WorldWideScience

Sample records for high image quality

  1. High-quality compressive ghost imaging

    Science.gov (United States)

    Huang, Heyan; Zhou, Cheng; Tian, Tian; Liu, Dongqi; Song, Lijun

    2018-04-01

    We propose a high-quality compressive ghost imaging method based on projected Landweber regularization and guided filter, which effectively reduce the undersampling noise and improve the resolution. In our scheme, the original object is reconstructed by decomposing of regularization and denoising steps instead of solving a minimization problem in compressive reconstruction process. The simulation and experimental results show that our method can obtain high ghost imaging quality in terms of PSNR and visual observation.

  2. Image Quality in High-resolution and High-cadence Solar Imaging

    Science.gov (United States)

    Denker, C.; Dineva, E.; Balthasar, H.; Verma, M.; Kuckein, C.; Diercke, A.; González Manrique, S. J.

    2018-03-01

    Broad-band imaging and even imaging with a moderate bandpass (about 1 nm) provides a photon-rich environment, where frame selection (lucky imaging) becomes a helpful tool in image restoration, allowing us to perform a cost-benefit analysis on how to design observing sequences for imaging with high spatial resolution in combination with real-time correction provided by an adaptive optics (AO) system. This study presents high-cadence (160 Hz) G-band and blue continuum image sequences obtained with the High-resolution Fast Imager (HiFI) at the 1.5-meter GREGOR solar telescope, where the speckle-masking technique is used to restore images with nearly diffraction-limited resolution. The HiFI employs two synchronized large-format and high-cadence sCMOS detectors. The median filter gradient similarity (MFGS) image-quality metric is applied, among others, to AO-corrected image sequences of a pore and a small sunspot observed on 2017 June 4 and 5. A small region of interest, which was selected for fast-imaging performance, covered these contrast-rich features and their neighborhood, which were part of Active Region NOAA 12661. Modifications of the MFGS algorithm uncover the field- and structure-dependency of this image-quality metric. However, MFGS still remains a good choice for determining image quality without a priori knowledge, which is an important characteristic when classifying the huge number of high-resolution images contained in data archives. In addition, this investigation demonstrates that a fast cadence and millisecond exposure times are still insufficient to reach the coherence time of daytime seeing. Nonetheless, the analysis shows that data acquisition rates exceeding 50 Hz are required to capture a substantial fraction of the best seeing moments, significantly boosting the performance of post-facto image restoration.

  3. CCD Astrophotography High-Quality Imaging from the Suburbs

    CERN Document Server

    Stuart, Adam

    2006-01-01

    This is a reference book for amateur astronomers who have become interested in CCD imaging. Those glorious astronomical images found in astronomy magazines might seem out of reach to newcomers to CCD imaging, but this is not the case. Great pictures are attainable with modest equipment. Adam Stuart’s many beautiful images, reproduced in this book, attest to the quality of – initially – a beginner’s efforts. Chilled-chip astronomical CCD-cameras and software are also wonderful tools for cutting through seemingly impenetrable light-pollution. CCD Astrophotography from the Suburbs describes one man’s successful approach to the problem of getting high-quality astronomical images under some of the most light-polluted conditions. Here is a complete and thoroughly tested program that will help every CCD-beginner to work towards digital imaging of the highest quality. It is equally useful to astronomers who have perfect observing conditions, as to those who have to observe from light-polluted city skies.

  4. Improving high resolution retinal image quality using speckle illumination HiLo imaging.

    Science.gov (United States)

    Zhou, Xiaolin; Bedggood, Phillip; Metha, Andrew

    2014-08-01

    Retinal image quality from flood illumination adaptive optics (AO) ophthalmoscopes is adversely affected by out-of-focus light scatter due to the lack of confocality. This effect is more pronounced in small eyes, such as that of rodents, because the requisite high optical power confers a large dioptric thickness to the retina. A recently-developed structured illumination microscopy (SIM) technique called HiLo imaging has been shown to reduce the effect of out-of-focus light scatter in flood illumination microscopes and produce pseudo-confocal images with significantly improved image quality. In this work, we adopted the HiLo technique to a flood AO ophthalmoscope and performed AO imaging in both (physical) model and live rat eyes. The improvement in image quality from HiLo imaging is shown both qualitatively and quantitatively by using spatial spectral analysis.

  5. Real-time computer treatment of THz passive device images with the high image quality

    Science.gov (United States)

    Trofimov, Vyacheslav A.; Trofimov, Vladislav V.

    2012-06-01

    We demonstrate real-time computer code improving significantly the quality of images captured by the passive THz imaging system. The code is not only designed for a THz passive device: it can be applied to any kind of such devices and active THz imaging systems as well. We applied our code for computer processing of images captured by four passive THz imaging devices manufactured by different companies. It should be stressed that computer processing of images produced by different companies requires using the different spatial filters usually. The performance of current version of the computer code is greater than one image per second for a THz image having more than 5000 pixels and 24 bit number representation. Processing of THz single image produces about 20 images simultaneously corresponding to various spatial filters. The computer code allows increasing the number of pixels for processed images without noticeable reduction of image quality. The performance of the computer code can be increased many times using parallel algorithms for processing the image. We develop original spatial filters which allow one to see objects with sizes less than 2 cm. The imagery is produced by passive THz imaging devices which captured the images of objects hidden under opaque clothes. For images with high noise we develop an approach which results in suppression of the noise after using the computer processing and we obtain the good quality image. With the aim of illustrating the efficiency of the developed approach we demonstrate the detection of the liquid explosive, ordinary explosive, knife, pistol, metal plate, CD, ceramics, chocolate and other objects hidden under opaque clothes. The results demonstrate the high efficiency of our approach for the detection of hidden objects and they are a very promising solution for the security problem.

  6. High-quality remote interactive imaging in the operating theatre

    Science.gov (United States)

    Grimstead, Ian J.; Avis, Nick J.; Evans, Peter L.; Bocca, Alan

    2009-02-01

    We present a high-quality display system that enables the remote access within an operating theatre of high-end medical imaging and surgical planning software. Currently, surgeons often use printouts from such software for reference during surgery; our system enables surgeons to access and review patient data in a sterile environment, viewing real-time renderings of MRI & CT data as required. Once calibrated, our system displays shades of grey in Operating Room lighting conditions (removing any gamma correction artefacts). Our system does not require any expensive display hardware, is unobtrusive to the remote workstation and works with any application without requiring additional software licenses. To extend the native 256 levels of grey supported by a standard LCD monitor, we have used the concept of "PseudoGrey" where slightly off-white shades of grey are used to extend the intensity range from 256 to 1,785 shades of grey. Remote access is facilitated by a customized version of UltraVNC, which corrects remote shades of grey for display in the Operating Room. The system is successfully deployed at Morriston Hospital, Swansea, UK, and is in daily use during Maxillofacial surgery. More formal user trials and quantitative assessments are being planned for the future.

  7. High image quality sub 100 picosecond gated framing camera development

    International Nuclear Information System (INIS)

    Price, R.H.; Wiedwald, J.D.

    1983-01-01

    A major challenge for laser fusion is the study of the symmetry and hydrodynamic stability of imploding fuel capsules. Framed x-radiographs of 10-100 ps duration, excellent image quality, minimum geometrical distortion (< 1%), dynamic range greater than 1000, and more than 200 x 200 pixels are required for this application. Recent progress on a gated proximity focused intensifier which meets these requirements is presented

  8. Image Quality Assessment of High-Resolution Satellite Images with Mtf-Based Fuzzy Comprehensive Evaluation Method

    Science.gov (United States)

    Wu, Z.; Luo, Z.; Zhang, Y.; Guo, F.; He, L.

    2018-04-01

    A Modulation Transfer Function (MTF)-based fuzzy comprehensive evaluation method was proposed in this paper for the purpose of evaluating high-resolution satellite image quality. To establish the factor set, two MTF features and seven radiant features were extracted from the knife-edge region of image patch, which included Nyquist, MTF0.5, entropy, peak signal to noise ratio (PSNR), average difference, edge intensity, average gradient, contrast and ground spatial distance (GSD). After analyzing the statistical distribution of above features, a fuzzy evaluation threshold table and fuzzy evaluation membership functions was established. The experiments for comprehensive quality assessment of different natural and artificial objects was done with GF2 image patches. The results showed that the calibration field image has the highest quality scores. The water image has closest image quality to the calibration field, quality of building image is a little poor than water image, but much higher than farmland image. In order to test the influence of different features on quality evaluation, the experiment with different weights were tested on GF2 and SPOT7 images. The results showed that different weights correspond different evaluating effectiveness. In the case of setting up the weights of edge features and GSD, the image quality of GF2 is better than SPOT7. However, when setting MTF and PSNR as main factor, the image quality of SPOT7 is better than GF2.

  9. Improvement of the image quality of a high-temperature vision system

    International Nuclear Information System (INIS)

    Fabijańska, Anna; Sankowski, Dominik

    2009-01-01

    In this paper, the issues of controlling and improving the image quality of a high-temperature vision system are considered. The image quality improvement is needed to measure the surface properties of metals and alloys. Two levels of image quality control and improvement are defined in the system. The first level in hardware aims at adjusting the system configuration to obtain the highest contrast and weakest aura images. When optimal configuration is obtained, the second level in software is applied. In this stage, image enhancement algorithms are applied which have been developed with consideration of distortions arising from the vision system components and specificity of images acquired during the measurement process. The developed algorithms have been applied in the vision system to images. The influence on the accuracy of wetting angles and surface tension determination are considered

  10. Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner

    OpenAIRE

    Kakinuma, Ryutaro; Moriyama, Noriyuki; Muramatsu, Yukio; Gomi, Shiho; Suzuki, Masahiro; Nagasawa, Hirobumi; Kusumoto, Masahiko; Aso, Tomohiko; Muramatsu, Yoshihisa; Tsuchida, Takaaki; Tsuta, Koji; Maeshima, Akiko Miyagi; Tochigi, Naobumi; Watanabe, Shun-ichi; Sugihara, Naoki

    2015-01-01

    Purpose: The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods: This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm × 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm × 16 or 0.5 mm × 64 detector-row CT scanner operating at 150 mAs. Images fr...

  11. An Ex Vivo Imaging Pipeline for Producing High- Quality and High-Resolution Diffusion-Weighted Imaging Datasets

    DEFF Research Database (Denmark)

    Dyrby, Tim Bjørn; Baaré, William F.C.; Alexander, Daniel C.

    2011-01-01

    Diffusion tensor (DT) imaging and related multifiber reconstruction algorithms allow the study of in vivo microstructure and, by means of tractography, structural connectivity. Although reconstruction algorithms are promising imaging tools, high‐quality diffusion‐weighted imaging (DWI) datasets...... complexity, to establish an ex vivo imaging pipeline for generating high‐quality DWI datasets. Perfusion fixation ensured that tissue characteristics were comparable to in vivo conditions. There were three main results: (i) heat conduction and unstable tissue mechanics accounted for time‐varying artefacts...... in the DWI dataset, which were present for up to 15 h after positioning brain tissue in the scanner; (ii) using fitted DT, q‐ball, and persistent angular structure magnetic resonance imaging algorithms, any b‐value between ∼2,000 and ∼8,000 s/mm2, with an optimal value around 4,000 s/mm2, allowed...

  12. Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner

    Science.gov (United States)

    Kakinuma, Ryutaro; Moriyama, Noriyuki; Muramatsu, Yukio; Gomi, Shiho; Suzuki, Masahiro; Nagasawa, Hirobumi; Kusumoto, Masahiko; Aso, Tomohiko; Muramatsu, Yoshihisa; Tsuchida, Takaaki; Tsuta, Koji; Maeshima, Akiko Miyagi; Tochigi, Naobumi; Watanabe, Shun-ichi; Sugihara, Naoki; Tsukagoshi, Shinsuke; Saito, Yasuo; Kazama, Masahiro; Ashizawa, Kazuto; Awai, Kazuo; Honda, Osamu; Ishikawa, Hiroyuki; Koizumi, Naoya; Komoto, Daisuke; Moriya, Hiroshi; Oda, Seitaro; Oshiro, Yasuji; Yanagawa, Masahiro; Tomiyama, Noriyuki; Asamura, Hisao

    2015-01-01

    Purpose The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner. Results The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU]) was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001). The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001) for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures. Conclusion Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners. PMID:26352144

  13. Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner.

    Directory of Open Access Journals (Sweden)

    Ryutaro Kakinuma

    Full Text Available The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT scanners.This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from both scanners were reconstructed at 0.1-mm intervals; the slice thickness was 0.25 mm for the U-HRCT scanner and 0.5 mm for the C-HRCT scanners. For both scanners, the display field of view was 80 mm. The image noise of each scanner was evaluated using a phantom. U-HRCT and C-HRCT images of 53 images selected from 37 lung nodules were then observed and graded using a 5-point score by 10 board-certified thoracic radiologists. The images were presented to the observers randomly and in a blinded manner.The image noise for U-HRCT (100.87 ± 0.51 Hounsfield units [HU] was greater than that for C-HRCT (40.41 ± 0.52 HU; P < .0001. The image quality of U-HRCT was graded as superior to that of C-HRCT (P < .0001 for all of the following parameters that were examined: margins of subsolid and solid nodules, edges of solid components and pulmonary vessels in subsolid nodules, air bronchograms, pleural indentations, margins of pulmonary vessels, edges of bronchi, and interlobar fissures.Despite a larger image noise, the prototype U-HRCT scanner had a significantly better image quality than the C-HRCT scanners.

  14. 3D conditional generative adversarial networks for high-quality PET image estimation at low dose.

    Science.gov (United States)

    Wang, Yan; Yu, Biting; Wang, Lei; Zu, Chen; Lalush, David S; Lin, Weili; Wu, Xi; Zhou, Jiliu; Shen, Dinggang; Zhou, Luping

    2018-07-01

    Positron emission tomography (PET) is a widely used imaging modality, providing insight into both the biochemical and physiological processes of human body. Usually, a full dose radioactive tracer is required to obtain high-quality PET images for clinical needs. This inevitably raises concerns about potential health hazards. On the other hand, dose reduction may cause the increased noise in the reconstructed PET images, which impacts the image quality to a certain extent. In this paper, in order to reduce the radiation exposure while maintaining the high quality of PET images, we propose a novel method based on 3D conditional generative adversarial networks (3D c-GANs) to estimate the high-quality full-dose PET images from low-dose ones. Generative adversarial networks (GANs) include a generator network and a discriminator network which are trained simultaneously with the goal of one beating the other. Similar to GANs, in the proposed 3D c-GANs, we condition the model on an input low-dose PET image and generate a corresponding output full-dose PET image. Specifically, to render the same underlying information between the low-dose and full-dose PET images, a 3D U-net-like deep architecture which can combine hierarchical features by using skip connection is designed as the generator network to synthesize the full-dose image. In order to guarantee the synthesized PET image to be close to the real one, we take into account of the estimation error loss in addition to the discriminator feedback to train the generator network. Furthermore, a concatenated 3D c-GANs based progressive refinement scheme is also proposed to further improve the quality of estimated images. Validation was done on a real human brain dataset including both the normal subjects and the subjects diagnosed as mild cognitive impairment (MCI). Experimental results show that our proposed 3D c-GANs method outperforms the benchmark methods and achieves much better performance than the state

  15. Adoption of high technology medical imaging and hospital quality and efficiency: Towards a conceptual framework.

    Science.gov (United States)

    Sandoval, Guillermo A; Brown, Adalsteinn D; Wodchis, Walter P; Anderson, Geoffrey M

    2018-05-17

    Measuring the value of medical imaging is challenging, in part, due to the lack of conceptual frameworks underlying potential mechanisms where value may be assessed. To address this gap, this article proposes a framework that builds on the large body of literature on quality of hospital care and the classic structure-process-outcome paradigm. The framework was also informed by the literature on adoption of technological innovations and introduces 2 distinct though related aspects of imaging technology not previously addressed specifically in the literature on quality of hospital care: adoption (a structural hospital characteristic) and use (an attribute of the process of care). The framework hypothesizes a 2-part causality where adoption is proposed to be a central, linking factor between hospital structural characteristics, market factors, and hospital outcomes (ie, quality and efficiency). The first part indicates that hospital structural characteristics and market factors influence or facilitate the adoption of high technology medical imaging within an institution. The presence of this technology, in turn, is hypothesized to improve the ability of the hospital to deliver high quality and efficient care. The second part describes this ability throughout 3 main mechanisms pointing to the importance of imaging use on patients, to the presence of staff and qualified care providers, and to some elements of organizational capacity capturing an enhanced clinical environment. The framework has the potential to assist empirical investigations of the value of adoption and use of medical imaging, and to advance understanding of the mechanisms that produce quality and efficiency in hospitals. Copyright © 2018 John Wiley & Sons, Ltd.

  16. Telemedicine + OCT: toward design of optimized algorithms for high-quality compressed images

    Science.gov (United States)

    Mousavi, Mahta; Lurie, Kristen; Land, Julian; Javidi, Tara; Ellerbee, Audrey K.

    2014-03-01

    Telemedicine is an emerging technology that aims to provide clinical healthcare at a distance. Among its goals, the transfer of diagnostic images over telecommunication channels has been quite appealing to the medical community. When viewed as an adjunct to biomedical device hardware, one highly important consideration aside from the transfer rate and speed is the accuracy of the reconstructed image at the receiver end. Although optical coherence tomography (OCT) is an established imaging technique that is ripe for telemedicine, the effects of OCT data compression, which may be necessary on certain telemedicine platforms, have not received much attention in the literature. We investigate the performance and efficiency of several lossless and lossy compression techniques for OCT data and characterize their effectiveness with respect to achievable compression ratio, compression rate and preservation of image quality. We examine the effects of compression in the interferogram vs. A-scan domain as assessed with various objective and subjective metrics.

  17. High-volume image quality assessment systems: tuning performance with an interactive data visualization tool

    Science.gov (United States)

    Bresnahan, Patricia A.; Pukinskis, Madeleine; Wiggins, Michael

    1999-03-01

    Image quality assessment systems differ greatly with respect to the number and types of mags they need to evaluate, and their overall architectures. Managers of these systems, however, all need to be able to tune and evaluate system performance, requirements often overlooked or under-designed during project planning. Performance tuning tools allow users to define acceptable quality standards for image features and attributes by adjusting parameter settings. Performance analysis tools allow users to evaluate and/or predict how well a system performs in a given parameter state. While image assessment algorithms are becoming quite sophisticated, duplicating or surpassing the human decision making process in their speed and reliability, they often require a greater investment in 'training' or fine tuning of parameters in order to achieve optimum performance. This process may involve the analysis of hundreds or thousands of images, generating a large database of files and statistics that can be difficult to sort through and interpret. Compounding the difficulty is the fact that personnel charged with tuning and maintaining the production system may not have the statistical or analytical background required for the task. Meanwhile, hardware innovations have greatly increased the volume of images that can be handled in a given time frame, magnifying the consequences of running a production site with an inadequately tuned system. In this paper, some general requirements for a performance evaluation and tuning data visualization system are discussed. A custom engineered solution to the tuning and evaluation problem is then presented, developed within the context of a high volume image quality assessment, data entry, OCR, and image archival system. A key factor influencing the design of the system was the context-dependent definition of image quality, as perceived by a human interpreter. This led to the development of a five-level, hierarchical approach to image quality

  18. Air-insufflated high-definition dacryoendoscopy yields significantly better image quality than conventional dacryoendoscopy

    Directory of Open Access Journals (Sweden)

    Sasaki T

    2017-08-01

    Full Text Available Tsugihisa Sasaki,1 Tsutomu Sounou,2 Hideki Tsuji,3 Kazuhisa Sugiyama4 1Sasaki Eye Clinic, Mikuni, Sakai, 2Department of Ophthalmology, Keiju Kanazawa Hospital, 3Department of Ophthalmology, Cancer Institute Hospital, 4Department of Ophthalmology and Visual Science, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan Purpose: To facilitate the analysis of lacrimal conditions, we utilized high-definition dacryoendoscopy (HDD and undertook observations with a pressure-controlled air-insufflation system. We report the safety and performance of HDD.Methods: In this retrospective, non-randomized clinical trial, 46 patients (14 males and 32 females; age range 39–91 years; mean age ± SD 70.3±12.0 years who had lacrimal disorders were examined with HDD and conventional dacryoendoscopy (CD. The high-definition dacryoendoscope had 15,000 picture element image fibers and an advanced objective lens. Its outer diameter was 0.9–1.2 mm. Air insufflation was controlled at 0–20 kPa with a digital manometer-based pressure-controlled air-insufflation system to evaluate the quality of the image. The HDD had an air/saline irrigation channel between the outer sheath (outer diameter =1.2 mm and the metal inner sheath of the endoscope. We used it and the CD in air, saline, and diluted milk saline with and without manual irrigation to quantitatively evaluate the effect of air pressure and saline irrigation on image quality.Results: In vivo, the most significant improvement in image quality was demonstrated with air-insufflated (5–15 kPa HDD, as compared with saline-irrigated HDD and saline-irrigated CD. No emphysema or damage was noted under observation with HDD. In vitro, no significant difference was demonstrated between air-insufflated HDD and saline-irrigated HDD. In vitro, the image quality of air-insufflated HDD was significantly improved as compared with that of saline-irrigated CD.Conclusion: Pressure-controlled (5–15 kPa air

  19. Task-based statistical image reconstruction for high-quality cone-beam CT

    Science.gov (United States)

    Dang, Hao; Webster Stayman, J.; Xu, Jennifer; Zbijewski, Wojciech; Sisniega, Alejandro; Mow, Michael; Wang, Xiaohui; Foos, David H.; Aygun, Nafi; Koliatsos, Vassilis E.; Siewerdsen, Jeffrey H.

    2017-11-01

    promising regularization method in MBIR by explicitly incorporating task-based imaging performance as the objective. The results demonstrate improved ICH conspicuity and support the development of high-quality CBCT systems.

  20. Comparison of the image quality between volumetric and conventional high-resolution CT with 64-slice row CT

    International Nuclear Information System (INIS)

    Gao Yanli; Zhang Lei; Zhao Xia; Ma Min; Zhai Renyou

    2008-01-01

    Objective: To compare the image quality between volumetric high-resolution CT (VHRCT) and conventional high-resolution CT (CHRCT), and investigate the feasibility of VHRCT. Methods: Catphan 412 phantom was scanned with protocols of CHRCT and VHRCT on a set of GE Lightspeed VCT. The spatial-resolution (LP/cm), noise (standard deviation in an ROI) and radiation close (CTDI) were recorded for each CT scan. Difference of noise between CHRCT and VHRCT were evaluated by paired t test. In clinical study, 32 patients were scanned with VHRCT and CHRCT protocols. The image quality of CHRCT and VHRCT was rated and compared. The quality difference between CHRCT and VHRCT was assessed by Wilcoxon paired signed rank sum test. Results: In phantom study, the in-plane spatial-resolution of both VHRCT and CHRCT was 11 LP/cm for axial images and 12 LP/cm for coronal reformatted images. The noise of VHRCT and CHRCT was (69.18±2.77)HU and (54.62±2.12) HU respectively (t=-15.929, P 0.05). The quality assessment scores of VHRCT coronal reformatted images and CHRCT coronal reformatted images were 3.05 and 1.88 respectively with significant difference (Z= -5.088, P<0.01). Conclusion: The image quality of VHRCT cross-sectional image is similar to that of CHRCT. Multiplanar images with high resolution of VHRCT are recommended. The radiation dose of VHRCT remains to be optimized. (authors)

  1. Imaging Food Quality

    DEFF Research Database (Denmark)

    Møller, Flemming

    Imaging and spectroscopy have long been established methods for food quality control both in the laboratories and online. An ever increasing number of analytical techniques are being developed into imaging methods and existing imaging methods to contain spectral information. Images and especially...... spectral images contain large amounts of data which should be analysed appropriately by techniques combining structure and spectral information. This dissertation deals with how different types of food quality can be measured by imaging techniques, analysed with appropriate image analysis techniques...... and finally use the image data to predict or visualise food quality. A range of different food quality parameters was addressed, i.e. water distribution in bread throughout storage, time series analysis of chocolate milk stability, yoghurt glossiness, graininess and dullness and finally structure and meat...

  2. Comparison of dose and image quality in protocols abdominal CT using high an low KVP

    International Nuclear Information System (INIS)

    Mas Munoz, I.; Alejo Luque, L.; Corredoira Silva, E.; Sanchez Munoz, F. J.; Serrada Hierro, A.

    2013-01-01

    This paper compares quantitatively low kV Protocol with the conventional Protocol of abdomen, analysing the image quality with objective physical parameters and calculating the corresponding dummy dose reduction. (Author)

  3. Social image quality

    Science.gov (United States)

    Qiu, Guoping; Kheiri, Ahmed

    2011-01-01

    Current subjective image quality assessments have been developed in the laboratory environments, under controlledconditions, and are dependent on the participation of limited numbers of observers. In this research, with the help of Web 2.0 and social media technology, a new method for building a subjective image quality metric has been developed where the observers are the Internet users. A website with a simple user interface that enables Internet users from anywhere at any time to vote for a better quality version of a pair of the same image has been constructed. Users' votes are recorded and used to rank the images according to their perceived visual qualities. We have developed three rank aggregation algorithms to process the recorded pair comparison data, the first uses a naive approach, the second employs a Condorcet method, and the third uses the Dykstra's extension of Bradley-Terry method. The website has been collecting data for about three months and has accumulated over 10,000 votes at the time of writing this paper. Results show that the Internet and its allied technologies such as crowdsourcing offer a promising new paradigm for image and video quality assessment where hundreds of thousands of Internet users can contribute to building more robust image quality metrics. We have made Internet user generated social image quality (SIQ) data of a public image database available online (http://www.hdri.cs.nott.ac.uk/siq/) to provide the image quality research community with a new source of ground truth data. The website continues to collect votes and will include more public image databases and will also be extended to include videos to collect social video quality (SVQ) data. All data will be public available on the website in due course.

