion by including additional breathing motion. The geometry calibration and acquisition protocol were obtained from a real-world C-arm system. For qualitative evaluation of the reconstruction results, the correlation of the morphology is used. Two segmentation-based quality measures are introduced which allow us to assess the 3D and 4D reconstruction quality. They are based on the spatial overlap of the vasculature reconstruction with the ground truth. The measures enable a comprehensive analysis and comparison of reconstruction results independent from the utilized reconstruction algorithm. An online platform (www.cavarev.com) is provided where the datasets can be downloaded, researchers can manage and publish algorithm results and download a reference C++ and Matlab implementation.

Rohkohl, Christopher; Hornegger, Joachim [Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander University Erlangen-Nuremberg, Martensstr. 3, 91058 Erlangen (Germany); Lauritsch, Guenter [Siemens AG, Healthcare Sector, Siemensstr. 1, 91301 Forchheim (Germany); Keil, Andreas, E-mail: christopher.rohkohl@informatik.uni-erlangen.d, E-mail: guenter.lauritsch@siemens.co, E-mail: andreas.keil@cs.tum.ed, E-mail: joachim.hornegger@informatik.uni-erlangen.d [Computer Aided Medical Procedures and Augmented Reality, TU Muenchen, Boltzmannstr. 3, 85748 Garching (Germany)

2010-05-21

199

CAVAREV-an open platform for evaluating 3D and 4D cardiac vasculature reconstruction  

International Nuclear Information System (INIS)

[en] The 3D reconstruction of cardiac vasculature, e.g. the coronary arteries, using C-arm CT (rotational angiography) is an active and challenging field of research. There are numerous publications on different reconstruction techniques. However, there is still a lack of comparability of achieved results for several reasons: foremost, datasets used in publications are not open to public and thus experiments are not reproducible by other researchers. Further, the results highly depend on the vasculature motion, i.e. cardiac and breathing motion patterns which are also not comparable across publications. We aim to close this gap by providing an open platform, called Cavarev (CArdiac VAsculature Reconstruction EValuation). It features two simulated dynamic projection datasets based on the 4D XCAT phantom with contrasted coronary arteries which was derived from patient data. In the first dataset, the vasculature undergoes a continuous periodic motion. The second dataset contains aperiodic heart motion by including additional breathing motion. The geometry calibration and acquisition protocol were obtained from a real-world C-arm system. For qualitative evaluation of the reconstruction results, the correlation of the morphology is used. Two segmentation-based quality measures are introduced which allow us to assess the 3D and 4D reconstruction quality. They are based on the spatial overlap of the vasculature reconstruction with the ground truth. The measures enable a comprehensive analysis and comparison of reconstruction results independent from the utilized reconstruction algorithm. An online platform (www.cavarev.com) is provided where the datasets can be downloaded, researchers can manage and publish algorithm results and download a reference C++ and Matlab implementation.

2010-05-21

200

Reconstructing the 3-D Trajectories of CMEs in the Inner Heliosphere  

CERN Document Server

A method for the full three-dimensional (3-D) reconstruction of the trajectories of coronal mass ejections (CMEs) using Solar TErrestrial RElations Observatory (STEREO) data is presented. Four CMEs that were simultaneously observed by the inner and outer coronagraphs (COR1 and 2) of the Ahead and Behind STEREO satellites were analysed. These observations were used to derive CME trajectories in 3-D out to ~15Rsun. The reconstructions using COR1/2 data support a radial propagation model. Assuming pseudo-radial propagation at large distances from the Sun (15-240Rsun), the CME positions were extrapolated into the Heliospheric Imager (HI) field-of-view. We estimated the CME velocities in the different fields-of-view. It was found that CMEs slower than the solar wind were accelerated, while CMEs faster than the solar wind were decelerated, with both tending to the solar wind velocity.

Maloney, Shane A; McAteer, R T James; 10.1007/s11207-009-9364-3

2009-01-01

 
 
 
 
201

Structured-light-based highly dense and robust 3D reconstruction.  

UK PubMed Central (United Kingdom)

In this paper, a structured-light-based highly dense and robust 3D reconstruction method is proposed by combining a Gray code and region-shifting pattern. The region-shifting pattern is transformed to the trapezoidal and triangle wave shifting pattern by combining all frames of the region-shifting pattern, and then the boundary of the trapezoidal wave shifting pattern and the peak and phase of the triangle wave shifting pattern are estimated. Through this technique, the spatial resolution is increased about three times. Consequently, the 3D points are reconstructed with a resolution much higher than a camera image resolution. Moreover, as the proposed method measures the boundary and the peak with all frames, it increases the signal-to-noise ratio and is more robust than the conventional methods that use only one or two frames to detect them.

Kim D; Lee S

2013-03-01

202

Robust Stereo-Vision Based 3D Object Reconstruction for the Assistive Robot FRIEND  

Directory of Open Access Journals (Sweden)

Full Text Available A key requirement of assistive robot vision is the robust 3D object reconstruction in complex environments for reliable autonomous object manipulation. In this paper the idea is presented of achieving high robustness of a complete robot vision system against external influences such as variable illumination by including feedback control of the object segmentation in stereo images. The approach used is to change the segmentation parameters in closed-loop so that object features extraction is driven to a desired result. Reliable feature extraction is necessary to fully exploit a neuro-fuzzy classifier which is the core of the proposed 2D object recognition method, predecessor of 3D object reconstruction. Experimental results on the rehabilitation assistive robotic system FRIEND demonstrate the effectiveness of the proposed method.

RISTIC-DURRANT, D.; GRIGORESCU, S. M.; GRASER, A.; COJBASIC, Z.; NIKOLIC, V.

2011-01-01

203

High sensitivity, total body PET scanning using 3D data acquisition and reconstruction  

International Nuclear Information System (INIS)

This paper reports on 2D total body PET studies generally suffer from poor and non-uniform signal-to-noise (S/N) properties, which are consequences of the limited scanning time at each axial position and the difference in direct and cross plane sensitivity. By combining 3D data acquisition and reconstruction with a quasi-continuous axial bed motion, gains in S/N of around 2 (equivalent to a sensitivity gain of 4) can be achieved for typical whole body activity concentrations. S/N uniformity is also considerably improved. In vivo studies further illustrate the improvement in image quality due to 3D data collection. However, the routine implementation of 3D total body imaging will require efficient ways of handling the vast amounts of data produced by these studies.

1992-01-01

204

Custom-made, 3D, intraoperative surgical guides for nasal reconstruction.  

UK PubMed Central (United Kingdom)

This article presents the use of an intraoperative surgical guide created by 3D laser surface scanning and rapid prototyping. The authors present outcomes of 3 patients in whom the nasal surgical guide was used intraoperatively for reconstruction of full-thickness, complex nasal defects. This effort highlights the multidisciplinary approach involving a surgeon and anaplastologist integrated with the latest technology to provide patients with the best possible outcomes.

Sultan B; Byrne PJ

2011-11-01

205

Post-traumatic hip paraosteoarthropathy. CT and 3D reconstruction analysis. Report on 2 cases  

Energy Technology Data Exchange (ETDEWEB)

Two cases of paraosteoarthropathy developed soon after hip trauma and without associated spinal disorders are described. CT perfectly discriminates ectopic bone formation from osseous fragments and calcified hematoma. These lesions display different signs and have different locations, which allows an easy differenciation. The aetiology of these traumatic osteomas (hip trauma associated with surgical repair in one case, coma in the other) is compared to literature. The effectiveness of CT with 3D reconstruction is emphasized in paraosteoarthropathy and hip trauma screening.

Laissy, J.P.; Assailly, Ch.; Benozio, M.; Roger, B.; Lavayssiere, R.

1988-01-01

206

Preoperative diagnosis of gastric cancer using 2-D magnetic resonance imaging with 3-D reconstruction techniques.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To investigate the clinical value of 2-D magnetic resonance imaging (MRI) with 3-D reconstruction techniques for the preoperative diagnosis and TNM-staging of gastric cancer. METHODS: Using a Philips Gyroscan NT 1.0T superconductive unit, MRI using the water-filling method was performed in 15 patients with suspected gastric cancers. The 2-D MRI sequences included TSE-T1WI, TSE-T2WI and fat suppression (SPIR). The source images of magnetic resonance hydrography (heavily TSE-T2WI sequence) were reconstructed using the Philips EasyVision viewing workstation. Four 3-D postprocessing algorithms, including maximum intensity projection, surface shaded viewing, volume rendering and virtual endoscopy, were performed and compared with the results of a barium study and endoscopy. All 15 patients with 16 gastric cancers had their diagnosis confirmed by postoperative pathological findings. RESULTS: 2-D MRI and 3-D reconstruction images were successfully obtained for all 15 patients. The maximum intensity projection, surface shaded viewing, and volume rendering images corresponded to the upper gastrointestinal series findings, and the virtual endoscopy images corresponded to the gastroscopic views. In 16 gastric lesions, MRI correctly diagnosed 14 (87.5%) advanced gastric cancers, and the tumor location, size and classification were also accurately identified. The accuracy of MRI for determining the preoperative TNM stage was 64.3% (9/14), and there was significant correlation between these results and those from the histopathological studies (P < 0.01). Based on T, N and M factors, the staging accuracy of MRI was 71.4% (10/14), 57.1% (8/14) and 85.7% (12/14), respectively. CONCLUSIONS: 2-D MRI with 3-D reconstruction is an effective method for the preoperative diagnosis and TNM staging of gastric cancer. However, the detection of early cancers or benign lesions and N-staging should be further studied.

Zhong L; Li L; Sun JH; Xu JR

2005-01-01

207

Technique for 3D shape reconstruction of spherical and aspheric surfaces using deflectometric principle  

Directory of Open Access Journals (Sweden)

Full Text Available We provide a description and analysis of a deflectometric technique for 3D measurements of optically smooth surfaces. It is presented that a surface reconstruction problem leads to a theoretical description by a nonlinear partial differential equation. Then, a surface shape can be calculated by solution of a derived equation. The presented method is noncontact and no reference surface is needed as in interferometry.

Mikš A.; Novák J.; Novák P.

2013-01-01

208

Design of the discrete skew geometry and iterative reconstruction of the MV3D scanner  

Energy Technology Data Exchange (ETDEWEB)

Design considerations for airport security volumetric imaging scanners differ significantly from those for medical CT scanners, despite the much they have in common. We describe what drives these differences, then describe how we account for these considerations with a combination of an innovative 'discrete skew' geometry and iterative reconstruction in the new L-3 MV3D security scanner product. (orig.)

Foland, Andrew D. [L-3 Communications, Security and Detection Systems, Woburn, MA (United States)

2011-07-01

209

3D reconstruction from a monocular vision system for unmanned ground vehicles  

Science.gov (United States)

In this paper we present a 3D reconstruction technique designed to support an autonomously navigated unmanned system. The algorithm and methods presented focus on the 3D reconstruction of a scene, with color and distance information, using only a single moving camera. In this way, the system may provide positional self-awareness for navigation within a known, GPS-denied area. It can also be used to construct a new model of unknown areas. Existing 3D reconstruction methods for GPS-denied areas often rely on expensive inertial measurement units to establish camera location and orientation. The algorithm proposed---after the preprocessing tasks of stabilization and video enhancement---performs Speeded-Up Robust Feature extraction, in which we locate unique stable points within every frame. Additional features are extracted using an optical flow method, with the resultant points fused and pruned based on several quality metrics. Each unique point is then tracked through the video sequence and assigned a disparity value used to compute the depth for each feature within the scene. The algorithm also assigns each feature point a horizontal and vertical coordinate using the camera's field of views specifications. From this, a resultant point cloud consists of thousands of feature points plotted from a particular camera position and direction, generated from pairs of sequential frames. The proposed method can use the yaw, pitch and roll information calculated from visual cues within the image data to accurately compute location and orientation. This positioning information enables the reconstruction of a robust 3D model particularly suitable for autonomous navigation and mapping tasks.

Tompkins, R. Cortland; Diskin, Yakov; Youssef, Menatoallah M.; Asari, Vijayan K.

2011-10-01

210

New method for 3D reconstruction of the human cranial vault from CT-scan data.  

UK PubMed Central (United Kingdom)

This study presents a new method for the 3D reconstruction of the human cranial vault from routine Computed Tomography (CT) data. The reconstruction method was based on the conceptualization of the shape of the cranial vault with a parametric description. An initialization was first realized with the identification of anatomical landmarks and contours on Digitally Reconstructed Radiographs (DRR) in order to obtain a pre-personalized reconstruction. Then an optimization of the reconstruction was performed to segment the internal and external surfaces of the cranial vault for thickness computation. The method was validated by comparing final reconstructions issued from our approach and from a manual slice-by-slice segmentation method on ten CT-scans. Errors were comparable to the CT image resolution, and less than 2 min were dedicated to the operator-dependent marking step. The reconstruction of internal and external surfaces of the cranial vault allows quantifying and visualizing of thickness throughout the cranial vault. This thickness mapping is useful for clinical purposes as additional pre-surgical information. Moreover, this study constitutes a first step in the personalized characterization of skull resistance directly from routine exams.

Laurent CP; Jolivet E; Hodel J; Decq P; Skalli W

2011-12-01

211

New method for 3D reconstruction of the human cranial vault from CT-scan data.  

Science.gov (United States)

This study presents a new method for the 3D reconstruction of the human cranial vault from routine Computed Tomography (CT) data. The reconstruction method was based on the conceptualization of the shape of the cranial vault with a parametric description. An initialization was first realized with the identification of anatomical landmarks and contours on Digitally Reconstructed Radiographs (DRR) in order to obtain a pre-personalized reconstruction. Then an optimization of the reconstruction was performed to segment the internal and external surfaces of the cranial vault for thickness computation. The method was validated by comparing final reconstructions issued from our approach and from a manual slice-by-slice segmentation method on ten CT-scans. Errors were comparable to the CT image resolution, and less than 2 min were dedicated to the operator-dependent marking step. The reconstruction of internal and external surfaces of the cranial vault allows quantifying and visualizing of thickness throughout the cranial vault. This thickness mapping is useful for clinical purposes as additional pre-surgical information. Moreover, this study constitutes a first step in the personalized characterization of skull resistance directly from routine exams. PMID:21764623

Laurent, Cédric P; Jolivet, Erwan; Hodel, Jerome; Decq, Philippe; Skalli, Wafa

2011-07-18

212

[The development of a system for 3D reconstruction from DICOM data and collaborative visualization].  

UK PubMed Central (United Kingdom)

Complex surgeries often need multi-disciplinary surgeons to work collaboratively and set synthesized operation plans. Aided by collaboration enabled three dimensional visualization software over network, operation plans can be made more intuitively and accurately. Because different disciplinary surgeons often work at different locations, a distributed collaboration virtue environment over network should be provided. By our knowledge, such a system does not exist yet. Toward this, we implement a platform upon Client/Server architecture over network. The 3D model is reconstructed from CT image data of DICOM format and the resulting mesh is then simplified, using the Visualization Toolkit (VTK). The simplified polygon mesh data is further seamlessly integrated into our 3D graphics system developed with the HOOPS/3DAF for displaying, where the model is converted to the lossless compression stream file format-HSF, which is suited for network transmission. Using this format, a collaboration enabled interactive visualization system is implemented upon Client/Server architecture, developed with HOOPS/NET toolkit. The reconstructed 3D model is clear, and the interactive collaboration with 3D visualization is fairly real-time. We then implemented a platform for developing collaborative surgery simulation software, into which the surgery operation simulation and prosthesis design function can be easily added.

Liu S; Liao W; Yu Q; Cheng X; Dai N; Zhang X

2007-10-01

213

Grid-pattern design for fast scene reconstruction by a 3D vision sensor  

Science.gov (United States)

This paper presents a method of pattern design for a 3D vision sensor, which is based on the principles of color-encoded structured light, to improve the reconstruction efficiency. Since an ordinary structured light system using an LCD projector needs to take several images (usually 8-12 images) for recovering the 3D scene, as a result its speed is limited and applications are restricted in acquisition of static environment. For dynamic cases, the 3D measurement is desired to only capture a single image. To realize this, a new method is to use a color projector which can be controlled by a computer to generate arbitrary desired color patterns. A problem of the color encoded projection is the unique indexing of the light codes in the image. It is essential that each light grid be uniquely identified by incorporating the local neighborhoods in the light pattern so that 3D reconstruction can be performed with only local analysis of the single image. This paper proposes a method in design of such grid patterns. Experiments are provided to demonstrate the proposed method with two, three, and four different colors. The maximum possible square matrices are illustrated.

Guan, Qiu; Chen, ShengYong; Wang, Wanliang; Li, Y. F.

2005-06-01

214

On the Performance Evaluation of 3D Reconstruction Techniques from a Sequence of Images  

Directory of Open Access Journals (Sweden)

Full Text Available The performance evaluation of 3D reconstruction techniques is not a simple problem to solve. This is not only due to the increased dimensionality of the problem but also due to the lack of standardized and widely accepted testing methodologies. This paper presents a unified framework for the performance evaluation of different 3D reconstruction techniques. This framework includes a general problem formalization, different measuring criteria, and a classification method as a first step in standardizing the evaluation process. Performance characterization of two standard 3D reconstruction techniques, stereo and space carving, is also presented. The evaluation is performed on the same data set using an image reprojection testing methodology to reduce the dimensionality of the evaluation domain. Also, different measuring strategies are presented and applied to the stereo and space carving techniques. These measuring strategies have shown consistent results in quantifying the performance of these techniques. Additional experiments are performed on the space carving technique to study the effect of the number of input images and the camera pose on its performance.

Ahmed Eid; Aly Farag

2005-01-01

215

A Method for Interactive 3D Reconstruction of Piecewise Planar Objects from Single Images  

UK PubMed Central (United Kingdom)

We present an approach for 3D reconstruction of objects from a single image. Obviously, constraints on the 3Dstructure are needed to perform this task. Our approach is based on user-provided coplanarity, perpendicularity andparallelism constraints. These are used to calibrate the image and perform 3D reconstruction. The method is described indetail and results are provided.1 IntroductionMethods for 3D reconstruction from images abound in the literature. A lot of effort has been spent on the developmentof multi-view approaches allowing for high accuracy and complete modeling of complex scenes. On one hand, researchis directed towards completely automatic systems; these are relatively difficult to realize and it is not clear yet if they areready for use by a non expert. On the other hand, commercial systems exist, but they usually require a high amount ofuser interaction (clicking on many points in many images) or a special camera setup (e.g. using structured light).The guidel...

Peter F Sturm; Stephen J Maybank

216

Applicator reconstruction in MRI 3D image-based dose planning of brachytherapy for cervical cancer  

International Nuclear Information System (INIS)

[en] Background and purpose: To elaborate a method for applicator reconstruction for MRI-based brachytherapy for cervical cancer. Materials and methods: Custom-made plastic catheters with a copper sulphate solution were made for insertion in the source channels of MR-CT compatible applicators: plastic and titanium tandem ring applicators, and titanium needles. The applicators were CT and MR scanned in a phantom for accurate 3D assessment of applicator visibility and geometry. A reconstruction method was developed and evaluated in 19 patient MR examinations with ring applicator (plastic: 14, titanium: 5). MR applicator reconstruction uncertainties related to inter-observer variation were evaluated. Results: The catheters were visible in the plastic applicator on T1-weighted images in phantom and in 14/14 clinical applications. On T2-weighted images, the catheters appeared weaker but still visible in phantom and in 13/14 MR clinical applications. In the titanium applicator, the catheters could not be separated from the artifacts from the applicator itself. However, these artifacts could be used to localize both titanium ring applicator (5/5 clinical applications) and needles (6/6 clinical applications). Standard deviations of inter-observer differences were below 2 mm in all directions. Conclusion: 3D applicator reconstruction based on MR imaging could be performed for plastic and titanium applicators. Plastic applicators proved well to be suited for MRI-based reconstruction. For improved practicability of titanium applicator reconstruction, development of MR applicator markers is essential. Reconstruction of titanium applicator and needles at 1.5 T MR requires geometric evaluations in phantoms before using the applicator in patients.

2009-01-01

217

Reconstruction of 3D Human Facial Images Using Partial Differential Equations  

Directory of Open Access Journals (Sweden)

Full Text Available One of the challenging problems in geometric modeling and computer graphics is the construction of realistic human facial geometry. Such geometry are essential for a wide range of applications, such as 3D face recognition, virtual reality applications, facial expression simulation and computer based plastic surgery application. This paper addresses a method for the construction of 3D geometry of human faces based on the use of Elliptic Partial Differential Equations (PDE). Here the geometry corresponding to a human face is treated as a set of surface patches, whereby each surface patch is represented using four boundary curves in the 3-space that formulate the appropriate boundary conditions for the chosen PDE. These boundary curves are extracted automatically using 3D data of human faces obtained using a 3D scanner. The solution of the PDE generates a continuous single surface patch describing the geometry of the original scanned data. In this study, through a number of experimental verifications we have shown the efficiency of the PDE based method for 3D facial surface reconstruction using scan data. In addition to this, we also show that our approach provides an efficient way of facial representation using a small set of parameters that could be utilized for efficient facial data storage and verification purposes.

Eyad Elyan; Hassan Ugail

2007-01-01

218

Optical 3D Surface Reconstruction by a Multi-Period Phase Shift Method  

Directory of Open Access Journals (Sweden)

Full Text Available One problem of classical phase shifting for optical 3D surface reconstruction is the occurrence of ambiguities due to the use of fringe projection. We generally derive a number-theoretical approach to calculate absolute phase measurements which can be used as a base for a reliable surface reconstruction without any ambiguity. The essence of our method is the application of pattern sequences with different periods whereby we homogeneously use all pictures which were taken for the measurement. This leads to a higher average accuracy in the surface reconstruction. Furthermore we propose a technique to avoid typical calculation errors that are produced in classical phase shifting caused by discontinuities, occlusions and reflections on the surface.

Erik Lilienblum; Bernd Michaelis

2007-01-01

219

Direct fourier methods in 3D-reconstruction from cone-beam data  

International Nuclear Information System (INIS)

The problem of 3D-reconstruction is encountered in both medical and industrial applications of X-ray tomography. A method able to utilize a complete set of projections complying with Tuys condition was proposed by Grangeat. His method is mathematically exact and consists of two distinct phases. In phase 1 cone-beam projection data are used to produce the derivative of the radon transform. In phase 2, after interpolation, the radon transform data are used to reconstruct the three-dimensional object function. To a large extent our method is an extension of the Grangeat method. Our aim is to reduce the computational complexity, i.e. to produce a faster method. The most taxing procedure during phase 1 is computation of line-integrals in the detector plane. By applying the direct Fourier method in reverse for this computation, we reduce the complexity of phase 1 from O(N4) to O(N3logN). Phase 2 can be performed either as a straight 3D-reconstruction or as a sequence of two 2D-reconstructions in vertical and horizontal planes, respectively. Direct Fourier methods can be applied for the 2D- and for the 3D-reconstruction, which reduces the complexity of phase 2 from O(N4) to O(N3logN) as well. In both cases, linogram techniques are applied. For 3D-reconstruction the inversion formula contains the second derivative filter instead of the well-known ramp-filter employed in the 2D-case. The derivative filter is more well-behaved than the 2D ramp-filter. This implies that less zeropadding is necessary which brings about a further reduction of the computational efforts. The method has been verified by experiments on simulated data. The image quality is satisfactory and independent of cone-beam angles. For a 5123 volume we estimate that our method is ten times faster than Grangeats method

1994-01-01

220

3D prostate histology reconstruction: An evaluation of image-based and fiducial-based algorithms.  