  4. High-Quality T2-Weighted 4-Dimensional Magnetic Resonance Imaging for Radiation Therapy Applications

    Energy Technology Data Exchange (ETDEWEB)

    Du, Dongsu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Caruthers, Shelton D. [Philips Healthcare, Cleveland, Ohio (United States); Glide-Hurst, Carri [Department of Radiation Oncology, Henry Ford Health System, Detroit, Michigan (United States); Low, Daniel A. [Department of Radiation Oncology, University of California-Los Angeles, Los Angeles, California (United States); Li, H. Harold; Mutic, Sasa [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Hu, Yanle, E-mail: Hu.Yanle@mayo.edu [Department of Radiation Oncology, Washington University School of Medicine, Saint Louis, Missouri (United States); Department of Radiation Oncology, Mayo Clinic in Arizona, Phoenix, Arizona (United States)

    2015-06-01

    Purpose: The purpose of this study was to improve triggering efficiency of the prospective respiratory amplitude-triggered 4-dimensional magnetic resonance imaging (4DMRI) method and to develop a 4DMRI imaging protocol that could offer T2 weighting for better tumor visualization, good spatial coverage and spatial resolution, and respiratory motion sampling within a reasonable amount of time for radiation therapy applications. Methods and Materials: The respiratory state splitting (RSS) and multi-shot acquisition (MSA) methods were analytically compared and validated in a simulation study by using the respiratory signals from 10 healthy human subjects. The RSS method was more effective in improving triggering efficiency. It was implemented in prospective respiratory amplitude-triggered 4DMRI. 4DMRI image datasets were acquired from 5 healthy human subjects. Liver motion was estimated using the acquired 4DMRI image datasets. Results: The simulation study showed the RSS method was more effective for improving triggering efficiency than the MSA method. The average reductions in 4DMRI acquisition times were 36% and 10% for the RSS and MSA methods, respectively. The human subject study showed that T2-weighted 4DMRI with 10 respiratory states, 60 slices at a spatial resolution of 1.5 × 1.5 × 3.0 mm{sup 3} could be acquired in 9 to 18 minutes, depending on the individual's breath pattern. Based on the acquired 4DMRI image datasets, the ranges of peak-to-peak liver displacements among 5 human subjects were 9.0 to 12.9 mm, 2.5 to 3.9 mm, and 0.5 to 2.3 mm in superior-inferior, anterior-posterior, and left-right directions, respectively. Conclusions: We demonstrated that with the RSS method, it was feasible to acquire high-quality T2-weighted 4DMRI within a reasonable amount of time for radiation therapy applications.

  5. Retinal image quality during accommodation.

    Science.gov (United States)

    López-Gil, Norberto; Martin, Jesson; Liu, Tao; Bradley, Arthur; Díaz-Muñoz, David; Thibos, Larry N

    2013-07-01

    We asked if retinal image quality is maximum during accommodation, or sub-optimal due to accommodative error, when subjects perform an acuity task. Subjects viewed a monochromatic (552 nm), high-contrast letter target placed at various viewing distances. Wavefront aberrations of the accommodating eye were measured near the endpoint of an acuity staircase paradigm. Refractive state, defined as the optimum target vergence for maximising retinal image quality, was computed by through-focus wavefront analysis to find the power of the virtual correcting lens that maximizes visual Strehl ratio. Despite changes in ocular aberrations and pupil size during binocular viewing, retinal image quality and visual acuity typically remain high for all target vergences. When accommodative errors lead to sub-optimal retinal image quality, acuity and measured image quality both decline. However, the effect of accommodation errors of on visual acuity are mitigated by pupillary constriction associated with accommodation and binocular convergence and also to binocular summation of dissimilar retinal image blur. Under monocular viewing conditions some subjects displayed significant accommodative lag that reduced visual performance, an effect that was exacerbated by pharmacological dilation of the pupil. Spurious measurement of accommodative error can be avoided when the image quality metric used to determine refractive state is compatible with the focusing criteria used by the visual system to control accommodation. Real focusing errors of the accommodating eye do not necessarily produce a reliably measurable loss of image quality or clinically significant loss of visual performance, probably because of increased depth-of-focus due to pupil constriction. When retinal image quality is close to maximum achievable (given the eye's higher-order aberrations), acuity is also near maximum. A combination of accommodative lag, reduced image quality, and reduced visual function may be a useful

  6. High-quality and small-capacity e-learning video featuring lecturer-superimposing PC screen images

    Science.gov (United States)

    Nomura, Yoshihiko; Murakami, Michinobu; Sakamoto, Ryota; Sugiura, Tokuhiro; Matsui, Hirokazu; Kato, Norihiko

    2006-10-01

    Information processing and communication technology are progressing quickly, and are prevailing throughout various technological fields. Therefore, the development of such technology should respond to the needs for improvement of quality in the e-learning education system. The authors propose a new video-image compression processing system that ingeniously employs the features of the lecturing scene. While dynamic lecturing scene is shot by a digital video camera, screen images are electronically stored by a PC screen image capturing software in relatively long period at a practical class. Then, a lecturer and a lecture stick are extracted from the digital video images by pattern recognition techniques, and the extracted images are superimposed on the appropriate PC screen images by off-line processing. Thus, we have succeeded to create a high-quality and small-capacity (HQ/SC) video-on-demand educational content featuring the advantages: the high quality of image sharpness, the small electronic file capacity, and the realistic lecturer motion.

  7. Image quality in mammography

    International Nuclear Information System (INIS)

    Haus, A.G.; Doi, K.; Metz, C.E.; Bernstein, J.

    1976-01-01

    In mammography, image quality is a function of the shape, size, and x-ray absorption properties of the anatomic part to be radiographed and of the lesion to be detected; it also depends on geometric unsharpness, and the resolution, characteristic curve and noise properties of the recording system. X-ray energy spectra, modulation transfer functions, Wiener spectra, characteristic and gradient curves, and radiographs of a breast phantom and of a resected breast specimen containing microcalcifications are used in a review of some current considerations of the factors, and the complex relationship among factors, that affect image quality in mammography. Image quality and patient radiation exposure in mammography are interrelated. An approach to the problem of evaluating the trade-off between diagnostic certainty and the cost or risk of performing a breast imaging procedure is discussed

  8. Design and image-quality performance of high resolution CMOS-based X-ray imaging detectors for digital mammography

    Science.gov (United States)

    Cha, B. K.; Kim, J. Y.; Kim, Y. J.; Yun, S.; Cho, G.; Kim, H. K.; Seo, C.-W.; Jeon, S.; Huh, Y.

    2012-04-01

    In digital X-ray imaging systems, X-ray imaging detectors based on scintillating screens with electronic devices such as charge-coupled devices (CCDs), thin-film transistors (TFT), complementary metal oxide semiconductor (CMOS) flat panel imagers have been introduced for general radiography, dental, mammography and non-destructive testing (NDT) applications. Recently, a large-area CMOS active-pixel sensor (APS) in combination with scintillation films has been widely used in a variety of digital X-ray imaging applications. We employed a scintillator-based CMOS APS image sensor for high-resolution mammography. In this work, both powder-type Gd2O2S:Tb and a columnar structured CsI:Tl scintillation screens with various thicknesses were fabricated and used as materials to convert X-ray into visible light. These scintillating screens were directly coupled to a CMOS flat panel imager with a 25 × 50 mm2 active area and a 48 μm pixel pitch for high spatial resolution acquisition. We used a W/Al mammographic X-ray source with a 30 kVp energy condition. The imaging characterization of the X-ray detector was measured and analyzed in terms of linearity in incident X-ray dose, modulation transfer function (MTF), noise-power spectrum (NPS) and detective quantum efficiency (DQE).

  9. Routine chest and abdominal high-pitch CT: An alternative low dose protocol with preserved image quality

    International Nuclear Information System (INIS)

    Amacker, Nadja A.; Mader, Caecilia; Alkadhi, Hatem; Leschka, Sebastian; Frauenfelder, Thomas

    2012-01-01

    Objective: To investigate the radiation dose and image quality of the high-pitch dual source computer tomography (DSCT) for routine chest and abdominal scans. Methods: 130 consecutive patients (62 female, 68 male, median age 55 years) were included. All patients underwent 128-slice high-pitch DSCT (chest n = 99; abdomen n = 84) at a pitch of 3.2. Two observers independently rated image quality using a 4-point score (1: excellent to 4: non-diagnostic). Image noise was measured and operational radiation dose quantities were recorded. An additional group of 132 patients (chest, n = 80; abdomen n = 52) scanned with standard-pitch CT matched for age, gender, and body mass index (BMI) served as control group. Results: Interobserver agreement for image quality rating was good (k = 0.74). Subjective image quality of high-pitch CT was diagnostic in all patients (median score chest; 2, median score abdomen: 2). Image noise of high-pitch CT was comparable to standard-pitch for the chest (p = 0.32) but increased in the abdomen (p < 0.0001). For high-pitch CT radiation dose was 4.4 ± 0.9 mSv (chest) and 6.5 ± 1.2 mSv (abdomen). These values were significantly lower compared to standard-pitch CT (chest: 5.5 ± 1.2 mSv; abdomen: 11.3 ± 3.8 mSv). Conclusion: Based on the technical background high-pitch dual source CT may serve as an alternative scan mode for low radiation dose routine chest and abdominal CT.

  10. Producing quality radiographic images

    International Nuclear Information System (INIS)

    Cullinan, A.M.

    1987-01-01

    This book gives an overview of physics, equipment, imaging, and quality assurance in the radiology department. The chapters are laid out with generous use of subheads to allow for quick reference, Points are illustrated with clear, uncluttered line diagrams and well-produced images. The accompanying explanations are miniature lessons by themselves. Inserted at various points throughout the text are important notes that highlight key concepts. The chapter ''Image Evaluation and Application of Radiographic Principles'' present a systematic approach to evaluating radiographs and contains several sample radiographs to illustrate the points made

  11. Optimization of Synthetic Aperture Image Quality

    DEFF Research Database (Denmark)

    Moshavegh, Ramin; Jensen, Jonas; Villagómez Hoyos, Carlos Armando

    2016-01-01

    Synthetic Aperture (SA) imaging produces high-quality images and velocity estimates of both slow and fast flow at high frame rates. However, grating lobe artifacts can appear both in transmission and reception. These affect the image quality and the frame rate. Therefore optimization of parameter...

  12. Assessing product image quality for online shopping

    Science.gov (United States)

    Goswami, Anjan; Chung, Sung H.; Chittar, Naren; Islam, Atiq

    2012-01-01

    Assessing product-image quality is important in the context of online shopping. A high quality image that conveys more information about a product can boost the buyer's confidence and can get more attention. However, the notion of image quality for product-images is not the same as that in other domains. The perception of quality of product-images depends not only on various photographic quality features but also on various high level features such as clarity of the foreground or goodness of the background etc. In this paper, we define a notion of product-image quality based on various such features. We conduct a crowd-sourced experiment to collect user judgments on thousands of eBay's images. We formulate a multi-class classification problem for modeling image quality by classifying images into good, fair and poor quality based on the guided perceptual notions from the judges. We also conduct experiments with regression using average crowd-sourced human judgments as target. We compute a pseudo-regression score with expected average of predicted classes and also compute a score from the regression technique. We design many experiments with various sampling and voting schemes with crowd-sourced data and construct various experimental image quality models. Most of our models have reasonable accuracies (greater or equal to 70%) on test data set. We observe that our computed image quality score has a high (0.66) rank correlation with average votes from the crowd sourced human judgments.

  13. Electrical Resistivity Imaging and the Saline Water Interface in High-Quality Coastal Aquifers

    Science.gov (United States)

    Costall, A.; Harris, B.; Pigois, J. P.

    2018-07-01

    Population growth and changing climate continue to impact on the availability of natural resources. Urbanization of vulnerable coastal margins can place serious demands on shallow groundwater. Here, groundwater management requires definition of coastal hydrogeology, particularly the seawater interface. Electrical resistivity imaging (ERI) appears to be ideally suited for this purpose. We investigate challenges and drivers for successful electrical resistivity imaging with field and synthetic experiments. Two decades of seawater intrusion monitoring provide a basis for creating a geo-electrical model suitable for demonstrating the significance of acquisition and inversion parameters on resistivity imaging outcomes. A key observation is that resistivity imaging with combinations of electrode arrays that include dipole-dipole quadrupoles can be configured to illuminate consequential elements of coastal hydrogeology. We extend our analysis of ERI to include a diverse set of hydrogeological settings along more than 100 km of the coastal margin passing the city of Perth, Western Australia. Of particular importance are settings with: (1) a classic seawater wedge in an unconfined aquifer, (2) a shallow unconfined aquifer over an impermeable substrate, and (3) a shallow multi-tiered aquifer system over a conductive impermeable substrate. We also demonstrate a systematic increase in the landward extent of the seawater wedge at sites located progressively closer to the highly urbanized center of Perth. Based on field and synthetic ERI experiments from a broad range of hydrogeological settings, we tabulate current challenges and future directions for this technology. Our research contributes to resolving the globally significant challenge of managing seawater intrusion at vulnerable coastal margins.

  14. Electrical Resistivity Imaging and the Saline Water Interface in High-Quality Coastal Aquifers

    Science.gov (United States)

    Costall, A.; Harris, B.; Pigois, J. P.

    2018-05-01

    Population growth and changing climate continue to impact on the availability of natural resources. Urbanization of vulnerable coastal margins can place serious demands on shallow groundwater. Here, groundwater management requires definition of coastal hydrogeology, particularly the seawater interface. Electrical resistivity imaging (ERI) appears to be ideally suited for this purpose. We investigate challenges and drivers for successful electrical resistivity imaging with field and synthetic experiments. Two decades of seawater intrusion monitoring provide a basis for creating a geo-electrical model suitable for demonstrating the significance of acquisition and inversion parameters on resistivity imaging outcomes. A key observation is that resistivity imaging with combinations of electrode arrays that include dipole-dipole quadrupoles can be configured to illuminate consequential elements of coastal hydrogeology. We extend our analysis of ERI to include a diverse set of hydrogeological settings along more than 100 km of the coastal margin passing the city of Perth, Western Australia. Of particular importance are settings with: (1) a classic seawater wedge in an unconfined aquifer, (2) a shallow unconfined aquifer over an impermeable substrate, and (3) a shallow multi-tiered aquifer system over a conductive impermeable substrate. We also demonstrate a systematic increase in the landward extent of the seawater wedge at sites located progressively closer to the highly urbanized center of Perth. Based on field and synthetic ERI experiments from a broad range of hydrogeological settings, we tabulate current challenges and future directions for this technology. Our research contributes to resolving the globally significant challenge of managing seawater intrusion at vulnerable coastal margins.

  15. Quality assurance: image production and film quality

    International Nuclear Information System (INIS)

    Abd Aziz Mhd Ramli

    2004-01-01

    The contents of this chapter are follows - Factors Affecting Image Quality and Patient Dose: Quality Control in Diagnostic Radiology, Mechanical Safety, Electrical Safety, Radiation Protection, Performance and Safety Standard, Calibration of QC Test Tools

  16. High-field, high-resolution, susceptibility-weighted magnetic resonance imaging: improved image quality by addition of contrast agent and higher field strength in patients with brain tumors

    International Nuclear Information System (INIS)

    Pinker, K.; Noebauer-Huhmann, I.M.; Szomolanyi, P.; Weber, M.; Grabner, G.; Trattnig, S.; Stavrou, I.; Knosp, E.; Hoeftberger, R.; Stadlbauer, A.

    2008-01-01

    To demonstrate intratumoral susceptibility effects in malignant brain tumors and to assess visualization of susceptibility effects before and after administration of the paramagnetic contrast agent MultiHance (gadobenate dimeglumine; Bracco Imaging), an agent known to have high relaxivity, with respect to susceptibility effects, image quality, and reduction of scan time. Included in the study were 19 patients with malignant brain tumors who underwent high-resolution, susceptibility-weighted (SW) MR imaging at 3 T before and after administration of contrast agent. In all patients, Multihance was administered intravenously as a bolus (0.1 mmol/kg body weight). MR images were individually evaluated by two radiologists with previous experience in the evaluation of pre- and postcontrast 3-T SW MR images with respect to susceptibility effects, image quality, and reduction of scan time. In the 19 patients 21 tumors were diagnosed, of which 18 demonstrated intralesional susceptibility effects both in pre- and postcontrast SW images, and 19 demonstrated contrast enhancement in both SW images and T1-weighted spin-echo MR images. Conspicuity of susceptibility effects and image quality were improved in postcontrast images compared with precontrast images and the scan time was also reduced due to decreased TE values from 9 min (precontrast) to 7 min (postcontrast). The intravenous administration of MultiHance, an agent with high relaxivity, allowed a reduction of scan time from 9 min to 7 min while preserving excellent susceptibility effects and image quality in SW images obtained at 3 T. Contrast enhancement and intralesional susceptibility effects can be assessed in one sequence. (orig.)

  17. Development and clinical translation of a cone-beam CT scanner for high-quality imaging of intracranial hemorrhage

    Science.gov (United States)

    Sisniega, A.; Xu, J.; Dang, H.; Zbijewski, W.; Stayman, J. W.; Mow, M.; Koliatsos, V. E.; Aygun, N.; Wang, X.; Foos, D. H.; Siewerdsen, J. H.

    2017-03-01

    Purpose: Prompt, reliable detection of intracranial hemorrhage (ICH) is essential for treatment of stroke and traumatic brain injury, and would benefit from availability of imaging directly at the point-of-care. This work reports the performance evaluation of a clinical prototype of a cone-beam CT (CBCT) system for ICH imaging and introduces novel algorithms for model-based reconstruction with compensation for data truncation and patient motion. Methods: The tradeoffs in dose and image quality were investigated as a function of analytical (FBP) and model-based iterative reconstruction (PWLS) algorithm parameters using phantoms with ICH-mimicking inserts. Image quality in clinical applications was evaluated in a human cadaver imaged with simulated ICH. Objects outside of the field of view (FOV), such as the head-holder, were found to introduce challenging truncation artifacts in PWLS that were mitigated with a novel multi-resolution reconstruction strategy. Following phantom and cadaver studies, the scanner was translated to a clinical pilot study. Initial clinical experience indicates the presence of motion in some patient scans, and an image-based motion estimation method that does not require fiducial tracking or prior patient information was implemented and evaluated. Results: The weighted CTDI for a nominal scan technique was 22.8 mGy. The high-resolution FBP reconstruction protocol achieved < 0.9 mm full width at half maximum (FWHM) of the point spread function (PSF). The PWLS soft-tissue reconstruction showed <1.2 mm PSF FWHM and lower noise than FBP at the same resolution. Effects of truncation in PWLS were mitigated with the multi-resolution approach, resulting in 60% reduction in root mean squared error compared to conventional PWLS. Cadaver images showed clear visualization of anatomical landmarks (ventricles and sulci), and ICH was conspicuous. The motion compensation method was shown in clinical studies to restore visibility of fine bone structures

  18. High-pitch spiral computed tomography: effect on image quality and radiation dose in pediatric chest computed tomography.

    Science.gov (United States)

    Lell, Michael M; May, Matthias; Deak, Paul; Alibek, Sedat; Kuefner, Michael; Kuettner, Axel; Köhler, Henrik; Achenbach, Stephan; Uder, Michael; Radkow, Tanja

    2011-02-01

    computed tomography (CT) is considered the method of choice in thoracic imaging for a variety of indications. Sedation is usually necessary to enable CT and to avoid deterioration of image quality because of patient movement in small children. We evaluated a new, subsecond high-pitch scan mode (HPM), which obviates the need of sedation and to hold the breath. a total of 60 patients were included in this study. 30 patients (mean age, 14 ± 17 month; range, 0-55 month) were examined with a dual source CT system in an HPM. Scan parameters were as follows: pitch = 3.0, 128 × 0.6 mm slice acquisition, 0.28 seconds gantry rotation time, ref. mAs adapted to the body weight (50-100 mAs) at 80 kV. Images were reconstructed with a slice thickness of 0.75 mm. None of the children was sedated for the CT examination and no breathing instructions were given. Image quality was assessed focusing on motion artifacts and delineation of the vascular structures and lung parenchyma. Thirty patients (mean age, 15 ± 17 month; range, 0-55 month) were examined under sedation on 2 different CT systems (10-slice CT, n = 18; 64-slice CT, n = 13 patients) in conventional pitch mode (CPM). Dose values were calculated from the dose length product provided in the patient protocol/dose reports, Monte Carlo simulations were performed to assess dose distribution for CPM and HPM. all scans were performed without complications. Image quality was superior with HPM, because of a significant reduction in motion artifacts, as compared to CPM with 10- and 64-slice CT. In the control group, artifacts were encountered at the level of the diaphragm (n = 30; 100%), the borders of the heart (n = 30; 100%), and the ribs (n = 20; 67%) and spine (n = 6; 20%), whereas motion artifacts were detected in the HPM-group only in 6 patients in the lung parenchyma next to the diaphragm or the heart (P detector width and pitch-value. high-pitch chest CT is a robust method to provide highest image quality making sedation

  19. Studies on image quality, high contrast resolution and dose for the axial skeleton and limbs with a new, dedicated CT system (ISO-C-3D)

    International Nuclear Information System (INIS)

    Rock, C.; Kotsianos, D.; Linsenmaier, U.; Fischer, T.

    2002-01-01

    Purpose: Evaluation of 3D-CT imaging of the axial skeleton and different joints of the lower and upper extremities with a new dedicated CT system (ISO-C-3D) based on a mobile isocentric C-arm image amplifier. Material and Methods: 27 cadaveric specimes of different joints of the lower and upper extremities and of the spinal column were examined with 3D-CT imaging (ISO-C-3d). All images were evaluated by 3 radiologists for image quality using a semiquantitative score (score value 1: poor quality; score value 4: excellent quality). In addition, dose measurements and measurements of high contrast resolution were performed in comparison to conventional and low-dose spiral CT using a high contrast phantom (Catphan, Phantom Laboratories). Results: Adequate image quality (mean score values 3-4) could be achieved with an applied dose comparable to low-dose CT in smaller joints such as wrist, elbow, ankle and knee. A remarkably inferior image quality resulted in imaging of the hip, lumbar and thoracic spine (mean score values 2-3) in spite of almost doubling the dose (dose increased by 85 percent). The image quality of shoulder examinations was insufficient (mean score value 1). Phantom studies showed a high-contrast resolution comparable to helical CT in the xy-axis (9 lp/cm). Conclusion: Preliminary results show, that image quality of C-arm-based CT-imaging (ISO-C-3D) seems to be adequate in smaller joints. ISO-C-3D images of the hip and axial skeleton show a decreased image quality, which does not seem to be sufficient for diagnosing subtle fractures. (orig.) [de

  20. A set of high quality colour images with Spanish norms for seven relevant psycholinguistic variables: the Nombela naming test.

    Science.gov (United States)

    Moreno-Martinez, Francisco Javier; Montoro, Pedro R; Laws, Keith R

    2011-05-01

    This paper presents a new corpus of 140 high quality colour images belonging to 14 subcategories and covering a range of naming difficulty. One hundred and six Spanish speakers named the items and provided data for several psycholinguistic variables: age of acquisition, familiarity, manipulability, name agreement, typicality and visual complexity. Furthermore, we also present lexical frequency data derived internet search hits. Apart from the large number of variables evaluated, these stimuli present an important advantage with respect to other comparable image corpora in so far as naming performance in healthy individuals is less prone to ceiling effect problems. Reliability and validity indexes showed that our items display similar psycholinguistic characteristics to those of other corpora. In sum, this set of ecologically valid stimuli provides a useful tool for scientists engaged in cognitive and neuroscience-based research.

  1. Impact of image segmentation on high-content screening data quality for SK-BR-3 cells

    Directory of Open Access Journals (Sweden)

    Li Yizheng

    2007-09-01

    Full Text Available Abstract Background High content screening (HCS is a powerful method for the exploration of cellular signalling and morphology that is rapidly being adopted in cancer research. HCS uses automated microscopy to collect images of cultured cells. The images are subjected to segmentation algorithms to identify cellular structures and quantitate their morphology, for hundreds to millions of individual cells. However, image analysis may be imperfect, especially for "HCS-unfriendly" cell lines whose morphology is not well handled by current image segmentation algorithms. We asked if segmentation errors were common for a clinically relevant cell line, if such errors had measurable effects on the data, and if HCS data could be improved by automated identification of well-segmented cells. Results Cases of poor cell body segmentation occurred frequently for the SK-BR-3 cell line. We trained classifiers to identify SK-BR-3 cells that were well segmented. On an independent test set created by human review of cell images, our optimal support-vector machine classifier identified well-segmented cells with 81% accuracy. The dose responses of morphological features were measurably different in well- and poorly-segmented populations. Elimination of the poorly-segmented cell population increased the purity of DNA content distributions, while appropriately retaining biological heterogeneity, and simultaneously increasing our ability to resolve specific morphological changes in perturbed cells. Conclusion Image segmentation has a measurable impact on HCS data. The application of a multivariate shape-based filter to identify well-segmented cells improved HCS data quality for an HCS-unfriendly cell line, and could be a valuable post-processing step for some HCS datasets.

  2. Laser beam welding quality monitoring system based in high-speed (10 kHz) uncooled MWIR imaging sensors

    Science.gov (United States)

    Linares, Rodrigo; Vergara, German; Gutiérrez, Raúl; Fernández, Carlos; Villamayor, Víctor; Gómez, Luis; González-Camino, Maria; Baldasano, Arturo; Castro, G.; Arias, R.; Lapido, Y.; Rodríguez, J.; Romero, Pablo

    2015-05-01

    The combination of flexibility, productivity, precision and zero-defect manufacturing in future laser-based equipment are a major challenge that faces this enabling technology. New sensors for online monitoring and real-time control of laserbased processes are necessary for improving products quality and increasing manufacture yields. New approaches to fully automate processes towards zero-defect manufacturing demand smarter heads where lasers, optics, actuators, sensors and electronics will be integrated in a unique compact and affordable device. Many defects arising in laser-based manufacturing processes come from instabilities in the dynamics of the laser process. Temperature and heat dynamics are key parameters to be monitored. Low cost infrared imagers with high-speed of response will constitute the next generation of sensors to be implemented in future monitoring and control systems for laser-based processes, capable to provide simultaneous information about heat dynamics and spatial distribution. This work describes the result of using an innovative low-cost high-speed infrared imager based on the first quantum infrared imager monolithically integrated with Si-CMOS ROIC of the market. The sensor is able to provide low resolution images at frame rates up to 10 KHz in uncooled operation at the same cost as traditional infrared spot detectors. In order to demonstrate the capabilities of the new sensor technology, a low-cost camera was assembled on a standard production laser welding head, allowing to register melting pool images at frame rates of 10 kHz. In addition, a specific software was developed for defect detection and classification. Multiple laser welding processes were recorded with the aim to study the performance of the system and its application to the real-time monitoring of laser welding processes. During the experiments, different types of defects were produced and monitored. The classifier was fed with the experimental images obtained. Self

  3. Image quality and dose in computed tomography

    International Nuclear Information System (INIS)

    Jurik, A.G.; Jessen, K.A.; Hansen, J.

    1997-01-01

    Radiation exposure to the patient during CT is relatively high, and it is therefore important to optimize the dose so that it is as low as possible but still consistent with required diagnostic image quality. There is no established method for measuring diagnostic image quality; therefore, a set of image quality criteria which must be fulfilled for optimal image quality was defined for the retroperitoneal space and the mediastinum. The use of these criteria for assessment of image quality was tested based on 113 retroperitoneal and 68 mediastinal examinations performed in seven different CT units. All the criteria, except one, were found to be usable for measuring diagnostic image quality. The fulfilment of criteria was related to the radiation dose given in the different departments. By examination of the retroperitoneal space the effective dose varied between 5.1 and 20.0 mSv (milli Sievert), and there was a slight correlation between dose and high percent of ''yes'' score for the image quality criteria. For examination of the mediastinum the dose range was 4.4-26.5 mSv, and there was no significant increment of image quality at high doses. The great variation of dose at different CT units was due partly to differences regarding the examination procedure, especially the number of slices and the mAs (milli ampere second), but inherent dose variation between different scanners also played a part. (orig.). With 6 figs., 6 tabs

  4. A spatial-spectral approach for deriving high signal quality eigenvectors for remote sensing image transformations

    DEFF Research Database (Denmark)

    Rogge, Derek; Bachmann, Martin; Rivard, Benoit

    2014-01-01

    Spectral decorrelation (transformations) methods have long been used in remote sensing. Transformation of the image data onto eigenvectors that comprise physically meaningful spectral properties (signal) can be used to reduce the dimensionality of hyperspectral images as the number of spectrally...... distinct signal sources composing a given hyperspectral scene is generally much less than the number of spectral bands. Determining eigenvectors dominated by signal variance as opposed to noise is a difficult task. Problems also arise in using these transformations on large images, multiple flight...... and spectral subsampling to the data, which is accomplished by deriving a limited set of eigenvectors for spatially contiguous subsets. These subset eigenvectors are compiled together to form a new noise reduced data set, which is subsequently used to derive a set of global orthogonal eigenvectors. Data from...

  5. Improved image quality and diagnostic potential using ultra-high-resolution computed tomography of the lung with small scan FOV: A prospective study.

    Science.gov (United States)

    Zhu, Huiyuan; Zhang, Lian; Wang, Yali; Hamal, Preeti; You, Xiaofang; Mao, Haixia; Li, Fei; Sun, Xiwen

    2017-01-01

    The aim of this study was to assess whether CT imaging using an ultra-high-resolution CT (UHRCT) scan with a small scan field of view (FOV) provides higher image quality and helps to reduce the follow-up period compared with a conventional high-resolution CT (CHRCT) scan. We identified patients with at least one pulmonary nodule at our hospital from July 2015 to November 2015. CHRCT and UHRCT scans were conducted in all enrolled patients. Three experienced radiologists evaluated the image quality using a 5-point score and made diagnoses. The paired images were displayed side by side in a random manner and annotations of scan information were removed. The following parameters including image quality, diagnostic confidence of radiologists, follow-up recommendations and diagnostic accuracy were assessed. A total of 52 patients (62 nodules) were included in this study. UHRCT scan provides a better image quality regarding the margin of nodules and solid internal component compared to that of CHRCT (P images than of CHRCT images (Pimages (P 0.05). These findings suggest that the UHRCT prototype scanner provides a better image quality of subsolid nodules compared to CHRCT and contributes significantly to reduce the patients' follow-up period.

  6. Image quality assessment using deep convolutional networks

    Science.gov (United States)

    Li, Yezhou; Ye, Xiang; Li, Yong

    2017-12-01

    This paper proposes a method of accurately assessing image quality without a reference image by using a deep convolutional neural network. Existing training based methods usually utilize a compact set of linear filters for learning features of images captured by different sensors to assess their quality. These methods may not be able to learn the semantic features that are intimately related with the features used in human subject assessment. Observing this drawback, this work proposes training a deep convolutional neural network (CNN) with labelled images for image quality assessment. The ReLU in the CNN allows non-linear transformations for extracting high-level image features, providing a more reliable assessment of image quality than linear filters. To enable the neural network to take images of any arbitrary size as input, the spatial pyramid pooling (SPP) is introduced connecting the top convolutional layer and the fully-connected layer. In addition, the SPP makes the CNN robust to object deformations to a certain extent. The proposed method taking an image as input carries out an end-to-end learning process, and outputs the quality of the image. It is tested on public datasets. Experimental results show that it outperforms existing methods by a large margin and can accurately assess the image quality on images taken by different sensors of varying sizes.

  7. High energy positron imaging

    International Nuclear Information System (INIS)

    Chen Shengzu

    2003-01-01

    The technique of High Energy Positron Imaging (HEPI) is the new development and extension of Positron Emission Tomography (PET). It consists of High Energy Collimation Imaging (HECI), Dual Head Coincidence Detection Imaging (DHCDI) and Positron Emission Tomography (PET). We describe the history of the development and the basic principle of the imaging methods of HEPI in details in this paper. Finally, the new technique of the imaging fusion, which combined the anatomical image and the functional image together are also introduced briefly

  8. Influence of high values of base plus fog in the quality of radiological image

    International Nuclear Information System (INIS)

    Barbieri, D.X.; Staevie, G.L.; Wagner, R.V.; Mazzola, A.

    1996-01-01

    This paper demonstrates how important is the Quality Control in X-ray clinics and departments. Specially, in case of Bf density, some factors must be monitored: processor parameters, dark room condition, chemicals, film storage, operators training and film quality. Bf greater than 0.30 should be avoided, because it impairs the diagnostic, resulting in film waste, repetition of examination, wear and tear of equipment and excess of X-Ray dose absorbed by the patient and operator. (authors). 5 refs., 5 figs

  9. Status for NEXIM New X-ray Imaging Modalities for safe and high quality food

    DEFF Research Database (Denmark)

    Einarsdottir, Hildur; Ersbøll, Bjarne Kjær; Larsen, Rasmus

    2014-01-01

    . The main focuses are determined to be threefold: 1)Improving the detectability of low density foreign bodies incidentally present in food products. 2)Development of new modalities for assessment of quality traits in food production, for instance connective tissue and fatty acid composition. 3)Develop...... to developing laboratory-based setups further towards an in-line scanning system. Additionally, close co-operation with industrial partners has further emphasized the need for new techniques for quality control, product development and foreign object detection....

  10. Automated jitter correction for IR image processing to assess the quality of W7-X high heat flux components

    International Nuclear Information System (INIS)

    Greuner, H; De Marne, P; Herrmann, A; Boeswirth, B; Schindler, T; Smirnow, M

    2009-01-01

    An automated IR image processing method was developed to evaluate the surface temperature distribution of cyclically loaded high heat flux (HHF) plasma facing components. IPP Garching will perform the HHF testing of a high percentage of the series production of the WENDELSTEIN 7-X (W7-X) divertor targets to minimize the number of undiscovered uncertainties in the finally installed components. The HHF tests will be performed as quality assurance (QA) complementary to the non-destructive examination (NDE) methods used during the manufacturing. The IR analysis of an HHF-loaded component detects growing debonding of the plasma facing material, made of carbon fibre composite (CFC), after a few thermal cycles. In the case of the prototype testing, the IR data was processed manually. However, a QA method requires a reliable, reproducible and efficient automated procedure. Using the example of the HHF testing of W7-X pre-series target elements, the paper describes the developed automated IR image processing method. The algorithm is based on an iterative two-step correlation analysis with an individually defined reference pattern for the determination of the jitter.

  11. Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

    Science.gov (United States)

    Wu, T.-H.; Liang, C.-H.; Wu, J.-K.; Lien, C.-Y.; Yang, B.-H.; Huang, Y.-H.; Lee, J. J. S.

    2009-07-01

    Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of 18F-fluorodeoxyglucose (18F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT may have a

  12. Integration of PET-CT and cone-beam CT for image-guided radiotherapy with high image quality and registration accuracy

    International Nuclear Information System (INIS)

    Wu, T-H; Liang, C-H; Wu, J-K; Lien, C-Y; Yang, B-H; Lee, J J S; Huang, Y-H

    2009-01-01

    Hybrid positron emission tomography-computed tomography (PET-CT) system enhances better differentiation of tissue uptake of 18 F-fluorodeoxyglucose ( 18 F-FDG) and provides much more diagnostic value in the non-small-cell lung cancer and nasopharyngeal carcinoma (NPC). In PET-CT, high quality CT images not only offer diagnostic value on anatomic delineation of the tissues but also shorten the acquisition time for attenuation correction (AC) compared with PET-alone imaging. The linear accelerators equipped with the X-ray cone-beam computed tomography (CBCT) imaging system for image-guided radiotherapy (IGRT) provides excellent verification on position setup error. The purposes of our study were to optimize the CT acquisition protocols of PET-CT and to integrate the PET-CT and CBCT for IGRT. The CT imaging parameters were modified in PET-CT for increasing the image quality in order to enhance the diagnostic value on tumour delineation. Reproducibility and registration accuracy via bone co-registration algorithm between the PET-CT and CBCT were evaluated by using a head phantom to simulate a head and neck treatment condition. Dose measurement in computed tomography dose index (CTDI) was also estimated. Optimization of the CT acquisition protocols of PET-CT was feasible in this study. Co-registration accuracy between CBCT and PET-CT on axial and helical modes was in the range of 1.06 to 2.08 and 0.99 to 2.05 mm, respectively. In our result, it revealed that the accuracy of the co-registration with CBCT on helical mode was more accurate than that on axial mode. Radiation doses in CTDI were 4.76 to 18.5 mGy and 4.83 to 18.79 mGy on axial and helical modes, respectively. Registration between PET-CT and CBCT is a state-of-the-art registration technology which could provide much information on diagnosis and accurate tumour contouring on radiotherapy while implementing radiotherapy procedures. This novelty technology of PET-CT and cone-beam CT integration for IGRT may have a

  13. Improved image quality and diagnostic potential using ultra-high-resolution computed tomography of the lung with small scan FOV: A prospective study.

    Directory of Open Access Journals (Sweden)

    Huiyuan Zhu

    Full Text Available The aim of this study was to assess whether CT imaging using an ultra-high-resolution CT (UHRCT scan with a small scan field of view (FOV provides higher image quality and helps to reduce the follow-up period compared with a conventional high-resolution CT (CHRCT scan. We identified patients with at least one pulmonary nodule at our hospital from July 2015 to November 2015. CHRCT and UHRCT scans were conducted in all enrolled patients. Three experienced radiologists evaluated the image quality using a 5-point score and made diagnoses. The paired images were displayed side by side in a random manner and annotations of scan information were removed. The following parameters including image quality, diagnostic confidence of radiologists, follow-up recommendations and diagnostic accuracy were assessed. A total of 52 patients (62 nodules were included in this study. UHRCT scan provides a better image quality regarding the margin of nodules and solid internal component compared to that of CHRCT (P 0.05. These findings suggest that the UHRCT prototype scanner provides a better image quality of subsolid nodules compared to CHRCT and contributes significantly to reduce the patients' follow-up period.

  14. An investigation on comprehensive evaluation and standard of image quality of high voltage chest radiograph

    International Nuclear Information System (INIS)

    Yan Shulin; Li Shuopeng; Zhao Bo; Niu Yantao

    1998-01-01

    Purpose: Based on clinical diagnostic demand, patient irradiation dose and imaging technical parameters, to establish a comprehensive evaluation method and standard in chest radiograph. Methods: (1) From 10 normal chest radiographs, the authors selected the evaluation area on thoracic PA (posteroanterior) radiographs and set up standard for diagnostic demand; (2) Using chest CT scans of 20 males and 20 females, the authors calculated the ratio of lung field to mediastinum; (3) Selecting 100 chest films using 125 kVp, the authors measured the standard density values of each evaluation area; (4) Body surface irradiation doses of 478 normal adults were measured. Results: (1) Based on diagnostic demand, the authors confirmed 7 evaluation areas and 4 physical evaluation factors. At the same time, evaluation standards were obtained; (2) Comprehensive evaluation methods were established; (3) Standard height, weight and body surface irradiation dose of Chinese normal adults were investigated preliminarily. Conclusion: Based on the concept of comprehensive evaluation, investigation on the evaluation methods and standard in chest PA radiograph was carried out which might be taken as the foundation for future approach on nation-wide basis

  15. Image quality in digital radiography

    International Nuclear Information System (INIS)

    Kuhn, H.

    1986-01-01

    The contribution deals with the potentials of digital radiography and critically evaluates the advantages of drawbacks of the image intensifier-tv-digital system; digitalisation of the X-ray film and scanning of luminescent storage foils. The evaluation is done in comparison with the image quality of the traditional, large-size X-ray picture. (orig.) [de

  16. Reduction of radiation exposure while maintaining high-quality fluoroscopic images during interventional cardiology using novel x-ray tube technology with extra beam filtering.

    Science.gov (United States)

    den Boer, A; de Feyter, P J; Hummel, W A; Keane, D; Roelandt, J R

    1994-06-01

    Radiographic technology plays an integral role in interventional cardiology. The number of interventions continues to increase, and the associated radiation exposure to patients and personnel is of major concern. This study was undertaken to determine whether a newly developed x-ray tube deploying grid-switched pulsed fluoroscopy and extra beam filtering can achieve a reduction in radiation exposure while maintaining fluoroscopic images of high quality. Three fluoroscopic techniques were compared: continuous fluoroscopy, pulsed fluoroscopy, and a newly developed high-output pulsed fluoroscopy with extra filtering. To ascertain differences in the quality of images and to determine differences in patient entrance and investigator radiation exposure, the radiated volume curve was measured to determine the required high voltage levels (kVpeak) for different object sizes for each fluoroscopic mode. The fluoroscopic data of 124 patient procedures were combined. The data were analyzed for radiographic projections, image intensifier field size, and x-ray tube kilovoltage levels (kVpeak). On the basis of this analysis, a reference procedure was constructed. The reference procedure was tested on a phantom or dummy patient by all three fluoroscopic modes. The phantom was so designed that the kilovoltage requirements for each projection were comparable to those needed for the average patient. Radiation exposure of the operator and patient was measured during each mode. The patient entrance dose was measured in air, and the operator dose was measured by 18 dosimeters on a dummy operator. Pulsed compared with continuous fluoroscopy could be performed with improved image quality at lower kilovoltages. The patient entrance dose was reduced by 21% and the operator dose by 54%. High-output pulsed fluoroscopy with extra beam filtering compared with continuous fluoroscopy improved the image quality, lowered the kilovoltage requirements, and reduced the patient entrance dose by 55% and

  17. Fast MR Imaging of the Paediatric Abdomen with CAIPIRINHA-Accelerated T1w 3D FLASH and with High-Resolution T2w HASTE: A Study on Image Quality

    Directory of Open Access Journals (Sweden)

    Mengxia Li

    2015-01-01

    Full Text Available The aim of this study was to explore the applicability of fast MR techniques to routine paediatric abdominopelvic MRI at 1.5 Tesla. “Controlled Aliasing in Parallel Imaging Results in Higher Acceleration-” (CAIPIRINHA- accelerated contrast-enhanced-T1w 3D FLASH imaging was compared to standard T1w 2D FLASH imaging with breath-holding in 40 paediatric patients and to respiratory-triggered T1w TSE imaging in 10 sedated young children. In 20 nonsedated patients, we compared T2w TIRM to fat-saturated T2w HASTE imaging. Two observers performed an independent and blinded assessment of overall image quality. Acquisition time was reduced by the factor of 15 with CAIPIRINHA-accelerated T1w FLASH and by 7 with T2w HASTE. With CAIPIRINHA and with HASTE, there were significantly less motion artefacts in nonsedated patients. In sedated patients, respiratory-triggered T1w imaging in general showed better image quality. However, satisfactory image quality was achieved with CAIPIRINHA in two sedated patients where respiratory triggering failed. In summary, fast scanning with CAIPIRINHA and HASTE presents a reliable high quality alternative to standard sequences in paediatric abdominal MRI. Paediatric patients, in particular, benefit greatly from fast image acquisition with less breath-hold cycles or shorter sedation.

  18. Image quality (IQ) guided multispectral image compression

    Science.gov (United States)

    Zheng, Yufeng; Chen, Genshe; Wang, Zhonghai; Blasch, Erik

    2016-05-01

    Image compression is necessary for data transportation, which saves both transferring time and storage space. In this paper, we focus on our discussion on lossy compression. There are many standard image formats and corresponding compression algorithms, for examples, JPEG (DCT -- discrete cosine transform), JPEG 2000 (DWT -- discrete wavelet transform), BPG (better portable graphics) and TIFF (LZW -- Lempel-Ziv-Welch). The image quality (IQ) of decompressed image will be measured by numerical metrics such as root mean square error (RMSE), peak signal-to-noise ratio (PSNR), and structural Similarity (SSIM) Index. Given an image and a specified IQ, we will investigate how to select a compression method and its parameters to achieve an expected compression. Our scenario consists of 3 steps. The first step is to compress a set of interested images by varying parameters and compute their IQs for each compression method. The second step is to create several regression models per compression method after analyzing the IQ-measurement versus compression-parameter from a number of compressed images. The third step is to compress the given image with the specified IQ using the selected compression method (JPEG, JPEG2000, BPG, or TIFF) according to the regressed models. The IQ may be specified by a compression ratio (e.g., 100), then we will select the compression method of the highest IQ (SSIM, or PSNR). Or the IQ may be specified by a IQ metric (e.g., SSIM = 0.8, or PSNR = 50), then we will select the compression method of the highest compression ratio. Our experiments tested on thermal (long-wave infrared) images (in gray scales) showed very promising results.

  19. Camera pose refinement by matching uncertain 3D building models with thermal infrared image sequences for high quality texture extraction

    Science.gov (United States)

    Iwaszczuk, Dorota; Stilla, Uwe

    2017-10-01

    Thermal infrared (TIR) images are often used to picture damaged and weak spots in the insulation of the building hull, which is widely used in thermal inspections of buildings. Such inspection in large-scale areas can be carried out by combining TIR imagery and 3D building models. This combination can be achieved via texture mapping. Automation of texture mapping avoids time consuming imaging and manually analyzing each face independently. It also provides a spatial reference for façade structures extracted in the thermal textures. In order to capture all faces, including the roofs, façades, and façades in the inner courtyard, an oblique looking camera mounted on a flying platform is used. Direct geo-referencing is usually not sufficient for precise texture extraction. In addition, 3D building models have also uncertain geometry. In this paper, therefore, methodology for co-registration of uncertain 3D building models with airborne oblique view images is presented. For this purpose, a line-based model-to-image matching is developed, in which the uncertainties of the 3D building model, as well as of the image features are considered. Matched linear features are used for the refinement of the exterior orientation parameters of the camera in order to ensure optimal co-registration. Moreover, this study investigates whether line tracking through the image sequence supports the matching. The accuracy of the extraction and the quality of the textures are assessed. For this purpose, appropriate quality measures are developed. The tests showed good results on co-registration, particularly in cases where tracking between the neighboring frames had been applied.

  20. 256-MDCT for evaluation of urolithiasis: iterative reconstruction allows for a significant reduction of the applied radiation dose while maintaining high subjective and objective image quality

    International Nuclear Information System (INIS)

    Veldhoen, Simon; Laqmani, Azien; Derlin, Thorsten; Karul, Murat; Hammerle, Diego; Adam, Gerhard; Regier, Marc; Buhk, Jan-Hendrick; Sehner, Susanne; Nagel, Hans D.; Chun, Felix

    2014-01-01

    Multidetector CT (MDCT) is the established imaging modality in diagnostics of urolithiasis. The aim of iterative reconstruction (IR) is to allow for a radiation dose reduction while maintaining high image quality. This study evaluates its performance in MDCT for assessment of urolithiasis. Fifty-two patients underwent non-contrast abdominal MDCT. Twenty-six patients were referred to MDCT under suspicion of urolithiasis, and examined using a dose-reduced scan protocol (RDCT). Twenty-six patients, who had undergone standard-dose MDCT, served as reference for radiation dose comparison. RDCT images were reconstructed using an IR system (iDose4™, Philips Healthcare, Cleveland, OH, USA). Objective image noise (OIN) was recorded and five radiologists rated the subjective image quality independently. Radiation parameters were derived from the scan protocols. The CTDIvol could be reduced by 50% to 5.8 mGy (P < 0.0001). The same reduction was achieved for DLP and effective dose to 253 ± 27 mGy*cm (P < 0.0001) and 3.9 ± 0.4 mSv (P < 0.0001). IR led to a reduction of the OIN of up to 61% compared with classic filtered back projection (FBP) (P < 0.0001). The OIN declined with increasing IR levels. RDCT with FBP showed the lowest scores of subjective image quality (2.32 ± 0.04). Mean scores improved with increasing IR levels. iDose6 was rated with the best mean score (3.66 ± 0.04). The evaluated IR-tool and protocol may be applied to achieve a considerable radiation dose reduction in MDCT for diagnostics of urolithiasis while maintaining a confident image quality. Best image quality, suitable for evaluation of the entire abdomen concerning differential diagnoses, was achieved with iDose6.

  1. Image quality of low-dose CCTA in obese patients: impact of high-definition computed tomography and adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Gebhard, Cathérine; Fuchs, Tobias A; Fiechter, Michael; Stehli, Julia; Stähli, Barbara E; Gaemperli, Oliver; Kaufmann, Philipp A

    2013-10-01

    The accuracy of coronary computed tomography angiography (CCTA) in obese persons is compromised by increased image noise. We investigated CCTA image quality acquired on a high-definition 64-slice CT scanner using modern adaptive statistical iterative reconstruction (ASIR). Seventy overweight and obese patients (24 males; mean age 57 years, mean body mass index 33 kg/m(2)) were studied with clinically-indicated contrast enhanced CCTA. Thirty-five patients underwent a standard definition protocol with filtered backprojection reconstruction (SD-FBP) while 35 patients matched for gender, age, body mass index and coronary artery calcifications underwent a novel high definition protocol with ASIR (HD-ASIR). Segment by segment image quality was assessed using a four-point scale (1 = excellent, 2 = good, 3 = moderate, 4 = non-diagnostic) and revealed better scores for HD-ASIR compared to SD-FBP (1.5 ± 0.43 vs. 1.8 ± 0.48; p ASIR as compared to 1.4 ± 0.4 mm for SD-FBP (p ASIR (388.3 ± 109.6 versus 350.6 ± 90.3 Hounsfield Units, HU; p ASIR vs. SD-ASIR respectively). Compared to a standard definition backprojection protocol (SD-FBP), a newer high definition scan protocol in combination with ASIR (HD-ASIR) incrementally improved image quality and visualization of distal coronary artery segments in overweight and obese individuals, without increasing image noise and radiation dose.

  2. Image quality of high-resolution CT with 16-channel multidetector-row CT. Comparison between helical scan and conventional step-shoot scan

    International Nuclear Information System (INIS)

    Sumikawa, Hiromitsu; Johkoh, Takeshi; Koyama, Mitsuhiro

    2005-01-01

    The aim of this study was to evaluate the image quality of high-resolution CT (HRCT) reconstructed from volumetric data with 16-channel multidetector-row CT (MDCT). Eleven autopsy lungs that were diagnosed histopathologically were scanned by 16-channel MDCT with the step-and-shoot scan mode and three helical scan modes. Each helical mode had each size of focal spot, pitch, and time of gantry rotation. HRCT images were reconstructed from the volumetric data with each helical mode and axial sequence data. Two observers evaluated the image quality and noted the most appropriate diagnosis for each imaging. Visualization of abnormal structures with one helical mode was equal to those with axial mode, whereas those with the other two helical modes were inferior to those with axial mode (Wilcoxon signed rank test; p<0.0001). There was no significant difference in diagnostic efficacy between modes. The image quality of HRCT with appropriate helical mode is equal to that with axial mode and diagnostic efficacy is equal among all modes. These results may indicate that sufficient HRCT images can be obtained by only one helical scan without the addition of conventional axial scans. (author)

  3. Quality of radiation field imaging

    International Nuclear Information System (INIS)

    Petr, I.

    1988-01-01

    The questions were studied of the quality of imaging the gamma radiation field and of the limits of the quality in directional detector scanning. A resolution angle was introduced to quantify the imaging quality, and its relation was sought with the detection effective half-angle of the directional detector. The resolution angle was defined for the simplest configuration of the radiation field consisting of two monoenergetic gamma beams in one plane. It was shown that the resolution angle decreases, i.e., resolution in imaging the radiation field is better, with the effective half-angle of the directional detector. It was also found that resolution of both gamma beams deteriorated when the beams were surrounded with an isotropic background field. If the beams are surrounded with a background field showing general distribution, the angle size will be affected not only by the properties of the detector but also by the distribution of the ambient radiation field and the method of its scanning. The method described can be applied in designing a directional detector necessary for imaging the presumed radiation field in the required quality. (Z.M.). 4 figs., 3 refs

  4. The semantics of image quality

    NARCIS (Netherlands)

    Janssen, T.J.W.M.; Blommaert, F.J.J.

    1996-01-01

    In this contribution we will discuss image quality in the context of the visuo-cognitive system as an information-processing system. To this end, we subdivide the information-processing as performed by the visuo-cognitive system into three distinct processes: (1) the construction of a visual

  5. One-pot fabrication of high-quality InP/ZnS (core/shell) quantum dots and their application to cellular imaging.

    Science.gov (United States)

    Hussain, Sahid; Won, Nayoun; Nam, Jutaek; Bang, Jiwon; Chung, Hyokyun; Kim, Sungjee

    2009-07-13

    True colors: High-quality InP and InP/ZnS quantum dots (QDs) are obtained by means of a simple one-pot method in the presence of polyethylene glycol (PEG). Rapid and size-controlled reactions lead to highly crystalline and nearly monodisperse QDs at relatively low temperatures. The particles emit from cyan blue to far-red, and are successfully used in cellular imaging (see figure).

  6. Analog and digital image quality:

    OpenAIRE

    Sardo, Alberto

    2004-01-01

    Background. Lastly the X ray facilities are moving to a slow, but continuous process of digitalization. The dry laser printers allow hardcopy images with optimum resolution and contrast for all the modalities. In breast imaging, thedelay of digitalization depends to the high cost of digital systems and, attimes, to the doubts of the diagnostic accuracy of reading the breast digital images. Conclusions. The Screen film mammography (SFM) is the most efficient diagnostic modality to detect the b...