UK PubMed Central (United Kingdom)

Purpose: Evaluation of in vivo prostate imaging modalities for determining the spatial distribution and aggressiveness of prostate cancer ideally requires accurate registration of images to an accepted reference standard, such as histopathological examination of radical prostatectomy specimens. Three-dimensional (3D) reconstruction of prostate histology facilitates these registration-based evaluations by reintroducing 3D spatial information lost during histology processing. Because the reconstruction accuracy may constrain the clinical questions that can be answered with these data, it is important to assess the tradeoffs between minimally disruptive methods based on intrinsic image information and potentially more robust methods based on extrinsic fiducial markers.Methods: Ex vivo magnetic resonance (MR) images and digitized whole-mount histology images from 12 radical prostatectomy specimens were used to evaluate four 3D histology reconstruction algorithms. 3D reconstructions were computed by registering each histology image to the corresponding ex vivo MR image using one of two similarity metrics (mutual information or fiducial registration error) and one of two search domains (affine transformations or a constrained subset thereof). The algorithms were evaluated for accuracy using the mean target registration error (TRE) computed from homologous intrinsic point landmarks (3-16 per histology section; 232 total) identified on histology and MR images, and for the sensitivity of TRE to rotational, translational, and scaling initialization errors.Results: The algorithms using fiducial registration error and mutual information had mean ± standard deviation TREs of 0.7 ± 0.4 and 1.2 ± 0.7 mm, respectively, and one algorithm using fiducial registration error and affine transforms had negligible sensitivities to initialization errors. The postoptimization values of the mutual information-based metric showed evidence of errors due to both the optimizer and the similarity metric, and variation of parameters of the mutual information-based metric did not improve its performance.Conclusions: The extrinsic fiducial-based algorithm had lower mean TRE and lower sensitivity to initialization than the intrinsic intensity-based algorithm using mutual information. A model relating statistical power to registration error for certain imaging validation study designs estimated that a reconstruction algorithm with a mean TRE of 0.7 mm would require 27% fewer subjects than the method used to initialize the algorithms (mean TRE 1.3 ± 0.7 mm), suggesting the choice of reconstruction technique can have a substantial impact on the design of imaging validation studies, and on their overall cost.

Gibson E; Gaed M; Go?mez JA; Moussa M; Romagnoli C; Pautler S; Chin JL; Crukley C; Bauman GS; Fenster A; Ward AD

2013-09-01

 
 
 
 
221

Ion track reconstruction in 3D using alumina-based fluorescent nuclear track detectors  

International Nuclear Information System (INIS)

Fluorescent nuclear track detectors (FNTDs) based on Al2O3: C, Mg single crystal combined with confocal microscopy provide 3D information on ion tracks with a resolution only limited by light diffraction. FNTDs are also ideal substrates to be coated with cells to engineer cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). This radiobiological tool enables a novel platform linking cell responses to physical dose deposition on a sub-cellular level in proton and heavy ion therapies. To achieve spatial correlation between single ion hits in the cell coating and its biological response the ion traversals have to be reconstructed in 3D using the depth information gained by the FNTD read-out. FNTDs were coated with a confluent human lung adenocarcinoma epithelial (A549) cell layer. Carbon ion irradiation of the hybrid detector was performed perpendicular and angular to the detector surface. In situ imaging of the fluorescently labeled cell layer and the FNTD was performed in a sequential read-out. Making use of the trajectory information provided by the FNTD the accuracy of 3D track reconstruction of single particles traversing the hybrid detector was studied. The accuracy is strongly influenced by the irradiation angle and therefore by complexity of the FNTD signal. Perpendicular irradiation results in highest accuracy with error of smaller than 0.10°. The ability of FNTD technology to provide accurate 3D ion track reconstruction makes it a powerful tool for radiobiological investigations in clinical ion beams, either being used as a substrate to be coated with living tissue or being implanted in vivo. (note)

2013-09-21

222

Ion track reconstruction in 3D using alumina-based fluorescent nuclear track detectors.  

Science.gov (United States)

Fluorescent nuclear track detectors (FNTDs) based on Al2O3: C, Mg single crystal combined with confocal microscopy provide 3D information on ion tracks with a resolution only limited by light diffraction. FNTDs are also ideal substrates to be coated with cells to engineer cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). This radiobiological tool enables a novel platform linking cell responses to physical dose deposition on a sub-cellular level in proton and heavy ion therapies. To achieve spatial correlation between single ion hits in the cell coating and its biological response the ion traversals have to be reconstructed in 3D using the depth information gained by the FNTD read-out. FNTDs were coated with a confluent human lung adenocarcinoma epithelial (A549) cell layer. Carbon ion irradiation of the hybrid detector was performed perpendicular and angular to the detector surface. In situ imaging of the fluorescently labeled cell layer and the FNTD was performed in a sequential read-out. Making use of the trajectory information provided by the FNTD the accuracy of 3D track reconstruction of single particles traversing the hybrid detector was studied. The accuracy is strongly influenced by the irradiation angle and therefore by complexity of the FNTD signal. Perpendicular irradiation results in highest accuracy with error of smaller than 0.10°. The ability of FNTD technology to provide accurate 3D ion track reconstruction makes it a powerful tool for radiobiological investigations in clinical ion beams, either being used as a substrate to be coated with living tissue or being implanted in vivo. PMID:23965401

Niklas, M; Bartz, J A; Akselrod, M S; Abollahi, A; Jäkel, O; Greilich, S

2013-08-22

223

Breast tomosynthesis imaging configuration analysis.  

UK PubMed Central (United Kingdom)

Traditional two-dimensional (2D) X-ray mammography is the most commonly used method for breast cancer diagnosis. Recently, a three-dimensional (3D) Digital Breast Tomosynthesis (DBT) system has been invented, which is likely to challenge the current mammography technology. The DBT system provides stunning 3D information, giving physicians increased detail of anatomical information, while reducing the chance of false negative screening. In this research, two reconstruction algorithms, Back Projection (BP) and Shift-And-Add (SAA), were used to investigate and compare View Angle (VA) and the number of projection images (N) with parallel imaging configurations. In addition, in order to better determine which method displayed better-quality imaging, Modulation Transfer Function (MTF) analyses were conducted with both algorithms, ultimately producing results which improve upon better breast cancer detection. Research studies find evidence that early detection of the disease is the best way to conquer breast cancer, and earlier detection results in the increase of life span for the affected person.

Rayford CE 2nd; Zhou W; Chen Y

2013-01-01

224

Breast tomosynthesis imaging configuration analysis.  

Science.gov (United States)

Traditional two-dimensional (2D) X-ray mammography is the most commonly used method for breast cancer diagnosis. Recently, a three-dimensional (3D) Digital Breast Tomosynthesis (DBT) system has been invented, which is likely to challenge the current mammography technology. The DBT system provides stunning 3D information, giving physicians increased detail of anatomical information, while reducing the chance of false negative screening. In this research, two reconstruction algorithms, Back Projection (BP) and Shift-And-Add (SAA), were used to investigate and compare View Angle (VA) and the number of projection images (N) with parallel imaging configurations. In addition, in order to better determine which method displayed better-quality imaging, Modulation Transfer Function (MTF) analyses were conducted with both algorithms, ultimately producing results which improve upon better breast cancer detection. Research studies find evidence that early detection of the disease is the best way to conquer breast cancer, and earlier detection results in the increase of life span for the affected person. PMID:23900440

Rayford, Cleveland E; Zhou, Weihua; Chen, Ying

2013-07-30

225

In vivo validation of CAAS QCA-3D coronary reconstruction using fusion of angiography and intravascular ultrasound (ANGUS).  

UK PubMed Central (United Kingdom)

OBJECTIVES: The CAAS QCA-3D system (Pie Medical Imaging BV, the Netherlands) was validated against 3D reconstructions based on fusion of angiography and intravascular ultrasound (ANGUS), allowing slice by slice validation of the lumen areas and 3D geometric values. BACKGROUND: Accurate online 3D reconstruction of human coronary arteries is of outmost importance during clinical practice in the catheterization laboratory. The CAAS QCA-3D system provides technology to 3D reconstruct human coronary arteries based on two or more angiographic images, but was not validated in realistic arteries before. METHODS: Ten patients were imaged using biplane angiography and an ECG gated (TomTec) intravascular ultrasound (IVUS) pullback (stepsize 0.5 mm, Boston Scientific). The coronary arteries were 3D reconstructed based on (a) fusion of biplane angiography and IVUS (ANGUS) and (b) CAAS QCA-3D using the biplane angiography images. For both systems the length, the curvature and the lumen areas at 0.5 mm spacing were calculated and compared. RESULTS: Bland-Altman analysis indicated that the CAAS QCA-3D system underestimated the lumen areas systematically by 0.45 +/- 1.49 mm2. The segment length was slightly underestimated by the CAAS QCA-3D system (62.1 +/- 11.3 vs. 63.2 +/- 11.4 mm; P < 0.05), while the curvature of the analyzed segments were not statistically different. CONCLUSIONS: The CAAS QCA-3D system allows 3D reconstruction of human coronary arteries based on biplane angiography. Validation against the ANGUS system showed that both the 3D geometry and lumen areas are highly correlated which makes the CAAS QCA-3D system a promising tool for applications in the catheterization laboratory and opens possibilities for computational fluid dynamics.

Schuurbiers JC; Lopez NG; Ligthart J; Gijsen FJ; Dijkstra J; Serruys PW; Van der Steen AF; Wentzel JJ

2009-04-01

226

Multimodal 3-D reconstruction of human anatomical structures using SurLens Visualization System.  

Science.gov (United States)

In the medical diagnosis and treatment planning, radiologists and surgeons rely heavily on the slices produced by medical imaging devices. Unfortunately, these image scanners could only present the 3-D human anatomical structure in 2-D. Traditionally, this requires medical professional concerned to study and analyze the 2-D images based on their expert experience. This is tedious, time consuming and prone to error; expecially when certain features are occluding the desired region of interest. Reconstruction procedures was earlier proposed to handle such situation. However, 3-D reconstruction system requires high performance computation and longer processing time. Integrating efficient reconstruction system into clinical procedures involves high resulting cost. Previously, brain's blood vessels reconstruction with MRA was achieved using SurLens Visualization System. However, adapting such system to other image modalities, applicable to the entire human anatomical structures, would be a meaningful contribution towards achieving a resourceful system for medical diagnosis and disease therapy. This paper attempts to adapt SurLens to possible visualisation of abnormalities in human anatomical structures using CT and MR images. The study was evaluated with brain MR images from the department of Surgery, University of North Carolina, United States and CT abdominal pelvic, from the Swedish National Infrastructure for Computing. The MR images contain around 109 datasets each of T1-FLASH, T2-Weighted, DTI and T1-MPRAGE. Significantly, visualization of human anatomical structure was achieved without prior segmentation. SurLens was adapted to visualize and display abnormalities, such as an indication of walderstrom's macroglobulinemia, stroke and penetrating brain injury in the human brain using Magentic Resonance (MR) images. Moreover, possible abnormalities in abdominal pelvic was also visualized using Computed Tomography (CT) slices. The study shows SurLens' functionality as a 3-D Multimodal Visualization System. PMID:23605637

Adeshina, A M; Hashim, R; Khalid, N E A; Abidin, S Z Z

2013-04-19

227

Multimodal 3-D reconstruction of human anatomical structures using SurLens Visualization System.  

UK PubMed Central (United Kingdom)

In the medical diagnosis and treatment planning, radiologists and surgeons rely heavily on the slices produced by medical imaging devices. Unfortunately, these image scanners could only present the 3-D human anatomical structure in 2-D. Traditionally, this requires medical professional concerned to study and analyze the 2-D images based on their expert experience. This is tedious, time consuming and prone to error; expecially when certain features are occluding the desired region of interest. Reconstruction procedures was earlier proposed to handle such situation. However, 3-D reconstruction system requires high performance computation and longer processing time. Integrating efficient reconstruction system into clinical procedures involves high resulting cost. Previously, brain's blood vessels reconstruction with MRA was achieved using SurLens Visualization System. However, adapting such system to other image modalities, applicable to the entire human anatomical structures, would be a meaningful contribution towards achieving a resourceful system for medical diagnosis and disease therapy. This paper attempts to adapt SurLens to possible visualisation of abnormalities in human anatomical structures using CT and MR images. The study was evaluated with brain MR images from the department of Surgery, University of North Carolina, United States and CT abdominal pelvic, from the Swedish National Infrastructure for Computing. The MR images contain around 109 datasets each of T1-FLASH, T2-Weighted, DTI and T1-MPRAGE. Significantly, visualization of human anatomical structure was achieved without prior segmentation. SurLens was adapted to visualize and display abnormalities, such as an indication of walderstrom's macroglobulinemia, stroke and penetrating brain injury in the human brain using Magentic Resonance (MR) images. Moreover, possible abnormalities in abdominal pelvic was also visualized using Computed Tomography (CT) slices. The study shows SurLens' functionality as a 3-D Multimodal Visualization System.

Adeshina AM; Hashim R; Khalid NE; Abidin SZ

2013-03-01

228

Computer-aided interactive surgical simulation for craniofacial anomalies based on 3-D surface reconstruction CT images  

Energy Technology Data Exchange (ETDEWEB)

We developed a computer-aided interactive surgical simulation system for craniofacial anomalies based on three-dimensional (3-D) surface reconstruction CT imaging. This system has four functions: (1) 3-D surface reconstruction display with an accelerated projection method; (2) Surgical simulation to cut, move, rotate, and reverse bone-blocks over the reference 3-D image on the CRT screen; (3) 3-D display of the simulated image in arbitrary views; and (4) Prediction of postoperative skin surface features displayed as 3-D images in arbitrary views. Retrospective surgical simulation has been performed on three patients who underwent the fronto-orbital advancement procedures for brachycephaly and two who underwent the reconstructive procedure for scaphocephaly. The predicted configurations of the cranium and skin surface were well simulated when compared to the postoperative images in 3-D arbitrary views. In practical use, this software might be used for an on-line system connected to a large scale general-purpose computer.

Fujioka, Mutsuhisa; Yokoi, Shigeki; Yasuda, Takami; Hashimoto, Yasuhiro; Toriwaki, Junnichiro; Nakajima, Hideo.

1988-10-01

229

Compressed sensing reconstruction for whole-heart imaging with 3D radial trajectories: a graphics processing unit implementation.  

UK PubMed Central (United Kingdom)

A disadvantage of three-dimensional (3D) isotropic acquisition in whole-heart coronary MRI is the prolonged data acquisition time. Isotropic 3D radial trajectories allow undersampling of k-space data in all three spatial dimensions, enabling accelerated acquisition of the volumetric data. Compressed sensing (CS) reconstruction can provide further acceleration in the acquisition by removing the incoherent artifacts due to undersampling and improving the image quality. However, the heavy computational overhead of the CS reconstruction has been a limiting factor for its application. In this article, a parallelized implementation of an iterative CS reconstruction method for 3D radial acquisitions using a commercial graphics processing unit is presented. The execution time of the graphics processing unit-implemented CS reconstruction was compared with that of the C++ implementation, and the efficacy of the undersampled 3D radial acquisition with CS reconstruction was investigated in both phantom and whole-heart coronary data sets. Subsequently, the efficacy of CS in suppressing streaking artifacts in 3D whole-heart coronary MRI with 3D radial imaging and its convergence properties were studied. The CS reconstruction provides improved image quality (in terms of vessel sharpness and suppression of noise-like artifacts) compared with the conventional 3D gridding algorithm, and the graphics processing unit implementation greatly reduces the execution time of CS reconstruction yielding 34-54 times speed-up compared with C++ implementation.

Nam S; Akçakaya M; Basha T; Stehning C; Manning WJ; Tarokh V; Nezafat R

2013-01-01

230

In vivo human 3D cardiac fibre architecture: reconstruction using curvilinear interpolation of diffusion tensor images.  

UK PubMed Central (United Kingdom)

In vivo imaging of the cardiac 3D fibre architecture is still a challenge, but it would have many clinical applications, for instance to better understand pathologies and to follow up remodelling after therapy. Recently, cardiac MRI enabled the acquisition of Diffusion Tensor images (DTI) of 2D slices. We propose a method for the complete 3D reconstruction of cardiac fibre architecture in the left ventricular myocardium from sparse in vivo DTI slices. This is achieved in two steps. First we map non-linearly the left ventricular geometry to a truncated ellipsoid. Second, we express coordinates and tensor components in Prolate Spheroidal System, where an anisotropic Gaussian kernel regression interpolation is performed. The framework is initially applied to a statistical cardiac DTI atlas in order to estimate the optimal anisotropic bandwidths. Then, it is applied to in vivo beating heart DTI data sparsely acquired on a healthy subject. Resulting in vivo tensor field shows good correlation with literature, especially the elevation (helix) angle transmural variation. To our knowledge, this is the first reconstruction of in vivo human 3D cardiac fibre structure. Such approach opens up possibilities in terms of analysis of the fibre architecture in patients.

Toussaint N; Sermesant M; Stoeck CT; Kozerke S; Batchelor PG

2010-01-01

231

Determination of Acceleration from 3D Reconstruction of Coronal Mass Ejections Observed by STEREO  

CERN Document Server

We employ a three-dimensional (3D) reconstruction technique, for the first time to study the kinematics of six coronal mass ejections (CMEs), using images obtained from the COR1 and COR2 coronagraphs on board the twin STEREO spacecraft, as also the eruptive prominences (EPs) associated with three of them using images from the Extreme UltraViolet Imager (EUVI). A feature in the EPs and leading edges (LEs) of all the CMEs was identified and tracked in images from the two spacecraft, and a stereoscopic reconstruction technique was used to determine the 3D coordinates of these features. True velocity and acceleration were determined from the temporal evolution of the true height of the CME features. Our study of kinematics of the CMEs in 3D reveals that the CME leading edge undergoes maximum acceleration typically below 2R$_\\{odot}$. The acceleration profiles of CMEs associated with flares and prominences exhibit different behaviour. While the CMEs not associated with prominences show a bimodal acceleration profi...

Joshi, Anand D

2011-01-01

232

Maxillary sinus 3D segmentation and reconstruction from cone beam CT data sets  

International Nuclear Information System (INIS)

Purpose: Segmentation of the maxillary sinuses for three-dimensional (3D) reconstruction, visualization and volumetry is sought using an automated algorithm applied to cone beam computed tomographic (CBCT) data sets. Materials and methods: Cone beam computed tomography (CBCT) data sets of three subjects aged 9, 17, and 27 were used in 3D segmentation and reconstruction. The maxillary sinuses were obtained by propagation from one start point in the right sinus and one start point in the left sinus to the whole regions of both sinuses. The procedure was based on voxel intensity distributions and common anatomic structures, specifically each middle meatus of the nasal cavity. A program was written in C++ and VTK languages to demonstrate the surface topological shapes of the maxillary sinuses. Results: The developed segmentation algorithm separated maxillary sinuses successfully permitting accurate comparisons. It was robust and efficient. 3D morphological features of the maxillary sinuses were observed from three human subjects. Conclusions: Automated segmentation of maxillary sinuses from CBCT data sets is feasible using the proposed method. This tool might be useful for visualization, pathological diagnosis, and treatment planning of maxillary sinus disorders. (orig.)

2006-01-01

233

Maxillary sinus 3D segmentation and reconstruction from cone beam CT data sets  

Energy Technology Data Exchange (ETDEWEB)

Purpose: Segmentation of the maxillary sinuses for three-dimensional (3D) reconstruction, visualization and volumetry is sought using an automated algorithm applied to cone beam computed tomographic (CBCT) data sets. Materials and methods: Cone beam computed tomography (CBCT) data sets of three subjects aged 9, 17, and 27 were used in 3D segmentation and reconstruction. The maxillary sinuses were obtained by propagation from one start point in the right sinus and one start point in the left sinus to the whole regions of both sinuses. The procedure was based on voxel intensity distributions and common anatomic structures, specifically each middle meatus of the nasal cavity. A program was written in C++ and VTK languages to demonstrate the surface topological shapes of the maxillary sinuses. Results: The developed segmentation algorithm separated maxillary sinuses successfully permitting accurate comparisons. It was robust and efficient. 3D morphological features of the maxillary sinuses were observed from three human subjects. Conclusions: Automated segmentation of maxillary sinuses from CBCT data sets is feasible using the proposed method. This tool might be useful for visualization, pathological diagnosis, and treatment planning of maxillary sinus disorders. (orig.)

Shi, Hongjian [Louisville Univ., KY (United States). Computer Vision and Image Processing Lab.; Scarfe, W.C.; Farman, A.G. [Louisville Univ., KY (United States). Div. of Radiology and Imaging Science

2006-08-15

234

3D surface reconstruction and visualization of the Drosophila wing imaginal disc at cellular resolution  

Science.gov (United States)

Quantifying and visualizing the shape of developing biological tissues provide information about the morphogenetic processes in multicellular organisms. The size and shape of biological tissues depend on the number, size, shape, and arrangement of the constituting cells. To better understand the mechanisms that guide tissues into their final shape, it is important to investigate the cellular arrangement within tissues. Here we present a data processing pipeline to generate 3D volumetric surface models of epithelial tissues, as well as geometric descriptions of the tissues' apical cell cross-sections. The data processing pipeline includes image acquisition, editing, processing and analysis, 2D cell mesh generation, 3D contourbased surface reconstruction, cell mesh projection, followed by geometric calculations and color-based visualization of morphological parameters. In their first utilization we have applied these procedures to construct a 3D volumetric surface model at cellular resolution of the wing imaginal disc of Drosophila melanogaster. The ultimate goal of the reported effort is to produce tools for the creation of detailed 3D geometric models of the individual cells in epithelial tissues. To date, 3D volumetric surface models of the whole wing imaginal disc have been created, and the apicolateral cell boundaries have been identified, allowing for the calculation and visualization of cell parameters, e.g. apical cross-sectional area of cells. The calculation and visualization of morphological parameters show position-dependent patterns of cell shape in the wing imaginal disc. Our procedures should offer a general data processing pipeline for the construction of 3D volumetric surface models of a wide variety of epithelial tissues.

Bai, Linge; Widmann, Thomas; Jülicher, Frank; Dahmann, Christian; Breen, David

2013-01-01

235

ROC analysis for assessment of lesion detection performance in 3D PET: Influence of reconstruction algorithms  

International Nuclear Information System (INIS)

Image quality in positron emission tomography (PET) can be assessed with physical parameters, as spatial resolution and signal-to-noise ratio, or using psychophysical approaches, which include the observer performance and the considered task (ROC analysis). For PET in oncology, such a task is the detection of hot lesions. The aim of the present study was to assess the lesion detection performance due to adequate modeling of the scanner and the measurement process in the image reconstruction process. We compared the standard OSEM software of the manufacturer with a sophisticated fully 3D iterative reconstruction technique (USC MAP). A rectangular phantom with 6 oblique line sources in a homogeneous background (2.6 kBq/ml 18F) was imaged dynamically with an ECAT EXACT HR+ scanner in 3D mode. Reconstructed activity contrasts varied between 15 and 0, as the line sources were filled with 11C (3.2 MBq/ml). Measured attenuation and standard randoms, dead time, and scatter corrections of the manufacturer were employed. For the ROC analysis, a software tool presented a cut-out of the phantom (15x15 pixels) to two observers. These cut-outs were rated (5 classes) and the area Az under the ROC curve was determined as a measure of detection performance. The improvement for Az with USC MAP compared to the OSEM reconstructions ranged between 0.02 and 0.23 for signal-to-noise ratios of the background between 2.8 and 3.1 and lesion contrast between 2.1 and 4.2. This study demonstrates that adequate modeling of the measurement process in the reconstruction algorithm improves the detection of small hot lesions markedly.

2003-01-01

236

A Digital 3D-Reconstruction of the Younger Dryas Baltic Ice Lake  

Science.gov (United States)

A digital 3D-reconstruction of the final stage of the ice dammed Baltic Ice Lake (BIL), dated to the very end of the Younger Dryas cold period (ca. 11 600 cal. yr BP) has been compiled using a combined bathymetric-topographic Digital Terrain Model (DTM), Scandinavian ice sheet limits, Baltic Sea Holocene bottom sediment thickness information, and a paleoshoreline database maintained at the Lund University. The combined bathymetric-topographic Digital Terrain Model (DTM) model used to reconstruct the ice dammed lake was compiled specifically for this study from publicly available data sets. The final DTM is in the form of a digital grid on Lamberts Equal Area projection with a resolution of 500 x 500 m, which permits a much more detailed reconstruction of the BIL than previously made. The lake was constructed through a series of experiments where mathematical algorithms were applied to fit the paleolake's surface through the shoreline database. The accumulated Holocene bottom sediments in the Baltic Sea were subsequently subtracted from the present bathymetry in our reconstruction. This allows us to estimate the Baltic Ice Lake's paleobathymetry, area, volume, and hypsometry, which will comprise key input data to lake/climate modeling exercises following this study. The Scandinavian ice sheet margin eventually retreated north of Mount Billingen, which was the high point in terrain of Southern central Sweden bordering to lower terrain further to the North. As a consequence, the BIL was catastrophically drained through this area, resulting in a 25 m drop of the lake level. With our digital BIL model we estimate that approximately 7, 800 km3 of water drained during this event and that the ice dammed lake area was reduced with ca 18 percent. The digital BIL reconstruction is analyzed using 3D-visualization techniques that provide new detailed information on the paleogeography in the area, both before and after the lake drainage, with implications for interpretations of geological records concerning the post-glacial environmental development of southern Scandinavia.

Jakobsson, M.; Alm, G.; Bjorck, S.; Lindeberg, G.; Svensson, N.

2005-12-01

237

Calibration target reconstruction for 3-D vision inspection system of large-scale engineering objects  

Science.gov (United States)

It is usually difficult to calibrate the 3-D vision inspection system that may be employed to measure the large-scale engineering objects. One of the challenges is how to in-situ build-up a large and precise calibration target. In this paper, we present a calibration target reconstruction strategy to solve such a problem. First, we choose one of the engineering objects to be inspected as a calibration target, on which we paste coded marks on the object surface. Next, we locate and decode marks to get homologous points. From multiple camera images, the fundamental matrix between adjacent images can be estimated, and then the essential matrix can be derived with priori known camera intrinsic parameters and decomposed to obtain camera extrinsic parameters. Finally, we are able to obtain the initial 3D coordinates with binocular stereo vision reconstruction, and then optimize them with the bundle adjustment by considering the lens distortions, leading to a high-precision calibration target. This reconstruction strategy has been applied to the inspection of an industrial project, from which the proposed method is successfully validated.

Yin, Yongkai; Peng, Xiang; Guan, Yingjian; Liu, Xiaoli; Li, Ameng

2010-11-01

238

3D Reconstruction: Novel Method for Finding of Corresponding Points using Pseudo Colors  

Directory of Open Access Journals (Sweden)

Full Text Available This paper deals with the reconstruction of spatial coordinates of an arbitrary point in a scene using two images scanned by a 3D camera or two displaced cameras. Calculations are based on the perspective geom-etry. Accurate determination of corresponding points is a fundamental step in this process. The usually used methods can have a problem with points, which lie in areas without sufficient contrast. This paper describes our proposed method based on the use of the relationship between the selected points and area feature points. The proposed method finds correspondence using a set of feature points found by SURF. An algorithm is proposed and described for quick removal of false correspondences, which could ruin the correct reconstruction. The new method, which makes use of pseudo color image representation (pseudo coloring) has been proposed subsequently. By means of this method it is possible to significantly increase the color contrast of the surveyed image, and therefore add more information to find the correct correspondence. Reliability of the found correspondence can be verified by reconstruction of 3D position of selected points. Executed experiments confirm our assumptions

L. Bolecek; V. Ricny; M. Slanina

2013-01-01

239

A multiple-point statistics algorithm for 3D pore space reconstruction from 2D images  

Science.gov (United States)

Fluid flow behavior in a porous medium is a function of the geometry and topology of its pore space. The construction of a three dimensional pore space model of a porous medium is therefore an important first step in characterizing the medium and predicting its flow properties. A stochastic technique for reconstruction of the 3D pore structure of unstructured random porous media from a 2D thin section training image is presented. The proposed technique relies on successive 2D multiple point statistics simulations coupled to a multi-scale conditioning data extraction procedure. The Single Normal Equation Simulation Algorithm (SNESIM), originally developed as a tool for reproduction of long-range, curvilinear features of geological structures, serves as the simulation engine. Various validating criteria such as marginal distributions of pore and grain, directional variograms, multiple-point connectivity curves, single phase effective permeability and two phase relative permeability calculations are used to analyze the results. The method is tested on a sample of Berea sandstone for which a 3D micro-CT scanning image is available. The results confirm that the equi-probable 3D realizations obtained preserve the typical patterns of the pore space that exist in thin sections, reproduce the long-range connectivities, capture the characteristics of anisotropy in both horizontal and vertical directions and have single and two phase flow characteristics consistent with those of the measured 3D micro-CT image.

Hajizadeh, Alireza; Safekordi, Aliakbar; Farhadpour, Farhad A.

2011-10-01

240

Fully 3D PET image reconstruction using a fourier preconditioned conjugate-gradient algorithm  

International Nuclear Information System (INIS)

Since the data sizes in fully 3D PET imaging are very large, iterative image reconstruction algorithms must converge in very few iterations to be useful. One can improve the convergence rate of the conjugate-gradient (CG) algorithm by incorporating preconditioning operators that approximate the inverse of the Hessian of the objective function. If the 3D cylindrical PET geometry were not truncated at the ends, then the Hessian of the penalized least-squares objective function would be approximately shift-invariant, i.e. G'G would be nearly block-circulant, where G is the system matrix. We propose a Fourier preconditioner based on this shift-invariant approximation to the Hessian. Results show that this preconditioner significantly accelerates the convergence of the CG algorithm with only a small increase in computation.

1996-01-01

 
 
 
 
241

Fully 3D PET image reconstruction using a fourier preconditioned conjugate-gradient algorithm  

Energy Technology Data Exchange (ETDEWEB)

Since the data sizes in fully 3D PET imaging are very large, iterative image reconstruction algorithms must converge in very few iterations to be useful. One can improve the convergence rate of the conjugate-gradient (CG) algorithm by incorporating preconditioning operators that approximate the inverse of the Hessian of the objective function. If the 3D cylindrical PET geometry were not truncated at the ends, then the Hessian of the penalized least-squares objective function would be approximately shift-invariant, i.e. G{prime}G would be nearly block-circulant, where G is the system matrix. We propose a Fourier preconditioner based on this shift-invariant approximation to the Hessian. Results show that this preconditioner significantly accelerates the convergence of the CG algorithm with only a small increase in computation.

Fessler, J.A.; Ficaro, E.P. [Univ. of Michigan, Ann Arbor, MI (United States)

1996-12-31

242

Effect of voxel size on the accuracy of 3D reconstructions with cone beam CT.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The various types of cone beam CT (CBCT) differ in several technical characteristics, notably their spatial resolution, which is defined by the acquisition voxel size. However, data are still lacking on the effects of voxel size on the metric accuracy of three-dimensional (3D) reconstructions. This study was designed to assess the effect of isotropic voxel size on the 3D reconstruction accuracy and reproducibility of CBCT data. METHODS: The study sample comprised 70 teeth (from the Institut d'Anatomie Normale, Strasbourg, France). The teeth were scanned with a KODAK 9500 3D® CBCT (Carestream Health, Inc., Marne-la-Vallée, France), which has two voxel sizes: 200 µm (CBCT 200 µm group) and 300 µm (CBCT 300 µm group). These teeth had also been scanned with the KODAK 9000 3D® CBCT (Carestream Health, Inc.) (CBCT 76 µm group) and the SCANCO Medical micro-CT XtremeCT (SCANCO Medical, Brüttisellen, Switzerland) (micro-CT 41 µm group) considered as references. After semi-automatic segmentation with AMIRA® software (Visualization Sciences Group, Burlington, MA), tooth volumetric measurements were obtained. RESULTS: The Bland-Altman method showed no difference in tooth volumes despite a slight underestimation for the CBCT 200 µm and 300 µm groups compared with the two reference groups. The underestimation was statistically significant for the volumetric measurements of the CBCT 300 µm group relative to the two reference groups (Passing-Bablok method). CONCLUSIONS: CBCT is not only a tool that helps in diagnosis and detection but it has the complementary advantage of being a measuring instrument, the accuracy of which appears connected to the size of the voxels. Future applications of such measurements with CBCT are discussed.

Maret D; Telmon N; Peters OA; Lepage B; Treil J; Inglèse JM; Peyre A; Kahn JL; Sixou M

2012-12-01

243

Effect of voxel size on accuracy of 3D reconstructions with cone beam CT.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The various types of cone beam CT (CBCT) differ by several technical characteristics, notably their spatial resolution, which is defined by the acquisition voxel size. However, data are still lacking on the effects of voxel size on the metric accuracy of three-dimensional (3D) reconstructions. This study was designed to assess the effect of isotropic voxel size on the 3D reconstruction accuracy and reproducibility of CBCT data. METHODS: The study sample comprised 70 teeth (from the Institut d'Anatomie Normale, Strasbourg, France). The teeth were scanned with a Kodak 9500 3D® CBCT, which has 2 voxel sizes: 200 µm (CBCT 200 µm group) and 300 µm (CBCT 300 µm group). These teeth had also been scanned with the Kodak 9000 3D® CBCT (CBCT 76 µm group) and the Scanco Medical micro-CT, XtremeCT (Micro-CT 41 µm group) considered as references. After semi-automatic segmentation with AMIRA software, tooth volumetric measurements were obtained. RESULTS: The Bland-Altman method showed no difference in tooth volumes despite a slight underestimation for the CBCT 200 µm and 300 µm groups compared with the two reference groups. The underestimation was statistically significant for the volumetric measurements of the CBCT 300 µm group relative to the two reference groups (Passing-Bablok method). CONCLUSIONS: CBCT is not only a tool that helps in diagnosis and detection but it has the complementary advantage of being a measuring instrument, the accuracy of which appears connected to the size of the voxels. Future applications of such measurements with CBCT are discussed.

Maret D; Telmon N; Peters OA; Lepage B; Treil J; Inglèse JM; Peyre A; Kahn JL; Sixou M

2012-05-01

244

Applications of 3-D reconstruction and 3-D image analysis using computer graphics in surgery of the oral and maxillofacial regions  

International Nuclear Information System (INIS)

Using the 2-D data provided by CT-Tomography and MRI-tomography of oral and maxillofacial diseases (cyst, benign tumor, primary tumor and regional lymphnodes of malignant tumor), 3-D images were reconstructed and spatial analysis was attempted. We report the general concepts. The hardware used consisted of the Hewlett-Packard HP-9000/300, which utilizes a 16-bit CPU. A digitizer was used to construct 3-D images from serial CT-tomography and MRI-tomography images. Output was displayed on a color monitor and photographs. The 3 cases on which we used this technique included a 19-year-old male with plunging ranula, a 50-year-old male with maxillary pleomorphic adenoma, and a 58-year-old male with squamous cell carcinoma of the maxillary sinus (T3N3M0). As 3-D reconstruction can be done in any arbitrary direction or cross section, it is possible to spatially determine the position of the disease inside the body, its progression, and its relationship with adjacent organs. Through image analysis, it is possible to better understand the volume and surface area of the disease. 3-D image reconstruction is an effective tool in the determination of diagnosis, therapeutic guidelines, and surgical indications, as well as effectiveness of treatment. (author).

1988-01-01

245

Applications of 3-D reconstruction and 3-D image analysis using computer graphics in surgery of the oral and maxillofacial regions  

Energy Technology Data Exchange (ETDEWEB)

Using the 2-D data provided by CT-Tomography and MRI-tomography of oral and maxillofacial diseases (cyst, benign tumor, primary tumor and regional lymphnodes of malignant tumor), 3-D images were reconstructed and spatial analysis was attempted. We report the general concepts. The hardware used consisted of the Hewlett-Packard HP-9000/300, which utilizes a 16-bit CPU. A digitizer was used to construct 3-D images from serial CT-tomography and MRI-tomography images. Output was displayed on a color monitor and photographs. The 3 cases on which we used this technique included a 19-year-old male with plunging ranula, a 50-year-old male with maxillary pleomorphic adenoma, and a 58-year-old male with squamous cell carcinoma of the maxillary sinus (T/sub 3/N/sub 3/M/sub 0/). As 3-D reconstruction can be done in any arbitrary direction or cross section, it is possible to spatially determine the position of the disease inside the body, its progression, and its relationship with adjacent organs. Through image analysis, it is possible to better understand the volume and surface area of the disease. 3-D image reconstruction is an effective tool in the determination of diagnosis, therapeutic guidelines, and surgical indications, as well as effectiveness of treatment.

Yamamoto, Koichi; Yamauchi, Asanori; Madachi, Fujio; Furuta, Isao

1988-12-01

246

Measuring stone volume - 3D software reconstruction or an ellipsoid algebra formula?  

UK PubMed Central (United Kingdom)

INTRODUCTION: Kidney stone volume may be helpful in predicting treatment outcome for renal stones. While the precise measurement of stone volume by 3D reconstruction can be accomplished using modern CT scanning software, this technique is not available in all hospitals or with routine acute colic scanning protocols. Therefore, maximum diameters as measured by either X-ray or CT are used in the calculation of stone volume based on a scalene ellipsoid formula, as recommended by the European Association of Urology. However, ellipsoids are not uniform . We sought to determine the optimal method for assessing stone volume, and thus stone burden, by comparing the accuracy of scalene, oblate, and prolate ellipsoid volume equations with 3D-reconstructed stone volume. METHODS: 100 stones with both X-ray and CT scan (1-2 mm slices) were reviewed. Complete and partial staghorn stones were excluded. Stone volume was calculated using software designed to measure tissue density of a certain range within a specified region of interest. Correlation coefficients among all measured outcomes were compared. Stone volumes were analysed to determine the average 'shape' of the stones. RESULTS: Maximum diameter on X-ray ranged from 3-25 mm and on CT from 3-36 mm, with a reasonable correlation (r=0.77). Smaller stones (<9 mm) trended towards prolate ellipsoids (rugby-ball shaped), stones between 9-15 mm towards oblate ellipsoids (disc shaped), and stones over 15 mm towards scalene ellipsoids. There was no difference in stone shape by location within the kidney. CONCLUSION: Since the average shape of renal stones changes with diameter, no single equation for estimating stone volume can be recommended. As the maximum diameter increases, calculated stone volume becomes less accurate, suggesting that larger stones have more asymmetric shapes. We recommend that research looking at stone clearance rates should use 3D-reconstructed stone volumes when available, followed by prolate, oblate, or scalene ellipsoid formulas depending on the maximum stone diameter.

Finch W; Johnston R; Shaida N; Winterbottom A; Wiseman O

2013-09-01

247

Molecular-Frame 3D Photoelectron Momentum Distributions by Tomographic Reconstruction  

DEFF Research Database (Denmark)

Naphthalene molecules are fixed in space by a laser field and rotated, in 2° steps, over 180°. For each orientation, they are ionized by an intense, circularly polarized femtosecond laser pulse, and the 2D projection of the photoelectron momentum distribution is recorded. The molecular-frame 3D momentum distribution is obtained by tomographic reconstruction from all 90 projections. It reveals an anisotropic electron distribution, angularly shifted in the polarization plane, that is not accessible by the 2D momentum images. Our theoretical analysis shows that the magnitude of the angular shift is very sensitive to the exact form of the laser-modified molecular potential.

Maurer, Jochen; Dimitrovski, Darko

2012-01-01

248

Implementation of the Hough Transform for 3D Track Reconstruction in Drift Chambers  

CERN Multimedia

The paper is devoted to the method for 3D reconstruction of the straight tracks in the tracking system consisting of the drift-chamber stereo layers. The method is based on the Hough-transform approach - the discrete case of more general Radon transform - and takes into account both coordinates of the hit wires and drift distances not only for the measurements in one projection, but also in the rotated stereo layers. The proposed method allows one to resolve the right-left ambiguity and provides the accordance between vertical and horizontal projections of the track.

Belkov, A A

2002-01-01

249

[Fast 3D model reconstruction of scoliotic spine using two X-ray images].  

UK PubMed Central (United Kingdom)

A whole technical way of reconstructing 3D model of the scoliotic spine from two X-ray images was proposed. From the experimental results of 30 patients with mild to severe scoliosis, we can conclude that the accuracy of locating vertebrae is 0.5 mm, the orientation accuracy was 1.5. After comparing the results with those using the previous methods, we found that the method proposed in this paper can get higher resolution with less computational time, making it suitable for clinical routine use.

Zeng X; Zhou H; Wang C; Chen G

2013-02-01

250

Detector modeling techniques for pre-clinical 3D PET reconstruction on the GPU  

Energy Technology Data Exchange (ETDEWEB)

This paper presents methods to the efficient handling of gamma interaction within the detector crystal matrix in ML-EM-based 3D reconstruction algorithms for positron emission tomography (PET). Geometric calculations as well as the approximation of inter-crystal scattering are executed on the GPU. The main characteristics of the scattering effect are captured by factorized models incorporating both on-the-fly simulation and the use of pre-computed data. The discussed methods involve the modification of the detector radius in the geometric model; applying 4D shifting of the LORs regarding the precalculated crystal-transport probability distributions; replacing the simulated detector response function by an approximated one; or full Monte Carlo simulation of the detector. Results of these different approaches are reported using phantom simulations as well as reconstructing real measurements performed on the NanoPET trademark /CT small animal PET scanner. (orig.)

Magdics, M.; Toth, B.; Szecsi, L. [Budapest Univ. of Technology and Economics (Hungary). Dept. of Control Engineering and Information Technology; Semmelweis Univ., Budapest (Hungary). Dept. of Diagnostic Radiology and Oncotherapy] [and others

2011-07-01

251

Towards the reconstruction of 3D orientation information from direction-sensitive X-ray projections  

Energy Technology Data Exchange (ETDEWEB)

For medical in vivo applications the resolution of a computed tomography (CT) scan is limited by the acceptable patient received dose. Thus it does not allow to image microstructures in the body. Novel X-ray contrast mechanisms provide two additional signal channels, phase contrast and dark-field contrast. In this study we report on our progress to use the dark-field signal to gain micro-structural information by reconstructing a tensor field describing the local sample scattering power. For that purpose we developed an experimental setup composed of an X-ray tube, a Talbot Lau interferometer, an Euler cradle to orient the sample and a detector. This setup allows a direct measurement of the sample scattering strength in all directions. The reconstruction of several test samples is done using filtered back-projection or the algebraic reconstruction technique. The definition of the physical model behind the reconstructed quantity is obtained from a second ansatz by using 3D density map (micro-CT) data as an input to a computer simulation of the whole setup. We consider this project important for diagnostic improvements in the case of bone pathologies. (orig.)

Malecki, Andreas; Biernath, Thomas; Bech, Martin; Potdevin, Guillaume; Pfeiffer, Franz [Technische Univ. Muenchen (Germany). Dept. of Physics (E17); Technische Univ. Muenchen (Germany). Inst. of Medical Engineering (IMETUM); Lasser, Tobias [Technische Univ. Muenchen (Germany). Chair for Computer Aided Medical Procedures and Augmented Reality (CAMP)

2011-07-01

252

Reconstruction of the upper ocean 3D dynamics from high-resolution sea surface height  

Science.gov (United States)

The present study investigates the reconstruction of the 3D dynamics of a turbulent mesoscale eddy field driven at a depth by a baroclinic instability of the Phillips type. It uses a high-resolution primitive equation simulation as a testbed. The method of reconstruction is based on potential vorticity principles and extends an earlier approach (Lapeyre and Klein, J Phys Oceanogr 36:165-176, 2006) to a regime where the signature of surface density anomalies on the dynamics is weak. The crux and the originality of the reconstruction lie in the estimation from sea surface height and surface density anomalies of the interior quasigeostrophic potential vorticity (PV) anomalies and its subsequent inversion. The estimation of PV anomalies relies on the vertical correlation between PV anomalies and on the knowledge on stratification and horizontal gradients of background PV. PV anomalies are accurately estimated over the first 500 m of the water column and over a wide range of wavenumbers. Density anomalies play a minor role in the PV estimation, though their omission leads to an overestimation of PV by a factor of less than 2 at scales of order 20 km and less. Inversion of the estimated PV leads to a geostrophic streamfunction which in turn provides reliable reconstructions of the relative vorticity and vertical velocity (via the omega equation).

Ponte, Aurelien L.; Klein, Patrice

2013-07-01

253

3D Equilibrium Reconstruction of DIII-D Discharges using V3FIT  

Science.gov (United States)

Non-axisymmetric perturbations to tokamak magnetic fields have become increasingly important for tokamak operation to modify pedestal profiles. Such modifications have led to ELM mitigation, triggering and full stabilization. These perturbations affect transport and stability at the plasma edge, but the physics mechanisms responsible for these changes are not fully understood. An open question is the degree of penetration of the applied fields, and whether these perturbations result in ideal distortions of the magnetic flux surfaces, create magnetic islands, or stochasticize the edge region. The V3FIT code is being used to reconstruct 3D equilibria for DIII-D discharges with the assumption of nested flux surfaces. The present work is a study of the ability of the V3FIT code to reliably reconstruct the plasma equilibrium state for a variety of discharge types with particular focus on the edge pedestal region. A diagnostic set consisting of magnetic diagnostics, ion and electron temperature and density profile and soft x-ray diagnostics is used for the reconstructions. The ability of these diagnostics to reconstruct equilibria that agree with observed toroidal asymmetries is assessed and the relative effectiveness of each diagnostic is determined.

Sontag, A. C.; Harris, J. H.; Shafer, M. W.; Unterberg, E. A.; Hanson, J. D.; Lao, L. L.

2012-10-01

254

Compressed sensing reconstruction of undersampled 3D NOESY spectra: application to large membrane proteins  

Energy Technology Data Exchange (ETDEWEB)

Central to structural studies of biomolecules are multidimensional experiments. These are lengthy to record due to the requirement to sample the full Nyquist grid. Time savings can be achieved through undersampling the indirectly-detected dimensions combined with non-Fourier Transform (FT) processing, provided the experimental signal-to-noise ratio is sufficient. Alternatively, resolution and signal-to-noise can be improved within a given experiment time. However, non-FT based reconstruction of undersampled spectra that encompass a wide signal dynamic range is strongly impeded by the non-linear behaviour of many methods, which further compromises the detection of weak peaks. Here we show, through an application to a larger {alpha}-helical membrane protein under crowded spectral conditions, the potential use of compressed sensing (CS) l{sub 1}-norm minimization to reconstruct undersampled 3D NOESY spectra. Substantial signal overlap and low sensitivity make this a demanding application, which strongly benefits from the improvements in signal-to-noise and resolution per unit time achieved through the undersampling approach. The quality of the reconstructions is assessed under varying conditions. We show that the CS approach is robust to noise and, despite significant spectral overlap, is able to reconstruct high quality spectra from data sets recorded in far less than half the amount of time required for regular sampling.

Bostock, Mark J. [University of Cambridge, Department of Biochemistry (United Kingdom); Holland, Daniel J. [University of Cambridge, Department of Chemical Engineering and Biotechnology (United Kingdom); Nietlispach, Daniel, E-mail: dn206@cam.ac.uk [University of Cambridge, Department of Biochemistry (United Kingdom)

2012-09-15

255

Compressed sensing reconstruction of undersampled 3D NOESY spectra: application to large membrane proteins  

International Nuclear Information System (INIS)

[en] Central to structural studies of biomolecules are multidimensional experiments. These are lengthy to record due to the requirement to sample the full Nyquist grid. Time savings can be achieved through undersampling the indirectly-detected dimensions combined with non-Fourier Transform (FT) processing, provided the experimental signal-to-noise ratio is sufficient. Alternatively, resolution and signal-to-noise can be improved within a given experiment time. However, non-FT based reconstruction of undersampled spectra that encompass a wide signal dynamic range is strongly impeded by the non-linear behaviour of many methods, which further compromises the detection of weak peaks. Here we show, through an application to a larger ?-helical membrane protein under crowded spectral conditions, the potential use of compressed sensing (CS) l1-norm minimization to reconstruct undersampled 3D NOESY spectra. Substantial signal overlap and low sensitivity make this a demanding application, which strongly benefits from the improvements in signal-to-noise and resolution per unit time achieved through the undersampling approach. The quality of the reconstructions is assessed under varying conditions. We show that the CS approach is robust to noise and, despite significant spectral overlap, is able to reconstruct high quality spectra from data sets recorded in far less than half the amount of time required for regular sampling.

2012-01-01

256

Applicability of 3D-CT facial reconstruction for forensic individual identification Aplicabilidade da reconstrução facial em 3D-TC para identificação individual forense  

Directory of Open Access Journals (Sweden)

Full Text Available Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by volume rendering technique with computer graphics tools. Ten (10) craniometric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution.A tomografia computadorizada (TC) tem sido utilizada em diversas áreas clínicas da Odontologia; utilizam-se tanto seus cortes originais quanto as reconstruções em duas e três dimensões (2D-TC e 3D-TC). O presente estudo propõe avaliar a precisão das medidas lineares realizadas na 3D-TC, utilizando a craniometria, para fins de identificação individual na Odontologia Forense. Cinco cabeças de cadáveres foram submetidas a tomografia computadorizada em espiral por meio de cortes axiais e reconstruções em 3D-TC foram obtidas por meio da técnica de volume, utilizando recursos da computação gráfica. Medidas craniométricas (n = 10) foram determinadas nas imagens em 3D-TC por dois examinadores independentemente, duas vezes cada um, e uma análise de erro padrão percentual das medidas intra- e inter-examinadores foi realizada. Os resultados demonstraram um erro padrão percentual baixo apresentado por essas medidas, variando entre 0,85% e 3,09%. Em conclusão, as medidas lineares obtidas nas estruturas ósseas e tegumentares foram consideradas precisas em 3D-TC, com alta qualidade e resolução de imagem.