  7. Comparison of prospective electrocardiography-gating high-pitch mode and without electrocardiography-synchronization high-pitch mode acquisition for the image quality and radiation doses of the aortic using dual-source CT

    International Nuclear Information System (INIS)

    Li Jian; Huan Yi; Zhao Hongliang; Wang Ying; Liu Ying; Wei Mengqi; Shi Mingguo; Zheng Minwen

    2013-01-01

    Objective: To evaluate the application of prospective ECG-gating Flash spiral scan mode dual-source CT in aortography, and compare it's image quality and radiation dose with without ECG-synchronization high-pitch spiral scanning mode. Methods: Fifty consecutive patients (Group A) with suspected aortic dissection or after operations for the aortic dissection were scanned with prospective ECG-gated high-pitch scan and another 50 consecutive patients (Group B) were analyzed by non-ECG-gated high-pitch scan. Image quality of the aortic was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated. The imaging quality of the aortic and the radiation dose were compared with Mann-whitney U and t test. Results: The average image quality score [(1.18 ± 0.40) in group A and (1.23 ± 0.31) in group B] showed no significant difference between group A and group B (U = 1.20, P = 0.23). The mean radiation dose of group A was lower than that of group B [(1.49 ± 0.38) mSv in group A, (2.79 ± 0.54) mSv in group B, t = 13.677, P < 0.05]. Conclusion: Prospective ECG-gated dual source CT Flash spiral scanning with low radiation dose and good image quality in the aortic dissection with high value of clinical application. (authors)

  8. Quality assurance for electronic portal imaging devices

    International Nuclear Information System (INIS)

    Shalev, S.; Rajapakshe, R.; Gluhchev, G.; Luchka, K.

    1997-01-01

    Electronic portal imaging devices (EPIDS) are assuming an ever-increasing role in the verification of radiation treatment accuracy. They are used both in a passive capacity, for the determination of field displacement distributions (''setup errors''), and also in an active role whereby the patient setup is corrected on the basis of electronic portal images. In spite of their potential impact on the precision of patient treatment, there are few quality assurance procedures available, and most of the EPIDS in clinical use are subject, at best, to only perfunctory quality assurance. The goals of this work are (a) to develop an objective and reproducible test for EPID image quality on the factory floor and during installation of the EPID on site; (b) to provide the user with a simple and accurate tool for acceptance, commissioning, and routine quality control; and (c) to initiate regional, national and international collaboration in the implementation of standardized, objective, and automated quality assurance procedures. To this end we have developed an automated test in which a simple test object is imaged daily, and the spatial and contrast resolution of the EPID are automatically evaluated in terms of ''acceptable'', ''warning'' and ''stop'' criteria. Our experience over two years shows the test to be highly sensitive, reproducible, and inexpensive in time and effort. Inter-institutional trials are under way in Canada, US and Europe which indicate large variations in EPID image quality from one EPID to another, and from one center to another. We expect the new standardized quality assurance procedure to lead to improved, and consistent image quality, increased operator acceptance of the technology, and agreement on uniform standards by equipment suppliers and health care agencies. (author)

  9. A universal color image quality metric

    NARCIS (Netherlands)

    Toet, A.; Lucassen, M.P.

    2003-01-01

    We extend a recently introduced universal grayscale image quality index to a newly developed perceptually decorrelated color space. The resulting color image quality index quantifies the distortion of a processed color image relative to its original version. We evaluated the new color image quality

  10. Free-breathing high-pitch 80kVp dual-source computed tomography of the pediatric chest: Image quality, presence of motion artifacts and radiation dose.

    Science.gov (United States)

    Bodelle, Boris; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Beeres, Martin; Vogl, Thomas J; Scholtz, Jan-Erik

    2017-04-01

    To investigate image quality, presence of motion artifacts and effects on radiation dose of 80kVp high-pitch dual-source CT (DSCT) in combination with an advanced modeled iterative reconstruction algorithm (ADMIRE) of the pediatric chest compared to single-source CT (SSCT). The study was approved by the institutional review board. Eighty-seven consecutive pediatric patients (mean age 9.1±4.9years) received either free-breathing high-pitch (pitch 3.2) chest 192-slice DSCT (group 1, n=31) or standard-pitch (pitch 1.2) 128-slice SSCT (group 2, n=56) with breathing-instructions by random assignment. Tube settings were similar in both groups with 80 kVp and 74 ref. mAs. Images were reconstructed using FBP for both groups. Additionally, ADMIRE was used in group 1. Effective thorax diameter, image noise, and signal-to-noise ratio (SNR) of the pectoralis major muscle and the thoracic aorta were calculated. Motion artifacts were measured as doubling boarders of the diaphragm and the heart. Images were rated by two blinded readers for overall image quality and presence of motion artifacts on 5-point-scales. Size specific dose estimates (SSDE, mGy) and effective dose (ED, mSv) were calculated. Age and effective thorax diameter showed no statistically significant differences in both groups. Image noise and SNR were comparable (p>0.64) for SSCT and DSCT with ADMIRE, while DSCT with FBP showed inferior results (pchest DSCT in combination with ADMIRE reduces motion artifacts and increases image quality while lowering radiation exposure in free-breathing pediatric patients without sedation. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Influence of high magnetic field strengths and parallel acquisition strategies on image quality in cardiac 2D CINE magnetic resonance imaging: comparison of 1.5 T vs. 3.0 T

    International Nuclear Information System (INIS)

    Gutberlet, Matthias; Schwinge, Kerstin; Freyhardt, Patrick; Spors, Birgit; Grothoff, Matthias; Denecke, Timm; Luedemann, Lutz; Felix, Roland; Noeske, Ralph; Niendorf, Thoralf

    2005-01-01

    The aim of this paper is to examine signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and image quality of cardiac CINE imaging at 1.5 T and 3.0 T. Twenty volunteers underwent cardiac magnetic resonance imaging (MRI) examinations using a 1.5-T and a 3.0-T scanner. Three different sets of breath-held, electrocardiogram-gated (ECG) CINE imaging techniques were employed, including: (1) unaccelerated SSFP (steady state free precession), (2) accelerated SSFP imaging and (3) gradient-echo-based myocardial tagging. Two-dimensional CINE SSFP at 3.0 T revealed an SNR improvement of 103% and a CNR increase of 19% as compared to the results obtained at 1.5 T. The SNR reduction in accelerated 2D CINE SSFP imaging was larger at 1.5 T (37%) compared to 3.0 T (26%). The mean SNR and CNR increase at 3.0 T obtained for the tagging sequence was 88% and 187%, respectively. At 3.0 T, the duration of the saturation bands persisted throughout the entire cardiac cycle. For comparison, the saturation bands were significantly diminished at 1.5 T during end-diastole. For 2D CINE SSFP imaging, no significant difference in the left ventricular volumetry and in the overall image quality was obtained. For myocardial tagging, image quality was significantly improved at 3.0 T. The SNR reduction in accelerated SSFP imaging was overcompensated by the increase in the baseline SNR at 3.0 T and did not result in any image quality degradation. For cardiac tagging techniques, 3.0 T was highly beneficial, which holds the promise to improve its diagnostic value. (orig.)

  12. Implementation of dictionary pair learning algorithm for image quality improvement

    Science.gov (United States)

    Vimala, C.; Aruna Priya, P.

    2018-04-01

    This paper proposes an image denoising on dictionary pair learning algorithm. Visual information is transmitted in the form of digital images is becoming a major method of communication in the modern age, but the image obtained after transmissions is often corrupted with noise. The received image needs processing before it can be used in applications. Image denoising involves the manipulation of the image data to produce a visually high quality image.

  13. Mathematical determination of image quality

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, H H

    1982-01-01

    The subjective term ''image quality'' is generally not easy to define and to measure. If, however, we limit ourselves, to determine certain anomalies in blurred images, then the task can be done more easily. The efficiency can in fact be measured and the results can be presented as ROC-characteristics (receiver operating characteristics). One can determine a relation between the characteristic and the noise distance of the imaging system, and this way the efficiency of an hypothetical ideal observer can be predicted. Furthermore one can compute noise distance and other statistical parameters of X-ray images distorted by quantum interference by special techniques that are founded on the so-called ''blur core''. The technique proved to be very successful in nuclear medicine, but is also valid in computerized tomography and X-ray diagnostics. The technique is explained without mathematical details. The question will be answered concerning the role mathematical analysis will play in the determination and optimization of the quality of diagnostic exposures.

  14. Quality assessment for online iris images

    CSIR Research Space (South Africa)

    Makinana, S

    2015-01-01

    Full Text Available Iris recognition systems have attracted much attention for their uniqueness, stability and reliability. However, performance of this system depends on quality of iris image. Therefore there is a need to select good quality images before features can...

  15. Image quality dependence on image processing software in ...

    African Journals Online (AJOL)

    Image quality dependence on image processing software in computed radiography. ... Agfa CR readers use MUSICA software, and an upgrade with significantly different image ... Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT

  16. Image quality in digital radiographic systems

    Directory of Open Access Journals (Sweden)

    Almeida Solange Maria de

    2003-01-01

    Full Text Available The aim of the present study was to evaluate the image quality of four direct digital radiographic systems. Radiographs were made of the maxillary central incisor and mandibular left molar regions of a dry skull, and an aluminum step-wedge. The X-ray generator operated at 10 mA, 60 and 70 kVp, and images were acquired with 3, 5, 8, 12, 24 and 48 exposure pulses. Six well-trained observers classified the images by means of scores from 1 to 3. Collected data were submitted to nonparametric statistical analysis using Fisher's exact test. Statistical analysis showed significant differences (p<0.01 in image quality with the four systems. Based on the results, it was possible to conclude that: 1 all of the digital systems presented good performance in producing acceptable images for diagnosis, if the exposures of the step-wedge and the maxillary central incisor region were made at 5 pulses, as well as at 8 pulses for the mandibular left molar region, selecting 60 or 70kVp; 2 higher percentages of acceptable images were obtained with the administration of lower radiation doses in CCD-sensors (charge-coupled device; 3 the Storage Phosphor systems produced acceptable images at a large range of exposure settings, that included low, intermediate and high radiation doses.

  17. Ultra-high resolution C-Arm CT arthrography of the wrist: Radiation dose and image quality compared to conventional multidetector computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Werncke, Thomas, E-mail: Werncke.Thomas@mh-hannover.de [Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover (Germany); Sonnow, Lena; Meyer, Bernhard C. [Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover (Germany); Lüpke, Matthias [University of Veterinary Medicine Hannover, Institute for General Radiology and Medical Physics, Bischofsholer Damm 15, 30173 Hannover (Germany); Hinrichs, Jan; Wacker, Frank K.; Falck, Christian von [Institute of Diagnostic and Interventional Radiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover (Germany)

    2017-04-15

    Objective: Objective of this phantom and cadaveric study was to compare the effective radiation dose (ED) and image quality (IQ) between C-arm computed tomography (CACT) using an ultra-high resolution 1 × 1 binning with a standard 16-slice CT (MDCT) arthrography of the wrist. Methods: ED was determined with thermoluminescence dosimetry using an anthropomorphic phantom and different patient positions. Imaging was conducted in 10 human cadaveric wrists after tri-compartmental injection of diluted iodinated contrast material and a wire phantom. IQ of MDCT was compared with CACT reconstructed with a soft (CACT1) and sharp (CACT2) kernel. High and low contrast resolution was determined. Three radiologists assessed IQ of wrist structures and occurrence of image artifacts using a 5-point Likert scale. Results: ED of MDCT was comparable to standard CACT (4.3 μSv/3.7 μSv). High contrast resolution was best for CACT2, decreased to CACT1 and MDCT. Low contrast resolution increased between CACT2 and MDCT (P < 0.001). IQ was best for CACT2 (1.3 ± 0.5), decreased to CACT1 (1.9 ± 0.6) and MDCT (3.5 ± 0.6). Non-compromising artifacts were only reported for CACT. Conclusions: The results of this phantom and cadaveric study indicate that ultra-high resolution C-Arm CT arthrography of the wrist bears the potential to outperform MDCT arthrography in terms of image quality and workflow at the cost of mildly increasing image artifacts while radiation dose to the patient is comparably low for both, MDCT and C-Arm CT.

  18. Improving the Image Quality of Synthetic Transmit Aperture Ultrasound Images - Achieving Real-Time In-Vivo Imaging

    DEFF Research Database (Denmark)

    Gammelmark, Kim

    in-vivo experiments, showed, that TMS imaging can increase the SNR by as much as 17 dB compared to the traditional imaging techniques, which improves the in-vivo image quality to a highly competitive level. An in-vivo evaluation of convex array TMS imaging for abdominal imaging applications......-vivo imaging, and that the obtained image quality is highly competitive with the techniques applied in current medical ultrasound scanners. Hereby, the goals of the PhD have been successfully achieved.......Synthetic transmit aperture (STA) imaging has the potential to increase the image quality of medical ultrasound images beyond the levels obtained by conventional imaging techniques (linear, phased, and convex array imaging). Currently, however, in-vivo applications of STA imaging is limited...

  19. Developing and validating a psychometric scale for image quality assessment

    International Nuclear Information System (INIS)

    Mraity, H.; England, A.; Hogg, P.

    2014-01-01

    Purpose: Using AP pelvis as a catalyst, this paper explains how a psychometric scale for image quality assessment can be created using Bandura's theory for self-efficacy. Background: Establishing an accurate diagnosis is highly dependent upon the quality of the radiographic image. Image quality, as a construct (i.e. set of attributes that makes up the image quality), continues to play an essential role in the field of diagnostic radiography. The process of assessing image quality can be facilitated by using criteria, such as the European Commission (EC) guidelines for quality criteria as published in 1996. However, with the advent of new technology (Computed Radiography and Digital Radiography), some of the EC criteria may no longer be suitable for assessing the visual quality of a digital radiographic image. Moreover, a lack of validated visual image quality scales in the literature can also lead to significant variations in image quality evaluation. Creating and validating visual image quality scales, using a robust methodology, could reduce variability and improve the validity and reliability of perceptual image quality evaluations

  20. Free-breathing high-pitch 80 kVp dual-source computed tomography of the pediatric chest: Image quality, presence of motion artifacts and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Bodelle, Boris, E-mail: bbodelle@googlemail.com; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Beeres, Martin; Vogl, Thomas J.; Scholtz, Jan-Erik

    2017-04-15

    Objectives: To investigate image quality, presence of motion artifacts and effects on radiation dose of 80 kVp high-pitch dual-source CT (DSCT) in combination with an advanced modeled iterative reconstruction algorithm (ADMIRE) of the pediatric chest compared to single-source CT (SSCT). Materials and methods: The study was approved by the institutional review board. Eighty-seven consecutive pediatric patients (mean age 9.1 ± 4.9 years) received either free-breathing high-pitch (pitch 3.2) chest 192-slice DSCT (group 1, n = 31) or standard-pitch (pitch 1.2) 128-slice SSCT (group 2, n = 56) with breathing-instructions by random assignment. Tube settings were similar in both groups with 80 kVp and 74 ref. mAs. Images were reconstructed using FBP for both groups. Additionally, ADMIRE was used in group 1. Effective thorax diameter, image noise, and signal-to-noise ratio (SNR) of the pectoralis major muscle and the thoracic aorta were calculated. Motion artifacts were measured as doubling boarders of the diaphragm and the heart. Images were rated by two blinded readers for overall image quality and presence of motion artifacts on 5-point-scales. Size specific dose estimates (SSDE, mGy) and effective dose (ED, mSv) were calculated. Results: Age and effective thorax diameter showed no statistically significant differences in both groups. Image noise and SNR were comparable (p > 0.64) for SSCT and DSCT with ADMIRE, while DSCT with FBP showed inferior results (p < 0.01). Motion artifacts were reduced significantly (p = 0.001) with DSCT. DSCT with ADMIRE showed the highest overall IQ (p < 0.0001). Radiation dose was lower for DSCT compared to SSCT (median SSDE: 0.82 mGy vs. 0.92 mGy, p < 0.02; median ED: 0.4 mSv vs. 0.48 mSv, p = 0.02). Conclusions: High-pitch 80 kVp chest DSCT in combination with ADMIRE reduces motion artifacts and increases image quality while lowering radiation exposure in free-breathing pediatric patients without sedation.

  1. Free-breathing high-pitch 80 kVp dual-source computed tomography of the pediatric chest: Image quality, presence of motion artifacts and radiation dose

    International Nuclear Information System (INIS)

    Bodelle, Boris; Fischbach, Constanze; Booz, Christian; Yel, Ibrahim; Frellesen, Claudia; Beeres, Martin; Vogl, Thomas J.; Scholtz, Jan-Erik

    2017-01-01

    Objectives: To investigate image quality, presence of motion artifacts and effects on radiation dose of 80 kVp high-pitch dual-source CT (DSCT) in combination with an advanced modeled iterative reconstruction algorithm (ADMIRE) of the pediatric chest compared to single-source CT (SSCT). Materials and methods: The study was approved by the institutional review board. Eighty-seven consecutive pediatric patients (mean age 9.1 ± 4.9 years) received either free-breathing high-pitch (pitch 3.2) chest 192-slice DSCT (group 1, n = 31) or standard-pitch (pitch 1.2) 128-slice SSCT (group 2, n = 56) with breathing-instructions by random assignment. Tube settings were similar in both groups with 80 kVp and 74 ref. mAs. Images were reconstructed using FBP for both groups. Additionally, ADMIRE was used in group 1. Effective thorax diameter, image noise, and signal-to-noise ratio (SNR) of the pectoralis major muscle and the thoracic aorta were calculated. Motion artifacts were measured as doubling boarders of the diaphragm and the heart. Images were rated by two blinded readers for overall image quality and presence of motion artifacts on 5-point-scales. Size specific dose estimates (SSDE, mGy) and effective dose (ED, mSv) were calculated. Results: Age and effective thorax diameter showed no statistically significant differences in both groups. Image noise and SNR were comparable (p > 0.64) for SSCT and DSCT with ADMIRE, while DSCT with FBP showed inferior results (p < 0.01). Motion artifacts were reduced significantly (p = 0.001) with DSCT. DSCT with ADMIRE showed the highest overall IQ (p < 0.0001). Radiation dose was lower for DSCT compared to SSCT (median SSDE: 0.82 mGy vs. 0.92 mGy, p < 0.02; median ED: 0.4 mSv vs. 0.48 mSv, p = 0.02). Conclusions: High-pitch 80 kVp chest DSCT in combination with ADMIRE reduces motion artifacts and increases image quality while lowering radiation exposure in free-breathing pediatric patients without sedation.

  2. MO-AB-210-00: Diagnostic Ultrasound Imaging Quality Control and High Intensity Focused Ultrasound Therapy Hands-On Workshop

    International Nuclear Information System (INIS)

    2015-01-01

    The goal of this ultrasound hands-on workshop is to demonstrate advancements in high intensity focused ultrasound (HIFU) and to demonstrate quality control (QC) testing in diagnostic ultrasound. HIFU is a therapeutic modality that uses ultrasound waves as carriers of energy. HIFU is used to focus a beam of ultrasound energy into a small volume at specific target locations within the body. The focused beam causes localized high temperatures and produces a well-defined regions of necrosis. This completely non-invasive technology has great potential for tumor ablation and targeted drug delivery. At the workshop, attendees will see configurations, applications, and hands-on demonstrations with on-site instructors at separate stations. The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. At the workshop, an array of ultrasound testing phantoms and ultrasound scanners will be provided for attendees to learn diagnostic ultrasound QC in a hands-on environment with live demonstrations of the techniques. Target audience: Medical physicists and other medical professionals in diagnostic imaging and radiation oncology with interest in high-intensity focused ultrasound and in diagnostic ultrasound QC. Learning Objectives: Learn ultrasound physics and safety for HIFU applications through live demonstrations Get an overview of the state-of-the art in HIFU technologies and equipment Gain familiarity with common elements of a quality control program for diagnostic ultrasound imaging Identify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools List of supporting vendors for HIFU and diagnostic ultrasound QC hands-on workshop: Philips Healthcare Alpinion Medical Systems Verasonics, Inc Zonare Medical Systems, Inc Computerized Imaging Reference Systems (CIRS), Inc. GAMMEX, Inc., Cablon Medical BV Steffen Sammet: NIH/NCI grant 5R25CA132822, NIH/NINDS grant 5R25NS

  3. MO-AB-210-00: Diagnostic Ultrasound Imaging Quality Control and High Intensity Focused Ultrasound Therapy Hands-On Workshop

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-06-15

    The goal of this ultrasound hands-on workshop is to demonstrate advancements in high intensity focused ultrasound (HIFU) and to demonstrate quality control (QC) testing in diagnostic ultrasound. HIFU is a therapeutic modality that uses ultrasound waves as carriers of energy. HIFU is used to focus a beam of ultrasound energy into a small volume at specific target locations within the body. The focused beam causes localized high temperatures and produces a well-defined regions of necrosis. This completely non-invasive technology has great potential for tumor ablation and targeted drug delivery. At the workshop, attendees will see configurations, applications, and hands-on demonstrations with on-site instructors at separate stations. The involvement of medical physicists in diagnostic ultrasound imaging service is increasing due to QC and accreditation requirements. At the workshop, an array of ultrasound testing phantoms and ultrasound scanners will be provided for attendees to learn diagnostic ultrasound QC in a hands-on environment with live demonstrations of the techniques. Target audience: Medical physicists and other medical professionals in diagnostic imaging and radiation oncology with interest in high-intensity focused ultrasound and in diagnostic ultrasound QC. Learning Objectives: Learn ultrasound physics and safety for HIFU applications through live demonstrations Get an overview of the state-of-the art in HIFU technologies and equipment Gain familiarity with common elements of a quality control program for diagnostic ultrasound imaging Identify QC tools available for testing diagnostic ultrasound systems and learn how to use these tools List of supporting vendors for HIFU and diagnostic ultrasound QC hands-on workshop: Philips Healthcare Alpinion Medical Systems Verasonics, Inc Zonare Medical Systems, Inc Computerized Imaging Reference Systems (CIRS), Inc. GAMMEX, Inc., Cablon Medical BV Steffen Sammet: NIH/NCI grant 5R25CA132822, NIH/NINDS grant 5R25NS

  4. Image quality analysis of digital mammographic equipments

    Energy Technology Data Exchange (ETDEWEB)

    Mayo, P.; Pascual, A.; Verdu, G. [Valencia Univ. Politecnica, Chemical and Nuclear Engineering Dept. (Spain); Rodenas, F. [Valencia Univ. Politecnica, Applied Mathematical Dept. (Spain); Campayo, J.M. [Valencia Univ. Hospital Clinico, Servicio de Radiofisica y Proteccion Radiologica (Spain); Villaescusa, J.I. [Hospital Clinico La Fe, Servicio de Proteccion Radiologica, Valencia (Spain)

    2006-07-01

    The image quality assessment of a radiographic phantom image is one of the fundamental points in a complete quality control programme. The good functioning result of all the process must be an image with an appropriate quality to carry out a suitable diagnostic. Nowadays, the digital radiographic equipments are replacing the traditional film-screen equipments and it is necessary to update the parameters to guarantee the quality of the process. Contrast-detail phantoms are applied to digital radiography to study the threshold contrast detail sensitivity at operation conditions of the equipment. The phantom that is studied in this work is C.D.M.A.M. 3.4, which facilitates the evaluation of image contrast and detail resolution. One of the most extended indexes to measure the image quality in an objective way is the Image Quality Figure (I.Q.F.). This parameter is useful to calculate the image quality taking into account the contrast and detail resolution of the image analysed. The contrast-detail curve is useful as a measure of the image quality too, because it is a graphical representation in which the hole thickness and diameter are plotted for each contrast-detail combination detected in the radiographic image of the phantom. It is useful for the comparison of the functioning of different radiographic image systems, for phantom images under the same exposition conditions. The aim of this work is to study the image quality of different images contrast-detail phantom C.D.M.A.M. 3.4, carrying out the automatic detection of the contrast-detail combination and to establish a parameter which characterize in an objective way the mammographic image quality. This is useful to compare images obtained at different digital mammographic equipments to study the functioning of the equipments. (authors)

  5. Image quality analysis of digital mammographic equipments

    International Nuclear Information System (INIS)

    Mayo, P.; Pascual, A.; Verdu, G.; Rodenas, F.; Campayo, J.M.; Villaescusa, J.I.

    2006-01-01

    The image quality assessment of a radiographic phantom image is one of the fundamental points in a complete quality control programme. The good functioning result of all the process must be an image with an appropriate quality to carry out a suitable diagnostic. Nowadays, the digital radiographic equipments are replacing the traditional film-screen equipments and it is necessary to update the parameters to guarantee the quality of the process. Contrast-detail phantoms are applied to digital radiography to study the threshold contrast detail sensitivity at operation conditions of the equipment. The phantom that is studied in this work is C.D.M.A.M. 3.4, which facilitates the evaluation of image contrast and detail resolution. One of the most extended indexes to measure the image quality in an objective way is the Image Quality Figure (I.Q.F.). This parameter is useful to calculate the image quality taking into account the contrast and detail resolution of the image analysed. The contrast-detail curve is useful as a measure of the image quality too, because it is a graphical representation in which the hole thickness and diameter are plotted for each contrast-detail combination detected in the radiographic image of the phantom. It is useful for the comparison of the functioning of different radiographic image systems, for phantom images under the same exposition conditions. The aim of this work is to study the image quality of different images contrast-detail phantom C.D.M.A.M. 3.4, carrying out the automatic detection of the contrast-detail combination and to establish a parameter which characterize in an objective way the mammographic image quality. This is useful to compare images obtained at different digital mammographic equipments to study the functioning of the equipments. (authors)

  6. Quality assurance for image-guided radiotherapy

    International Nuclear Information System (INIS)

    Marinello, Ginette

    2008-01-01

    The topics discussed include, among others, the following: Quality assurance program; Image guided radiotherapy; Commissioning and quality assurance; Check of agreement between visual and displayed scales; quality controls: electronic portal imaging device (EPID), MV-kV and kV-kV, cone-beam CT (CBCT), patient doses. (P.A.)