Sara dos Santos Rocha; Dalton Luiz de Paula Ramos; Marcelo de Gusmão Paraíso Cavalcanti

2003-01-01

257

Applicability of 3D-CT facial reconstruction for forensic individual identification/ Aplicabilidade da reconstrução facial em 3D-TC para identificação individual forense  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese A tomografia computadorizada (TC) tem sido utilizada em diversas áreas clínicas da Odontologia; utilizam-se tanto seus cortes originais quanto as reconstruções em duas e três dimensões (2D-TC e 3D-TC). O presente estudo propõe avaliar a precisão das medidas lineares realizadas na 3D-TC, utilizando a craniometria, para fins de identificação individual na Odontologia Forense. Cinco cabeças de cadáveres foram submetidas a tomografia computadorizada em espiral por (more) meio de cortes axiais e reconstruções em 3D-TC foram obtidas por meio da técnica de volume, utilizando recursos da computação gráfica. Medidas craniométricas (n = 10) foram determinadas nas imagens em 3D-TC por dois examinadores independentemente, duas vezes cada um, e uma análise de erro padrão percentual das medidas intra- e inter-examinadores foi realizada. Os resultados demonstraram um erro padrão percentual baixo apresentado por essas medidas, variando entre 0,85% e 3,09%. Em conclusão, as medidas lineares obtidas nas estruturas ósseas e tegumentares foram consideradas precisas em 3D-TC, com alta qualidade e resolução de imagem. Abstract in english Computed tomography (CT) is used in several clinical dentistry applications even by axial slices and two and three-dimensional reconstructed images (2D-CT and 3D-CT). The purpose of the current study is to assess the precision of linear measurements made in 3D-CT using craniometric patterns for individual identification in Forensic Dentistry. Five cadaver heads were submitted to a spiral computed tomography using axial slices, and 3D-CT reconstructions were obtained by vo (more) lume rendering technique with computer graphics tools. Ten (10) craniometric measurements were determined in 3D-CT images by two examiners independently, twice each, and the standard error of intra- and inter-examiner measurements was assessed. The results demonstrated a low standard error of those measurements, from 0.85% to 3.09%. In conclusion, the linear measurements obtained in osseous and soft tissue structures were considered to be precise in 3D-CT with high imaging quality and resolution.

Rocha, Sara dos Santos; Ramos, Dalton Luiz de Paula; Cavalcanti, Marcelo de Gusmão Paraíso

2003-03-01

258

Status of equilibrium reconstruction with EFIT at TEXTOR including 3D effects  

Energy Technology Data Exchange (ETDEWEB)

The equilibrium reconstruction code EFIT has been installed at the iron core tokamak TEXTOR and its applicability to TEXTOR conditions and configurations is analyzed. EFIT uses an interleaved Picard and fitting iteration scheme to solve the Grad-Shafranov equation with experimental data as constraints. Magnetic diagnostics are used as basic input. The problem of equilibrium reconstruction is ill posed, especially from external magnetic data only. To resolve this additional input from internal MSE and kinetic measurements is needed. It is found that the available magnetic diagnostics at TEXTOR are insufficient in number and distribution to obtain key plasma parameters such as e.g. {beta}{sub pol} to an acceptable accuracy. Hence, an extension of the diagnostic system is proposed on the basis of EFIT tests. A 3D correction for the magnetic field ripple of the toroidal field coils based on earlier work has now been made available for TEXTOR. Further steps to incorporate 3D perturbations of the dynamic ergodic divertor on the equilibrium are undertaken and first results are given.

Wiegmann, Christopher; Zimmermann, Oliver; Reiter, Detlev [Institut fuer Plasmaphysik, Forschungszentrum Juelich GmbH, EURATOM-Association, Trilateral Euregio Cluster, 52425 Juelich (Germany); Zwingmann, Wolfgang [Association EURATOM-CEA/DSM/DRFC Cadarache, 13108 St-Paul-Lez-Durance (France)

2007-07-01

259

Reimaging Past Worlds: Issues and Challenges in the Use of 3D Graphics for Historical Reconstructions  

Directory of Open Access Journals (Sweden)

Full Text Available 3D computer rendering technology allows researchers to present their scenes with fully navigable and interactive virtual recreations of past environments. Completing an accurate and effective historical CG reconstruction is a complex process, in which researchers must carefully balance a number of important and independent factors. At the research stage, creators must determine whether the product will be directly illustrative or more broadly interpretive, and how they will evaluate evidence from sources of difference media. Once they begin designing the reconstruction, the level of visual detail that creators select is crucial. High detail projects display greater realism, but are more expensive and time consuming. Conversely lower detail scenes are better suited for multiple media formats, and are most efficient, customizable, and cost-effective. A scholar’s consideration of these issues will help determine the number of collaborators and software necessary, as well as the project’s output format. 3D computer graphics offer an unparalleled opportunity to present visions of the past to the public, but only thoughtfully planned projects will realize their full potential.

James Coltrain

2009-01-01

260

Assessing 3D tunnel position in ACL reconstruction using a novel single image 3D-2D registration  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The routinely used procedure for evaluating tunnel positions following anterior cruciate ligament (ACL) reconstructions based on standard X-ray images is known to pose difficulties in terms of obtaining accurate measures, especially in providing three-dimensional tunnel positions. This is largely du...

Kang, X; Yau, WP; Otake, Y; Cheung, PYS; Hu, Y; Taylor, RH

 
 
 
 
261

Development and implementation of a web-enabled 3D consultation tool for breast augmentation surgery based on 3D-image reconstruction of 2D pictures.  

UK PubMed Central (United Kingdom)

BACKGROUND: Producing a rich, personalized Web-based consultation tool for plastic surgeons and patients is challenging. OBJECTIVE: (1) To develop a computer tool that allows individual reconstruction and simulation of 3-dimensional (3D) soft tissue from ordinary digital photos of breasts, (2) to implement a Web-based, worldwide-accessible preoperative surgical planning platform for plastic surgeons, and (3) to validate this tool through a quality control analysis by comparing 3D laser scans of the patients with the 3D reconstructions with this tool from original 2-dimensional (2D) pictures of the same patients. METHODS: The proposed system uses well-established 2D digital photos for reconstruction into a 3D torso, which is then available to the user for interactive planning. The simulation is performed on dedicated servers, accessible via Internet. It allows the surgeon, together with the patient, to previsualize the impact of the proposed breast augmentation directly during the consultation before a surgery is decided upon. We retrospectively conduced a quality control assessment of available anonymized pre- and postoperative 2D digital photographs of patients undergoing breast augmentation procedures. The method presented above was used to reconstruct 3D pictures from 2D digital pictures. We used a laser scanner capable of generating a highly accurate surface model of the patient's anatomy to acquire ground truth data. The quality of the computed 3D reconstructions was compared with the ground truth data used to perform both qualitative and quantitative evaluations. RESULTS: We evaluated the system on 11 clinical cases for surface reconstructions and 4 clinical cases of postoperative simulations, using laser surface scan technologies showing a mean reconstruction error between 2 and 4 mm and a maximum outlier error of 16 mm. Qualitative and quantitative analyses from plastic surgeons demonstrate the potential of these new emerging technologies. CONCLUSIONS: We tested our tool for 3D, Web-based, patient-specific consultation in the clinical scenario of breast augmentation. This example shows that the current state of development allows for creation of responsive and effective Web-based, 3D medical tools, even with highly complex and time-consuming computation, by off-loading them to a dedicated high-performance data center. The efficient combination of advanced technologies, based on analysis and understanding of human anatomy and physiology, will allow the development of further Web-based reconstruction and predictive interfaces at different scales of the human body. The consultation tool presented herein exemplifies the potential of combining advancements in the core areas of computer science and biomedical engineering with the evolving areas of Web technologies. We are confident that future developments based on a multidisciplinary approach will further pave the way toward personalized Web-enabled medicine.

de Heras Ciechomski P; Constantinescu M; Garcia J; Olariu R; Dindoyal I; Le Huu S; Reyes M

2012-01-01

262

A System for an Accurate 3D Reconstruction in Video Endoscopy Capsule  

Directory of Open Access Journals (Sweden)

Full Text Available Since few years, the gastroenterologic examinations could have been realised by wireless video capsules. Although the images make it possible to analyse some diseases, the diagnosis could be improved by the use of the 3D Imaging techniques implemented in the video capsule. The work presented here is related to Cyclope, an embedded active vision system that is able to give in real time both 3D information and texture. The challenge is to realise this integrated sensor with constraints on size, consumption, and computational resources with inherent limitation of video capsule. In this paper, we present the hardware and software development of a wireless multispectral vision sensor which allows to transmit, a 3D reconstruction of a scene in realtime. multispectral acquisitions grab both texture and IR pattern images at least at 25 frames/s separately. The different Intellectual Properties designed allow to compute specifics algorithms in real time while keeping accuracy computation. We present experimental results with the realization of a large-scale demonstrator using an SOPC prototyping board.

Kolar Anthony; Romain Olivier; Ayoub Jade; Faura David; Viateur Sylvain; Granado Bertrand; Graba Tarik

2009-01-01

263

Clinical evaluation of an algebraic 3-D reconstruction method for cold thyroid nodules detection using pinhole SPECT; Evaluation clinique d'une methode algebrique de reconstruction 3D pour la detection des nodules thyroidiens froids par tomo scintigraphie stenopeique  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to demonstrate the clinical usefulness of pinhole collimation tomography (pinhole SPECT) with an algebraic regularized reconstruction method. This original method for tomographic reconstruction was used for 3-D analysis of thyroid nodules. The aim was to increase the sensitivity of thyroid cold nodules detection by comparison with standard planar imaging. Methods: Thirty patients were studied, each of them having 1 or 2 nodules recognized with ultrasound. The 39 nodule sizes ranged from 4 to 27 mm. The tomographic images were obtained from the 3-D-volume reconstructed with the algebraic regularized algorithm. Three nuclear physicians reviewed the planar images alone, and then with the 3-D data. In both sessions the observers had to identify the nodules as 'cold' or 'warm'. Results: They showed a statistically significant increase of cold nodules detection between the conventional images and the 3-D analysis added to the planar data (p < 0.01). The first observer detected 20 cold nodules on planar alone and 30 with 3-D. The second and third observers detected 14 cold nodules on planar alone and 30 with 3-D. The improvement was due to a significant increase of sensitivity for nodules smaller than 10 mm. Conclusion: Using pinhole-SPECT with an algebraic method adapted to 3-D reconstruction significantly improves the detection of cold thyroid nodules by comparison to conventional planar imaging. (author)

Desvignes, P.; Laurette, I.; Koulibaly, P.M.; Migneco, O.; Bussiere, F.; Darcourt, J. [Centre Antoine-Lacassagne, Service de Medecine Nucleaire, 06 - Nice (France); Universite de Nice-Sophia Antipolis, Lab. de Biophysique et de Traitement de l' Image, 06 (France)

2000-06-01

264

CUDA based Level Set Method for 3D Reconstruction of Fishes from Large Acoustic Data  

DEFF Research Database (Denmark)

Acoustic images present views of underwater dynamics, even in high depths. With multi-beam echo sounders (SONARs), it is possible to capture series of 2D high resolution acoustic images. 3D reconstruction of the water column and subsequent estimation of fish abundance and fish species identification is highly desirable for planning sustainable fisheries. Main hurdles in analysing acoustic images are the presence of speckle noise and the vast amount of acoustic data. This paper presents a level set formulation for simultaneous fish reconstruction and noise suppression from raw acoustic images. Despite the presence of speckle noise blobs, actual fish intensity values can be distinguished by extremely high values, varying exponentially from the background. Edge detection generally gives excessive false edges that are not reliable. Our approach to reconstruction is based on level set evolution using Mumford-Shah segmentation functional that does not depend on edges in an image. We use the implicit function in conjunction with the image to robustly estimate a threshold for suppressing noise in the image by solving a second differential equation. We provide details of our estimation of suppressing threshold and show its convergence as the evolution proceeds. We also present a GPU based streaming computation of the method using NVIDIA's CUDA framework to handle large volume data-sets. Our implementation is optimised for memory usage to handle large volumes.

Sharma, Ojaswa; Anton, François

2009-01-01

265

An evaluation of three-dimensional surface-reconstruction CT (3D-CT) in children with craniosynostosis  

International Nuclear Information System (INIS)

In this study, 3D-CT images were reconstructed from axial computed tomographic scans using the new software on 10 children with craniosynostosis. The authors discuss the advantages of the 3D-CT imaging technique in the diagnosis and surgical planning for craniosynostosis. The following conclusions may be drawn: 1) The images obtained from the new 3D-CT software are more accurate and realistic than the images previously reported by Vannier and Marsh. Reconstruction artifacts, known as pseudoforamina, have not appeared in the 3D-CT images reconstructed by the new software, and the top axial view of the 3D-CT reveals precisely anatomical details of the intracranial skull base. 2) The use of this new method provides accurate anatomical data which cannot be obtained by means of conventional radiological techniques in living subjects. 3) This technique of three-dimensional reconstruction from CT scans is most helpful in surgical planning and in the postoperative assessments of surgical results for craniosynostosis. The 3D-CT images allow the surgeon to visualize precisely the abnormalities of the skull to be corrected by the craniofacial surgery. Based on our experience with this study, we would expect that three-dimensional surface reconstruction from CT scans will henceforth be widely used in the planning of craniofacial surgery and in the postoperative follow-up assessment of craniosynostosis or craniofacial anomalies. (J.P.N.).

1987-01-01

266

Evaluation of three-dimensional surface-reconstruction CT (3D-CT) in children with craniosynostosis  

Energy Technology Data Exchange (ETDEWEB)

In this study, 3D-CT images were reconstructed from axial computed tomographic scans using the new software on 10 children with craniosynostosis. The authors discuss the advantages of the 3D-CT imaging technique in the diagnosis and surgical planning for craniosynostosis. The following conclusions may be drawn: 1) The images obtained from the new 3D-CT software are more accurate and realistic than the images previously reported by Vannier and Marsh. Reconstruction artifacts, known as pseudoforamina, have not appeared in the 3D-CT images reconstructed by the new software, and the top axial view of the 3D-CT reveals precisely anatomical details of the intracranial skull base. 2) The use of this new method provides accurate anatomical data which cannot be obtained by means of conventional radiological techniques in living subjects. 3) This technique of three-dimensional reconstruction from CT scans is most helpful in surgical planning and in the postoperative assessments of surgical results for craniosynostosis. The 3D-CT images allow the surgeon to visualize precisely the abnormalities of the skull to be corrected by the craniofacial surgery. Based on our experience with this study, we would expect that three-dimensional surface reconstruction from CT scans will henceforth be widely used in the planning of craniofacial surgery and in the postoperative follow-up assessment of craniosynostosis or craniofacial anomalies. (J.P.N.).

Nishimoto, Hiroshi; Tsukiyama, Takashi; Nishimura, Jirou; Fujioka, Mutsuhisa; Tsubokawa, Takashi

1987-10-01

267

Adaptive Geometric Tessellation for 3D Reconstruction of Anisotropically Developing Cells in Multilayer Tissues from Sparse Volumetric Microscopy Images  

Science.gov (United States)

The need for quantification of cell growth patterns in a multilayer, multi-cellular tissue necessitates the development of a 3D reconstruction technique that can estimate 3D shapes and sizes of individual cells from Confocal Microscopy (CLSM) image slices. However, the current methods of 3D reconstruction using CLSM imaging require large number of image slices per cell. But, in case of Live Cell Imaging of an actively developing tissue, large depth resolution is not feasible in order to avoid damage to cells from prolonged exposure to laser radiation. In the present work, we have proposed an anisotropic Voronoi tessellation based 3D reconstruction framework for a tightly packed multilayer tissue with extreme z-sparsity (2–4 slices/cell) and wide range of cell shapes and sizes. The proposed method, named as the ‘Adaptive Quadratic Voronoi Tessellation’ (AQVT), is capable of handling both the sparsity problem and the non-uniformity in cell shapes by estimating the tessellation parameters for each cell from the sparse data-points on its boundaries. We have tested the proposed 3D reconstruction method on time-lapse CLSM image stacks of the Arabidopsis Shoot Apical Meristem (SAM) and have shown that the AQVT based reconstruction method can correctly estimate the 3D shapes of a large number of SAM cells.

Chakraborty, Anirban; Perales, Mariano M.; Reddy, G. Venugopala; Roy-Chowdhury, Amit K.

2013-01-01

268

Adaptive geometric tessellation for 3D reconstruction of anisotropically developing cells in multilayer tissues from sparse volumetric microscopy images.  

Science.gov (United States)

The need for quantification of cell growth patterns in a multilayer, multi-cellular tissue necessitates the development of a 3D reconstruction technique that can estimate 3D shapes and sizes of individual cells from Confocal Microscopy (CLSM) image slices. However, the current methods of 3D reconstruction using CLSM imaging require large number of image slices per cell. But, in case of Live Cell Imaging of an actively developing tissue, large depth resolution is not feasible in order to avoid damage to cells from prolonged exposure to laser radiation. In the present work, we have proposed an anisotropic Voronoi tessellation based 3D reconstruction framework for a tightly packed multilayer tissue with extreme z-sparsity (2-4 slices/cell) and wide range of cell shapes and sizes. The proposed method, named as the 'Adaptive Quadratic Voronoi Tessellation' (AQVT), is capable of handling both the sparsity problem and the non-uniformity in cell shapes by estimating the tessellation parameters for each cell from the sparse data-points on its boundaries. We have tested the proposed 3D reconstruction method on time-lapse CLSM image stacks of the Arabidopsis Shoot Apical Meristem (SAM) and have shown that the AQVT based reconstruction method can correctly estimate the 3D shapes of a large number of SAM cells. PMID:23940509

Chakraborty, Anirban; Perales, Mariano M; Reddy, G Venugopala; Roy-Chowdhury, Amit K

2013-08-05

269

Clinical evaluation of an algebraic 3-D reconstruction method for cold thyroid nodules detection using pinhole SPECT  

International Nuclear Information System (INIS)

[en] The purpose of this study was to demonstrate the clinical usefulness of pinhole collimation tomography (pinhole SPECT) with an algebraic regularized reconstruction method. This original method for tomographic reconstruction was used for 3-D analysis of thyroid nodules. The aim was to increase the sensitivity of thyroid cold nodules detection by comparison with standard planar imaging. Methods: Thirty patients were studied, each of them having 1 or 2 nodules recognized with ultrasound. The 39 nodule sizes ranged from 4 to 27 mm. The tomographic images were obtained from the 3-D-volume reconstructed with the algebraic regularized algorithm. Three nuclear physicians reviewed the planar images alone, and then with the 3-D data. In both sessions the observers had to identify the nodules as 'cold' or 'warm'. Results: They showed a statistically significant increase of cold nodules detection between the conventional images and the 3-D analysis added to the planar data (p

2000-01-01

270

3D Scanning Cloud Radar Observations at Azores during the ARM AMF field campaign: Reconstruction and study of 3D cloud structures and properties  

Science.gov (United States)

The U.S. Department of Energy Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) has been operating at Graciosa Island (Azores) since May 2009. This 21-month field campaign focuses on the study of marine stratus clouds. The ARM/AMF instrumentation and location provides a unique opportunity to observe the cloud properties of marine stratocumulus utilizing a variety of active and passive remote sensors. In addition to the standard profiling instrumentation, the first scanning W-band (94-GHz) ARM Cloud Radar (SWACR) was deployed for a short two-month period (October-November 2009). Several scan strategies were tested during the SWACR deployment. The scan strategies were designed specifically to provide the ability to reconstruct the 3D cloud structure. The raw radar observations are quality controlled with the identification of radar volumes with significant detections, water vapor attenuation and unfolding of the radar Doppler velocity. The observations are also transformed from the original radar coordinate system (spherical) to a Cartesian coordinate system using an adaptive gridding algorithm. The 3D gridding of the radar observables, along with spatial data analysis, allow us to evaluate important issues, specifically spatial variability of cloud and drizzle structures. Column profiles of SWACR observables are used in combination with Liquid Water Path measurements from the collocated Microwave Radiometer (MWR) to develop new relationships to compute Liquid Water Content (LWC). The best possible estimate of the 3D LWC structure is reconstructed by assessing both our relationship and other known relationships between radar reflectivity and LWC. This is required in order to use the 3D cloud observations for radiative transfer modeling. Additional drizzle-identification techniques are also being developed to allow the isolation of 3D cloud-only or liquid-only fields. These types of variables have a key impact on the understanding of the radiative budget of marine stratocumulus. Furthermore, this type of analysis can provide key information for the modeling of such clouds.

Bowley, K.; Jo, I.; Tatarevic, A.; Kollias, P.

2010-12-01

271

An evaluation of exact and approximate 3-D reconstruction algorithms for a high-resolution small-animal PET scanner  

International Nuclear Information System (INIS)

MicroPET is a low-cost, high-resolution positron emission tomography (PET) scanner designed for imaging small animals. MicroPET operates exclusively without septa, acquiring fully three-dimensional (3-D) data sets. The performance of the projection-reprojection (3DRP), variable axial rebinning (VARB), single slice rebinning (SSRB), and Fourier rebinning (FORE) methods for reconstruction of microPET data were evaluated. The algorithms were compared with respect to resolution, noise variance, and reconstruction time. Results suggested that the 3DRP algorithm gives the best combination of resolution and noise performance in 9 min of reconstruction time on a Sun UltraSparc I workstation. The FORE algorithm provided the most acceptable accelerated method of reconstruction, giving similar resolution performance with a 10%--20% degradation in noise variance in under 2 min. Significant degradation in the axial resolution was measured with the VARB and SSRB methods, offsetting the decrease in reconstruction time achieved with those methods. In-plane angular mashing of the 3-D data before reconstruct ion led to a 50% reduction in reconstruction time but also introduced unacceptable tangential blurring artifacts. This thorough evaluation of analytical 3-D reconstruction techniques allowed for optimal selection of a reconstruction method for the diverse range of microPET applications

1998-01-01

272

3D Reconstruction Using Interval Methods on The Kinect Device Coupled With an IMU  

Directory of Open Access Journals (Sweden)

Full Text Available The principle behind VSLAM applications like 3D object reconstruction or indoor mapping is to estimate the spatial transformation between two large clouds of points, which represent two poses of the same scene. They can further be processed to obtain detailed surfaces. Since its introduction in 1992, the standard algorithm for finding the alignment between two point clouds is ICP (Iterative Closest Point) and its variants, combined with RANSAC (RANdom SAmple Consensus). This paper presents a new approach using interval analysis. The idea is to define large intervals for the transformation parameters between the poses then to successively contract those intervals using the equations of the transformation of corresponding points between the poses. To contract those intervals faster, we added an IMU (Inertial Measurement Unit) to our system so the initial intervals of the parameters are already small before applying the contractions. We implemented our algorithm using the middleware ROS (Robot Operating System) and stated our performances.

Aymeric Bethencourt; Luc Jaulin

2013-01-01

273

Morphology and function of Bast's valve: additional insight in its functioning using 3D-reconstruction.  

Science.gov (United States)

The utriculo-endolymphatic valve was discovered by Bast in 1928. The function of Bast's valve is still unclear. By means of orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy 3D-reconstructions of the valve and its surrounding region are depicted. The shape of the duct at the utricular side is that of a flattened funnel. In the direction of the endolymphatic duct and sac this funnel runs into a very narrow duct. The valve itself has a rigid 'arch-like' configuration. The opposing thin, one cell-layer thick, utricular membrane is highly compliant. We propose that opening and closure of the valve occurs through movement of the flexible base/utricular membrane away from and toward the relatively rigid valve lip. PMID:17724606

Hofman, R; Segenhout, J M; Buytaert, J A N; Dirckx, J J J; Wit, H P

2007-08-28

274

Morphology and function of Bast's valve: additional insight in its functioning using 3D-reconstruction.  

UK PubMed Central (United Kingdom)

The utriculo-endolymphatic valve was discovered by Bast in 1928. The function of Bast's valve is still unclear. By means of orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy 3D-reconstructions of the valve and its surrounding region are depicted. The shape of the duct at the utricular side is that of a flattened funnel. In the direction of the endolymphatic duct and sac this funnel runs into a very narrow duct. The valve itself has a rigid 'arch-like' configuration. The opposing thin, one cell-layer thick, utricular membrane is highly compliant. We propose that opening and closure of the valve occurs through movement of the flexible base/utricular membrane away from and toward the relatively rigid valve lip.

Hofman R; Segenhout JM; Buytaert JA; Dirckx JJ; Wit HP

2008-02-01

275

A novel 3D reconstruction approach by dynamic (de)focused light  

Science.gov (United States)

In this paper, we propose a novel active 3D recovery method based on dynamic (de)focused light. The method combines both depth from focus (DFF) and depth from defocus (DFD) techniques. With this approach, optimized illumination pattern is projected on the object in order to enforce strong dominant texture on the surface. The imaging system is specifically constructed to keep the whole object sharp in all captured images. Consequently, only projected patterns experience the defocused deformation according to an object depth. Projected light pattern images are acquired within certain focused ranges similar to DFF approach, while the focus measures across these images are calculated for depth estimation by using DFD manner. This guarantees that at least one focus or near-focus image within depth of field exists in the computation. Therefore, the final reconstruction is supposed to be prominent to the one obtained from DFD and also less computational extensive compared to DFF provided.

Lertrusdachakul, Intuon; Fougerolle, Yohan D.; Laligant, Olivier

2010-02-01

276

3D reconstruction of the flow and vortical field in a rotating sharp U turn channel  

Energy Technology Data Exchange (ETDEWEB)

Particle image velocimetry experiments have been carried out to obtain visualizations and measurements of the main and secondary flow fields in a square channel with a sharp U turn. Both the main and the secondary flow fields have been used to perform a 3D reconstruction of the mean flow and vortical fields in the turn region and in the outlet duct. In order to study the influence of the rotation, tests both in stationary (absence of rotation, Re=20,000) and in rotating (Re=20,000 and Ro=0.3) conditions have been performed. The results show that the Coriolis and centrifugal forces, caused by the rotation, yield strong modifications to the symmetrical flow and vortical fields that are generated, in the static case, only by the abrupt inversion of the flow direction. (orig.)

Gallo, Mauro [Institute of Fluid Dynamics, ETH Zuerich, Zuerich (Switzerland); Astarita, Tommaso [DIAS, University of Naples ' ' Federico II' ' , Naples (Italy)

2010-06-15

277

Spectral phase-corrected GRAPPA reconstruction of three-dimensional echo-planar spectroscopic imaging (3D-EPSI).  

UK PubMed Central (United Kingdom)

MR spectroscopic (MRS) images from a large volume of brain can be obtained using a 3D echo-planar spectroscopic imaging (3D-EPSI) sequence. However, routine applications of 3D-EPSI are still limited by a long scan time. In this communication, a new approach termed "spectral phase-corrected generalized autocalibrating partially parallel acquisitions" (SPC-GRAPPA) is introduced for the reconstruction of 3D-EPSI data to accelerate data acquisition while preserving the accuracy of quantitation of brain metabolites. In SPC-GRAPPA, voxel-by-voxel spectral phase alignment between metabolite 3D-EPSI from individual coil elements is performed in the frequency domain, utilizing the whole spectrum from interleaved water reference 3D-EPSI for robust estimation of the zero-order phase correction. The performance of SPC-GRAPPA was compared with that of fully encoded 3D-EPSI and conventional GRAPPA. Analysis of whole-brain 3D-EPSI data reconstructed by SPC-GRAPPA demonstrates that SPC-GRAPPA with an acceleration factor of 1.5 yields results very similar to those obtained by fully encoded 3D-EPSI, and is more accurate than conventional GRAPPA.

Zhu X; Ebel A; Ji JX; Schuff N

2007-05-01

278

Spectral phase-corrected GRAPPA reconstruction of three-dimensional echo-planar spectroscopic imaging (3D-EPSI).  

Science.gov (United States)

MR spectroscopic (MRS) images from a large volume of brain can be obtained using a 3D echo-planar spectroscopic imaging (3D-EPSI) sequence. However, routine applications of 3D-EPSI are still limited by a long scan time. In this communication, a new approach termed "spectral phase-corrected generalized autocalibrating partially parallel acquisitions" (SPC-GRAPPA) is introduced for the reconstruction of 3D-EPSI data to accelerate data acquisition while preserving the accuracy of quantitation of brain metabolites. In SPC-GRAPPA, voxel-by-voxel spectral phase alignment between metabolite 3D-EPSI from individual coil elements is performed in the frequency domain, utilizing the whole spectrum from interleaved water reference 3D-EPSI for robust estimation of the zero-order phase correction. The performance of SPC-GRAPPA was compared with that of fully encoded 3D-EPSI and conventional GRAPPA. Analysis of whole-brain 3D-EPSI data reconstructed by SPC-GRAPPA demonstrates that SPC-GRAPPA with an acceleration factor of 1.5 yields results very similar to those obtained by fully encoded 3D-EPSI, and is more accurate than conventional GRAPPA. PMID:17457872

Zhu, Xiaoping; Ebel, Andreas; Ji, Jim X; Schuff, Norbert

2007-05-01

279

Integration of knowledge to support automatic object reconstruction from images and 3D data  

International Nuclear Information System (INIS)

Object reconstruction is a important task in many fields of application as it allows to generate digital representations of our physical world used as base for analysis, planning, construction, visualization or other aims. A reconstruction itself normally is based on reliable data (images, 3D point clouds for example) expressing the object in his complete extension. This data then has to be compiled and analyzed in order to extract all necessary geometrical elements, which represent the object and form a digital copy of it. Traditional strategies are largely based on manual interaction and interpretation, because with increasing complexity of objects human understanding is inevitable to achieve acceptable and reliable results. But human interaction is time consuming and expensive, why many research has already been invested to integrate algorithmic support, what allows to speed up the process and reduce manual work load. Presently most such algorithms are data-driven and concentrate on specific features of the objects, being accessible to numerical models. By means of these models, which normally will represent geometrical (flatness, roughness, for example) or physical features (color, texture), the data is classified and analyzed. This is succesful for objects with a limited complexity, but gets to its limits with increasing complexity of objects. Then purely numerical strategies are not able to sufficiently model the reality. Therefore, the intention of our approach is to take human cogni-tive strategy as an example, and to simulate extraction processes based on available knowledge for the objects of interest. Such processes will introduce a semantic structure for the objects and guide the algorithms used to detect and recognize objects, which will yield a higher effectiveness. Hence, our research proposes an approach using knowledge to guide the algorithms in 3D point cloud and image processing.

2011-01-01

280

Assessment of multi-directional MTF for breast tomosynthesis.  

UK PubMed Central (United Kingdom)

A method was developed to assess the multi-directional modulation transfer function (MTF) of breast tomosynthesis imaging systems using a sphere phantom. The method was initially developed based on a simulation dataset. Projections were simulated for a uniform voxelized breast phantom with sphere inserts using a fluence modeled from a 28 kVp beam incident upon an indirect flat-panel detector. Based on cascaded systems modeling, characteristic noise and blurring were added to each projection. The projections were reconstructed using a standard filtered backprojection technique, producing a 3D volume with an isotropic voxel size of 200 µm. ROIs that completely encompassed single spheres were extracted and conical regions were prescribed along the three major axes extending from the centroids. Pixels within the cones were used to form edge spread functions (ESFs), from which the directional MTFs were calculated. Binning size and conical range were adjusted to maximize the accuracy and to minimize the noise of the MTF. A method was further devised to remove out-of-plane artifacts from the ESF in the x-y plane. Finally, the method was applied to experimentally assess the directional MTF of a prototype tomosynthesis system. Comparisons of the sphere-based MTF along the different axes and the theoretical MTF yielded good agreement. A 30° angular cone and a 20 µm sampling were found to provide an ideal trade-off between the noise and accuracy of the measurement. The removal of artifacts in ESF yielded 'modified' MTFs that enabled a resolution-only characterization of the in-slice resolution of tomosynthesis. Drop-off frequencies in the x- and y-directional MTFs were 1.6 cycles mm(-1) and 1.5 cycles mm(-1), respectively. The presented method of separating the effective resolution and artifacts from the measured ESF was found experimentally implementable and is expected to facilitate the interpretation of MTF measurements in tomosynthesis.

Samei E; Murphy S; Richard S

2013-03-01

 
 
 
 
281

Assessment of multi-directional MTF for breast tomosynthesis  

Science.gov (United States)

A method was developed to assess the multi-directional modulation transfer function (MTF) of breast tomosynthesis imaging systems using a sphere phantom. The method was initially developed based on a simulation dataset. Projections were simulated for a uniform voxelized breast phantom with sphere inserts using a fluence modeled from a 28 kVp beam incident upon an indirect flat-panel detector. Based on cascaded systems modeling, characteristic noise and blurring were added to each projection. The projections were reconstructed using a standard filtered backprojection technique, producing a 3D volume with an isotropic voxel size of 200 µm. ROIs that completely encompassed single spheres were extracted and conical regions were prescribed along the three major axes extending from the centroids. Pixels within the cones were used to form edge spread functions (ESFs), from which the directional MTFs were calculated. Binning size and conical range were adjusted to maximize the accuracy and to minimize the noise of the MTF. A method was further devised to remove out-of-plane artifacts from the ESF in the x-y plane. Finally, the method was applied to experimentally assess the directional MTF of a prototype tomosynthesis system. Comparisons of the sphere-based MTF along the different axes and the theoretical MTF yielded good agreement. A 30° angular cone and a 20 µm sampling were found to provide an ideal trade-off between the noise and accuracy of the measurement. The removal of artifacts in ESF yielded ‘modified’ MTFs that enabled a resolution-only characterization of the in-slice resolution of tomosynthesis. Drop-off frequencies in the x- and y-directional MTFs were 1.6 cycles mm-1 and 1.5 cycles mm-1, respectively. The presented method of separating the effective resolution and artifacts from the measured ESF was found experimentally implementable and is expected to facilitate the interpretation of MTF measurements in tomosynthesis.

Samei, E.; Murphy, S.; Richard, S.

2013-03-01

282

Locating the Acupoint Baihui (GV20) Beneath the Cerebral Cortex with MRI Reconstructed 3D Neuroimages.  

UK PubMed Central (United Kingdom)

Baihui (GV20) is one of the most important acupoints of the Du meridian (the government vessel) and is commonly used in neurology and psychiatry and as a distal point of anorectal disorders by general practitioners. The anatomical relationship between the scalp region of the acupoint and the underlying corresponding cortex remains obscure. In this study, we first prepared the indicator for MRI scanning on a GE 1.5 T excite machine in a mode suitable for 3D reconstruction. The 3D Avizo software system (version 6.0, Mercury Computer Systems, Inc., Germany) was then used for image processing and the resulting data subsequently analyzed using descriptive statistics and analysis of variance (ANOVA). The mean distance from the Baihui anterior to the central sulcus in the adult group was greater than that in the child group (22.7 ± 2.2 and 19.7 ± 2.2?mm, resp., P = .042), whereas in the child group the distance between the Baihui anterior and the precentral sulcus was greater than in the adult group (6.8 ± 0.8 and 3.8 ± 0.8?mm, resp., P < .001). This MRI presentation demonstrates that the location of Baihui (GV20) can be identified using the distance from the central or precentral sulcus.

Shen EY; Chen FJ; Chen YY; Lin MF

2011-01-01

283

Locating the Acupoint Baihui (GV20) Beneath the Cerebral Cortex with MRI Reconstructed 3D Neuroimages.  

Science.gov (United States)

Baihui (GV20) is one of the most important acupoints of the Du meridian (the government vessel) and is commonly used in neurology and psychiatry and as a distal point of anorectal disorders by general practitioners. The anatomical relationship between the scalp region of the acupoint and the underlying corresponding cortex remains obscure. In this study, we first prepared the indicator for MRI scanning on a GE 1.5 T excite machine in a mode suitable for 3D reconstruction. The 3D Avizo software system (version 6.0, Mercury Computer Systems, Inc., Germany) was then used for image processing and the resulting data subsequently analyzed using descriptive statistics and analysis of variance (ANOVA). The mean distance from the Baihui anterior to the central sulcus in the adult group was greater than that in the child group (22.7 ± 2.2 and 19.7 ± 2.2?mm, resp., P = .042), whereas in the child group the distance between the Baihui anterior and the precentral sulcus was greater than in the adult group (6.8 ± 0.8 and 3.8 ± 0.8?mm, resp., P < .001). This MRI presentation demonstrates that the location of Baihui (GV20) can be identified using the distance from the central or precentral sulcus. PMID:21785620

Shen, Ein-Yiao; Chen, Fun-Jou; Chen, Yun-Yin; Lin, Ming-Fan

2011-02-14

284

Ion track reconstruction in 3D using alumina-based fluorescent nuclear track detectors  

CERN Document Server

Fluorescent nuclear track detectors (FNTDs) based on Al2O3:C,Mg single crystal combined with confocal microscopy provide 3D information on ion tracks with a resolution only limited by light diffraction. FNTDs are also ideal substrates to be coated with cells to engineer cell-fluorescent ion track hybrid detectors. This radiobiological tool enables a novel platform linking cell responses to physical dose deposition on a sub-cellular level in proton and heavy ion therapies. To achieve spatial correlation between single ion hits in the cell coating and its biological response the ion traversals have to be reconstructed in 3D using the depth information gained by the FNTD read-out. FNTDs were coated with a confluent human lung adenocarcinoma epithelial cell layer. Carbon ion irradiation of the hybrid detector was performed perpendicular and angular to the detector surface. In-situ imaging of the fluorescently labeled cell layer and the FNTD was performed in a sequential read-out. Making use of the trajectory info...

Niklas, Martin; Akselrod, Mark S; Abollahi, Amir; Jäkel, Oliver; Greilich, Steffen

2013-01-01

285

3D reconstruction of TMJ after resection of the cyst and the stress-strain analyses.  

UK PubMed Central (United Kingdom)

The aim of this article is 3D analysis of the temporomandibular joint (TMJ) patient, who underwent surgery, during which the right TMJ was resected along with the ramus of mandible and consequently the joint was reconstructed with subtotal replacement. The main goal is to give a suitable formulation of mathematical model, which describes the changes of stresses in TMJ incurred after the surgery. The TMJ is a complex, sensitive and highly mobile joint which works bilaterally so each side influences the contralateral joint and because of this the distribution of the stresses is changed in the healthy joint as well. Detailed knowledge about function these are necessary for clinical application of temporomandibular joint prosthesis and also help us estimate the lifetime of the prosthesis a possibilities of alteration in the contra lateral joint components. The geometry for the 3D models is taken from the CT scan date and its numerical solution is based on the theory of semi-coercive unilateral contact problems in linear elasticity. This article provides medical part with case report, discretion of treatment, than the methods of mathematical modeling and his possibilities are described and finally results are reported.

Mahdian N; Dostálová T; Dan?k J; Nedoma J; Kohout J; Hubá?ek M; Hli?áková P

2013-06-01

286

3D reconstruction of TMJ after resection of the cyst and the stress-strain analyses.  

Science.gov (United States)

The aim of this article is 3D analysis of the temporomandibular joint (TMJ) patient, who underwent surgery, during which the right TMJ was resected along with the ramus of mandible and consequently the joint was reconstructed with subtotal replacement. The main goal is to give a suitable formulation of mathematical model, which describes the changes of stresses in TMJ incurred after the surgery. The TMJ is a complex, sensitive and highly mobile joint which works bilaterally so each side influences the contralateral joint and because of this the distribution of the stresses is changed in the healthy joint as well. Detailed knowledge about function these are necessary for clinical application of temporomandibular joint prosthesis and also help us estimate the lifetime of the prosthesis a possibilities of alteration in the contra lateral joint components. The geometry for the 3D models is taken from the CT scan date and its numerical solution is based on the theory of semi-coercive unilateral contact problems in linear elasticity. This article provides medical part with case report, discretion of treatment, than the methods of mathematical modeling and his possibilities are described and finally results are reported. PMID:23332173

Mahdian, Nima; Dostálová, Tat'jana; Dan?k, Josef; Nedoma, Ji?í; Kohout, Josef; Hubá?ek, Milan; Hli?áková, Petra

2013-01-15

287

GPU accelerated generation of digitally reconstructed radiographs for 2-D/3-D image registration.  

UK PubMed Central (United Kingdom)

Recent advances in programming languages for graphics processing units (GPUs) provide developers with a convenient way of implementing applications which can be executed on the CPU and GPU interchangeably. GPUs are becoming relatively cheap, powerful, and widely available hardware components, which can be used to perform intensive calculations. The last decade of hardware performance developments shows that GPU-based computation is progressing significantly faster than CPU-based computation, particularly if one considers the execution of highly parallelisable algorithms. Future predictions illustrate that this trend is likely to continue. In this paper, we introduce a way of accelerating 2-D/3-D image registration by developing a hybrid system which executes on the CPU and utilizes the GPU for parallelizing the generation of digitally reconstructed radiographs (DRRs). Based on the advancements of the GPU over the CPU, it is timely to exploit the benefits of many-core GPU technology by developing algorithms for DRR generation. Although some previous work has investigated the rendering of DRRs using the GPU, this paper investigates approximations which reduce the computational overhead while still maintaining a quality consistent with that needed for 2-D/3-D registration with sufficient accuracy to be clinically acceptable in certain applications of radiation oncology. Furthermore, by comparing implementations of 2-D/3-D registration on the CPU and GPU, we investigate current performance and propose an optimal framework for PC implementations addressing the rigid registration problem. Using this framework, we are able to render DRR images from a 256×256×133 CT volume in ~24 ms using an NVidia GeForce 8800 GTX and in ~2 ms using NVidia GeForce GTX 580. In addition to applications requiring fast automatic patient setup, these levels of performance suggest image-guided radiation therapy at video frame rates is technically feasible using relatively low cost PC architecture.

Dorgham OM; Laycock SD; Fisher MH

2012-09-01

288

Three-dimensional (3-D) reconstruction of the spine from a single X-ray image and prior vertebra models.  

Science.gov (United States)

The lateral bending test is routinely used by clinicians for the preoperative assessment of spinal mobility. The evaluation of bending motion is usually based on the qualitative analysis of a two-dimensional (2-D) antero-posterior X-ray image. The aim of this paper is to introduce a novel three-dimensional (3-D) reconstruction technique that is a prerequisite for the quantitative 3-D analysis of lateral bending motion. An algorithm was developed for the 3-D reconstruction of the spine from a single X-ray image. The X-ray is calibrated using a small calibration object and an explicit calibration algorithm. The information contained in the single X-ray is completed by registering a priori 3-D geometric models of individual vertebrae. Part of the error yielded by the 3-D/2-D registration is corrected by a vertebral alignment constraint that aims to minimize intervertebral dislocations. Three-dimensional models of 15 different scoliosis patients, obtained from a standard stereo-radiographic 3-D reconstruction, were used in simulation and validation experiments. Experimental results show that the new method is robust and accurate. With pessimistic levels of simulated noise, the average root mean square reconstruction error is 2.89 mm, which is appropriate for common clinical applications. PMID:15376511

Novosad, Justin; Cheriet, Farida; Petit, Yvan; Labelle, Hubert

2004-09-01

289

Comparison of 3D reconstructive technologies used for morphometric research and the translation of knowledge using a decision matrix.  

UK PubMed Central (United Kingdom)

The use of three-dimensional (3D) models for education, pre-operative assessment, presurgical planning, and measurement have become more prevalent. With the increase in prevalence of 3D models there has also been an increase in 3D reconstructive software programs that are used to create these models. These software programs differ in reconstruction concepts, operating system requirements, user features, cost, and no one program has emerged as the standard. The purpose of this study was to conduct a systematic comparison of three widely available 3D reconstructive software programs, Amira(®) , OsiriX, and Mimics(®) , with respect to the software's ability to be used in two broad themes: morphometric research and education to translate morphological knowledge. Cost, system requirements, and inherent features of each program were compared. A novel concept selection tool, a decision matrix, was used to objectify comparisons of usability of the interface, quality of the output, and efficiency of the tools. Findings indicate that Mimics was the best-suited program for construction of 3D anatomical models and morphometric analysis, but for creating a learning tool the results were less clear. OsiriX was very user-friendly; however, it had limited capabilities. Conversely, although Amira had endless potential and could create complex dynamic videos, it had a challenging interface. These results provide a resource for morphometric researchers and educators to assist the selection of appropriate reconstruction programs when starting a new 3D modeling project. Anat Sci Educ. © 2013 American Association of Anatomists.

Martin CM; Roach VA; Nguyen N; Rice CL; Wilson TD

2013-04-01

290

A 3-D reconstruction solution to current density imaging based on acoustoelectric effect by deconvolution: a simulation study.  

UK PubMed Central (United Kingdom)

Hybrid imaging modality combining ultrasound scanning and electrical current density imaging through the acoustoelectric (AE) effect may potentially provide solutions to imaging electrical activities and properties of biological tissues with high spatial resolution. In this study, a 3-D reconstruction solution to ultrasound current source density imaging (UCSDI) by means of Wiener deconvolution is proposed and evaluated through computer simulations. As compared to previous 2-D UCSDI problem, in a 3-D volume conductor with broadly distributed current density field, the AE signal becomes a 3-D convolution between the electric field and the acoustic field, and effective 3-D reconstruction algorithm has not been developed so far. In the proposed method, a 3-D ultrasound scanning is performed while the corresponding AE signals are collected from multiple electrode pairs attached on the surface of the imaging object. From the collected AE signals, the acoustic field and electric field were first decoupled by Wiener deconvolution. Then, the current density distribution was reconstructed by inverse projection. Our simulations using artificial current fields in homogeneous phantoms suggest that the proposed method is feasible and robust against noise. It is also shown that using the proposed method, it is feasible to reconstruct 3-D current density distribution in an inhomogeneous conductive medium.

Yang R; Li X; Song A; He B; Yan R

2013-05-01

291

An Integrated System for 3D Hip Joint Reconstruction from 2D X-rays: A Preliminary Validation Study.  

UK PubMed Central (United Kingdom)

The acquisition of conventional X-ray radiographs remains the standard imaging procedure for the diagnosis of hip-related problems. However, recent studies demonstrated the benefit of using three-dimensional (3D) surface models in the clinical routine. 3D surface models of the hip joint are useful for assessing the dynamic range of motion in order to identify possible pathologies such as femoroacetabular impingement. In this paper, we present an integrated system which consists of X-ray radiograph calibration and subsequent 2D/3D hip joint reconstruction for diagnosis and planning of hip-related problems. A mobile phantom with two different sizes of fiducials was developed for X-ray radiograph calibration, which can be robustly detected within the images. On the basis of the calibrated X-ray images, a 3D reconstruction method of the acetabulum was developed and applied together with existing techniques to reconstruct a 3D surface model of the hip joint. X-ray radiographs of dry cadaveric hip bones and one cadaveric specimen with soft tissue were used to prove the robustness of the developed fiducial detection algorithm. Computed tomography scans of the cadaveric bones were used to validate the accuracy of the integrated system. The fiducial detection sensitivity was in the same range for both sizes of fiducials. While the detection sensitivity was 97.96% for the large fiducials, it was 97.62% for the small fiducials. The acetabulum and the proximal femur were reconstructed with a mean surface distance error of 1.06 and 1.01 mm, respectively. The results for fiducial detection sensitivity and 3D surface reconstruction demonstrated the capability of the integrated system for 3D hip joint reconstruction from 2D calibrated X-ray radiographs.

Schumann S; Liu L; Tannast M; Bergmann M; Nolte LP; Zheng G

2013-10-01

292

An Integrated System for 3D Hip Joint Reconstruction from 2D X-rays: A Preliminary Validation Study.  