  7. The influence of environment temperature on SEM image quality

    International Nuclear Information System (INIS)

    Chen, Li; Liu, Junshan

    2015-01-01

    As the structure dimension goes down to the nano-scale, it often requires a scanning electron microscope (SEM) to provide image magnification up to 100 000  ×. However, SEM images at such a high magnification usually suffer from high resolution value and low signal-to-noise ratio, which results in low quality of the SEM image. In this paper, the quality of the SEM image is improved by optimizing the environment temperature. The experimental results indicate that at 100 000  ×, the quality of the SEM image is influenced by the environment temperature, whereas at 50 000  × it is not. At 100 000  × the best SEM image quality can be achieved from the environment temperature ranging 292 from 294 K, and the SEM image quality evaluated by the double stimulus continuous quality scale method can increase from grade 1 to grade 5. It is expected that this image quality improving method can be used in routine measurements with ordinary SEMs to get high quality images by optimizing the environment temperature. (paper)

  8. Statistical reconstruction for cone-beam CT with a post-artifact-correction noise model: application to high-quality head imaging

    International Nuclear Information System (INIS)

    Dang, H; Stayman, J W; Sisniega, A; Xu, J; Zbijewski, W; Siewerdsen, J H; Wang, X; Foos, D H; Aygun, N; Koliatsos, V E

    2015-01-01

    Non-contrast CT reliably detects fresh blood in the brain and is the current front-line imaging modality for intracranial hemorrhage such as that occurring in acute traumatic brain injury (contrast ∼40–80 HU, size  >  1 mm). We are developing flat-panel detector (FPD) cone-beam CT (CBCT) to facilitate such diagnosis in a low-cost, mobile platform suitable for point-of-care deployment. Such a system may offer benefits in the ICU, urgent care/concussion clinic, ambulance, and sports and military theatres. However, current FPD-CBCT systems face significant challenges that confound low-contrast, soft-tissue imaging. Artifact correction can overcome major sources of bias in FPD-CBCT but imparts noise amplification in filtered backprojection (FBP). Model-based reconstruction improves soft-tissue image quality compared to FBP by leveraging a high-fidelity forward model and image regularization. In this work, we develop a novel penalized weighted least-squares (PWLS) image reconstruction method with a noise model that includes accurate modeling of the noise characteristics associated with the two dominant artifact corrections (scatter and beam-hardening) in CBCT and utilizes modified weights to compensate for noise amplification imparted by each correction. Experiments included real data acquired on a FPD-CBCT test-bench and an anthropomorphic head phantom emulating intra-parenchymal hemorrhage. The proposed PWLS method demonstrated superior noise-resolution tradeoffs in comparison to FBP and PWLS with conventional weights (viz. at matched 0.50 mm spatial resolution, CNR = 11.9 compared to CNR = 5.6 and CNR = 9.9, respectively) and substantially reduced image noise especially in challenging regions such as skull base. The results support the hypothesis that with high-fidelity artifact correction and statistical reconstruction using an accurate post-artifact-correction noise model, FPD-CBCT can achieve image quality allowing reliable detection of

  9. Practical evaluation of clinical image quality (4). Determination of image quality in digital radiography system

    International Nuclear Information System (INIS)

    Katayama, Reiji

    2016-01-01

    Recently, for medical imaging, digital radiography systems are widely used in clinical practices. However, a study in the past reported that a patient radiation exposure level by digital radiography is in fact not lower than that by analog radiography system. High level of attention needs to be paid for over-exposure when using the conventional analog radiography with a screen and a film, as it results in high density of the film. However, for digital radiography systems, since the automatic adjusting function of image density is equipped with them, no attention for radiation dose need to be paid. Thus technologists tend to be careless and results in higher chance for over-exposure. Current digital radiography systems are high-performance in the image properties and capable of patient dose reduction. Especially, the image quality of the flat panel detector system is recognized, higher than that of the computed radiography system by imaging plates, in both objective and subjective evaluations. Therefore, we technologists are responsible for optimizing the balance between the image quality of the digital radiogram and the radiation dose required for each case. Moreover, it is also required for us as medical technologists to make effective use of such evaluation result of medical images for patients. (author)

  10. Improving image quality in portal venography with spectral CT imaging

    International Nuclear Information System (INIS)

    Zhao, Li-qin; He, Wen; Li, Jian-ying; Chen, Jiang-hong; Wang, Ke-yang; Tan, Li

    2012-01-01

    Objective: To investigate the effect of energy spectral CT on the image quality of CT portal venography in cirrhosis patients. Materials and methods: 30 portal hypertension patients underwent spectral CT examination using a single-tube, fast dual tube voltage switching technique. 101 sets of monochromatic images were generated from 40 keV to 140 keV. Image noise and contrast-to-noise ratio (CNR) for portal veins from the monochromatic images were measured. An optimal monochromatic image set was selected for obtaining the best CNR for portal veins. The image noise and CNR of the intra-hepatic portal vein and extra-hepatic main stem at the selected monochromatic level were compared with those from the conventional polychromatic images. Image quality was also assessed and compared. Results: The monochromatic images at 51 keV were found to provide the best CNR for both the intra-hepatic and extra-hepatic portal veins. At this energy level, the monochromatic images had about 100% higher CNR than the polychromatic images with a moderate 30% noise increase. The qualitative image quality assessment was also statistically higher with monochromatic images at 51 keV. Conclusion: Monochromatic images at 51 keV for CT portal venography could improve CNR for displaying hepatic portal veins and improve the overall image quality.

  11. Improving image quality in portal venography with spectral CT imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Li-qin, E-mail: zhaolqzr@sohu.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); He, Wen, E-mail: hewen1724@sina.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); Li, Jian-ying, E-mail: jianying.li@med.ge.com [CT Advanced Application and Research, GE Healthcare, 100176 China (China); Chen, Jiang-hong, E-mail: chenjianghong1973@hotmail.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); Wang, Ke-yang, E-mail: ke7ke@sina.com [Department of Radiology, Beijing Friendship Hospital Affiliated to Capital Medical University, Beijing,100050 (China); Tan, Li, E-mail: Litan@ge.com [CT product, GE Healthcare, 100176 China (China)

    2012-08-15

    Objective: To investigate the effect of energy spectral CT on the image quality of CT portal venography in cirrhosis patients. Materials and methods: 30 portal hypertension patients underwent spectral CT examination using a single-tube, fast dual tube voltage switching technique. 101 sets of monochromatic images were generated from 40 keV to 140 keV. Image noise and contrast-to-noise ratio (CNR) for portal veins from the monochromatic images were measured. An optimal monochromatic image set was selected for obtaining the best CNR for portal veins. The image noise and CNR of the intra-hepatic portal vein and extra-hepatic main stem at the selected monochromatic level were compared with those from the conventional polychromatic images. Image quality was also assessed and compared. Results: The monochromatic images at 51 keV were found to provide the best CNR for both the intra-hepatic and extra-hepatic portal veins. At this energy level, the monochromatic images had about 100% higher CNR than the polychromatic images with a moderate 30% noise increase. The qualitative image quality assessment was also statistically higher with monochromatic images at 51 keV. Conclusion: Monochromatic images at 51 keV for CT portal venography could improve CNR for displaying hepatic portal veins and improve the overall image quality.

  12. Process perspective on image quality evaluation

    Science.gov (United States)

    Leisti, Tuomas; Halonen, Raisa; Kokkonen, Anna; Weckman, Hanna; Mettänen, Marja; Lensu, Lasse; Ritala, Risto; Oittinen, Pirkko; Nyman, Göte

    2008-01-01

    The psychological complexity of multivariate image quality evaluation makes it difficult to develop general image quality metrics. Quality evaluation includes several mental processes and ignoring these processes and the use of a few test images can lead to biased results. By using a qualitative/quantitative (Interpretation Based Quality, IBQ) methodology, we examined the process of pair-wise comparison in a setting, where the quality of the images printed by laser printer on different paper grades was evaluated. Test image consisted of a picture of a table covered with several objects. Three other images were also used, photographs of a woman, cityscape and countryside. In addition to the pair-wise comparisons, observers (N=10) were interviewed about the subjective quality attributes they used in making their quality decisions. An examination of the individual pair-wise comparisons revealed serious inconsistencies in observers' evaluations on the test image content, but not on other contexts. The qualitative analysis showed that this inconsistency was due to the observers' focus of attention. The lack of easily recognizable context in the test image may have contributed to this inconsistency. To obtain reliable knowledge of the effect of image context or attention on subjective image quality, a qualitative methodology is needed.

  13. Balancing patient dose and image quality

    International Nuclear Information System (INIS)

    Martin, C.J.; Sutton, D.G.; Sharp, P.F.

    1999-01-01

    The formation of images in diagnostic radiology involves a complex interdependence of many factors. The ideal balance is to obtain an image which is adequate for the clinical purpose with the minimum radiation dose. Factors which affect radiation dose and image quality can be grouped under three headings; radiation quality, photon fluence and removal of scattered radiation. If optimal performance is to be achieved, it is necessary to understand how these factors influence image formation and affect radiation dose, and apply methodology for image quality and dose analysis at each stage in the development and use of X-ray equipment

  14. Encryption of QR code and grayscale image in interference-based scheme with high quality retrieval and silhouette problem removal

    Science.gov (United States)

    Qin, Yi; Wang, Hongjuan; Wang, Zhipeng; Gong, Qiong; Wang, Danchen

    2016-09-01

    In optical interference-based encryption (IBE) scheme, the currently available methods have to employ the iterative algorithms in order to encrypt two images and retrieve cross-talk free decrypted images. In this paper, we shall show that this goal can be achieved via an analytical process if one of the two images is QR code. For decryption, the QR code is decrypted in the conventional architecture and the decryption has a noisy appearance. Nevertheless, the robustness of QR code against noise enables the accurate acquisition of its content from the noisy retrieval, as a result of which the primary QR code can be exactly regenerated. Thereafter, a novel optical architecture is proposed to recover the grayscale image by aid of the QR code. In addition, the proposal has totally eliminated the silhouette problem existing in the previous IBE schemes, and its effectiveness and feasibility have been demonstrated by numerical simulations.

  15. Recognizable or Not: Towards Image Semantic Quality Assessment for Compression

    Science.gov (United States)

    Liu, Dong; Wang, Dandan; Li, Houqiang

    2017-12-01

    Traditionally, image compression was optimized for the pixel-wise fidelity or the perceptual quality of the compressed images given a bit-rate budget. But recently, compressed images are more and more utilized for automatic semantic analysis tasks such as recognition and retrieval. For these tasks, we argue that the optimization target of compression is no longer perceptual quality, but the utility of the compressed images in the given automatic semantic analysis task. Accordingly, we propose to evaluate the quality of the compressed images neither at pixel level nor at perceptual level, but at semantic level. In this paper, we make preliminary efforts towards image semantic quality assessment (ISQA), focusing on the task of optical character recognition (OCR) from compressed images. We propose a full-reference ISQA measure by comparing the features extracted from text regions of original and compressed images. We then propose to integrate the ISQA measure into an image compression scheme. Experimental results show that our proposed ISQA measure is much better than PSNR and SSIM in evaluating the semantic quality of compressed images; accordingly, adopting our ISQA measure to optimize compression for OCR leads to significant bit-rate saving compared to using PSNR or SSIM. Moreover, we perform subjective test about text recognition from compressed images, and observe that our ISQA measure has high consistency with subjective recognizability. Our work explores new dimensions in image quality assessment, and demonstrates promising direction to achieve higher compression ratio for specific semantic analysis tasks.

  16. Influence of radiation dose on image quality

    Energy Technology Data Exchange (ETDEWEB)

    Reichmann, S; Aastrand, K [Sahlgrenska Sjukhuset, Goeteborg (Sweden)

    1979-01-01

    When the speed of a recording medium is doubled the background quantum mottle is increased by a factor ..sqrt..2. However, the signal/noise ratio is changed not in proportion to the square root of the exposure, but in a linear fashion, i.e. by a factor 2. The change in the depiction of objects with a very high attenuation difference in relation to its surroundings appears not to be linear, but proportional to the square root of the exposure. Such objects (metal wire meshes, lead bar grids) should thus be avoided in routine evaluation of image quality since they give incomplete information as to image impairment when high-speed recording media are used.

  17. Influence of radiation dose on image quality

    International Nuclear Information System (INIS)

    Reichmann, S.; Aastrand, K.

    1979-01-01

    When the speed of a recording medium is doubled the background quantum mottle is increased by a factor √2. However, the signal/noise ratio is changed not in proportion to the square root of the exposure, but in a linear fashion, i.e. by a factor 2. The change in the depiction of objects with a very high attenuation difference in relation to its surroundings appears not to be linear, but proportional to the square root of the exposure. Such objects (metal wire meshes, lead bar grids) should thus be avoided in routine evaluation of image quality since they give incomplete information as to image impairment when high-speed recording media are used. (Auth.)

  18. Hyperspectral Image Analysis of Food Quality

    DEFF Research Database (Denmark)

    Arngren, Morten

    inspection.Near-infrared spectroscopy can address these issues by offering a fast and objectiveanalysis of the food quality. A natural extension to these single spectrumNIR systems is to include image information such that each pixel holds a NIRspectrum. This augmented image information offers several......Assessing the quality of food is a vital step in any food processing line to ensurethe best food quality and maximum profit for the farmer and food manufacturer.Traditional quality evaluation methods are often destructive and labourintensive procedures relying on wet chemistry or subjective human...... extensions to the analysis offood quality. This dissertation is concerned with hyperspectral image analysisused to assess the quality of single grain kernels. The focus is to highlight thebenefits and challenges of using hyperspectral imaging for food quality presentedin two research directions. Initially...

  19. Image quality at synthetic brain magnetic resonance imaging in children

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Mi; Cho, Seung Hyun; Kim, Won Hwa; Kim, Hye Jung [Kyungpook National University Hospital, Department of Radiology, Daegu (Korea, Republic of); Choi, Young Hun; Cheon, Jung-Eun; Kim, In-One [Seoul National University College of Medicine, Department of Radiology and Institute of Radiation Medicine, Seoul (Korea, Republic of); Cho, Hyun-Hae [Ewha Womans University Mokdong Hospital, Department of Radiology, Seoul (Korea, Republic of); You, Sun-Kyoung [Chungnam National University Hospital, Department of Radiology, Daejeon (Korea, Republic of); Park, Sook-Hyun [Kyungpook National University Hospital, Department of Pediatrics, Daegu (Korea, Republic of); Hwang, Moon Jung [GE Healthcare, MR Applications and Workflow, Seoul (Korea, Republic of)

    2017-11-15

    The clinical application of the multi-echo, multi-delay technique of synthetic magnetic resonance imaging (MRI) generates multiple sequences in a single acquisition but has mainly been used in adults. To evaluate the image quality of synthetic brain MR in children compared with that of conventional images. Twenty-nine children (median age: 6 years, range: 0-16 years) underwent synthetic and conventional imaging. Synthetic (T2-weighted, T1-weighted and fluid-attenuated inversion recovery [FLAIR]) images with settings matching those of the conventional images were generated. The overall image quality, gray/white matter differentiation, lesion conspicuity and image degradations were rated on a 5-point scale. The relative contrasts were assessed quantitatively and acquisition times for the two imaging techniques were compared. Synthetic images were inferior due to more pronounced image degradations; however, there were no significant differences for T1- and T2-weighted images in children <2 years old. The quality of T1- and T2-weighted images were within the diagnostically acceptable range. FLAIR images showed greatly reduced quality. Gray/white matter differentiation was comparable or better in synthetic T1- and T2-weighted images, but poorer in FLAIR images. There was no effect on lesion conspicuity. Synthetic images had equal or greater relative contrast. Acquisition time was approximately two-thirds of that for conventional sequences. Synthetic T1- and T2-weighted images were diagnostically acceptable, but synthetic FLAIR images were not. Lesion conspicuity and gray/white matter differentiation were comparable to conventional MRI. (orig.)

  20. IMAGE QUALITY FORECASTING FOR SPACE OBJECTS

    Directory of Open Access Journals (Sweden)

    A. I. Altukhov

    2013-05-01

    Full Text Available The article deals with an approach to quality predicting of the space objects images, which can be used to plan optoelectronic systems of remote sensing satellites work programs. The proposed approach is based on evaluation of the optoelectronic equipment transfer properties and calculation of indexes images quality considering the influence of the orbital shooting conditions.

  1. Increased Frame Rate for Plane Wave Imaging Without Loss of Image Quality

    DEFF Research Database (Denmark)

    Jensen, Jonas; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2015-01-01

    Clinical applications of plane wave imaging necessitate the creation of high-quality images with the highest possible frame rate for improved blood flow tracking and anatomical imaging. However, linear array transducers create grating lobe artefacts, which degrade the image quality especially...... in the near field for λ-pitch transducers. Artefacts can only partly be suppressed by increasing the number of emissions, and this paper demonstrates how the frame rate can be increased without loss of image quality by using λ/2-pitch transducers. The number of emissions and steering angles are optimized...

  2. Quality Control in Mammography: Image Quality and Patient Doses

    International Nuclear Information System (INIS)

    Ciraj Bjelac, O.; Arandjic, D.; Boris Loncar, B.; Kosutic, D.

    2008-01-01

    Mammography is method of choice for early detection of breast cancer. The purpose of this paper is preliminary evaluation the mammography practice in Serbia, in terms of both quality control indicators, i.e. image quality and patient doses. The survey demonstrated considerable variations in technical parameters that affect image quality and patients doses. Mean glandular doses ranged from 0.12 to 2.8 mGy, while reference optical density ranged from 1.2 to 2.8. Correlation between image contrast and mean glandular doses was demonstrated. Systematic implementation of quality control protocol should provide satisfactory performance of mammography units and maintain satisfactory image quality and keep patient doses as low as reasonably practicable. (author)

  3. Performance evaluation of a direct-conversion flat-panel detector system in imaging and quality assurance for a high-dose-rate 192Ir source

    Science.gov (United States)

    Miyahara, Yoshinori; Hara, Yuki; Nakashima, Hiroto; Nishimura, Tomonori; Itakura, Kanae; Inomata, Taisuke; Kitagaki, Hajime

    2018-03-01

    In high-dose-rate (HDR) brachytherapy, a direct-conversion flat-panel detector (d-FPD) clearly depicts a 192Ir source without image halation, even under the emission of high-energy gamma rays. However, it was unknown why iridium is visible when using a d-FPD. The purpose of this study was to clarify the reasons for visibility of the source core based on physical imaging characteristics, including the modulation transfer functions (MTF), noise power spectral (NPS), contrast transfer functions, and linearity of d-FPD to high-energy gamma rays. The acquired data included: x-rays, [X]; gamma rays, [γ] dual rays (X  +  γ), [D], and subtracted data for depicting the source ([D]  -  [γ]). In the quality assurance (QA) test for the positional accuracy of a source core, the coordinates of each dwelling point were compared between the planned and actual source core positions using a CT/MR-compatible ovoid applicator and a Fletcher-Williamson applicator. The profile curves of [X] and ([D]  -  [γ]) matched well on MTF and NPS. The contrast resolutions of [D] and [X] were equivalent. A strongly positive linear correlation was found between the output data of [γ] and source strength (r 2  >  0.99). With regard to the accuracy of the source core position, the largest coordinate difference (3D distance) was noted at the maximum curvature of the CT/MR-compatible ovoid and Fletcher-Williamson applicators, showing 1.74  ±  0.02 mm and 1.01  ±  0.01 mm, respectively. A d-FPD system provides high-quality images of a source, even when high-energy gamma rays are emitted to the detector, and positional accuracy tests with clinical applicators are useful in identifying source positions (source movements) within the applicator for QA.

  4. Modified-BRISQUE as no reference image quality assessment for structural MR images.

    Science.gov (United States)

    Chow, Li Sze; Rajagopal, Heshalini

    2017-11-01

    An effective and practical Image Quality Assessment (IQA) model is needed to assess the image quality produced from any new hardware or software in MRI. A highly competitive No Reference - IQA (NR - IQA) model called Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE) initially designed for natural images were modified to evaluate structural MR images. The BRISQUE model measures the image quality by using the locally normalized luminance coefficients, which were used to calculate the image features. The modified-BRISQUE model trained a new regression model using MR image features and Difference Mean Opinion Score (DMOS) from 775 MR images. Two types of benchmarks: objective and subjective assessments were used as performance evaluators for both original and modified-BRISQUE models. There was a high correlation between the modified-BRISQUE with both benchmarks, and they were higher than those for the original BRISQUE. There was a significant percentage improvement in their correlation values. The modified-BRISQUE was statistically better than the original BRISQUE. The modified-BRISQUE model can accurately measure the image quality of MR images. It is a practical NR-IQA model for MR images without using reference images. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Image Quality in Vascular Radiology

    International Nuclear Information System (INIS)

    Vanhavere, F.; Struelens, L.

    2005-01-01

    In vascular radiology, the radiologists use the radiological image to diagnose or treat a specific vascular structure. From literature, we know that related doses are high and that large dose variability exists between different hospitals. The application of the optimization principle is therefore necessary and is obliged by the new legislation. So far, very little fieldwork has been performed and no practical instructions are available to do the necessary work. It's indisputable that obtaining quantitative data is of great interest for optimization purposes. In order to gain insight into these doses and the possible measures for dose reduction, we performed a comparative study in 7 hospitals. Patient doses will be measured and calculated for specific procedures in vascular radiology and evaluated against their most influencing parameters. In view of optimization purposes, a protocol for dose audit will be set-up. From the results and conclusions in this study, experimentally based guidelines will be proposed, in order to improve clinical practice in vascular radiology

  6. MRI quality control: six imagers studied using eleven unified image quality parameters

    International Nuclear Information System (INIS)

    Ihalainen, T.; Sipilae, O.; Savolainen, S.

    2004-01-01

    Quality control of the magnetic resonance imagers of different vendors in the clinical environment is non-harmonised, and comparing the performance is difficult. The purpose of this study was to develop and apply a harmonised long-term quality control protocol for the six imagers in our organisation in order to assure that they fulfil the same basic image quality requirements. The same Eurospin phantom set and identical imaging parameters were used with each imager. Values of 11 comparable parameters describing the image quality were measured. Automatic image analysis software was developed to objectively analyse the images. The results proved that the imagers were operating at a performance level adequate for clinical imaging. Some deficiencies were detected in image uniformity and geometry. The automated analysis of the Eurospin phantom images was successful. The measurements were successfully repeated after 2 weeks on one imager and after half a year on all imagers. As an objective way of examining the image quality, this kind of comparable and objective quality control of different imagers is considered as an essential step towards harmonisation of the clinical MRI studies through a large hospital organisation. (orig.)

  7. STANDARDIZING QUALITY ASSESSMENT OF FUSED REMOTELY SENSED IMAGES

    Directory of Open Access Journals (Sweden)

    C. Pohl

    2017-09-01

    Full Text Available The multitude of available operational remote sensing satellites led to the development of many image fusion techniques to provide high spatial, spectral and temporal resolution images. The comparison of different techniques is necessary to obtain an optimized image for the different applications of remote sensing. There are two approaches in assessing image quality: 1. Quantitatively by visual interpretation and 2. Quantitatively using image quality indices. However an objective comparison is difficult due to the fact that a visual assessment is always subject and a quantitative assessment is done by different criteria. Depending on the criteria and indices the result varies. Therefore it is necessary to standardize both processes (qualitative and quantitative assessment in order to allow an objective image fusion quality evaluation. Various studies have been conducted at the University of Osnabrueck (UOS to establish a standardized process to objectively compare fused image quality. First established image fusion quality assessment protocols, i.e. Quality with No Reference (QNR and Khan's protocol, were compared on varies fusion experiments. Second the process of visual quality assessment was structured and standardized with the aim to provide an evaluation protocol. This manuscript reports on the results of the comparison and provides recommendations for future research.

  8. Standardizing Quality Assessment of Fused Remotely Sensed Images

    Science.gov (United States)

    Pohl, C.; Moellmann, J.; Fries, K.

    2017-09-01

    The multitude of available operational remote sensing satellites led to the development of many image fusion techniques to provide high spatial, spectral and temporal resolution images. The comparison of different techniques is necessary to obtain an optimized image for the different applications of remote sensing. There are two approaches in assessing image quality: 1. Quantitatively by visual interpretation and 2. Quantitatively using image quality indices. However an objective comparison is difficult due to the fact that a visual assessment is always subject and a quantitative assessment is done by different criteria. Depending on the criteria and indices the result varies. Therefore it is necessary to standardize both processes (qualitative and quantitative assessment) in order to allow an objective image fusion quality evaluation. Various studies have been conducted at the University of Osnabrueck (UOS) to establish a standardized process to objectively compare fused image quality. First established image fusion quality assessment protocols, i.e. Quality with No Reference (QNR) and Khan's protocol, were compared on varies fusion experiments. Second the process of visual quality assessment was structured and standardized with the aim to provide an evaluation protocol. This manuscript reports on the results of the comparison and provides recommendations for future research.

  9. Physical evaluation of prototype high-performance anti-scatter grids: potential for improved digital radiographic image quality

    International Nuclear Information System (INIS)

    Fetterly, Kenneth A; Schueler, Beth A

    2009-01-01

    Grid evaluation for a screen-film x-ray system has typically included independent measurement of the opposing contrast improvement factor and Bucky factor. Neither of these metrics, however, is appropriate when assessing grid performance in a digital imaging environment. For digital radiographic systems, the benefit of an anti-scatter grid is well characterized by the quantum signal-to-noise ratio improvement factor (K SNR ) provided by the grid. The purpose of this work was to measure K SNR of prototype grids designed for use with digital radiographic systems. The prototype grids had 5 mm tall lead septa, fiber interspace material, line rate N = 25 and 36 cm -1 and ratio r = 15 and 21, respectively. The primary and scatter transmission properties of the grids were measured, and K SNR was evaluated over a phantom thickness range of 10-50 cm. To provide a comparison, the K SNR of similarly constructed N44r15 and N80r15 grids is also reported. K SNR of the prototype grids ranged from 1.4 for the 10 cm phantom to 2.4 for the 50 cm phantom. For the thickest phantom, the SNR improvement factor of the prototype grids was 18-83% higher than that of the N44r15 and N80r15 grids, respectively. (note)

  10. Image Quality in Screening Mammography in Croatia

    International Nuclear Information System (INIS)

    Brnic, Z.; Klasic, B.; Popic-Ramac, J.; Ljevar, A.

    2011-01-01

    Mortality reduction through screening mammography (SMG) is possible only with examination of high image quality (IQ), which should be performed with acceptable patient breast radiation dose (BRD). Besides film processing control, equipment assessment with breast phantom and dosimetry, periodical external mammographic IQ assessment (MIQA) is needed, including image labelling (L), breast positioning (BP), exposure (EX) and artefacts (AR) assessment. The nationwide breast cancer screening program (NBSP) has been introduced in Croatia in 2006, and the MIQA is initiated as the first step in establishing quality assurance/quality control (QA/QC) framework in breast imaging in Croatia. The current study was aimed: (1) to provide objective evidence about the technical MIQ in NBSP in Croatia, (2) to compare MIQ between different types of mammographic units (MUs), (3) to identify the common deficiencies, and (4) to propose corrective activities. Mammograms (MGs) for IQA were collected from a total of 84 MUs which participate in NBSP, which represents 70 % of all MUs nationwide: A total of 420 MG examinations were reviewed. Each MU was requested to submit ''what they consider to be their five best representative MGs, each one performed in one of five consecutive workdays''. Mean age of MG machines was 7.76 years (range 2 - 21), with no difference between four MU types. This very first study of MIQ in Croatia corroborated our intuitive impression of inadequate IQ, staff training and equipment in many MUs nationwide. As MIQ strongly influences BC detection rate, suboptimal QA/QC always carries a risk to compromise the success of NBSP. Deficiencies in SMG, especially in ID and BP reflect different level of competency of radiological staff in Croatia. Differences in MIQ in various MU types are determined by their organization, equipment, education, working habits and motivation. More efforts are needed to train both RTs and radiologists to implement and maintain QA/QC in their

  11. PLEIADES-HR IMAGE QUALITY COMMISSIONING

    Directory of Open Access Journals (Sweden)

    L. Lebègue

    2012-07-01

    Full Text Available PLEIADES is the highest resolution civilian earth observing system ever developed in Europe. This imagery program is conducted by the French National Space Agency, CNES. It operates since 2012 a first satellite PLEIADES-HR launched on 2011 December 17th, a second one should be launched by the end of the year. Each satellite is designed to provide optical 70 cm resolution coloured images to civilian and defence users. The Image Quality requirements were defined from users studies from the different spatial imaging applications, taking into account the trade-off between on-board technological complexity and ground processing capacity. The assessment of the image quality and the calibration operation have been performed by CNES Image Quality team during the 6 month commissioning phase that followed the satellite launch. These activities cover many topics gathered in two families : radiometric and geometric image quality. The new capabilities offered by PLEIADES-HR agility allowed to imagine new methods of image calibration and performance assessment. Starting from an overview of the satellite characteristics, this paper presents all the calibration operations that were conducted during the commissioning phase and also gives the main results for every image quality performance.

  12. Image quality in coronary computed tomography angiography

    DEFF Research Database (Denmark)

    Precht, Helle; Gerke, Oke; Thygesen, Jesper

    2018-01-01

    Background Computed tomography (CT) technology is rapidly evolving and software solution developed to optimize image quality and/or lower radiation dose. Purpose To investigate the influence of adaptive statistical iterative reconstruction (ASIR) at different radiation doses in coronary CT...

  13. Quality control of imaging devices

    International Nuclear Information System (INIS)

    Soni, P.S.

    1992-01-01

    Quality assurance in nuclear medicine refers collectively to all aspects of a nuclear medicine service. It would include patient scheduling, radiopharmaceutical preparation and dispensing, radiation protection of patients, staff and general public, preventive maintenance and the care of instruments, methodology, data interpretation and records keeping, and many other small things which contribute directly or indirectly to the overall quality of a nuclear medicine service in a hospital. Quality Control, on the other hand, refers to a signal component of the system and is usually applied in relation to a specific instrument and its performance

  14. Quality measures in applications of image restoration.

    Science.gov (United States)

    Kriete, A; Naim, M; Schafer, L

    2001-01-01

    We describe a new method for the estimation of image quality in image restoration applications. We demonstrate this technique on a simulated data set of fluorescent beads, in comparison with restoration by three different deconvolution methods. Both the number of iterations and a regularisation factor are varied to enforce changes in the resulting image quality. First, the data sets are directly compared by an accuracy measure. These values serve to validate the image quality descriptor, which is developed on the basis of optical information theory. This most general measure takes into account the spectral energies and the noise, weighted in a logarithmic fashion. It is demonstrated that this method is particularly helpful as a user-oriented method to control the output of iterative image restorations and to eliminate the guesswork in choosing a suitable number of iterations.

  15. Tradeoffs between image quality and dose

    International Nuclear Information System (INIS)

    Seibert, J.A.

    2004-01-01

    Image quality takes on different perspectives and meanings when associated with the concept of as low as reasonably achievable (ALARA), which is chiefly focused on radiation dose delivered as a result of a medical imaging procedure. ALARA is important because of the increased radiosensitivity of children to ionizing radiation and the desire to keep the radiation dose low. By the same token, however, image quality is also important because of the need to provide the necessary information in a radiograph in order to make an accurate diagnosis. Thus, there are tradeoffs to be considered between image quality and radiation dose, which is the main topic of this article. ALARA does not necessarily mean the lowest radiation dose, nor, when implemented, does it result in the least desirable radiographic images. With the recent widespread implementation of digital radiographic detectors and displays, a new level of flexibility and complexity confronts the technologist, physicist, and radiologist in optimizing the pediatric radiography exam. This is due to the separation of the acquisition, display, and archiving events that were previously combined by the screen-film detector, which allows for compensation for under- and overexposures, image processing, and on-line image manipulation. As explained in the article, different concepts must be introduced for a better understanding of the tradeoffs encountered when dealing with digital radiography and ALARA. In addition, there are many instances during the image acquisition/display/interpretation process in which image quality and associated dose can be compromised. This requires continuous diligence to quality control and feedback mechanisms to verify that the goals of image quality, dose and ALARA are achieved. (orig.)

  16. Psychophysical evaluation of image quality : from judgment to impression

    NARCIS (Netherlands)

    Ridder, de H.; Rogowitz, B.E.; Pappas, T.N.

    1998-01-01

    Designs of imaging systems, image processing algorithms etc. usually take for granted that methods for assessing perceived image quality produce unbiased estimates of the viewers' quality impression. Quality judgments, however, are affected by the judgment strategies induced by the experimental

  17. Image Quality Assessment via Quality-aware Group Sparse Coding

    Directory of Open Access Journals (Sweden)

    Minglei Tong

    2014-12-01

    Full Text Available Image quality assessment has been attracting growing attention at an accelerated pace over the past decade, in the fields of image processing, vision and machine learning. In particular, general purpose blind image quality assessment is technically challenging and lots of state-of-the-art approaches have been developed to solve this problem, most under the supervised learning framework where the human scored samples are needed for training a regression model. In this paper, we propose an unsupervised learning approach that work without the human label. In the off-line stage, our method trains a dictionary covering different levels of image quality patch atoms across the training samples without knowing the human score, where each atom is associated with a quality score induced from the reference image; at the on-line stage, given each image patch, our method performs group sparse coding to encode the sample, such that the sample quality can be estimated from the few labeled atoms whose encoding coefficients are nonzero. Experimental results on the public dataset show the promising performance of our approach and future research direction is also discussed.

  18. The art of assessing quality for images and video

    International Nuclear Information System (INIS)

    Deriche, M.

    2011-01-01

    The early years of this century have witnessed a tremendous growth in the use of digital multimedia data for di?erent communication applications. Researchers from around the world are spending substantial research efforts in developing techniques for improving the appearance of images/video. However, as we know, preserving high quality is a challenging task. Images are subject to distortions during acquisition, compression, transmission, analysis, and reconstruction. For this reason, the research area focusing on image and video quality assessment has attracted a lot of attention in recent years. In particular, compression applications and other multimedia applications need powerful techniques for evaluating quality objectively without human interference. This tutorial will cover the di?erent faces of image quality assessment. We will motivate the need for robust image quality assessment techniques, then discuss the main algorithms found in the literature with a critical perspective. We will present the di?erent metrics used for full reference, reduced reference and no reference applications. We will then discuss the difference between image and video quality assessment. In all of the above, we will take a critical approach to explain which metric can be used for which application. Finally we will discuss the different approaches to analyze the performance of image/video quality metrics, and end the tutorial with some perspectives on newly introduced metrics and their potential applications.

  19. The use of the general image quality equation in the design and evaluation of imaging systems

    Science.gov (United States)

    Cota, Steve A.; Florio, Christopher J.; Duvall, David J.; Leon, Michael A.

    2009-08-01

    The design of any modern imaging system is the end result of many trade studies, each seeking to optimize image quality within real world constraints such as cost, schedule and overall risk. The National Imagery Interpretability Rating Scale (NIIRS) is a useful measure of image quality, because, by characterizing the overall interpretability of an image, it combines into one metric those contributors to image quality to which a human interpreter is most sensitive. The main drawback to using a NIIRS rating as a measure of image quality in engineering trade studies is the fact that it is tied to the human observer and cannot be predicted from physical principles and engineering parameters alone. The General Image Quality Equation (GIQE) of Leachtenauer et al. 1997 [Appl. Opt. 36, 8322-8328 (1997)] is a regression of actual image analyst NIIRS ratings vs. readily calculable engineering metrics, and provides a mechanism for using the expected NIIRS rating of an imaging system in the design and evaluation process. In this paper, we will discuss how we use the GIQE in conjunction with The Aerospace Corporation's Parameterized Image Chain Analysis & Simulation SOftware (PICASSO) to evaluate imager designs, taking a hypothetical high resolution commercial imaging system as an example.

  20. Quality assurance in diagnostic radiology - assessing the fluoroscopic image quality

    International Nuclear Information System (INIS)

    Tabakov, S.

    1995-01-01

    The X-ray fluoroscopic image has a considerably lower resolution than the radiographic one. This requires a careful quality control aiming at optimal use of the fluoroscopic equipment. The basic procedures for image quality assessment of Image Intensifier/TV image are described. Test objects from Leeds University (UK) are used as prototypes. The results from examining 50 various fluoroscopic devices are shown. Their limiting spatial resolution varies between 0.8 lp/mm (at maximum II field size) and 2.24 lp/mm (at minimum field size). The mean value of the limiting spatial resolution for a 23 cm Image Intensifier is about 1.24 lp/mm. The mean limits of variation of the contrast/detail diagram for various fluoroscopic equipment are graphically expressed. 14 refs., 1 fig. (author)

  1. Retinal image quality assessment based on image clarity and content

    Science.gov (United States)

    Abdel-Hamid, Lamiaa; El-Rafei, Ahmed; El-Ramly, Salwa; Michelson, Georg; Hornegger, Joachim

    2016-09-01

    Retinal image quality assessment (RIQA) is an essential step in automated screening systems to avoid misdiagnosis caused by processing poor quality retinal images. A no-reference transform-based RIQA algorithm is introduced that assesses images based on five clarity and content quality issues: sharpness, illumination, homogeneity, field definition, and content. Transform-based RIQA algorithms have the advantage of considering retinal structures while being computationally inexpensive. Wavelet-based features are proposed to evaluate the sharpness and overall illumination of the images. A retinal saturation channel is designed and used along with wavelet-based features for homogeneity assessment. The presented sharpness and illumination features are utilized to assure adequate field definition, whereas color information is used to exclude nonretinal images. Several publicly available datasets of varying quality grades are utilized to evaluate the feature sets resulting in area under the receiver operating characteristic curve above 0.99 for each of the individual feature sets. The overall quality is assessed by a classifier that uses the collective features as an input vector. The classification results show superior performance of the algorithm in comparison to other methods from literature. Moreover, the algorithm addresses efficiently and comprehensively various quality issues and is suitable for automatic screening systems.

  2. High Dynamic Range Imaging Using Multiple Exposures

    Science.gov (United States)

    Hou, Xinglin; Luo, Haibo; Zhou, Peipei; Zhou, Wei

    2017-06-01

    It is challenging to capture a high-dynamic range (HDR) scene using a low-dynamic range (LDR) camera. This paper presents an approach for improving the dynamic range of cameras by using multiple exposure images of same scene taken under different exposure times. First, the camera response function (CRF) is recovered by solving a high-order polynomial in which only the ratios of the exposures are used. Then, the HDR radiance image is reconstructed by weighted summation of the each radiance maps. After that, a novel local tone mapping (TM) operator is proposed for the display of the HDR radiance image. By solving the high-order polynomial, the CRF can be recovered quickly and easily. Taken the local image feature and characteristic of histogram statics into consideration, the proposed TM operator could preserve the local details efficiently. Experimental result demonstrates the effectiveness of our method. By comparison, the method outperforms other methods in terms of imaging quality.

  3. Image quality evaluation of full reference algorithm

    Science.gov (United States)

    He, Nannan; Xie, Kai; Li, Tong; Ye, Yushan

    2018-03-01

    Image quality evaluation is a classic research topic, the goal is to design the algorithm, given the subjective feelings consistent with the evaluation value. This paper mainly introduces several typical reference methods of Mean Squared Error(MSE), Peak Signal to Noise Rate(PSNR), Structural Similarity Image Metric(SSIM) and feature similarity(FSIM) of objective evaluation methods. The different evaluation methods are tested by Matlab, and the advantages and disadvantages of these methods are obtained by analyzing and comparing them.MSE and PSNR are simple, but they are not considered to introduce HVS characteristics into image quality evaluation. The evaluation result is not ideal. SSIM has a good correlation and simple calculation ,because it is considered to the human visual effect into image quality evaluation,However the SSIM method is based on a hypothesis,The evaluation result is limited. The FSIM method can be used for test of gray image and color image test, and the result is better. Experimental results show that the new image quality evaluation algorithm based on FSIM is more accurate.

  4. ANALYSIS OF THE EFFECTS OF IMAGE QUALITY ON DIGITAL MAP GENERATION FROM SATELLITE IMAGES

    Directory of Open Access Journals (Sweden)

    H. Kim

    2012-07-01

    Full Text Available High resolution satellite images are widely used to produce and update a digital map since they became widely available. It is well known that the accuracy of digital map produced from satellite images is decided largely by the accuracy of geometric modelling. However digital maps are made by a series of photogrammetric workflow. Therefore the accuracy of digital maps are also affected by the quality of satellite images, such as image interpretability. For satellite images, parameters such as Modulation Transfer Function(MTF, Signal to Noise Ratio(SNR and Ground Sampling Distance(GSD are used to present images quality. Our previous research stressed that such quality parameters may not represent the quality of image products such as digital maps and that parameters for image interpretability such as Ground Resolved Distance(GRD and National Imagery Interpretability Rating Scale(NIIRS need to be considered. In this study, we analyzed the effects of the image quality on accuracy of digital maps produced by satellite images. QuickBird, IKONOS and KOMPSAT-2 imagery were used to analyze as they have similar GSDs. We measured various image quality parameters mentioned above from these images. Then we produced digital maps from the images using a digital photogrammetric workstation. We analyzed the accuracy of the digital maps in terms of their location accuracy and their level of details. Then we compared the correlation between various image quality parameters and the accuracy of digital maps. The results of this study showed that GRD and NIIRS were more critical for map production then GSD, MTF or SNR.

  5. TH-B-207B-00: Pediatric Image Quality Optimization

    International Nuclear Information System (INIS)

    2016-01-01

    This imaging educational program will focus on solutions to common pediatric image quality optimization challenges. The speakers will present collective knowledge on best practices in pediatric imaging from their experience at dedicated children’s hospitals. One of the most commonly encountered pediatric imaging requirements for the non-specialist hospital is pediatric CT in the emergency room setting. Thus, this educational program will begin with optimization of pediatric CT in the emergency department. Though pediatric cardiovascular MRI may be less common in the non-specialist hospitals, low pediatric volumes and unique cardiovascular anatomy make optimization of these techniques difficult. Therefore, our second speaker will review best practices in pediatric cardiovascular MRI based on experiences from a children’s hospital with a large volume of cardiac patients. Learning Objectives: To learn techniques for optimizing radiation dose and image quality for CT of children in the emergency room setting. To learn solutions for consistently high quality cardiovascular MRI of children

  6. TH-B-207B-00: Pediatric Image Quality Optimization

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    This imaging educational program will focus on solutions to common pediatric image quality optimization challenges. The speakers will present collective knowledge on best practices in pediatric imaging from their experience at dedicated children’s hospitals. One of the most commonly encountered pediatric imaging requirements for the non-specialist hospital is pediatric CT in the emergency room setting. Thus, this educational program will begin with optimization of pediatric CT in the emergency department. Though pediatric cardiovascular MRI may be less common in the non-specialist hospitals, low pediatric volumes and unique cardiovascular anatomy make optimization of these techniques difficult. Therefore, our second speaker will review best practices in pediatric cardiovascular MRI based on experiences from a children’s hospital with a large volume of cardiac patients. Learning Objectives: To learn techniques for optimizing radiation dose and image quality for CT of children in the emergency room setting. To learn solutions for consistently high quality cardiovascular MRI of children.

  7. Toward optimal color image quality of television display

    Science.gov (United States)

    MacDonald, Lindsay W.; Endrikhovski, Sergej N.; Bech, Soren; Jensen, Kaj

    1999-12-01

    A general framework and first experimental results are presented for the `OPTimal IMage Appearance' (OPTIMA) project, which aims to develop a computational model for achieving optimal color appearance of natural images on adaptive CRT television displays. To achieve this goal we considered the perceptual constraints determining quality of displayed images and how they could be quantified. The practical value of the notion of optimal image appearance was translated from the high level of the perceptual constraints into a method for setting the display's parameters at the physical level. In general, the whole framework of quality determination includes: (1) evaluation of perceived quality; (2) evaluation of the individual perceptual attributes; and (3) correlation between the physical measurements, psychometric parameters and the subjective responses. We performed a series of psychophysical experiments, with observers viewing a series of color images on a high-end consumer television display, to investigate the relationships between Overall Image Quality and four quality-related attributes: Brightness Rendering, Chromatic Rendering, Visibility of Details and Overall Naturalness. The results of the experiments presented in this paper suggest that these attributes are highly inter-correlated.

  8. High-pitch computed tomography of the lung in pediatric patients. An intraindividual comparison of image quality and radiation dose to conventional 64-MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Tsiflikas, I.; Thomas, C.; Ketelsen, D.; Claussen, C.D.; Schaefer, J.F. [University Hospital of Tuebingen (Germany). Diagnostic and Interventional Radiology; Seitz, G.; Warmann, S. [University Hospital of Tuebingen (Germany). Pediatric Surgery

    2014-06-15

    Purpose: The aim of this study was to investigate frequencies of typical artifacts in low-dose pediatric lung examinations using high-pitch computed tomography (HPCT) compared to MDCT, and to estimate the effective radiation dose (E{sub eff}). Materials and Methods: Institutional review board approval for this retrospective study was obtained. 35 patients (17 boys, 18 girls; mean age 112 ± 69 months) were included and underwent MDCT and follow-up scan by HPCT or vice versa (mean follow-up time 87 days), using the same tube voltage and current. The total artifact score (0-8) was defined as the sum of artifacts arising from movement, breathing or pulsation of the heart or pulmonary vessels (0 - no; 1 - moderate; 2 - severe artifacts). E{sub eff} was estimated according to the European Guidelines on Quality Criteria for Multislice Computed Tomography. The Mann-Whitney U test was used to analyze differences between the patient groups. The Spearman's rank correlation coefficient was used for correlation of ordinal variables. Results: The scan time was significantly lower for HPCT compared to MDCT (0.72 ± 0.13 s vs. 3.65 ± 0.81s; p < 0.0001). In 28 of 35 (80 %) HPCT examinations no artifacts were visible, whereas in MDCT artifacts occurred in all examinations. The frequency of pulsation artifacts and breathing artifacts was higher in MDCT compared to HPCT (100% vs. 17% and 31% vs. 6%). The total artifact score significantly correlated with the patient's age in MDCT (r=-0.42; p=0.01), but not in HPCT (r=-0.32; p=0.07). The estimated E{sub eff} was significantly lower in HPCT than in MDCT (1.29±0.31 vs. 1.47±0.37 mSv; p < 0.0001). Conclusion: Our study indicates that the use of HPCT has advantages for pediatric lung imaging with a reduction of breathing and pulsation artifacts. Moreover, the estimated E{sub eff} was lower. In addition, examinations can be performed without sedation or breath-hold without losing image quality. (orig.)

  9. HDR Image Quality Enhancement Based on Spatially Variant Retinal Response

    Directory of Open Access Journals (Sweden)

    Horiuchi Takahiko

    2010-01-01

    Full Text Available There is a growing demand for being able to display high dynamic range (HDR images on low dynamic range (LDR devices. Tone mapping is a process for enhancing HDR image quality on an LDR device by converting the tonal values of the original image from HDR to LDR. This paper proposes a new tone mapping algorithm for enhancing image quality by deriving a spatially-variant operator for imitating S-potential response in human retina, which efficiently improves local contrasts while conserving good global appearance. The proposed tone mapping operator is studied from a system construction point of view. It is found that the operator is regarded as a natural extension of the Retinex algorithm by adding a global adaptation process to the local adaptation. The feasibility of the proposed algorithm is examined in detail on experiments using standard HDR images and real HDR scene images, comparing with conventional tone mapping algorithms.

  10. Image quality, radiation dose, and diagnostic accuracy of prospectively ECG-triggered high-pitch coronary CT angiography at 70 kVp in a clinical setting: comparison with invasive coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Long Jiang; Qi, Li; Zhou, Chang Sheng; Zhao, Yan E.; Li, Xie; Lu, Guang Ming [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Wang, Yining; Cao, Jian; Jin, Zhengyu [Peking Union Medical College Hospital, Department of Radiology, Beijing (China); Schoepf, U.J. [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Meinel, Felix G. [Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Ludwig-Maximilians-University Hospital, Institute for Clinical Radiology, Munich (Germany); Bayer, Richard R. [Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Gong, Jian Bin [Jinling Hospital, Medical School of Nanjing University, Department of Cardiology, Nanjing, Jiangsu (China)

    2016-03-15

    To investigate image quality, radiation dose, and diagnostic performance of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp compared to invasive coronary angiography (ICA) as reference standard. Forty-three patients underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp using 30 cc (11 g iodine) contrast medium and ICA. Subjective and objective image quality was evaluated for each CCTA study. CCTA performance for diagnosing ≥50 % stenosis was assessed. Results were stratified according to heart rate (HR), body mass index (BMI), Agatston score, and image quality. At CCTA, 94.3 % (500/530) of coronary segments were of diagnostic quality. Using ICA as reference standard, sensitivity and accuracy were 100 % and 93.0 % on a per-patient basis. Per-vessel and per-segment performances were 92.2 % and 89.5 %; 79.5 % and 88.3 %, respectively. No differences were found in diagnostic accuracy between different HR, BMI, and calcification subgroups (all P > 0.05) on a per-patient basis. However, low image quality reduced diagnostic accuracy on a per-patient, per-vessel and per-segment basis (all P < 0.05). The mean effective radiation dose was 0.2 ± 0.0 mSv. Our presented protocol results in an effective radiation dose of 0.2 mSv and high diagnostic accuracy for stenosis detection in a selected, non-obese population. (orig.)

  11. Measures of Image Quality. Chapter 4

    Energy Technology Data Exchange (ETDEWEB)

    Maidment, A. D.A. [University of Pennsylvania, Philadelphia (United States)

    2014-09-15

    A medical image is a pictorial representation of a measurement of an object or function of the body. This information can be acquired in one to three spatial dimensions. It can be static or dynamic, meaning that it can also be measured as a function of time. Certain fundamental properties can be associated with all of these data. Firstly, no image can exactly represent the object or function; at best, one has a measurement with an associated error equal to the difference between the true object and the measured image. Secondly, no two images will be identical, even if acquired with the same imaging system of the same anatomic region; this variability is generally referred to as noise. There are many different ways to acquire medical image data; the various mechanisms of acquisition are described in detail in the subsequent chapters. However, regardless of the method of image formation, one must be able to judge the fidelity of the image in an attempt to answer the question “How accurately does the image portray the body or the bodily function?” This judgement falls under the rubric of ‘image quality’. In this chapter, methods of quantifying image quality are described.

  12. Subjective matters: from image quality to image psychology

    Science.gov (United States)

    Fedorovskaya, Elena A.; De Ridder, Huib

    2013-03-01

    From the advent of digital imaging through several decades of studies, the human vision research community systematically focused on perceived image quality and digital artifacts due to resolution, compression, gamma, dynamic range, capture and reproduction noise, blur, etc., to help overcome existing technological challenges and shortcomings. Technological advances made digital images and digital multimedia nearly flawless in quality, and ubiquitous and pervasive in usage, provide us with the exciting but at the same time demanding possibility to turn to the domain of human experience including higher psychological functions, such as cognition, emotion, awareness, social interaction, consciousness and Self. In this paper we will outline the evolution of human centered multidisciplinary studies related to imaging and propose steps and potential foci of future research.

  13. Quality criteria for cardiac images: An update

    International Nuclear Information System (INIS)

    Bernardi, G.; Bar, O.; Jezewski, T.; Vano, E.; Maccia, C.; Trianni, A.; Padovani, R.

    2008-01-01

    The DIMOND II and III Cardiology Groups have agreed on quality criteria for cardiac images and developed a scoring system, to provide a tool to test quality of coronary angiograms, which was demonstrated to be of value in clinical practice. In the last years, digital flat panel technology has been introduced in cardiac angiographic systems and the radiological technique may have been influenced by the better performance of these new detectors. This advance in digital imaging, together with the lesson learned from previous studies, warranted the revision of the quality criteria for cardiac angiographic images as formerly defined. DIMOND criteria were reassessed to allow a simpler evaluation of angiograms. Clinical criteria were simplified and separated from technical criteria. Furthermore, the characteristics of an optimised angiographic technique have been outlined. (authors)

  14. Quality evaluation of no-reference MR images using multidirectional filters and image statistics.

    Science.gov (United States)

    Jang, Jinseong; Bang, Kihun; Jang, Hanbyol; Hwang, Dosik

    2018-09-01

    This study aimed to develop a fully automatic, no-reference image-quality assessment (IQA) method for MR images. New quality-aware features were obtained by applying multidirectional filters to MR images and examining the feature statistics. A histogram of these features was then fitted to a generalized Gaussian distribution function for which the shape parameters yielded different values depending on the type of distortion in the MR image. Standard feature statistics were established through a training process based on high-quality MR images without distortion. Subsequently, the feature statistics of a test MR image were calculated and compared with the standards. The quality score was calculated as the difference between the shape parameters of the test image and the undistorted standard images. The proposed IQA method showed a >0.99 correlation with the conventional full-reference assessment methods; accordingly, this proposed method yielded the best performance among no-reference IQA methods for images containing six types of synthetic, MR-specific distortions. In addition, for authentically distorted images, the proposed method yielded the highest correlation with subjective assessments by human observers, thus demonstrating its superior performance over other no-reference IQAs. Our proposed IQA was designed to consider MR-specific features and outperformed other no-reference IQAs designed mainly for photographic images. Magn Reson Med 80:914-924, 2018. © 2018 International Society for Magnetic Resonance in Medicine. © 2018 International Society for Magnetic Resonance in Medicine.