Science.gov (United States)

The acquisition of conventional X-ray radiographs remains the standard imaging procedure for the diagnosis of hip-related problems. However, recent studies demonstrated the benefit of using three-dimensional (3D) surface models in the clinical routine. 3D surface models of the hip joint are useful for assessing the dynamic range of motion in order to identify possible pathologies such as femoroacetabular impingement. In this paper, we present an integrated system which consists of X-ray radiograph calibration and subsequent 2D/3D hip joint reconstruction for diagnosis and planning of hip-related problems. A mobile phantom with two different sizes of fiducials was developed for X-ray radiograph calibration, which can be robustly detected within the images. On the basis of the calibrated X-ray images, a 3D reconstruction method of the acetabulum was developed and applied together with existing techniques to reconstruct a 3D surface model of the hip joint. X-ray radiographs of dry cadaveric hip bones and one cadaveric specimen with soft tissue were used to prove the robustness of the developed fiducial detection algorithm. Computed tomography scans of the cadaveric bones were used to validate the accuracy of the integrated system. The fiducial detection sensitivity was in the same range for both sizes of fiducials. While the detection sensitivity was 97.96% for the large fiducials, it was 97.62% for the small fiducials. The acetabulum and the proximal femur were reconstructed with a mean surface distance error of 1.06 and 1.01 mm, respectively. The results for fiducial detection sensitivity and 3D surface reconstruction demonstrated the capability of the integrated system for 3D hip joint reconstruction from 2D calibrated X-ray radiographs. PMID:23670657

Schumann, Steffen; Liu, Li; Tannast, Moritz; Bergmann, Mathias; Nolte, Lutz-P; Zheng, Guoyan

2013-05-14

293

A 3D Freehand Ultrasound System for Multi-view Reconstructions from Sparse 2D Scanning Planes  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background A significant limitation of existing 3D ultrasound systems comes from the fact that the majority of them work with fixed acquisition geometries. As a result, the users have very limited control over the geometry of the 2D scanning planes. Methods We present a low-cost and flexible ultrasound imaging system that integrates several image processing components to allow for 3D reconstructions from limited numbers of 2D image planes and multiple acoustic views. Our approach is based on a 3D freehand ultrasound system that allows users to control the 2D acquisition imaging using conventional 2D probes. For reliable performance, we develop new methods for image segmentation and robust multi-view registration. We first present a new hybrid geometric level-set approach that provides reliable segmentation performance with relatively simple initializations and minimum edge leakage. Optimization of the segmentation model parameters and its effect on performance is carefully discussed. Second, using the segmented images, a new coarse to fine automatic multi-view registration method is introduced. The approach uses a 3D Hotelling transform to initialize an optimization search. Then, the fine scale feature-based registration is performed using a robust, non-linear least squares algorithm. The robustness of the multi-view registration system allows for accurate 3D reconstructions from sparse 2D image planes. Results Volume measurements from multi-view 3D reconstructions are found to be consistently and significantly more accurate than measurements from single view reconstructions. The volume error of multi-view reconstruction is measured to be less than 5% of the true volume. We show that volume reconstruction accuracy is a function of the total number of 2D image planes and the number of views for calibrated phantom. In clinical in-vivo cardiac experiments, we show that volume estimates of the left ventricle from multi-view reconstructions are found to be in better agreement with clinical measures than measures from single view reconstructions. Conclusions Multi-view 3D reconstruction from sparse 2D freehand B-mode images leads to more accurate volume quantification compared to single view systems. The flexibility and low-cost of the proposed system allow for fine control of the image acquisition planes for optimal 3D reconstructions from multiple views.

Yu Honggang; Pattichis Marios S; Agurto Carla; Beth Goens M

2011-01-01

294

A 3D freehand ultrasound system for multi-view reconstructions from sparse 2D scanning planes.  

UK PubMed Central (United Kingdom)

BACKGROUND: A significant limitation of existing 3D ultrasound systems comes from the fact that the majority of them work with fixed acquisition geometries. As a result, the users have very limited control over the geometry of the 2D scanning planes. METHODS: We present a low-cost and flexible ultrasound imaging system that integrates several image processing components to allow for 3D reconstructions from limited numbers of 2D image planes and multiple acoustic views. Our approach is based on a 3D freehand ultrasound system that allows users to control the 2D acquisition imaging using conventional 2D probes.For reliable performance, we develop new methods for image segmentation and robust multi-view registration. We first present a new hybrid geometric level-set approach that provides reliable segmentation performance with relatively simple initializations and minimum edge leakage. Optimization of the segmentation model parameters and its effect on performance is carefully discussed. Second, using the segmented images, a new coarse to fine automatic multi-view registration method is introduced. The approach uses a 3D Hotelling transform to initialize an optimization search. Then, the fine scale feature-based registration is performed using a robust, non-linear least squares algorithm. The robustness of the multi-view registration system allows for accurate 3D reconstructions from sparse 2D image planes. RESULTS: Volume measurements from multi-view 3D reconstructions are found to be consistently and significantly more accurate than measurements from single view reconstructions. The volume error of multi-view reconstruction is measured to be less than 5% of the true volume. We show that volume reconstruction accuracy is a function of the total number of 2D image planes and the number of views for calibrated phantom. In clinical in-vivo cardiac experiments, we show that volume estimates of the left ventricle from multi-view reconstructions are found to be in better agreement with clinical measures than measures from single view reconstructions. CONCLUSIONS: Multi-view 3D reconstruction from sparse 2D freehand B-mode images leads to more accurate volume quantification compared to single view systems. The flexibility and low-cost of the proposed system allow for fine control of the image acquisition planes for optimal 3D reconstructions from multiple views.

Yu H; Pattichis MS; Agurto C; Beth Goens M

2011-01-01

295

A non-negative fast multiplicative algorithm in 3D scatter-compensated SPET reconstruction  

International Nuclear Information System (INIS)

Single-photon emission tomographic (SPET) reconstruction can be improved, especially for noisy images, by using the iterative expectation-maximization of the maximum-likelihood (EM-ML) algorithm. Its application to clinical routine is, however, hampered by the high number of iterations necessary to achieve acceptable results. Therefore various methods have been developed to accelerate the EM-ML algorithm. In this paper a new accelerated EM-ML-like multiplicative algorithm is proposed for SPET reconstruction. Contrary to some other accelerating methods, it preserves two of the most important properties of the EM-ML, namely pixel positivity inside the patient body and null activity outside. The convergence speed is improved by a factor which can reach 100 in high spatial frequency or low count regions. Good estimates in the low count region are obtained without any smoothing, even at typical routine clinical count rates. The algorithm used in conjunction with the 3D effective one scatter path model provides high-quality SPET images and accurate quantitation. (orig.). With 3 figs.

1996-01-01

296

Orientation determination by wavelets matching for 3D reconstruction of very noisy electron microscopic virus images  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In order to perform a 3D reconstruction of electron microscopic images of viruses, it is necessary to determine the orientation (Euler angels) of the 2D projections of the virus. The projections containing high resolution information are usually very noisy. This paper proposes a new method, based on weighted-projection matching in wavelet space for virus orientation determination. In order to speed the retrieval of the best match between projections from a model and real virus particle, a hierarchical correlation matching method is also proposed. Results A data set of 600 HSV-1 capsid particle images in different orientations was used to test the proposed method. An initial model of about 40 Å resolutions was used to generate projections of an HSV-1 capsid. Results show that a significant improvement, in terms of accuracy and speed, is obtained for the initial orientation estimates of noisy herpes virus images. For the bacteriophage (P22), the proposed method gave the correct reconstruction compared to the model, while the classical method failed to resolve the correct orientations of the smooth spherical P22 viruses. Conclusion This paper introduces a new method for orientation determination of low contrast images and highly noisy virus particles. This method is based on weighted projection matching in wavelet space, which increases the accuracy of the orientations. A hierarchical implementation of this method increases the speed of orientation determination. The estimated number of particles needed for a higher resolution reconstruction increased exponentially. For a 6 Å resolution reconstruction of the HSV virus, 50,000 particles are necessary. The results show that the proposed method reduces the amount of data needed in a reconstruction by at least 50 %. This may result in savings 2 to 3 man-years invested in acquiring images from the microscope and data processing. Furthermore, the proposed method is able to determine orientations for some difficult particles like P22 with accuracy and consistency. Recently a low PH sindbis capsid was determined with the proposed method, where other methods based on the common line fail.

Saad Ali

2005-01-01

297

Initial experiences with three-dimensional reconstruction of CT images using a peripheral 3D image postprocessor; 3D-Rekonstruktionen von CT-Untersuchungen an einem peripheren 3D-Bildnachverarbeitungsrechner - erste Erfahrungen  

Energy Technology Data Exchange (ETDEWEB)

The use of three-dimensional information reconstructed from data provided by computerized tomography has so far been limited to the domain of skeletal and vascular examinations, as the 3D algorithms of the relevant scanners were tailored towards the requirements of those diagnostic procedures. This study was performed in order to find out whether one particular image postprocessor (Voxel-Flinger from Reality Imaging, Ohio) would also be suitable for three-dimensional displays of organs and tissues other than the vessels or skeleton. In displays of the skeleton, surface reconstructions prepared with the Voxel-Flinger proved to be just as good as those of computerized tomography, while the speed of imaging was increased. Unlike the 3D images on computerized tomography, the displays on the Voxel-Flinger even permitted to differentiate between soft tissues, fluid spaces, tissues containing fat and air (vertebral disk, ventricular system). In all, the Voxel-Flinger was found to be superior here in that it ensured high-speed visualization of a number of different tissues. (orig.) [Deutsch] Die Moeglichkeiten dreidimensionaler Rekonstruktionen von computertomographischen Daten (3D-CT) beschraenkten sich bislang auf den Bereich der Skelett- und Gefaessdiagnostik, da die 3D-Algorithmen der Computertomographiegeraete nur fuer diese Fragestellungen geeignet waren. Mit dieser Studie wurde geprueft, ob mit einerm speziellen Bildnachverarbeitungsgeraet (``Voxel-Flinger``, Reality Imaging, Ohio) 3D-Darstellungen auch anderer Organe bzw. Gewebe moeglich sind. Bei der Skelettdarstellung waren die Oberflaechenrekonstruktionen des Voxel-Flingers denen des Computertomographen ebenbuertig, wiesen jedoch eine hoehere Darstellungsgeschwindigkeit auf. Im Gegensatz zur 3D-Darstellung am Computertomographen gelang mit dem Voxel-Flinger auch die Darstellung und Differenzierung von Weichteilgeweben, Fluessigkeitsraeumen, fetthaltigem Gewebe und Luft (z.B. Bandscheibe, Ventrikelsystem). Insgesamt konnte mit dem Voxel-Flinger durch die schnelle Darstellung verschiedener Gewebe eine Verbesserung der Visualisierung erreicht werden. (orig.)

Lemke, A.J. [Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin, Strahlenklinik und Poliklinik (Germany); Hosten, N. [Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin, Strahlenklinik und Poliklinik (Germany); Beier, J. [Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin, Deutsches Herzzentrum (Germany); Neumann, K. [Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin, Strahlenklinik und Poliklinik (Germany); Rieger, J. [Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin, Strahlenklinik und Poliklinik (Germany); Felix, R. [Universitaetsklinikum Rudolf Virchow, Freie Univ. Berlin, Strahlenklinik und Poliklinik (Germany)

1994-10-01

298

Fast Generation of Virtual X-ray Images for Reconstruction of 3D Anatomy.  

Science.gov (United States)

We propose a novel GPU-based approach to render virtual X-ray projections of deformable tetrahedral meshes. These meshes represent the shape and the internal density distribution of a particular anatomical structure and are derived from statistical shape and intensity models (SSIMs). We apply our method to improve the geometric reconstruction of 3D anatomy (e.g. pelvic bone) from 2D X-ray images. For that purpose, shape and density of a tetrahedral mesh are varied and virtual X-ray projections are generated within an optimization process until the similarity between the computed virtual X-ray and the respective anatomy depicted in a given clinical X-ray is maximized. The OpenGL implementation presented in this work deforms and projects tetrahedral meshes of high resolution (200.000+ tetrahedra) at interactive rates. It generates virtual X-rays that accurately depict the density distribution of an anatomy of interest. Compared to existing methods that accumulate X-ray attenuation in deformable meshes, our novel approach significantly boosts the deformation/projection performance. The proposed projection algorithm scales better with respect to mesh resolution and complexity of the density distribution, and the combined deformation and projection on the GPU scales better with respect to the number of deformation parameters. The gain in performance allows for a larger number of cycles in the optimization process. Consequently, it reduces the risk of being stuck in a local optimum. We believe that our approach will improve treatments in orthopedics, where 3D anatomical information is essential. PMID:24051834

Ehlke, Moritz; Ramm, Heiko; Lamecker, Hans; Hege, Hans-Christian; Zachow, Stefan

2013-12-01

299

Reproducibility of Frankfort horizontal plane on 3D multi-planar reconstructed MR images.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The purpose of this study was to determine the accuracy and reliability of Frankfort horizontal plane identification using displays of multi-planar reconstructed MRI images, and propose it as a sufficiently stable and standardized reference plane for craniofacial structures. MATERIALS AND METHODS: MRI images of 43 subjects were obtained from the longitudinal population based cohort study SHIP-2 using a T1-weighted 3D sequence. Five examiners independently identified the three landmarks that form FH plane. Intra-examiner reproducibility and inter-examiner reliability, correlation coefficients (ICC), coefficient of variability and Bland-Altman plots were obtained for all landmarks coordinates to assess reproducibility. Intra-examiner reproducibility and inter-examiner reliability in terms of location and plane angulation were also assessed. RESULTS: Intra- and inter-examiner reliabilities for X, Y and Z coordinates of all three landmarks were excellent with ICC values ranging from 0.914 to 0.998. Differences among examiners were more in X and Z than in Y dimensions. The Bland-Altman analysis demonstrated excellent intra- as well as inter-examiner agreement between examiners in all coordinates for all landmarks. Intra-examiner reproducibility and inter-examiner reliability of the three landmarks in terms of distance showed mean differences between 1.3 to 2.9 mm, Mean differences in plane angulation were between 1.0° to 1.5° among examiners. CONCLUSION: This study revealed excellent intra-examiner reproducibility and inter-examiner reliability of Frankfort Horizontal plane through 3D landmark identification in MRI. Sufficiently stable landmark-based reference plane could be used for different treatments and studies.

Daboul A; Schwahn C; Schaffner G; Soehnel S; Samietz S; Aljaghsi A; Habes M; Habes M; Hegenscheid K; Puls R; Klinke T; Biffar R

2012-01-01

300

Body mass estimations for Plateosaurus engelhardti using laser scanning and 3D reconstruction methods.  

UK PubMed Central (United Kingdom)

Both body mass and surface area are factors determining the essence of any living organism. This should also hold true for an extinct organism such as a dinosaur. The present report discusses the use of a new 3D laser scanner method to establish body masses and surface areas of an Asian elephant (Zoological Museum of Copenhagen, Denmark) and of Plateosaurus engelhardti, a prosauropod from the Upper Triassic, exhibited at the Paleontological Museum in Tübingen (Germany). This method was used to study the effect that slight changes in body shape had on body mass for P. engelhardti. It was established that body volumes varied between 0.79 m(3) (slim version) and 1.14 m(3) (robust version), resulting in a presumable body mass of 630 and 912 kg, respectively. The total body surface areas ranged between 8.8 and 10.2 m(2), of which, in both reconstructions of P. engelhardti, approximately 33% account for the thorax area alone. The main difference between the two models is in the tail and hind limb reconstruction. The tail of the slim version has a surface area of 1.98 m(2), whereas that of the robust version has a surface area of 2.73 m(2). The body volumes calculated for the slim version were as follows: head 0.006 m(3), neck 0.016 m(3), fore limbs 0.020 m(3), hind limbs 0.08 m(3), thoracic cavity 0.533 m(3), and tail 0.136 m(3). For the robust model, the following volumes were established: 0.01 m(3) head, neck 0.026 m(3), fore limbs 0.025 m(3), hind limbs 0.18 m(3), thoracic cavity 0.616 m(3), and finally, tail 0.28 m(3). Based on these body volumes, scaling equations were used to assess the size that the organs of this extinct dinosaur have.

Gunga HC; Suthau T; Bellmann A; Friedrich A; Schwanebeck T; Stoinski S; Trippel T; Kirsch K; Hellwich O

2007-08-01

 
 
 
 
301

A software-based x-ray scatter correction method for breast tomosynthesis  

International Nuclear Information System (INIS)

Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients. Methods: A Monte Carlo (MC) simulation of x-ray scatter, with geometry matching that of the cranio-caudal (CC) view of a DBT clinical prototype, was developed using the Geant4 toolkit and used to generate maps of the scatter-to-primary ratio (SPR) of a number of homogeneous standard-shaped breasts of varying sizes. Dimension-matched SPR maps were then deformed and registered to DBT acquisition projections, allowing for the estimation of the primary x-ray signal acquired by the imaging system. Noise filtering of the estimated projections was then performed to reduce the impact of the quantum noise of the x-ray scatter. Three dimensional (3D) reconstruction was then performed using the maximum likelihood-expectation maximization (MLEM) method. This process was tested on acquisitions of a heterogeneous 50/50 adipose/glandular tomosynthesis phantom with embedded masses, fibers, and microcalcifications and on acquisitions of patients. The image quality of the reconstructions of the scatter-corrected and uncorrected projections was analyzed by studying the signal-difference-to-noise ratio (SDNR), the integral of the signal in each mass lesion (integrated mass signal, IMS), and the modulation transfer function (MTF). Results: The reconstructions of the scatter-corrected projections demonstrated superior image quality. The SDNR of masses embedded in a 5 cm thick tomosynthesis phantom improved 60%-66%, while the SDNR of the smallest mass in an 8 cm thick phantom improved by 59% (p

2011-01-01

302

3D RBI-EM reconstruction with spherically-symmetric basis function for SPECT rotating slat collimator  

International Nuclear Information System (INIS)

A single photon emission computed tomography (SPECT) rotating slat collimator with strip detector acquires distance-weighted plane integral data, along with the attenuation factor and distance-dependent detector response. In order to image a 3D object, the slat collimator device has first to spin around its axis and then rotate around the object to produce 3D projection measurements. Compared to the slice-by-slice 2D reconstruction for the parallel-hole collimator and line integral data, a more complex 3D reconstruction is needed for the slat collimator and plane integral data. In this paper, we propose a 3D RBI-EM reconstruction algorithm with spherically-symmetric basis function, also called 'blobs', for the slat collimator. It has a closed and spherically symmetric analytical expression for the 3D Radon transform, which makes it easier to compute the plane integral than the voxel. It is completely localized in the spatial domain and nearly band-limited in the frequency domain. Its size and shape can be controlled by several parameters to have desired reconstructed image quality. A mathematical lesion phantom study has demonstrated that the blob reconstruction can achieve better contrast-noise trade-offs than the voxel reconstruction without greatly degrading the image resolution. A real lesion phantom study further confirmed this and showed that a slat collimator with CZT detector has better image quality than the conventional parallel-hole collimator with NaI detector. The improvement might be due to both the slat collimation and the better energy resolution of the CZT detector.

2004-06-07

303

AX-PET: A novel PET detector concept with full 3D reconstruction  

International Nuclear Information System (INIS)

We describe the concept and first experimental tests of a novel 3D axial Positron Emission Tomography (PET) geometry. It allows for a new way of measuring the interaction point in the detector with very high precision. It is based on a matrix of long Lutetium-Yttrium OxyorthoSilicate (LYSO) crystals oriented in the axial direction, each coupled to one Geiger Mode Avalanche Photodiode (G-APD) array. To derive the axial coordinate, Wave Length Shifter (WLS) strips are mounted orthogonally and interleaved between the crystals. The light from the WLS strips is read by custom-made G-APDs. The weighted mean of the signals in the WLS strips has proven to give very precise axial resolution. The achievable resolution along the three axes is mainly driven by the dimensions of the LYSO crystals and WLS strips. This concept is inherently free of parallax errors. Furthermore, it will allow identification of Compton interactions in the detector and for reconstruction of a fraction of them, which is expected to enhance image quality and sensitivity. We present the results of proof-of-principle tests and qualification measurements of the various components prepared to build a larger scale demonstrator consisting of two matrices of 8x6 LYSO crystals and 312 WLS strips.

2009-10-21

304

Reconstruction of divergence-free velocity fields from cine 3D phase-contrast flow measurements.  

UK PubMed Central (United Kingdom)

Three-dimensional phase-contrast velocity vector field mapping shows great potential for clinical applications; however measurement inaccuracies may limit the utility and robustness of the technique. While parts of the error in the measured velocity fields can be minimized by background phase estimation in static tissue and magnetic field monitoring, considerable inaccuracies remain. The present work introduces divergence-reduction processing of 3D phase-contrast flow data based on a synergistic combination of normalized convolution and divergence-free radial basis functions. It is demonstrated that this approach effectively addresses erroneous flow for image reconstructions from both fully sampled and undersampled data. Using computer simulations and in vivo data acquired in the aorta of healthy subjects and a stenotic valve patient it is shown that divergence arising from measurement imperfections can be reduced by up to 87% resulting in improved vector field representations. Based on the results obtained it is concluded that integration of the divergence-free condition into postprocessing of vector fields presents an efficient approach to addressing flow field inaccuracies.

Busch J; Giese D; Wissmann L; Kozerke S

2013-01-01

305

SCORPIO-VVER with advanced 3D power reconstruction and limit checking  

International Nuclear Information System (INIS)

The SCORPIO-VVER core monitoring system has proved since the first installation at Dukovany NPP in 1999 to be a valuable tool for the reactor operators and reactor physicists. It is now installed on four units of Dukovany NPP and two units of Bohunice NPP replacing the original Russian VK3 system. By both Czech and Slovak nuclear regulatory bodies it was licensed as a Technical Specification Surveillance tool. Since its first installation, the development of SCORPIO-VVER system continues along with the changes in VVER reactors operation. The system is being adapted according the utility needs and several notable improvements in physical modules of the system were introduced. The latest most significant changes were done in connection with implementation of a new digital I and C system, loading of the optimized Gadolinium bearing Gd 2 fuel assemblies, improvements in the area of core design (neutron physics, core thermal hydraulics and fuel thermal mechanics) and improvements in the predictive part of the system (Strategy Generator). Next to the adaptation of the system to up-rated unit conditions the currently running upgrades (Upgrade 2 at EBO Slovakia, Upgrade 5 at EDU Czech Republic) include further improvements of methods applied in physical modules. Among the most important changes are the improvement of 3D power reconstruction with increased importance to the SPND detectors measurements and the implementation of the on-line shutdown margin calculation. (authors)

2008-01-01

306

Automatic Reconstruction of Fault Networks from Seismicity Catalogs: 3D Optimal Anisotropic Dynamic Clustering  

CERN Multimedia

We propose a new pattern recognition method that is able to reconstruct the 3D structure of the active part of a fault network using the spatial location of earthquakes. The method is a generalization of the so-called dynamic clustering method, that originally partitions a set of datapoints into clusters, using a global minimization criterion over the spatial inertia of those clusters. The new method improves on it by taking into account the full spatial inertia tensor of each cluster, in order to partition the dataset into fault-like, anisotropic clusters. Given a catalog of seismic events, the output is the optimal set of plane segments that fits the spatial structure of the data. Each plane segment is fully characterized by its location, size and orientation. The main tunable parameter is the accuracy of the earthquake localizations, which fixes the resolution, i.e. the residual variance of the fit. The resolution determines the number of fault segments needed to describe the earthquake catalog, the better...

Ouillon, G; Sornette, D; Ouillon, Guy; Ducorbier, Caroline; Sornette, Didier

2007-01-01

307

3D reconstruction of skin pathological tissue: the understanding of microrelief pattern and dermal ridge.  

UK PubMed Central (United Kingdom)

AIM: Most studies about the structures of the human skin have been on the general histologic features of the skin. The purpose of this study was to understand the relationship between the microrelief (MR) pattern and histologic structure of the human skin, and to find the usefulness of the three-dimensional reconstruction (3DR) technique of pathological skin tissue. MATERIALS, SUBJECTS, AND METHODS: Human skin specimens were obtained from the medial forearm, abdomen, and volar aspects of the finger tips of cadavers. Two-dimensional surface-viewed images of the skin showing MR patterns were obtained using dry dermoscopy. Histologic structures of the skin were evaluated by 3D images obtained using the 3DR technique. RESULTS: MR was deeper and wider in the abdomen than in the medial side of the forearm. In the medial side of the forearm, 10.27 rete ridges were distributed in a plateau, on average. In the abdomen, about 14.37 rete ridges were distributed in a plateau. From 3DR technique, MR pattern thought to be a superordinate concept to rete ridges. CONCLUSION: The 3DR technique was useful and may allow a better understanding of the pathogenetic changes in the skin surface in aging skin.

Oh GN; Yoon JH; Kye HS; Kim DH; Kim JY; Choi JE; Seo SH; Kye YC; Ahn HH; Rhyu IJ

2013-08-01

308

Reconstructed 3D flame structures in noise-controlled swirl-stabilized combustor  

Science.gov (United States)

Flame structures of turbulent premixed flames in a noise-controlled, swirl-stabilized combustor are investigated to clarify the mechanism of combustion noise reduction by the secondary fuel injection. Planar laser-induced fluorescence (PLIF) is conducted for several cases with different secondary fuel injection, and 3D flame structure is reconstructed from PLIF results on multiple planes. The secondary fuel injection suppresses the fluctuation of high-temperature gas in the recirculation zone and reduces Reynolds stress and entropy terms in the acoustic sound source. In the flame zone, effects of the injection frequency are discussed by introducing mean progress variable. The flame brush is very wide for the no control case, whereas it becomes thin and is confined to a narrow space for the secondary fuel injection cases. The investigated combustor gives minimum sound level at a relevant fuel injection frequency, which is very low compared with the natural acoustic mode of the combustor. The flame brush becomes very thin, and self-induced oscillations of the flame brush disappear at this relevant frequency. The oscillation of the flame brush represents large-scale fluctuation of the mean heat release rate. The relations between characteristics of flame brush and combustion noise are discussed by introducing instantaneous and dynamical effects of flame front on the entropy term of the sound source. The secondary fuel injection works for the control of the entropy term in the sound source because the thin flame brush represents suppression of the instantaneous and dynamical effects.

Tanahashi, Mamoru; Inoue, Shohei; Shimura, Masayasu; Taka, Shohei; Choi, Gyung-Min; Miyauchi, Toshio

2008-09-01

309

Morphology and function of Bast’s valve: additional insight in its functioning using 3D-reconstruction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The utriculo-endolymphatic valve was discovered by Bast in 1928. The function of Bast’s valve is still unclear. By means of orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy 3D-reconstructions of the valve and its surrounding region are depicted. The shape of the duct at the utricu...

Hofman, R.; Segenhout, J. M.; Buytaert, J. A. N.; Dirckx, J. J. J.; Wit, H. P.

310

Postoperative assessment of surgical results using three dimensional surface reconstruction CT (3D-CT) in a craniofacial anomaly  

Energy Technology Data Exchange (ETDEWEB)

In 1983, Michael W. Vannier and Jeffrey L. Marsh developed a computer method that reconstructs three dimensional (3D) born and soft tissue surfaces, given a high resolution CT scan-series of the facial skeleton. This method has been applied to craniofacial anomalies, basal encephaloceles, and musculoskeletal anomalies. In this study, a postoperative assessment of the craniofacial surgical results has been accomplished using this 3D-CT in 2 children with craniofacial dysmorphism. The authors discuss the advantages of this 3D-CT imaging method in the postoperative assessments of craniofacial anomalies. Results are detailed in the following listing : 1) a postoperative 3D-CT reveals the anatomical details corrected by the craniofacial surgery more precisely and stereographically than conventional radiological methods ; 2) secondary changes of the cranium after the surgery, such as bony formation in the area of the osteotomy and postoperative asymmetric deformities, are detected early by the 3D-CT imaging technique, and, 3) 3D-CT mid-sagittal and top axial views of the intracranial skull base are most useful in postoperative assessments of the surgical results. Basesd on our experience, we expect that three dimensional surface reconstructions from CT scans will become to be used widely in the postoperative assessments of the surgical results of craniofacial anomalies.

Nishimura, Jiro; Sato, Kaoru; Nishimoto, Hiroshi; Tsukiyama, Takashi; Fujioka, Mutsuhisa; Akagawa, Tetsuya.

1988-07-01

311

Postoperative assessment of surgical results using three dimensional surface reconstruction CT (3D-CT) in a craniofacial anomaly  

International Nuclear Information System (INIS)

In 1983, Michael W. Vannier and Jeffrey L. Marsh developed a computer method that reconstructs three dimensional (3D) born and soft tissue surfaces, given a high resolution CT scan-series of the facial skeleton. This method has been applied to craniofacial anomalies, basal encephaloceles, and musculoskeletal anomalies. In this study, a postoperative assessment of the craniofacial surgical results has been accomplished using this 3D-CT in 2 children with craniofacial dysmorphism. The authors discuss the advantages of this 3D-CT imaging method in the postoperative assessments of craniofacial anomalies. Results are detailed in the following listing : 1) a postoperative 3D-CT reveals the anatomical details corrected by the craniofacial surgery more precisely and stereographically than conventional radiological methods ; 2) secondary changes of the cranium after the surgery, such as bony formation in the area of the osteotomy and postoperative asymmetric deformities, are detected early by the 3D-CT imaging technique, and, 3) 3D-CT mid-sagittal and top axial views of the intracranial skull base are most useful in postoperative assessments of the surgical results. Basesd on our experience, we expect that three dimensional surface reconstructions from CT scans will become to be used widely in the postoperative assessments of the surgical results of craniofacial anomalies. (author).

1988-01-01

312

Comparison of 3D reconstructive technologies used for morphometric research and the translation of knowledge using a decision matrix.  

UK PubMed Central (United Kingdom)

The use of three-dimensional (3D) models for education, pre-operative assessment, presurgical planning, and measurement have become more prevalent. With the increase in prevalence of 3D models there has also been an increase in 3D reconstructive software programs that are used to create these models. These software programs differ in reconstruction concepts, operating system requirements, user features, cost, and no one program has emerged as the standard. The purpose of this study was to conduct a systematic comparison of three widely available 3D reconstructive software programs, Amira(®) , OsiriX, and Mimics(®) , with respect to the software's ability to be used in two broad themes: morphometric research and education to translate morphological knowledge. Cost, system requirements, and inherent features of each program were compared. A novel concept selection tool, a decision matrix, was used to objectify comparisons of usability of the interface, quality of the output, and efficiency of the tools. Findings indicate that Mimics was the best-suited program for construction of 3D anatomical models and morphometric analysis, but for creating a learning tool the results were less clear. OsiriX was very user-friendly; however, it had limited capabilities. Conversely, although Amira had endless potential and could create complex dynamic videos, it had a challenging interface. These results provide a resource for morphometric researchers and educators to assist the selection of appropriate reconstruction programs when starting a new 3D modeling project. Anat Sci Educ 6: 393-403. © 2013 American Association of Anatomists.

Martin CM; Roach VA; Nguyen N; Rice CL; Wilson TD

2013-11-01

313

Comparison of 3D reconstructive technologies used for morphometric research and the translation of knowledge using a decision matrix.  

Science.gov (United States)

The use of three-dimensional (3D) models for education, pre-operative assessment, presurgical planning, and measurement have become more prevalent. With the increase in prevalence of 3D models there has also been an increase in 3D reconstructive software programs that are used to create these models. These software programs differ in reconstruction concepts, operating system requirements, user features, cost, and no one program has emerged as the standard. The purpose of this study was to conduct a systematic comparison of three widely available 3D reconstructive software programs, Amira(®) , OsiriX, and Mimics(®) , with respect to the software's ability to be used in two broad themes: morphometric research and education to translate morphological knowledge. Cost, system requirements, and inherent features of each program were compared. A novel concept selection tool, a decision matrix, was used to objectify comparisons of usability of the interface, quality of the output, and efficiency of the tools. Findings indicate that Mimics was the best-suited program for construction of 3D anatomical models and morphometric analysis, but for creating a learning tool the results were less clear. OsiriX was very user-friendly; however, it had limited capabilities. Conversely, although Amira had endless potential and could create complex dynamic videos, it had a challenging interface. These results provide a resource for morphometric researchers and educators to assist the selection of appropriate reconstruction programs when starting a new 3D modeling project. Anat Sci Educ 6: 393-403. © 2013 American Association of Anatomists. PMID:23633266

Martin, Charys M; Roach, Victoria A; Nguyen, Ngan; Rice, Charles L; Wilson, Timothy D

2013-04-30

314

Optimizing radioimmunotherapy by matching dose distribution with tumor structure using 3D reconstructions of serial images.  

UK PubMed Central (United Kingdom)

The biological effect of radioimmunotherapy (RIT) is most commonly assessed in terms of the absorbed radiation dose. In tumor, conventional dosimetry methods assume a uniform radionuclide and calculate a mean dose throughout the tumor. However, the vasculature of solid tumors tends to be highly irregular and the systemic delivery of antibodies is therefore heterogeneous. Tumor-specific antibodies preferentially localize in the viable, radiosensitive parts of the tumor whereas non-specific antibodies can penetrate into the necrosis where the dose is wasted. As a result, the observed biological effect can be very different to the predicted effect from conventional dose estimates. The purpose of this study is to assess the potential for optimizing the biological effect of RIT by matching the dose-distribution with tumor structure through the selection of appropriate antibodies and radionuclides. Storage phosphor plate technology was used to acquire images of the antibody distribution in serial tumor sections. Images of the distributions of a trivalent (TFM), bivalent (A5B7-IgG), monovalent (MFE-23) and a non-specific antibody (MOPC) were obtained. These images were registered with corresponding images showing tumor morphology. Serial images were reconstructed to form 3D maps of the antibody distribution and tumor structure. Convolution of the image of antibody distribution with beta dose point kernals generated dose-rate distributions for 14C, 131I and 90Y. These were statistically compared with the tumor structure. The highest correlation was obtained for the multivalent antibodies combined with 131I, due to specific retention in viable areas of tumor coupled with the fact that much of the dose was deposted locally. With decreasing avidity the correlation also decreased and with the non-specific antibody this correlation was negative, indicating higher concentrations in the necrotic regions. In conclusion, the dose distribution can be optimized in tumor by selecting the appropriate antibodies and radionuclides. This has the potential to lead to a considerable enhancement of the efficacy of RIT in the clinic.

Flynn AA; Pedley RB; Green AJ; Boxer GM; Boden R; Begent RH

2001-10-01

315

Sphincteric musculature of female canine urethra in comparison to woman including 3D reconstruction.  

UK PubMed Central (United Kingdom)

The circular arranged sphincteric musculature of bladder neck of female dogs and women were studied histomorphologically. 3D reconstructions of the anatomy of the bladder neck improve the understanding of construction principles of the musculature of the lower urinary tract and help to compare both species. Our own investigations based on 12 adult female canine and 15 female human autopsy preparations. The special feature of our study was the extensive en bloc preparation of all the organs of the lower urinary tract and surrounding organs. The organ blocks were reprocessed in complete serial sections from the bladder outlet down to the bulb of vestibuli. Despite different detailed construction, in both species the striated sphincter musculature of the urethra is an independent morphological unit. There is no continuation of pelvic floor muscles to the urethra. In humans, the urethral sphincter consists of a smooth muscular part (m. sphincter urethrae glaber) and a striated part (m. sphincter urethrae transversostriatus). In the female dog, striated muscle fibres encircle the urethra in the middle third exclusively. In the distal third of the urethra, it encircles the urethra and the vagina. In the female dog, the lamellae of detrusor continue directly to the urethra. Throughout the cranial and middle third of the urethra, smooth muscle cell bundles form a homogenous compact sphincteric muscle originating from the middle circular layer of detrusor. In that way, no true bladder neck sphincter according to the m. sphincter vesicae in women exists in dogs. According to the smooth muscular part of the m. sphincter urethrae in women, for this musculature the term m. sphincter urethrae glaber is suggested. Despite a superficial resemblance, this study revealed a considerable difference of circular sphincteric muscle components between female dog and woman suggesting that functional studies in respect to urinary continence obtained in dogs cannot be attributed without qualification to humans.

Stolzenburg JU; Dorschner W; Postenjak M; Salomon FV; Jurina K; Do M; Neuhaus J

2002-01-01

316

Método de Regularización de Mallas Cuadrilaterales en Reconstrucción de Objetos 3D Regularization Method of Quadrilaterals Mesh for 3D Object Reconstruction  

Directory of Open Access Journals (Sweden)

Full Text Available Se propone un método de regularización de una malla cuadrilateral mediante Geodésicas y B-Splines aplicado a la reconstrucción de objetos 3D. El procedimiento realizado, se resume en tres etapas principales: i) selección de cuadriláteros; ii) regularización de los cuadriláteros y generación de puntos, utilizando B-Splines; y iii) emparejamiento de puntos regularizados mediante geodésicas con el método de la marcha rápida (fast marching method, FMM). En el proceso de experimentación, la regularización de la malla cuadrilateral y la representación computacional de los modelos se hicieron con una imagen de rango del objeto cultural moai. A pesar de que el objeto tiene topología arbitraria irregular, el método propuesto dio resultados adecuados en la conservación de los detalles finos del objeto.A regularization method of a quadrilateral mesh by means Geodesics and B-Splines, applied to 3D objects reconstruction, is proposed. The procedure can be summarized in three main steps: i) selection of quadrilaterals; ii) regularization of quadrilaterals and generation of points using B-Splines; and iii) matching regularized points by means of Fast Marching Method geodesic (FMM). In the process of experimentation, the regularization of the representation of the quadrilateral mesh and the representation of the computational models were done with a range image of the cultural object moai. Despite having an irregular arbitrary topology, the proposed method gave adequate results in the conservation of the fine detail of the object.

Sandra P Mateus

2008-01-01

317

Método de Regularización de Mallas Cuadrilaterales en Reconstrucción de Objetos 3D/ Regularization Method of Quadrilaterals Mesh for 3D Object Reconstruction  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Se propone un método de regularización de una malla cuadrilateral mediante Geodésicas y B-Splines aplicado a la reconstrucción de objetos 3D. El procedimiento realizado, se resume en tres etapas principales: i) selección de cuadriláteros; ii) regularización de los cuadriláteros y generación de puntos, utilizando B-Splines; y iii) emparejamiento de puntos regularizados mediante geodésicas con el método de la marcha rápida (fast marching method, FMM). En el proc (more) eso de experimentación, la regularización de la malla cuadrilateral y la representación computacional de los modelos se hicieron con una imagen de rango del objeto cultural moai. A pesar de que el objeto tiene topología arbitraria irregular, el método propuesto dio resultados adecuados en la conservación de los detalles finos del objeto. Abstract in english A regularization method of a quadrilateral mesh by means Geodesics and B-Splines, applied to 3D objects reconstruction, is proposed. The procedure can be summarized in three main steps: i) selection of quadrilaterals; ii) regularization of quadrilaterals and generation of points using B-Splines; and iii) matching regularized points by means of Fast Marching Method geodesic (FMM). In the process of experimentation, the regularization of the representation of the quadrilate (more) ral mesh and the representation of the computational models were done with a range image of the cultural object moai. Despite having an irregular arbitrary topology, the proposed method gave adequate results in the conservation of the fine detail of the object.

Mateus, Sandra P

2008-01-01

318

3D image reconstruction for PET by multi-slice rebinning and axial filtering. [Positron Emission Tomography (PET)  

Energy Technology Data Exchange (ETDEWEB)

Two different approaches are used at present to reconstruct from 3D coincidence data in PET. We refer to these approaches as the single-slice rebinning approach and the fully-3D approach. The single-slice rebinning approach involves geometrical approximations, but it requires the least possible amount of computation. Fully-3D reconstruction algorithms, both iterative and non-iterative, do not make such approximations, but require much more computation. Multi-slice rebinning with axial filtering is a new approach which attempts to achieve the geometrical accuracy of the fully-3D approach with the simplicity and modest amount of computation of the single-slice rebinning approach. The first step (multi-slice rebinning) involves rebinning of coincidence lines into a stack of 2D sinograms, where multiple sinograms are incremented for each oblique coincidence line. This operation is followed by an axial filtering operation, either before or after slice-by-slice reconstruction, to reduce the blurring in the axial direction. Tests with simulated and experimental data indicate that the new method has better geometrical accuracy than single-slice rebinning, at the cost of only a modest increase in computation. 11 refs.

Lewitt, R.M. (UGM Medical Systems, Inc., Philadelphia, PA (United States) Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Radiology); Muehllehner, G. (UGM Medical Systems, Inc., Philadelphia, PA (United States)); Karp, J.S. (Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Radiology)

1991-01-01

319

Reconstruction of 3D objects from multi-frequency experimental data with a fast DBIM-BCGS method  

International Nuclear Information System (INIS)

The objective of this work is to perform image reconstruction of 3D dielectric targets from multi-frequency experimental data by using a fast DBIM-BCGS method that combines the distorted Born iterative method (DBIM) and the stabilized biconjugate-gradient fast Fourier transform (BCGS-FFT) method. In this reconstruction technique, the BCGS-FFT method is used as a forward scattering method for solving the volume integral equations governing the 3D scattering problem; it provides both the predicted scattered fields due to 3D heterogeneous objects and the Fréchet derivatives in the inverse scattering problem. The plane-wave source model and the point receiver model are used in the inversion procedure to invert the calibrated scattering data obtained from Institut Fresnel's measurements. The multi-frequency experimental data are processed with the frequency-hopping approach to obtain high-resolution 3D images. The reconstruction of five different targets from the measured scattered fields verifies the capability and the effectiveness of the DBIM-BCGS method

2009-01-01

320

Digital breast tomosynthesis. Technical principles, current clinical relevance and future perspectives  

International Nuclear Information System (INIS)

In recent years digital full field mammography has increasingly replaced conventional film mammography. High quality imaging is guaranteed by high quantum efficiency and very good contrast resolution with optimized dosing even for women with dense glandular tissue. However, digital mammography remains a projection procedure by which overlapping tissue limits the detectability of subtle alterations. Tomosynthesis is a procedure developed from digital mammography for slice examination of breasts which eliminates the effects of overlapping tissue and allows 3D imaging of breasts. A curved movement of the X-ray tube during scanning allows the acquisition of many 2D images from different angles. Subseqently, reconstruction algorithms employing a shift and add method improve the recognition of details at a defined level and at the same time eliminate smear artefacts due to overlapping structures. The total dose corresponds to that of conventional mammography imaging. The technical procedure, including the number of levels, suitable anodes/filter combinations, angle regions of images and selection of reconstruction algorithms, is presently undergoing optimization. Previous studies on the clinical value of tomosynthesis have examined screening parameters, such as recall rate and detection rate as well as information on tumor extent for histologically proven breast tumors. More advanced techniques, such as contrast medium-enhanced tomosynthesis, are presently under development and dual-energy imaging is of particular importance. (orig.)

2010-01-01

 
 
 
 
321

3D RECONSTRUCTION OF PHALANGEAL AND METACARPAL BONES OF MALE JUDO PLAYERS AND SEDENTARY MEN BY MDCT IMAGES  

Directory of Open Access Journals (Sweden)

Full Text Available This study has been performed to reveal hand bone peculiarities of elite male judoists by comparing their phalangeal and metacarpal bones with those of sedentary men on the basis of biometric ratio of the bones by means of three-dimensional (3D) reconstruction of multidetector computed tomography (MDCT) images. For this purpose, the axial images of the right and left hands of 8 elite male judo players (mean age: 22.0 ± 2.9 years, mean weight: 64.0 ± 4.9 kg) and 8 sedentary men (mean age: 26.0 ± 2.8 years, mean weight: 69.0 ± 3.6 kg) were obtained from MDCT. After semi-automatic segmentation and manual editing, the tracings of bone surfaces were stacked and overlaid to be reconstructed as the 3D images by the 3D program. All biometrical measurements of the reconstructed images of the bones were automatically calculated by this program to analyze statistically. This study showed that the differences between biometric ratios of judoist and sedentary men's hand bones were significant contrary to null hypothesis which was established as there is no difference between biometric hand bone ratios of these men of both groups. Therefore null hypothesis was rejected. Author suggests that intense clutching actions practised in judo sports can most probably lead to some hand bone proliferations. 3D reconstructed results belonging to the judo players and sedentary men help orthopaedists to diagnose pathological formations related to hand bones of judoists and may be used for anatomical education in medicine faculties, respectively. We hope that the results from the biometric and reconstructive techniques carried out in this work will contribute to the present knowledge on judoist and shed light on the future studies on sports medicine related to skeletal structure of other sportsmen

Ibrahim Kalayci

2008-01-01

322

Clinically feasible reconstruction of 3D whole-body PET/CT data using blurred anatomical labels  

International Nuclear Information System (INIS)

We present the results of utilizing aligned anatomical information from CT images to locally adjust image smoothness during the reconstruction of three-dimensional (3D) whole-body positron emission tomography (PET) data. The ability of whole-body PET imaging to detect malignant neoplasms is becoming widely recognized. Potentially useful, however, is the role of whole-body PET in quantitative estimation of tracer uptake. The utility of PET in oncology is often limited by the high level of statistical noise in the images. Reduction in noise can be obtained by incorporating a priori image smoothness information from correlated anatomical information during the reconstruction of PET data. A combined PET/CT scanner allows the acquisition of accurately aligned PET and x-ray CT whole-body data. We use the Fourier rebinning algorithm (FORE) to accurately convert the 3D PET data to two-dimensional (2D) data to accelerate the image reconstruction process. The 2D datasets are reconstructed with successive over-relaxation of a penalized weighted least squares (PWLS) objective function to model the statistics of the acquisition, data corrections, and rebinning. A 3D voxel label model is presented that incorporates the anatomical information via the penalty weights of the PWLS objective function. This combination of FORE + PWLS + labels was developed as it allows for both reconstruction of 3D whole-body data sets in clinically feasible times and also the inclusion of anatomical information in such a way that convergence can be guaranteed. Since mismatches between anatomical (CT) and functional (PET) data are unavoidable in practice, the labels are 'blurred' to reflect the uncertainty associated with the anatomical information. Simulated and experimental results show the potential advantage of incorporating anatomical information by using blurred labels to calculate the penalty weights. We conclude that while the effect of this method on detection tasks is complicated and unclear, there is an improvement on the estimation task. (author)

2002-01-07

323

Building Reconstruction From Aerial Images And Creation Of 3D Topologic Data Structure  

UK PubMed Central (United Kingdom)

The interest in 3D GIS increases due to developments in technology and necessity of users tocope with more complex tasks. Questions related to data acquisition, data storage, data analysisand data visualization are topics for investigations. A key issue on the way of building a 3Dmodel, is an adequate data structure capable to respond to various user queries. The paperelaborates on problems related to 3D model construction for buildings from aerial images, usingmanual stereo digitizing. The approach relies on a data model based on the 3D Formal DataStructure, which supports 3D topology. The emphasis of the presented work is on an automaticdata structuring. The outcomes from the implementation work show that topology facilitates theprocess of both data acquisition and data visualization.1 Introduction1.1 3D-GISA demand for 3D geo-referenced information and systems supplying 3D analysis andvisualization appears in various areas of human life. The need for 3D spatial inform...

324

GPU acceleration of 3D forward and backward projection using separable footprints for X-ray CT image reconstruction  

Energy Technology Data Exchange (ETDEWEB)

Iterative 3D image reconstruction methods can improve image quality over conventional filtered back projection (FBP) in X-ray computed tomography. However, high computational costs deter the routine use of iterative reconstruction clinically. The separable footprint method for forward and back-projection simplifies the integrals over a detector cell in a way that is quite accurate and also has a relatively efficient CPU implementation. In this project, we implemented the separable footprints method for both forward and backward projection on a graphics processing unit (GPU) with NVDIA's parallel computing architecture (CUDA). This paper describes our GPU kernels for the separable footprint method and simulation results. (orig.)

Wu, Meng; Fessler, Jeffrey A. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Electrical Engineering and Computer Science

2011-07-01

325

The accurate 3-D reconstruction of the geometric configuration of vascular trees from X-ray recordings  

International Nuclear Information System (INIS)

The authors describe a method for the accurate reconstruction and display of the three dimensional (3-D) configuration of a vascular tree from two X-ray views. In order to achieve this, the precise location and orientation of the X-ray equipment must be known for both views. Each vessel segment of the vascular tree is identified and located in each view and the calibre of each vessel segment is calculated and, from the resulting 3-D data set, a 2-D image of the vascular tree, from any chosen viewpoint is reconstructed. The blood vessels are represented by cylinders joined by spheres and shaded to give the impression of depth, the third dimension. (Auth.).

1984-10-05

326

3D reconstruction of a patient-specific surface model of the proximal femur from calibrated x-ray radiographs: A validation study  

Energy Technology Data Exchange (ETDEWEB)

Twenty-three femurs (one plastic bone and twenty-two cadaver bones) with both nonpathologic and pathologic cases were considered to validate a statistical shape model based technique for three-dimensional (3D) reconstruction of a patient-specific surface model from calibrated x-ray radiographs. The 3D reconstruction technique is based on an iterative nonrigid registration of the features extracted from a statistically instantiated 3D surface model to those interactively identified from the radiographs. The surface models reconstructed from the radiographs were compared to the associated ground truths derived either from a 3D CT-scan reconstruction method or from a 3D laser-scan reconstruction method and an average error distance of 0.95 mm were found. Compared to the existing works, our approach has the advantage of seamlessly handling both nonpathologic and pathologic cases even when the statistical shape model that we used was constructed from surface models of nonpathologic bones.