  15. Assessing microscope image focus quality with deep learning.

    Science.gov (United States)

    Yang, Samuel J; Berndl, Marc; Michael Ando, D; Barch, Mariya; Narayanaswamy, Arunachalam; Christiansen, Eric; Hoyer, Stephan; Roat, Chris; Hung, Jane; Rueden, Curtis T; Shankar, Asim; Finkbeiner, Steven; Nelson, Philip

    2018-03-15

    Large image datasets acquired on automated microscopes typically have some fraction of low quality, out-of-focus images, despite the use of hardware autofocus systems. Identification of these images using automated image analysis with high accuracy is important for obtaining a clean, unbiased image dataset. Complicating this task is the fact that image focus quality is only well-defined in foreground regions of images, and as a result, most previous approaches only enable a computation of the relative difference in quality between two or more images, rather than an absolute measure of quality. We present a deep neural network model capable of predicting an absolute measure of image focus on a single image in isolation, without any user-specified parameters. The model operates at the image-patch level, and also outputs a measure of prediction certainty, enabling interpretable predictions. The model was trained on only 384 in-focus Hoechst (nuclei) stain images of U2OS cells, which were synthetically defocused to one of 11 absolute defocus levels during training. The trained model can generalize on previously unseen real Hoechst stain images, identifying the absolute image focus to within one defocus level (approximately 3 pixel blur diameter difference) with 95% accuracy. On a simpler binary in/out-of-focus classification task, the trained model outperforms previous approaches on both Hoechst and Phalloidin (actin) stain images (F-scores of 0.89 and 0.86, respectively over 0.84 and 0.83), despite only having been presented Hoechst stain images during training. Lastly, we observe qualitatively that the model generalizes to two additional stains, Hoechst and Tubulin, of an unseen cell type (Human MCF-7) acquired on a different instrument. Our deep neural network enables classification of out-of-focus microscope images with both higher accuracy and greater precision than previous approaches via interpretable patch-level focus and certainty predictions. The use of

  16. Effect of Matrix Size on the Image Quality of Ultra-high-resolution CT of the Lung: Comparison of 512 × 512, 1024 × 1024, and 2048 × 2048.

    Science.gov (United States)

    Hata, Akinori; Yanagawa, Masahiro; Honda, Osamu; Kikuchi, Noriko; Miyata, Tomo; Tsukagoshi, Shinsuke; Uranishi, Ayumi; Tomiyama, Noriyuki

    2018-01-16

    This study aimed to assess the effect of matrix size on the spatial resolution and image quality of ultra-high-resolution computed tomography (U-HRCT). Slit phantoms and 11 cadaveric lungs were scanned on U-HRCT. Slit phantom scans were reconstructed using a 20-mm field of view (FOV) with 1024 matrix size and a 320-mm FOV with 512, 1024, and 2048 matrix sizes. Cadaveric lung scans were reconstructed using 512, 1024, and 2048 matrix sizes. Three observers subjectively scored the images on a three-point scale (1 = worst, 3 = best), in terms of overall image quality, noise, streak artifact, vessel, bronchi, and image findings. The median score of the three observers was evaluated by Wilcoxon signed-rank test with Bonferroni correction. Noise was measured quantitatively and evaluated with the Tukey test. A P value of matrix had the highest resolution and was significantly better than the 1024 matrix in terms of overall quality, solid nodule, ground-glass opacity, emphysema, intralobular reticulation, honeycombing, and clarity of vessels (P matrix (P matrix size maintained the spatial resolution and improved the image quality and assessment of lung diseases, despite an increase in image noise, when compared to a 512 matrix size. Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  17. Parameters related to the image quality in computed tomography -CT

    International Nuclear Information System (INIS)

    Alonso, T.C.; Silva, T.A.; Mourão, A.P.; Silva, T.A.

    2015-01-01

    Quality control programs in computed tomography, CT, should be continuously reviewed to always ensure the best image quality with the lowest possible dose for the patient in the diagnostic process. The quality control in CT aims to design and implement a set of procedures that allows the verification of their operating conditions within the specified requirements for its use. In Brazil, the Ministry of Health (MOH), the Technical Rules (Resolution NE in 1016.) - Radiology Medical - 'Equipment and Safety Performance' establishes a reference to the analysis of tests on TC. A large number of factors such as image noise, slice thickness (resolution of the Z axis), low contrast resolution and high contrast resolution and the radiation dose can be affected by the selection of technical parameters in exams. The purpose of this study was to investigate how changes in image acquisition protocols modify its quality and determine the advantages and disadvantages between the different aspects of image quality, especially the reduction of patient radiation dose. A preliminary procedure is to check the operating conditions of the CT measurements were performed on a scanner with 64-MDCT scanner (GE Healthcare, BrightSpeed) in the service of the Molecular Imaging Center (Cimol) of the Federal University of Minas Gerais (UFMG). When performing the image quality tests we used a simulator, Catphan-600, this device has five modules, and in each you can perform a series of tests. Different medical imaging practices have different requirements for acceptable image quality. The results of quality control tests showed that the analyzed equipment is in accordance with the requirements established by current regulations. [pt

  18. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    Science.gov (United States)

    Abu Anas, Emran Mohammad; Kim, Jae Gon; Lee, Soo Yeol; Kamrul Hasan, Md

    2011-10-01

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  19. High-quality 3D correction of ring and radiant artifacts in flat panel detector-based cone beam volume CT imaging

    International Nuclear Information System (INIS)

    Anas, Emran Mohammad Abu; Hasan, Md Kamrul; Kim, Jae Gon; Lee, Soo Yeol

    2011-01-01

    The use of an x-ray flat panel detector is increasingly becoming popular in 3D cone beam volume CT machines. Due to the deficient semiconductor array manufacturing process, the cone beam projection data are often corrupted by different types of abnormalities, which cause severe ring and radiant artifacts in a cone beam reconstruction image, and as a result, the diagnostic image quality is degraded. In this paper, a novel technique is presented for the correction of error in the 2D cone beam projections due to abnormalities often observed in 2D x-ray flat panel detectors. Template images are derived from the responses of the detector pixels using their statistical properties and then an effective non-causal derivative-based detection algorithm in 2D space is presented for the detection of defective and mis-calibrated detector elements separately. An image inpainting-based 3D correction scheme is proposed for the estimation of responses of defective detector elements, and the responses of the mis-calibrated detector elements are corrected using the normalization technique. For real-time implementation, a simplification of the proposed off-line method is also suggested. Finally, the proposed algorithms are tested using different real cone beam volume CT images and the experimental results demonstrate that the proposed methods can effectively remove ring and radiant artifacts from cone beam volume CT images compared to other reported techniques in the literature.

  20. Image Acquisition and Quality in Digital Radiography.

    Science.gov (United States)

    Alexander, Shannon

    2016-09-01

    Medical imaging has undergone dramatic changes and technological breakthroughs since the introduction of digital radiography. This article presents information on the development of digital radiography and types of digital radiography systems. Aspects of image quality and radiation exposure control are highlighted as well. In addition, the article includes related workplace changes and medicolegal considerations in the digital radiography environment. ©2016 American Society of Radiologic Technologists.

  1. IMPROVING THE QUALITY OF NEAR-INFRARED IMAGING OF IN VIVOBLOOD VESSELS USING IMAGE FUSION METHODS

    DEFF Research Database (Denmark)

    Jensen, Andreas Kryger; Savarimuthu, Thiusius Rajeeth; Sørensen, Anders Stengaard

    2009-01-01

    We investigate methods for improving the visual quality of in vivo images of blood vessels in the human forearm. Using a near-infrared light source and a dual CCD chip camera system capable of capturing images at visual and nearinfrared spectra, we evaluate three fusion methods in terms...... of their capability of enhancing the blood vessels while preserving the spectral signature of the original color image. Furthermore, we investigate a possibility of removing hair in the images using a fusion rule based on the "a trous" stationary wavelet decomposition. The method with the best overall performance...... with both speed and quality in mind is the Intensity Injection method. Using the developed system and the methods presented in this article, it is possible to create images of high visual quality with highly emphasized blood vessels....

  2. Ultrasound Image Quality Assessment: A framework for evaluation of clinical image quality

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Pedersen, Mads Møller; Nikolov, Svetoslav Ivanov

    2010-01-01

    Improvement of ultrasound images should be guided by their diagnostic value. Evaluation of clinical image quality is generally performed subjectively, because objective criteria have not yet been fully developed and accepted for the evaluation of clinical image quality. Based on recommendation 50...... information, which is fast enough to get sufficient number of scans under realistic operating conditions, so that statistical evaluation is valid and reliable....

  3. Subjective evaluation of compressed image quality

    Science.gov (United States)

    Lee, Heesub; Rowberg, Alan H.; Frank, Mark S.; Choi, Hyung-Sik; Kim, Yongmin

    1992-05-01

    Lossy data compression generates distortion or error on the reconstructed image and the distortion becomes visible as the compression ratio increases. Even at the same compression ratio, the distortion appears differently depending on the compression method used. Because of the nonlinearity of the human visual system and lossy data compression methods, we have evaluated subjectively the quality of medical images compressed with two different methods, an intraframe and interframe coding algorithms. The evaluated raw data were analyzed statistically to measure interrater reliability and reliability of an individual reader. Also, the analysis of variance was used to identify which compression method is better statistically, and from what compression ratio the quality of a compressed image is evaluated as poorer than that of the original. Nine x-ray CT head images from three patients were used as test cases. Six radiologists participated in reading the 99 images (some were duplicates) compressed at four different compression ratios, original, 5:1, 10:1, and 15:1. The six readers agree more than by chance alone and their agreement was statistically significant, but there were large variations among readers as well as within a reader. The displacement estimated interframe coding algorithm is significantly better in quality than that of the 2-D block DCT at significance level 0.05. Also, 10:1 compressed images with the interframe coding algorithm do not show any significant differences from the original at level 0.05.

  4. REQUIREMENTS FOR IMAGE QUALITY OF EMERGENCY SPACECRAFTS

    Directory of Open Access Journals (Sweden)

    A. I. Altukhov

    2015-05-01

    Full Text Available The paper deals with the method for formation of quality requirements to the images of emergency spacecrafts. The images are obtained by means of remote sensing of near-earth space orbital deployment in the visible range. of electromagnetic radiation. The method is based on a joint taking into account conditions of space survey, characteristics of surveillance equipment, main design features of the observed spacecrafts and orbital inspection tasks. Method. Quality score is the predicted linear resolution image that gives the possibility to create a complete view of pictorial properties of the space image obtained by electro-optical system from the observing satellite. Formulation of requirements to the numerical value of this indicator is proposed to perform based on the properties of remote sensing system, forming images in the conditions of outer space, and the properties of the observed emergency spacecraft: dimensions, platform construction of the satellite, on-board equipment placement. For method implementation the authors have developed a predictive model of requirements to a linear resolution for images of emergency spacecrafts, making it possible to select the intervals of space shooting and get the satellite images required for quality interpretation. Main results. To verify the proposed model functionality we have carried out calculations of the numerical values for the linear resolution of the image, ensuring the successful task of determining the gross structural damage of the spacecrafts and identifying changes in their spatial orientation. As input data were used with dimensions and geometric primitives corresponding to the shape of deemed inspected spacecrafts: Resurs-P", "Canopus-B", "Electro-L". Numerical values of the linear resolution images have been obtained, ensuring the successful task solution for determining the gross structural damage of spacecrafts.

  5. Saliency image of feature building for image quality assessment

    Science.gov (United States)

    Ju, Xinuo; Sun, Jiyin; Wang, Peng

    2011-11-01

    The purpose and method of image quality assessment are quite different for automatic target recognition (ATR) and traditional application. Local invariant feature detectors, mainly including corner detectors, blob detectors and region detectors etc., are widely applied for ATR. A saliency model of feature was proposed to evaluate feasibility of ATR in this paper. The first step consisted of computing the first-order derivatives on horizontal orientation and vertical orientation, and computing DoG maps in different scales respectively. Next, saliency images of feature were built based auto-correlation matrix in different scale. Then, saliency images of feature of different scales amalgamated. Experiment were performed on a large test set, including infrared images and optical images, and the result showed that the salient regions computed by this model were consistent with real feature regions computed by mostly local invariant feature extraction algorithms.

  6. Image Quality Assessment of JPEG Compressed Mars Science Laboratory Mastcam Images using Convolutional Neural Networks

    Science.gov (United States)

    Kerner, H. R.; Bell, J. F., III; Ben Amor, H.

    2017-12-01

    The Mastcam color imaging system on the Mars Science Laboratory Curiosity rover acquires images within Gale crater for a variety of geologic and atmospheric studies. Images are often JPEG compressed before being downlinked to Earth. While critical for transmitting images on a low-bandwidth connection, this compression can result in image artifacts most noticeable as anomalous brightness or color changes within or near JPEG compression block boundaries. In images with significant high-frequency detail (e.g., in regions showing fine layering or lamination in sedimentary rocks), the image might need to be re-transmitted losslessly to enable accurate scientific interpretation of the data. The process of identifying which images have been adversely affected by compression artifacts is performed manually by the Mastcam science team, costing significant expert human time. To streamline the tedious process of identifying which images might need to be re-transmitted, we present an input-efficient neural network solution for predicting the perceived quality of a compressed Mastcam image. Most neural network solutions require large amounts of hand-labeled training data for the model to learn the target mapping between input (e.g. distorted images) and output (e.g. quality assessment). We propose an automatic labeling method using joint entropy between a compressed and uncompressed image to avoid the need for domain experts to label thousands of training examples by hand. We use automatically labeled data to train a convolutional neural network to estimate the probability that a Mastcam user would find the quality of a given compressed image acceptable for science analysis. We tested our model on a variety of Mastcam images and found that the proposed method correlates well with image quality perception by science team members. When assisted by our proposed method, we estimate that a Mastcam investigator could reduce the time spent reviewing images by a minimum of 70%.

  7. Review of Image Quality Measures for Solar Imaging

    Science.gov (United States)

    Popowicz, Adam; Radlak, Krystian; Bernacki, Krzysztof; Orlov, Valeri

    2017-12-01

    Observations of the solar photosphere from the ground encounter significant problems caused by Earth's turbulent atmosphere. Before image reconstruction techniques can be applied, the frames obtained in the most favorable atmospheric conditions (the so-called lucky frames) have to be carefully selected. However, estimating the quality of images containing complex photospheric structures is not a trivial task, and the standard routines applied in nighttime lucky imaging observations are not applicable. In this paper we evaluate 36 methods dedicated to the assessment of image quality, which were presented in the literature over the past 40 years. We compare their effectiveness on simulated solar observations of both active regions and granulation patches, using reference data obtained by the Solar Optical Telescope on the Hinode satellite. To create images that are affected by a known degree of atmospheric degradation, we employed the random wave vector method, which faithfully models all the seeing characteristics. The results provide useful information about the method performances, depending on the average seeing conditions expressed by the ratio of the telescope's aperture to the Fried parameter, D/r0. The comparison identifies three methods for consideration by observers: Helmli and Scherer's mean, the median filter gradient similarity, and the discrete cosine transform energy ratio. While the first method requires less computational effort and can be used effectively in virtually any atmospheric conditions, the second method shows its superiority at good seeing (D/r0<4). The third method should mainly be considered for the post-processing of strongly blurred images.

  8. Medical Imaging Image Quality Assessment with Monte Carlo Methods

    International Nuclear Information System (INIS)

    Michail, C M; Fountos, G P; Kalyvas, N I; Valais, I G; Kandarakis, I S; Karpetas, G E; Martini, Niki; Koukou, Vaia

    2015-01-01

    The aim of the present study was to assess image quality of PET scanners through a thin layer chromatography (TLC) plane source. The source was simulated using a previously validated Monte Carlo model. The model was developed by using the GATE MC package and reconstructed images obtained with the STIR software for tomographic image reconstruction, with cluster computing. The PET scanner simulated in this study was the GE DiscoveryST. A plane source consisted of a TLC plate, was simulated by a layer of silica gel on aluminum (Al) foil substrates, immersed in 18F-FDG bath solution (1MBq). Image quality was assessed in terms of the Modulation Transfer Function (MTF). MTF curves were estimated from transverse reconstructed images of the plane source. Images were reconstructed by the maximum likelihood estimation (MLE)-OSMAPOSL algorithm. OSMAPOSL reconstruction was assessed by using various subsets (3 to 21) and iterations (1 to 20), as well as by using various beta (hyper) parameter values. MTF values were found to increase up to the 12th iteration whereas remain almost constant thereafter. MTF improves by using lower beta values. The simulated PET evaluation method based on the TLC plane source can be also useful in research for the further development of PET and SPECT scanners though GATE simulations. (paper)

  9. Dose and diagnostic image quality in digital tomosynthesis imaging of facial bones in pediatrics

    Science.gov (United States)

    King, J. M.; Hickling, S.; Elbakri, I. A.; Reed, M.; Wrogemann, J.

    2011-03-01

    The purpose of this study was to evaluate the use of digital tomosynthesis (DT) for pediatric facial bone imaging. We compared the eye lens dose and diagnostic image quality of DT facial bone exams relative to digital radiography (DR) and computed tomography (CT), and investigated whether we could modify our current DT imaging protocol to reduce patient dose while maintaining sufficient diagnostic image quality. We measured the dose to the eye lens for all three modalities using high-sensitivity thermoluminescent dosimeters (TLDs) and an anthropomorphic skull phantom. To assess the diagnostic image quality of DT compared to the corresponding DR and CT images, we performed an observer study where the visibility of anatomical structures in the DT phantom images were rated on a four-point scale. We then acquired DT images at lower doses and had radiologists indicate whether the visibility of each structure was adequate for diagnostic purposes. For typical facial bone exams, we measured eye lens doses of 0.1-0.4 mGy for DR, 0.3-3.7 mGy for DT, and 26 mGy for CT. In general, facial bone structures were visualized better with DT then DR, and the majority of structures were visualized well enough to avoid the need for CT. DT imaging provides high quality diagnostic images of the facial bones while delivering significantly lower doses to the lens of the eye compared to CT. In addition, we found that by adjusting the imaging parameters, the DT effective dose can be reduced by up to 50% while maintaining sufficient image quality.

  10. Learning Receptive Fields and Quality Lookups for Blind Quality Assessment of Stereoscopic Images.

    Science.gov (United States)

    Shao, Feng; Lin, Weisi; Wang, Shanshan; Jiang, Gangyi; Yu, Mei; Dai, Qionghai

    2016-03-01

    Blind quality assessment of 3D images encounters more new challenges than its 2D counterparts. In this paper, we propose a blind quality assessment for stereoscopic images by learning the characteristics of receptive fields (RFs) from perspective of dictionary learning, and constructing quality lookups to replace human opinion scores without performance loss. The important feature of the proposed method is that we do not need a large set of samples of distorted stereoscopic images and the corresponding human opinion scores to learn a regression model. To be more specific, in the training phase, we learn local RFs (LRFs) and global RFs (GRFs) from the reference and distorted stereoscopic images, respectively, and construct their corresponding local quality lookups (LQLs) and global quality lookups (GQLs). In the testing phase, blind quality pooling can be easily achieved by searching optimal GRF and LRF indexes from the learnt LQLs and GQLs, and the quality score is obtained by combining the LRF and GRF indexes together. Experimental results on three publicly 3D image quality assessment databases demonstrate that in comparison with the existing methods, the devised algorithm achieves high consistent alignment with subjective assessment.

  11. Fourier transform based scalable image quality measure.

    Science.gov (United States)

    Narwaria, Manish; Lin, Weisi; McLoughlin, Ian; Emmanuel, Sabu; Chia, Liang-Tien

    2012-08-01

    We present a new image quality assessment (IQA) algorithm based on the phase and magnitude of the 2D (twodimensional) Discrete Fourier Transform (DFT). The basic idea is to compare the phase and magnitude of the reference and distorted images to compute the quality score. However, it is well known that the Human Visual Systems (HVSs) sensitivity to different frequency components is not the same. We accommodate this fact via a simple yet effective strategy of nonuniform binning of the frequency components. This process also leads to reduced space representation of the image thereby enabling the reduced-reference (RR) prospects of the proposed scheme. We employ linear regression to integrate the effects of the changes in phase and magnitude. In this way, the required weights are determined via proper training and hence more convincing and effective. Lastly, using the fact that phase usually conveys more information than magnitude, we use only the phase for RR quality assessment. This provides the crucial advantage of further reduction in the required amount of reference image information. The proposed method is therefore further scalable for RR scenarios. We report extensive experimental results using a total of 9 publicly available databases: 7 image (with a total of 3832 distorted images with diverse distortions) and 2 video databases (totally 228 distorted videos). These show that the proposed method is overall better than several of the existing fullreference (FR) algorithms and two RR algorithms. Additionally, there is a graceful degradation in prediction performance as the amount of reference image information is reduced thereby confirming its scalability prospects. To enable comparisons and future study, a Matlab implementation of the proposed algorithm is available at http://www.ntu.edu.sg/home/wslin/reduced_phase.rar.

  12. Developing 3D Imaging Programmes-Workflow and Quality Control

    OpenAIRE

    Hess, M.; Robson, S.; Serpico, M.; Amati, G.; Pridden, I.; Nelson, T.

    2016-01-01

    This article reports on a successful project for 3D imaging research, digital applications, and use of new technologies in the museum. The article will focus on the development and implementation of a viable workflow for the production of high-quality 3D models of museum objects, based on the 3D laser scanning and photogrammetry of selected ancient Egyptian artefacts. The development of a robust protocol for the complete process chain for imaging cultural heritage artefacts, from the acquisit...

  13. THE MULTIWAVELENGTH SURVEY BY YALE-CHILE (MUSYC): DEEP MEDIUM-BAND OPTICAL IMAGING AND HIGH-QUALITY 32-BAND PHOTOMETRIC REDSHIFTS IN THE ECDF-S

    International Nuclear Information System (INIS)

    Cardamone, Carolin N.; Van Dokkum, Pieter G.; Urry, C. Megan; Brammer, Gabriel; Taniguchi, Yoshi; Gawiser, Eric; Bond, Nicholas; Taylor, Edward; Damen, Maaike; Treister, Ezequiel; Cobb, Bethany E.; Schawinski, Kevin; Lira, Paulina; Murayama, Takashi; Saito, Tomoki; Sumikawa, Kentaro

    2010-01-01

    We present deep optical 18-medium-band photometry from the Subaru telescope over the ∼30' x 30' Extended Chandra Deep Field-South, as part of the Multiwavelength Survey by Yale-Chile (MUSYC). This field has a wealth of ground- and space-based ancillary data, and contains the GOODS-South field and the Hubble Ultra Deep Field. We combine the Subaru imaging with existing UBVRIzJHK and Spitzer IRAC images to create a uniform catalog. Detecting sources in the MUSYC 'BVR' image we find ∼40,000 galaxies with R AB 3.5. For 0.1 < z < 1.2, we find a 1σ scatter in Δz/(1 + z) of 0.007, similar to results obtained with a similar filter set in the COSMOS field. As a demonstration of the data quality, we show that the red sequence and blue cloud can be cleanly identified in rest-frame color-magnitude diagrams at 0.1 < z < 1.2. We find that ∼20% of the red sequence galaxies show evidence of dust emission at longer rest-frame wavelengths. The reduced images, photometric catalog, and photometric redshifts are provided through the public MUSYC Web site.

  14. Integrative image segmentation optimization and machine learning approach for high quality land-use and land-cover mapping using multisource remote sensing data

    Science.gov (United States)

    Gibril, Mohamed Barakat A.; Idrees, Mohammed Oludare; Yao, Kouame; Shafri, Helmi Zulhaidi Mohd

    2018-01-01

    The growing use of optimization for geographic object-based image analysis and the possibility to derive a wide range of information about the image in textual form makes machine learning (data mining) a versatile tool for information extraction from multiple data sources. This paper presents application of data mining for land-cover classification by fusing SPOT-6, RADARSAT-2, and derived dataset. First, the images and other derived indices (normalized difference vegetation index, normalized difference water index, and soil adjusted vegetation index) were combined and subjected to segmentation process with optimal segmentation parameters obtained using combination of spatial and Taguchi statistical optimization. The image objects, which carry all the attributes of the input datasets, were extracted and related to the target land-cover classes through data mining algorithms (decision tree) for classification. To evaluate the performance, the result was compared with two nonparametric classifiers: support vector machine (SVM) and random forest (RF). Furthermore, the decision tree classification result was evaluated against six unoptimized trials segmented using arbitrary parameter combinations. The result shows that the optimized process produces better land-use land-cover classification with overall classification accuracy of 91.79%, 87.25%, and 88.69% for SVM and RF, respectively, while the results of the six unoptimized classifications yield overall accuracy between 84.44% and 88.08%. Higher accuracy of the optimized data mining classification approach compared to the unoptimized results indicates that the optimization process has significant impact on the classification quality.

  15. REMOTE SENSING IMAGE QUALITY ASSESSMENT EXPERIMENT WITH POST-PROCESSING

    Directory of Open Access Journals (Sweden)

    W. Jiang

    2018-04-01

    Full Text Available This paper briefly describes the post-processing influence assessment experiment, the experiment includes three steps: the physical simulation, image processing, and image quality assessment. The physical simulation models sampled imaging system in laboratory, the imaging system parameters are tested, the digital image serving as image processing input are produced by this imaging system with the same imaging system parameters. The gathered optical sampled images with the tested imaging parameters are processed by 3 digital image processes, including calibration pre-processing, lossy compression with different compression ratio and image post-processing with different core. Image quality assessment method used is just noticeable difference (JND subject assessment based on ISO20462, through subject assessment of the gathered and processing images, the influence of different imaging parameters and post-processing to image quality can be found. The six JND subject assessment experimental data can be validated each other. Main conclusions include: image post-processing can improve image quality; image post-processing can improve image quality even with lossy compression, image quality with higher compression ratio improves less than lower ratio; with our image post-processing method, image quality is better, when camera MTF being within a small range.

  16. Objective assessment of image quality VI: imaging in radiation therapy

    International Nuclear Information System (INIS)

    Barrett, Harrison H; Kupinski, Matthew A; Müeller, Stefan; Halpern, Howard J; Morris, John C III; Dwyer, Roisin

    2013-01-01

    Earlier work on objective assessment of image quality (OAIQ) focused largely on estimation or classification tasks in which the desired outcome of imaging is accurate diagnosis. This paper develops a general framework for assessing imaging quality on the basis of therapeutic outcomes rather than diagnostic performance. By analogy to receiver operating characteristic (ROC) curves and their variants as used in diagnostic OAIQ, the method proposed here utilizes the therapy operating characteristic or TOC curves, which are plots of the probability of tumor control versus the probability of normal-tissue complications as the overall dose level of a radiotherapy treatment is varied. The proposed figure of merit is the area under the TOC curve, denoted AUTOC. This paper reviews an earlier exposition of the theory of TOC and AUTOC, which was specific to the assessment of image-segmentation algorithms, and extends it to other applications of imaging in external-beam radiation treatment as well as in treatment with internal radioactive sources. For each application, a methodology for computing the TOC is presented. A key difference between ROC and TOC is that the latter can be defined for a single patient rather than a population of patients. (paper)

  17. High intensity radiation imaging system

    International Nuclear Information System (INIS)

    Barrett, H.H.