Zheng Guoyan; Schumann, Steffen [ARTORG Center for Biomedical Engineering Research, University of Bern, Stauffacherstrasse 78, H-3014 Bern (Switzerland)

2009-04-15

327

3D reconstruction of a patient-specific surface model of the proximal femur from calibrated x-ray radiographs: A validation study  

International Nuclear Information System (INIS)

[en] Twenty-three femurs (one plastic bone and twenty-two cadaver bones) with both nonpathologic and pathologic cases were considered to validate a statistical shape model based technique for three-dimensional (3D) reconstruction of a patient-specific surface model from calibrated x-ray radiographs. The 3D reconstruction technique is based on an iterative nonrigid registration of the features extracted from a statistically instantiated 3D surface model to those interactively identified from the radiographs. The surface models reconstructed from the radiographs were compared to the associated ground truths derived either from a 3D CT-scan reconstruction method or from a 3D laser-scan reconstruction method and an average error distance of 0.95 mm were found. Compared to the existing works, our approach has the advantage of seamlessly handling both nonpathologic and pathologic cases even when the statistical shape model that we used was constructed from surface models of nonpathologic bones.

2009-01-01

328

3-D reconstruction of the spine from biplanar radiographs based on contour matching using the Hough transform.  

Science.gov (United States)

The purpose of this study was to develop and evaluate a method for three-dimensional (3-D) reconstruction of the spine from biplanar radiographs. The approach was based on vertebral contour matching for estimating vertebral orientations and locations. Vertebral primitives were initially positioned under constraint of the 3-D spine midline, which was estimated from manually identified control points. Vertebral orientations and locations were automatically adjusted by matching projections of 3-D primitives with vertebral edges on biplanar radiographs based on the generalized Hough transform technique with a deformation tolerant matching strategy. We used graphics processing unit to accelerate reconstruction. Accuracy and precision were evaluated using radiographs from 15 scoliotic patients and a spine model in 24 poses. On in vivo radiographs, accuracy was within 2.8° for orientation and 2.4 mm for location; precision was within 2.3° for orientation and 2.1 mm for location. results were slightly better on model radiographs than on in vivo radiographs but without significance (p>0.05). The duration for user intervention was less than 2 min, and the computation time was within 3 min. Results indicated the method's reliability. It is a promising tool to determine 3-D spinal geometry with acceptable user interaction. PMID:23412567

Zhang, Junhua; Lv, Liang; Shi, Xinling; Wang, Yuanyuan; Guo, Fei; Zhang, Yufeng; Li, Hongjian

2013-02-12

329

3-D reconstruction of the spine from biplanar radiographs based on contour matching using the Hough transform.  

UK PubMed Central (United Kingdom)

The purpose of this study was to develop and evaluate a method for three-dimensional (3-D) reconstruction of the spine from biplanar radiographs. The approach was based on vertebral contour matching for estimating vertebral orientations and locations. Vertebral primitives were initially positioned under constraint of the 3-D spine midline, which was estimated from manually identified control points. Vertebral orientations and locations were automatically adjusted by matching projections of 3-D primitives with vertebral edges on biplanar radiographs based on the generalized Hough transform technique with a deformation tolerant matching strategy. We used graphics processing unit to accelerate reconstruction. Accuracy and precision were evaluated using radiographs from 15 scoliotic patients and a spine model in 24 poses. On in vivo radiographs, accuracy was within 2.8° for orientation and 2.4 mm for location; precision was within 2.3° for orientation and 2.1 mm for location. results were slightly better on model radiographs than on in vivo radiographs but without significance (p>0.05). The duration for user intervention was less than 2 min, and the computation time was within 3 min. Results indicated the method's reliability. It is a promising tool to determine 3-D spinal geometry with acceptable user interaction.

Zhang J; Lv L; Shi X; Wang Y; Guo F; Zhang Y; Li H

2013-07-01

330

[Development of 3-D reconstruction system of the craniofacial hard tissue based on 2-D digital radiograph].  

UK PubMed Central (United Kingdom)

PURPOSE: In this study, we used data from digital cephalometric radiograph to develop a 3-D craniofacial reconstruction system. The system was developed by Visual C++6.0, VTK on the platform of Windows XP, to increase the level of orthognathic diagnosis and treatment, and promote the communication between doctors and patients. METHODS: A model based on CT images was established as a standard model. Then the 3-D coordinate system was constructal and 64 feature points were set up as the initial feature points. The digital radiograph of the patient was adjusted to accord coordinate system of the model and regulated the feature points of the frontal and lateral cephalograms were regulated as the target feature points. Based on a certain deformation algorithm, deformed the standard model was deformed according to the feature points established in the digital radiograph, then the model of craniofacial hard tissue in patient was achieved. RESULTS: The 3-D model reflecting the actual surface construction of the craniofacial hard tissue was constructed. The 3-D image of the model constructed was lively and clear, which could be rotated and zoomed arbitrarily. CONCLUSIONS: Separated deformation and then fusion, the hard tissue reconstruction break through convention. Occlusal relation essentially rebuilt is carried out. This system could be used in clinic for diagnosis and operation simulation.

Feng YP; Zhou H; Zhai PF; Zhang YN; Sun LL

2010-10-01

331

Reconstruction of potential part of 3D vector field by using singular value decomposition  

Science.gov (United States)

In this paper we suggest the method of 3D vector tomography problem solving. The problem consists in determination of potential part of 3D vector field by its known the normal Radon transform. The singular value decomposition of the normal Radon transform operator is obtained. Based on obtained decomposition inversion formula is derived. The decomposition can be the basis for numerical solution of given problem.

Polyakova, Anna

2013-02-01

332

Reconstruction of potential part of 3D vector field by using singular value decomposition  

International Nuclear Information System (INIS)

In this paper we suggest the method of 3D vector tomography problem solving. The problem consists in determination of potential part of 3D vector field by its known the normal Radon transform. The singular value decomposition of the normal Radon transform operator is obtained. Based on obtained decomposition inversion formula is derived. The decomposition can be the basis for numerical solution of given problem.

2013-02-08

333

A software-based x-ray scatter correction method for breast tomosynthesis  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To develop a software-based scatter correction method for digital breast tomosynthesis (DBT) imaging and investigate its impact on the image quality of tomosynthesis reconstructions of both phantoms and patients. Methods: A Monte Carlo (MC) simulation of x-ray scatter, with geometry matching that of the cranio-caudal (CC) view of a DBT clinical prototype, was developed using the Geant4 toolkit and used to generate maps of the scatter-to-primary ratio (SPR) of a number of homogeneous standard-shaped breasts of varying sizes. Dimension-matched SPR maps were then deformed and registered to DBT acquisition projections, allowing for the estimation of the primary x-ray signal acquired by the imaging system. Noise filtering of the estimated projections was then performed to reduce the impact of the quantum noise of the x-ray scatter. Three dimensional (3D) reconstruction was then performed using the maximum likelihood-expectation maximization (MLEM) method. This process was tested on acquisitions of a heterogeneous 50/50 adipose/glandular tomosynthesis phantom with embedded masses, fibers, and microcalcifications and on acquisitions of patients. The image quality of the reconstructions of the scatter-corrected and uncorrected projections was analyzed by studying the signal-difference-to-noise ratio (SDNR), the integral of the signal in each mass lesion (integrated mass signal, IMS), and the modulation transfer function (MTF). Results: The reconstructions of the scatter-corrected projections demonstrated superior image quality. The SDNR of masses embedded in a 5 cm thick tomosynthesis phantom improved 60%-66%, while the SDNR of the smallest mass in an 8 cm thick phantom improved by 59% (p < 0.01). The IMS of the masses in the 5 cm thick phantom also improved by 15%-29%, while the IMS of the masses in the 8 cm thick phantom improved by 26%-62% (p < 0.01). Some embedded microcalcifications in the tomosynthesis phantoms were visible only in the scatter-corrected reconstructions. The visibility of the findings in two patient images was also improved by the application of the scatter correction algorithm. The MTF of the images did not change after application of the scatter correction algorithm, indicating that spatial resolution was not adversely affected. Conclusions: Our software-based scatter correction algorithm exhibits great potential in improving the image quality of DBT acquisitions of both phantoms and patients. The proposed algorithm does not require a time-consuming MC simulation for each specific case to be corrected, making it applicable in the clinical realm.

Jia Feng, Steve Si; Sechopoulos, Ioannis [Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, and Department of Radiology and Imaging Sciences and Winship Cancer Institute, Emory University, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 (United States); Department of Radiology and Imaging Sciences, Hematology and Medical Oncology and Winship Cancer Institute, Emory University, 1701 Uppergate Drive Northeast, Suite 5018, Atlanta, Georgia 30322 (United States)

2011-12-15

334

3-D reconstruction of phase grating via digital micro-holography  

Energy Technology Data Exchange (ETDEWEB)

Digital micro-holography technique, a combination of digital holography with microscopy, can be used to measure and analyse the micro-structure and status information of samples when the digital hologram registered is reconstructed numerically by some numerical methods based on the principle of scalar diffraction or coherent image. By summarizing the development of digital micro-holography, Fresnel approximation reconstruction algorithm and two-wavelength technique are introduced to study the three dimensional phase reconstruction of phase grating. Experimental results show good agreement with true parameters of phase grating. It also analyses the aberration of the image reconstructed by Fresnel approximation approach and two-wavelength technique.

Zhou Wenjing [Department of Precision Mechanical Engineering, Shanghai University No.149, Yanchang Rd., Shanghai 200072 (China); Yu Yingjie [Department of Precision Mechanical Engineering, Shanghai University No.149, Yanchang Rd., Shanghai, 200072 (China)

2007-07-15

335

3-D reconstructions of the early-November 2004 CDAW geomagnetic storms: analysis of Ooty IPS speed and density data  

Directory of Open Access Journals (Sweden)

Full Text Available Interplanetary scintillation (IPS) remote-sensing observations provide a view of the solar wind covering a wide range of heliographic latitudes and heliocentric distances from the Sun between ~0.1 AU and 3.0 AU. Such observations are used to study the development of solar coronal transients and the solar wind while propagating out through interplanetary space. They can also be used to measure the inner-heliospheric response to the passage of coronal mass ejections (CMEs) and co-rotating heliospheric structures. IPS observations can, in general, provide a speed estimate of the heliospheric material crossing the observing line of site; some radio antennas/arrays can also provide a radio scintillation level. We use a three-dimensional (3-D) reconstruction technique which obtains perspective views from outward-flowing solar wind and co-rotating structure as observed from Earth by iteratively fitting a kinematic solar wind model to these data. Using this 3-D modelling technique, we are able to reconstruct the velocity and density of CMEs as they travel through interplanetary space. For the time-dependent model used here with IPS data taken from the Ootacamund (Ooty) Radio Telescope (ORT) in India, the digital resolution of the tomography is 10° by 10° in both latitude and longitude with a half-day time cadence. Typically however, the resolutions range from 10° to 20° in latitude and longitude, with a half- to one-day time cadence for IPS data dependant upon how much data are used as input to the tomography. We compare reconstructed structures during early-November 2004 with in-situ measurements from the Wind spacecraft orbiting the Sun-Earth L1-Point to validate the 3-D tomographic reconstruction results and comment on how these improve upon prior reconstructions.

M. M. Bisi; B. V. Jackson; J. M. Clover; P. K. Manoharan; M. Tokumaru; P. P. Hick; A. Buffington

2009-01-01

336

3D PET image reconstruction including both motion correction and registration directly into an MR or stereotaxic spatial atlas.  

UK PubMed Central (United Kingdom)

This work explores the feasibility and impact of including both the motion correction and the image registration transformation parameters from positron emission tomography (PET) image space to magnetic resonance (MR), or stereotaxic, image space within the system matrix of PET image reconstruction. This approach is motivated by the fields of neuroscience and psychiatry, where PET is used to investigate differences in activation patterns between different groups of participants, requiring all images to be registered to a common spatial atlas. Currently, image registration is performed after image reconstruction which introduces interpolation effects into the final image. Furthermore, motion correction (also requiring registration) introduces a further level of interpolation, and the overall result of these operations can lead to resolution degradation and possibly artifacts. It is important to note that performing such operations on a post-reconstruction basis means, strictly speaking, that the final images are not ones which maximize the desired objective function (e.g. maximum likelihood (ML), or maximum a posteriori reconstruction (MAP)). To correctly seek parameter estimates in the desired spatial atlas which are in accordance with the chosen reconstruction objective function, it is necessary to include the transformation parameters for both motion correction and registration within the system modeling stage of image reconstruction. Such an approach not only respects the statistically chosen objective function (e.g. ML or MAP), but furthermore should serve to reduce the interpolation effects. To evaluate the proposed method, this work investigates registration (including motion correction) using 2D and 3D simulations based on the high resolution research tomograph (HRRT) PET scanner geometry, with and without resolution modeling, using the ML expectation maximization (MLEM) reconstruction algorithm. The quality of reconstruction was assessed using bias-variance and root mean squared error analyses, comparing the proposed method to conventional post-reconstruction registration methods. An overall reduction in bias (for a cold region: from 41% down to 31% (2D) and 97% down to 65% (3D), and for a hot region: from 11% down to 8% (2D) and from 16% down to 14% (3D)) and in root mean squared error analyses (for a cold region: from 43% to 37% (2D) and from 97% to 65% (3D), and for a hot region: from 11% to 9% (2D) and from 16% down to 14% (3D)) in reconstructed regional mean activities (full regions of interest; all with statistical significance: p < 5 × 10(-10)) is found when including the motion correction and registration in the system matrix of the MLEM reconstruction, with resolution modeling. However, this improvement in performance comes with an extra computational cost of about 40 min. In this context, this work constitutes an important step toward the goal of estimating parameters of interest directly from the raw Poisson-distributed PET data, and hence toward the complete elimination of post-processing steps.

Gravel P; Verhaeghe J; Reader AJ

2013-01-01

337

Reconstructing 3D x-ray CT images of polymer gel dosimeters using the zero-scan method  

International Nuclear Information System (INIS)

In this study x-ray CT has been used to produce a 3D image of an irradiated PAGAT gel sample, with noise-reduction achieved using the 'zero-scan' method. The gel was repeatedly CT scanned and a linear fit to the varying Hounsfield unit of each pixel in the 3D volume was evaluated across the repeated scans, allowing a zero-scan extrapolation of the image to be obtained. To minimise heating of the CT scanner's x-ray tube, this study used a large slice thickness (1 cm), to provide image slices across the irradiated region of the gel, and a relatively small number of CT scans (63), to extrapolate the zero-scan image. The resulting set of transverse images shows reduced noise compared to images from the initial CT scan of the gel, without being degraded by the additional radiation dose delivered to the gel during the repeated scanning. The full, 3D image of the gel has a low spatial resolution in the longitudinal direction, due to the selected scan parameters. Nonetheless, important features of the dose distribution are apparent in the 3D x-ray CT scan of the gel. The results of this study demonstrate that the zero-scan extrapolation method can be applied to the reconstruction of multiple x-ray CT slices, to provide useful 2D and 3D images of irradiated dosimetry gels.

2013-06-26

338

Postoperative follow-up study of craniosynostosis using three-dimensional surface reconstruction CT (3D-CT)  

International Nuclear Information System (INIS)

In 1983, Michael W. Vannier and Jeffrey L. Marsh developed a computer method that reconstructs three-dimensional images from high-resolution CT-scan series of the facial skeleton. This method has been applied to craniofacial anomalies, basal encephalocele, and other skeletal pathologies. In this study, the postoperative assessment of craniofacial surgical results has been accomplished using 3D-CT techniques in craniosynostosis. The results are as follows: 1) Postoperative 3D-CTs reveal the bony anatomical details corrected by the craniofacial surgery more precisely and more stereographically than do conventional radiological techniques. 2) Secondary changes in the cranium after the surgery, such as reossification at the area of osteotomies or postoperative asymmetric skull deformities, are more early detected by the 3D-CT imaging technique than by a craniogram. 3) In 3D-CT images, internal views of the skull, such mid-sagittal, rear internal, or top axial views of the intracranial skull base, are most useful in postoperative assessments of the surgical results and of postoperative secondary changes in the cranium. Based on our experience, we expect that 3D-CT imaging techniques will become more important in the management of craniosynostosis. (author).

1988-01-01

339

Postoperative follow-up study of craniosynostosis using three-dimensional surface reconstruction CT (3D-CT)  

Energy Technology Data Exchange (ETDEWEB)

In 1983, Michael W. Vannier and Jeffrey L. Marsh developed a computer method that reconstructs three-dimensional images from high-resolution CT-scan series of the facial skeleton. This method has been applied to craniofacial anomalies, basal encephalocele, and other skeletal pathologies. In this study, the postoperative assessment of craniofacial surgical results has been accomplished using 3D-CT techniques in craniosynostosis. The results are as follows: (1) Postoperative 3D-CTs reveal the bony anatomical details corrected by the craniofacial surgery more precisely and more stereographically than do conventional radiological techniques. (2) Secondary changes in the cranium after the surgery, such as reossification at the area of osteotomies or postoperative asymmetric skull deformities, are more early detected by the 3D-CT imaging technique than by a craniogram. (3) In 3D-CT images, internal views of the skull, such mid-sagittal, rear internal, or top axial views of the intracranial skull base, are most useful in postoperative assessments of the surgical results and of postoperative secondary changes in the cranium. Based on our experience, we expect that 3D-CT imaging techniques will become more important in the management of craniosynostosis.

Nishimoto, Hiroshi; Tsukiyama, Takashi; Nishimura, Jiro; Fujioka, Mutsuhisa; Tsubokawa, Takashi.

1988-12-01

340

3D Dose reconstruction: Banding artefacts in cine mode EPID images during VMAT delivery  

International Nuclear Information System (INIS)

Cine (continuous) mode images obtained during VMAT delivery are heavily degraded by banding artefacts. We have developed a method to reconstruct the pulse sequence (and hence dose deposited) from open field images. For clinical VMAT fields we have devised a frame averaging strategy that greatly improves image quality and dosimetric information for three-dimensional dose reconstruction.

2013-06-26

 
 
 
 
341

Dynamic 3D Scene Depth Reconstruction via Optical Flow Field Rectification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we propose a depth propagation scheme based on optical flow field rectification towards more accurate depth reconstruction. In depth reconstruction, the occlusions and low-textural regions easily result in optical flow field errors, which lead ambiguous depth value or holes without de...

Yang, You; Liu, Qiong; Ji, Rongrong; Gao, Yue

342

Motion compensated digital tomosynthesis.  

UK PubMed Central (United Kingdom)

BACKGROUND AND PURPOSE: Digital tomosynthesis (DTS) is a limited angle image reconstruction method for cone beam projections that offers patient surveillance capabilities during VMAT based SBRT delivery. Motion compensation (MC) has the potential to mitigate motion artifacts caused by respiratory motion, such as blur. The purpose of this feasibility study was therefore to develop and evaluate motion-compensated DTS (MC-DTS). MATERIAL AND METHODS: MC-DTS images were reconstructed by back projection of X-ray projection images acquired over 30° arcs. Back projection lines were deformed according to an a priori motion model derived from the 4D planning CT. MC-DTS was evaluated on a respiratory motion phantom and 3 lung cancer patients. Respiratory artifact reduction was assessed visually and quantified by fitting a cumulative Gaussian function to profiles along the background-GTV transition in the CC direction. RESULTS: MC reconstruction was fast enough to keep up with image acquisition and considerably reduced motion blur visually. Quantitatively, MC reduced the background-GTV transition distance by 49%. CONCLUSION: Motion compensation considerably improved the image quality of DTS images of lung cancer patients, giving an opportunity for more accurate DTS guidance and intra-fraction monitoring concurrent with VMAT delivery.

van der Reijden A; van Herk M; Sonke JJ

2013-10-01

343

A simple way to reconstruct a human 3-d hypodermis: a useful tool for pharmacological functionality.  

UK PubMed Central (United Kingdom)

BACKGROUND: Adipose tissue engineering has been hampered by the inability to culture mature adipocytes. Adipose-derived stem cell (ASC) culture opens the way for the preparation of human 3-D hypodermis in large quantities. These models play a role in obesity-related active molecules and slimming agent screening. Moreover, they contribute to a better understanding of the mechanisms underpinning obesity. MATERIALS AND METHODS: Freshly extracted ASC from fat tissue were characterized by flow cytometry for CD73, CD90, CD105, HLA-ABC, CD14 and CD45 markers and by Western blot for pref-1. Their differentiation in mature adipocytes was followed by lipid and adiponectin secretion or by oil red O staining and radioimmunoassay. Neosynthesized extracellular matrix (ECM) of 3-D hypodermis was investigated by immunohistochemistry (collagen type I, V and VI) and transmission electron microscopy. RESULTS: Our results demonstrate that the culture of preadipocytes in proliferation medium for 15 days followed by 16 days of culture in differentiation medium allowed production of the thickest single-layer hypodermis in which preadipocytes and mature adipocytes coexist and synthesize adiponectin and ECM components. Functionality of our 3-D single-layer hypodermis was demonstrated both by a 3.5-fold glycerol production after its stimulation with norepinephrine (adrenergic agonist) and by its slimming after caffeine treatment versus the nontreated 3-D hypodermis. CONCLUSION: This economic 3-D model, easy to prepare and giving reproducible results after the treatment of actives, is useful for pharmacotoxicological trials as an alternative to animal experimentation.

Lequeux C; Auxenfans C; Thépot A; Géloën A; André V; Damour O; Mojallal A

2012-01-01

344

Assessment of landmark measurements of craniofacial images from 2D and 3D reconstructions of spiral CT  

Science.gov (United States)

Purpose: The purpose of this study is to compare the accuracy of facial linear measurements obtained from volumetric spiral CT using 2D versus 3D reconstruction, and test the repeatability of these measurements. Material and Methods: The population consisted of 5 cadaver heads that were scanned to a Spiral CT scanner (120 Kvp and 200 mA, Toshiba Xpress S/X Toshiba-America, Medical System Inc., Tustin, CA) with high- resolution contiguous slices. Heads were scanned with 3 mm thick axial slices and a 2 mm/sec table feed. The CT data were archived on optical disks, and then transferred to a networked computer workstation (Sun Microsystems with Cemax version 1.4 software, Fremont, CA), to generate 2D and 3D images for manipulation and analyses. Repeated measurements were done on 2D and 3D images reconstructed from spiral CT scans on the workstation. Linear measurements were done by 2 observers with 2 sessions each, using several unique and conventional craniometric anatomic landmarks. The soft tissues were then partially removed and physical measurements of the same landmarks were repeated by an electromagnetic (3 space) digitizer (Polhemus Navigation Sciences Division, Mc Donnell Douglas Electronic Company, Colchester, VE). Analyses of variance were done to compare 2D versus 3D methods, and the accuracy of measurements between both imaging techniques. Results: The results showed statistically significant differences between 2D and 3D images for the majority of measurements. The 3D image measurements were not statistically different from the physical measurements. However, some of the 2D image landmarks differed from physical measurements. The repeatability of measurements was high by spiral CT-based craniofacial imaging. Conclusion: New computer graphics technology combined with 3D volumetric imaging by spiral CT can distinguish the craniofacial anatomy with greater accuracy than previously reported measurements and with greater accuracy than measurements from 2DCT images. These 3D measurements are essential to diagnostic and treatment planning of craniofacial injuries, anomalies and for craniofacial identification.

Cavalcanti, Marcelo G.; Haller, John W.; Vannier, Michael W.

1998-06-01

345

Program package for accurate 3D field reconstruction from boundary measurements  

CERN Multimedia

The problem of the magnetic field reconstruction inside a subregion in R sup 3 from magnetic measurements on the closed boundary of this subregion is considered. The efficiency of the proposed method, algorithm and associated software for the precision magnet system is discussed. The results of the software verification, numerical experiments as well as the ones of the field reconstruction using boundary measurements in the magnet M1 of the separator COMBAS are given. Requirements to the position accuracy of sensors consistent with the required accuracy of the magnetic field reconstruction are defined. Recommendations on the magnetic scheme design for the field mapping are given.

Artyukh, A G; Belyakova, T V

2002-01-01

346

Program Package for Accurate 3D Field Reconstruction from Boundary Measurements  

CERN Multimedia

The problem of magnetic field reconstruction inside a sub-region in R^3 from magnetic measurements on the closed boundary of this subregion is considered. Efficiency of the proposed method, algorithm and associated software for precision magnet system is discussed. The results of the software verification, numerical experiments as well as th