    1976-01-01

    A nuclear imaging system is described for mapping a spatially distributed source of high energy nuclear particles from a living organ which has selectively absorbed a radioactive compound in which the nuclear energy is spatially coded by a zone plate positioned between the source and a spatial detector, and a half tone screen is positioned between the source and the zone plate to increase the definition of the image

  18. High resolution metric imaging payload

    Science.gov (United States)

    Delclaud, Y.

    2017-11-01

    Alcatel Space Industries has become Europe's leader in the field of high and very high resolution optical payloads, in the frame work of earth observation system able to provide military government with metric images from space. This leadership allowed ALCATEL to propose for the export market, within a French collaboration frame, a complete space based system for metric observation.

  19. Digital imaging in diagnostic radiology. Image quality - radiation exposure

    International Nuclear Information System (INIS)

    Schmidt, T.; Stieve, F.E.

    1996-01-01

    The publication contains the 37 lectures of the symposium on digital imaging in diagnostic radiology, held in November 1995 at Kloster Seeon, as well as contributions enhancing the information presented in the lectures. The publication reflects the state of the art in this subject field, discusses future trends and gives recommendations and information relating to current practice in radiology. In-depth information is given about R and D activities for the digitalisation of X-ray pictures and the image quality required to meet the purposes of modern diagnostics. Further aspects encompass radiological protection and dose optimization as well as optimization of examination methods. (vhe) [de

  20. Radiation dose and image quality for paediatric interventional cardiology

    Science.gov (United States)

    Vano, E.; Ubeda, C.; Leyton, F.; Miranda, P.

    2008-08-01

    Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 µGy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 µGy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.

  1. Radiation dose and image quality for paediatric interventional cardiology

    Energy Technology Data Exchange (ETDEWEB)

    Vano, E [Radiology Department, Medicine School, Complutense University and San Carlos University Hospital, 28040 Madrid (Spain); Ubeda, C [Clinical Sciences Department, Faculty of the Science of Health, Tarapaca University, 18 de Septiembre 2222, Arica (Chile); Leyton, F [Institute of Public Health of Chile, Marathon 1000, Nunoa, Santiago (Chile); Miranda, P [Hemodynamic Department, Cardiovascular Service, Luis Calvo Mackenna Hospital, Avenida Antonio Varas 360, Providencia, Santiago (Chile)], E-mail: eliseov@med.ucm.es

    2008-08-07

    Radiation dose and image quality for paediatric protocols in a biplane x-ray system used for interventional cardiology have been evaluated. Entrance surface air kerma (ESAK) and image quality using a test object and polymethyl methacrylate (PMMA) phantoms have been measured for the typical paediatric patient thicknesses (4-20 cm of PMMA). Images from fluoroscopy (low, medium and high) and cine modes have been archived in digital imaging and communications in medicine (DICOM) format. Signal-to-noise ratio (SNR), figure of merit (FOM), contrast (CO), contrast-to-noise ratio (CNR) and high contrast spatial resolution (HCSR) have been computed from the images. Data on dose transferred to the DICOM header have been used to test the values of the dosimetric display at the interventional reference point. ESAK for fluoroscopy modes ranges from 0.15 to 36.60 {mu}Gy/frame when moving from 4 to 20 cm PMMA. For cine, these values range from 2.80 to 161.10 {mu}Gy/frame. SNR, FOM, CO, CNR and HCSR are improved for high fluoroscopy and cine modes and maintained roughly constant for the different thicknesses. Cumulative dose at the interventional reference point resulted 25-45% higher than the skin dose for the vertical C-arm (depending of the phantom thickness). ESAK and numerical image quality parameters allow the verification of the proper setting of the x-ray system. Knowing the increases in dose per frame when increasing phantom thicknesses together with the image quality parameters will help cardiologists in the good management of patient dose and allow them to select the best imaging acquisition mode during clinical procedures.

  2. Diagnostic image quality of video-digitized chest images

    International Nuclear Information System (INIS)

    Winter, L.H.; Butler, R.B.; Becking, W.B.; Warnars, G.A.O.; Haar Romeny, B. ter; Ottes, F.P.; Valk, J.-P.J. de

    1989-01-01

    The diagnostic accuracy obtained with the Philips picture archiving and communications subsystem was investigated by means of an observer performance study using receiver operating characteristic (ROC) analysis. The image qualities of conventional films and video digitized images were compared. The scanner had a 1024 x 1024 x 8 bit memory. The digitized images were displayed on a 60 Hz interlaced display monitor 1024 lines. Posteroanterior (AP) roetgenograms of a chest phantom with superimposed simulated interstitial pattern disease (IPD) were produced; there were 28 normal and 40 abnormal films. Normal films were produced by the chest phantom alone. Abnormal films were taken of the chest phantom with varying degrees of superimposed simulated intersitial disease (PND) for an observer performance study, because the results of a simulated interstitial pattern disease study are less likely to be influenced by perceptual capabilities. The conventional films and the video digitized images were viewed by five experienced observers during four separate sessions. Conventional films were presented on a viewing box, the digital images were displayed on the monitor described above. The presence of simulated intersitial disease was indicated on a 5-point ROC certainty scale by each observer. We analyzed the differences between ROC curves derived from correlated data statistically. The mean time required to evaluate 68 digitized images is approximately four times the mean time needed to read the convential films. The diagnostic quality of the video digitized images was significantly lower (at the 5% level) than that of the conventional films (median area under the curve (AUC) of 0.71 and 0.94, respectively). (author). 25 refs.; 2 figs.; 4 tabs

  3. Optimization of the alpha image reconstruction. An iterative CT-image reconstruction with well-defined image quality metrics

    International Nuclear Information System (INIS)

    Lebedev, Sergej; Sawall, Stefan; Knaup, Michael; Kachelriess, Marc

    2017-01-01

    Optimization of the AIR-algorithm for improved convergence and performance. TThe AIR method is an iterative algorithm for CT image reconstruction. As a result of its linearity with respect to the basis images, the AIR algorithm possesses well defined, regular image quality metrics, e.g. point spread function (PSF) or modulation transfer function (MTF), unlike other iterative reconstruction algorithms. The AIR algorithm computes weighting images α to blend between a set of basis images that preferably have mutually exclusive properties, e.g. high spatial resolution or low noise. The optimized algorithm uses an approach that alternates between the optimization of rawdata fidelity using an OSSART like update and regularization using gradient descent, as opposed to the initially proposed AIR using a straightforward gradient descent implementation. A regularization strength for a given task is chosen by formulating a requirement for the noise reduction and checking whether it is fulfilled for different regularization strengths, while monitoring the spatial resolution using the voxel-wise defined modulation transfer function for the AIR image. The optimized algorithm computes similar images in a shorter time compared to the initial gradient descent implementation of AIR. The result can be influenced by multiple parameters that can be narrowed down to a relatively simple framework to compute high quality images. The AIR images, for instance, can have at least a 50% lower noise level compared to the sharpest basis image, while the spatial resolution is mostly maintained. The optimization improves performance by a factor of 6, while maintaining image quality. Furthermore, it was demonstrated that the spatial resolution for AIR can be determined using regular image quality metrics, given smooth weighting images. This is not possible for other iterative reconstructions as a result of their non linearity. A simple set of parameters for the algorithm is discussed that provides

  4. Optimization of the alpha image reconstruction. An iterative CT-image reconstruction with well-defined image quality metrics

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Sergej; Sawall, Stefan; Knaup, Michael; Kachelriess, Marc [German Cancer Research Center, Heidelberg (Germany).

    2017-10-01

    Optimization of the AIR-algorithm for improved convergence and performance. TThe AIR method is an iterative algorithm for CT image reconstruction. As a result of its linearity with respect to the basis images, the AIR algorithm possesses well defined, regular image quality metrics, e.g. point spread function (PSF) or modulation transfer function (MTF), unlike other iterative reconstruction algorithms. The AIR algorithm computes weighting images α to blend between a set of basis images that preferably have mutually exclusive properties, e.g. high spatial resolution or low noise. The optimized algorithm uses an approach that alternates between the optimization of rawdata fidelity using an OSSART like update and regularization using gradient descent, as opposed to the initially proposed AIR using a straightforward gradient descent implementation. A regularization strength for a given task is chosen by formulating a requirement for the noise reduction and checking whether it is fulfilled for different regularization strengths, while monitoring the spatial resolution using the voxel-wise defined modulation transfer function for the AIR image. The optimized algorithm computes similar images in a shorter time compared to the initial gradient descent implementation of AIR. The result can be influenced by multiple parameters that can be narrowed down to a relatively simple framework to compute high quality images. The AIR images, for instance, can have at least a 50% lower noise level compared to the sharpest basis image, while the spatial resolution is mostly maintained. The optimization improves performance by a factor of 6, while maintaining image quality. Furthermore, it was demonstrated that the spatial resolution for AIR can be determined using regular image quality metrics, given smooth weighting images. This is not possible for other iterative reconstructions as a result of their non linearity. A simple set of parameters for the algorithm is discussed that provides

  5. Dried fruits quality assessment by hyperspectral imaging

    Science.gov (United States)

    Serranti, Silvia; Gargiulo, Aldo; Bonifazi, Giuseppe

    2012-05-01

    Dried fruits products present different market values according to their quality. Such a quality is usually quantified in terms of freshness of the products, as well as presence of contaminants (pieces of shell, husk, and small stones), defects, mould and decays. The combination of these parameters, in terms of relative presence, represent a fundamental set of attributes conditioning dried fruits humans-senses-detectable-attributes (visual appearance, organolectic properties, etc.) and their overall quality in terms of marketable products. Sorting-selection strategies exist but sometimes they fail when a higher degree of detection is required especially if addressed to discriminate between dried fruits of relatively small dimensions and when aiming to perform an "early detection" of pathogen agents responsible of future moulds and decays development. Surface characteristics of dried fruits can be investigated by hyperspectral imaging (HSI). In this paper, specific and "ad hoc" applications addressed to propose quality detection logics, adopting a hyperspectral imaging (HSI) based approach, are described, compared and critically evaluated. Reflectance spectra of selected dried fruits (hazelnuts) of different quality and characterized by the presence of different contaminants and defects have been acquired by a laboratory device equipped with two HSI systems working in two different spectral ranges: visible-near infrared field (400-1000 nm) and near infrared field (1000-1700 nm). The spectra have been processed and results evaluated adopting both a simple and fast wavelength band ratio approach and a more sophisticated classification logic based on principal component (PCA) analysis.

  6. Fundamental factors influencing portal image quality

    International Nuclear Information System (INIS)

    Jaffray, D.A.

    1995-01-01

    It has been recognized that improved methods of verifying radiation field placement in external beam radiotherapy are required in order to make frequent checks of field placement feasible. As a result, a large number of electronic portal imaging systems have been developed as possible replacements for film. These developments have produced digital systems with faster acquisition and improved display contrast, however, the quality of the images acquired with such systems is still disappointing. This presentation examines many of the fundamental factors which limit the quality of radiographs obtained with a megavoltage radiotherapy beam. The size and shape of the radiation sources (focal and extra-focal) in radiotherapy machines and their influence on the spatial resolution of portal images are examined. Monte Carlo simulations of x-ray interactions within the patient determined that a significant fraction of the x-ray scatter generated in the patient is due to bremsstrahlung and positron annihilation. Depending on the detector, the scatter signal can reduce the differential signal-to-noise by 20%. Furthermore, a Monte Carlo study of the interaction of x-rays within typical fluoroscopic imaging detectors (metal plate/phosphor screen) demonstrates the degrading effect of energy absorption noise on the detective quantum efficiency of fluoroscopic based imaging systems. Finally, the spatial frequency content in the x-ray shadowgram is demonstrated to change with x-ray energy, resulting in images that appear to have reduced spatial resolution at megavoltage energies. The relative magnitude of each of these factors will be presented and recommendations for the next generation of portal imaging systems will be made

  7. Automated Quality Assurance Applied to Mammographic Imaging

    Directory of Open Access Journals (Sweden)

    Anne Davis

    2002-07-01

    Full Text Available Quality control in mammography is based upon subjective interpretation of the image quality of a test phantom. In order to suppress subjectivity due to the human observer, automated computer analysis of the Leeds TOR(MAM test phantom is investigated. Texture analysis via grey-level co-occurrence matrices is used to detect structures in the test object. Scoring of the substructures in the phantom is based on grey-level differences between regions and information from grey-level co-occurrence matrices. The results from scoring groups of particles within the phantom are presented.

  8. Exploratory survey of image quality on CR digital mammography imaging systems in Mexico

    International Nuclear Information System (INIS)

    Gaona, E.; Rivera, T.; Arreola, M.; Franco, J.; Molina, N.; Alvarez, B.; Azorín, C.G.; Casian, G.

    2014-01-01

    The purpose of this study was to assess the current status of image quality and dose in computed radiographic digital mammography (CRDM) systems. Studies included CRDM systems of various models and manufacturers which dose and image quality comparisons were performed. Due to the recent rise in the use of digital radiographic systems in Mexico, CRDM systems are rapidly replacing conventional film-screen systems without any regard to quality control or image quality standards. Study was conducted in 65 mammography facilities which use CRDM systems in the Mexico City and surrounding States. The systems were tested as used clinically. This means that the dose and beam qualities were selected using the automatic beam selection and photo-timed features. All systems surveyed generate laser film hardcopies for the radiologist to read on a scope or mammographic high luminance light box. It was found that 51 of CRDM systems presented a variety of image artefacts and non-uniformities arising from inadequate acquisition and processing, as well as from the laser printer itself. Undisciplined alteration of image processing settings by the technologist was found to be a serious prevalent problem in 42 facilities. Only four of them showed an image QC program which is periodically monitored by a medical physicist. The Average Glandular Dose (AGD) in the surveyed systems was estimated to have a mean value of 2.4 mGy. To improve image quality in mammography and make more efficient screening mammographic in early detection of breast cancer is required new legislation. - Highlights: • Radiation dose in CR digital mammography (CRDM) systems was determined. • Image quality related with dose in CR digital mammography (CRDM) systems was analysed. • Image processing artefacts were observed and correlated with dose. • Measured entrance dose by TL phosphors could be good parameter for radiation protection optimization in patient

  9. Objective analysis of image quality of video image capture systems

    Science.gov (United States)

    Rowberg, Alan H.

    1990-07-01

    As Picture Archiving and Communication System (PACS) technology has matured, video image capture has become a common way of capturing digital images from many modalities. While digital interfaces, such as those which use the ACR/NEMA standard, will become more common in the future, and are preferred because of the accuracy of image transfer, video image capture will be the dominant method in the short term, and may continue to be used for some time because of the low cost and high speed often associated with such devices. Currently, virtually all installed systems use methods of digitizing the video signal that is produced for display on the scanner viewing console itself. A series of digital test images have been developed for display on either a GE CT9800 or a GE Signa MRI scanner. These images have been captured with each of five commercially available image capture systems, and the resultant images digitally transferred on floppy disk to a PC1286 computer containing Optimast' image analysis software. Here the images can be displayed in a comparative manner for visual evaluation, in addition to being analyzed statistically. Each of the images have been designed to support certain tests, including noise, accuracy, linearity, gray scale range, stability, slew rate, and pixel alignment. These image capture systems vary widely in these characteristics, in addition to the presence or absence of other artifacts, such as shading and moire pattern. Other accessories such as video distribution amplifiers and noise filters can also add or modify artifacts seen in the captured images, often giving unusual results. Each image is described, together with the tests which were performed using them. One image contains alternating black and white lines, each one pixel wide, after equilibration strips ten pixels wide. While some systems have a slew rate fast enough to track this correctly, others blur it to an average shade of gray, and do not resolve the lines, or give

  10. Reducing the absorbed dose in analogue radiography of infant chest images by improving the image quality, using image processing techniques

    International Nuclear Information System (INIS)

    Karimian, A.; Yazdani, S.; Askari, M. A.

    2011-01-01

    Radiographic inspection is one of the most widely employed techniques for medical testing methods. Because of poor contrast and high un-sharpness of radiographic image quality in films, converting radiographs to a digital format and using further digital image processing is the best method of enhancing the image quality and assisting the interpreter in their evaluation. In this research work, radiographic films of 70 infant chest images with different sizes of defects were selected. To digitise the chest images and employ image processing the two algorithms (i) spatial domain and (ii) frequency domain techniques were used. The MATLAB environment was selected for processing in the digital format. Our results showed that by using these two techniques, the defects with small dimensions are detectable. Therefore, these suggested techniques may help medical specialists to diagnose the defects in the primary stages and help to prevent more repeat X-ray examination of paediatric patients. (authors)

  11. Improve Image Quality of Transversal Relaxation Time PROPELLER and FLAIR on Magnetic Resonance Imaging

    Science.gov (United States)

    Rauf, N.; Alam, D. Y.; Jamaluddin, M.; Samad, B. A.

    2018-03-01

    The Magnetic Resonance Imaging (MRI) is a medical imaging technique that uses the interaction between the magnetic field and the nuclear spins. MRI can be used to show disparity of pathology by transversal relaxation time (T2) weighted images. Some techniques for producing T2-weighted images are Periodically Rotated Overlapping Parallel Lines with Enhanced Reconstruction (PROPELLER) and Fluid Attenuated Inversion Recovery (FLAIR). A comparison of T2 PROPELLER and T2 FLAIR parameters in MRI image has been conducted. And improve Image Quality the image by using RadiAnt DICOM Viewer and ENVI software with method of image segmentation and Region of Interest (ROI). Brain images were randomly selected. The result of research showed that Time Repetition (TR) and Time Echo (TE) values in all types of images were not influenced by age. T2 FLAIR images had longer TR value (9000 ms), meanwhile T2 PROPELLER images had longer TE value (100.75 - 102.1 ms). Furthermore, areas with low and medium signal intensity appeared clearer by using T2 PROPELLER images (average coefficients of variation for low and medium signal intensity were 0.0431 and 0.0705, respectively). As for areas with high signal intensity appeared clearer by using T2 FLAIR images (average coefficient of variation was 0.0637).

  12. Self-Organizing Maps for Fingerprint Image Quality Assessment

    DEFF Research Database (Denmark)

    Olsen, Martin Aastrup; Tabassi, Elham; Makarov, Anton

    2013-01-01

    Fingerprint quality assessment is a crucial task which needs to be conducted accurately in various phases in the biometric enrolment and recognition processes. Neglecting quality measurement will adversely impact accuracy and efficiency of biometric recognition systems (e.g. verification and iden......Fingerprint quality assessment is a crucial task which needs to be conducted accurately in various phases in the biometric enrolment and recognition processes. Neglecting quality measurement will adversely impact accuracy and efficiency of biometric recognition systems (e.g. verification...... machine learning techniques. We train a self-organizing map (SOM) to cluster blocks of fingerprint images based on their spatial information content. The output of the SOM is a high-level representation of the finger image, which forms the input to a Random Forest trained to learn the relationship between...

  13. Fast High-Quality Noise

    DEFF Research Database (Denmark)

    Frisvad, Jeppe Revall; Wyvill, Geoff

    2007-01-01

    At the moment the noise functions available in a graphics programmer's toolbox are either slow to compute or they involve grid-line artifacts making them of lower quality. In this paper we present a real-time noise computation with no grid-line artifacts or other regularity problems. In other words......, we put a new tool in the box that computes fast high-quality noise. In addition to being free of artifacts, the noise we present does not rely on tabulated data (everything is computed on the fly) and it is easy to adjust quality vs. quantity for the noise. The noise is based on point rendering (like...... spot noise), but it extends to more than two dimensions. The fact that it is based on point rendering makes art direction of the noise much easier....

  14. Image quality and dose differences caused by vendor-specific image processing of neonatal radiographs

    International Nuclear Information System (INIS)

    Sensakovic, William F.; O'Dell, M.C.; Letter, Haley; Kohler, Nathan; Rop, Baiywo; Cook, Jane; Logsdon, Gregory; Varich, Laura

    2016-01-01

    Image processing plays an important role in optimizing image quality and radiation dose in projection radiography. Unfortunately commercial algorithms are black boxes that are often left at or near vendor default settings rather than being optimized. We hypothesize that different commercial image-processing systems, when left at or near default settings, create significant differences in image quality. We further hypothesize that image-quality differences can be exploited to produce images of equivalent quality but lower radiation dose. We used a portable radiography system to acquire images on a neonatal chest phantom and recorded the entrance surface air kerma (ESAK). We applied two image-processing systems (Optima XR220amx, by GE Healthcare, Waukesha, WI; and MUSICA"2 by Agfa HealthCare, Mortsel, Belgium) to the images. Seven observers (attending pediatric radiologists and radiology residents) independently assessed image quality using two methods: rating and matching. Image-quality ratings were independently assessed by each observer on a 10-point scale. Matching consisted of each observer matching GE-processed images and Agfa-processed images with equivalent image quality. A total of 210 rating tasks and 42 matching tasks were performed and effective dose was estimated. Median Agfa-processed image-quality ratings were higher than GE-processed ratings. Non-diagnostic ratings were seen over a wider range of doses for GE-processed images than for Agfa-processed images. During matching tasks, observers matched image quality between GE-processed images and Agfa-processed images acquired at a lower effective dose (11 ± 9 μSv; P < 0.0001). Image-processing methods significantly impact perceived image quality. These image-quality differences can be exploited to alter protocols and produce images of equivalent image quality but lower doses. Those purchasing projection radiography systems or third-party image-processing software should be aware that image processing

  15. Image quality and dose differences caused by vendor-specific image processing of neonatal radiographs

    Energy Technology Data Exchange (ETDEWEB)

    Sensakovic, William F.; O' Dell, M.C.; Letter, Haley; Kohler, Nathan; Rop, Baiywo; Cook, Jane; Logsdon, Gregory; Varich, Laura [Florida Hospital, Imaging Administration, Orlando, FL (United States)

    2016-10-15

    Image processing plays an important role in optimizing image quality and radiation dose in projection radiography. Unfortunately commercial algorithms are black boxes that are often left at or near vendor default settings rather than being optimized. We hypothesize that different commercial image-processing systems, when left at or near default settings, create significant differences in image quality. We further hypothesize that image-quality differences can be exploited to produce images of equivalent quality but lower radiation dose. We used a portable radiography system to acquire images on a neonatal chest phantom and recorded the entrance surface air kerma (ESAK). We applied two image-processing systems (Optima XR220amx, by GE Healthcare, Waukesha, WI; and MUSICA{sup 2} by Agfa HealthCare, Mortsel, Belgium) to the images. Seven observers (attending pediatric radiologists and radiology residents) independently assessed image quality using two methods: rating and matching. Image-quality ratings were independently assessed by each observer on a 10-point scale. Matching consisted of each observer matching GE-processed images and Agfa-processed images with equivalent image quality. A total of 210 rating tasks and 42 matching tasks were performed and effective dose was estimated. Median Agfa-processed image-quality ratings were higher than GE-processed ratings. Non-diagnostic ratings were seen over a wider range of doses for GE-processed images than for Agfa-processed images. During matching tasks, observers matched image quality between GE-processed images and Agfa-processed images acquired at a lower effective dose (11 ± 9 μSv; P < 0.0001). Image-processing methods significantly impact perceived image quality. These image-quality differences can be exploited to alter protocols and produce images of equivalent image quality but lower doses. Those purchasing projection radiography systems or third-party image-processing software should be aware that image

  16. Using a web-based image quality assurance reporting system to improve image quality.

    Science.gov (United States)

    Czuczman, Gregory J; Pomerantz, Stuart R; Alkasab, Tarik K; Huang, Ambrose J

    2013-08-01

    The purpose of this study is to show the impact of a web-based image quality assurance reporting system on the rates of three common image quality errors at our institution. A web-based image quality assurance reporting system was developed and used beginning in April 2009. Image quality endpoints were assessed immediately before deployment (period 1), approximately 18 months after deployment of a prototype reporting system (period 2), and approximately 12 months after deployment of a subsequent upgraded department-wide reporting system (period 3). A total of 3067 axillary shoulder radiographs were reviewed for correct orientation, 355 shoulder CT scans were reviewed for correct reformatting of coronal and sagittal images, and 346 sacral MRI scans were reviewed for correct acquisition plane of axial images. Error rates for each review period were calculated and compared using the Fisher exact test. Error rates of axillary shoulder radiograph orientation were 35.9%, 7.2%, and 10.0%, respectively, for the three review periods. The decrease in error rate between periods 1 and 2 was statistically significant (p < 0.0001). Error rates of shoulder CT reformats were 9.8%, 2.7%, and 5.8%, respectively, for the three review periods. The decrease in error rate between periods 1 and 2 was statistically significant (p = 0.03). Error rates for sacral MRI axial sequences were 96.5%, 32.5%, and 3.4%, respectively, for the three review periods. The decrease in error rates between periods 1 and 2 and between periods 2 and 3 was statistically significant (p < 0.0001). A web-based system for reporting image quality errors may be effective for improving image quality.

  17. A fourier transform quality measure for iris images

    CSIR Research Space (South Africa)

    Makinana, S

    2014-08-01

    Full Text Available to ensure that good quality images are selected for feature extraction, in order to improve iris recognition system. In addition, this research proposes a measure of iris image quality using a Fourier Transform. The experimental results demonstrate...

  18. A factorial experiment on image quality and radiation dose

    International Nuclear Information System (INIS)

    Norrman, E.; Persliden, J.

    2005-01-01

    To find if factorial experiments can be used in the optimisation of diagnostic imaging, a factorial experiment was performed to investigate some of the factors that influence image quality, kerma area product (KAP) and effective dose (E). In a factorial experiment the factors are varied together instead of one at a time, making it possible to discover interactions between the factors as well as major effects. The factors studied were tube potential, tube loading, focus size and filtration. Each factor was set to two levels (low and high). The influence of the factors on the response variables (image quality, KAP and E) was studied using a direct digital detector. The major effects of each factor on the response variables were estimated as well as the interaction effects between factors. The image quality, KAP and E were mainly influenced by tube loading, tube potential and filtration. There were some active interactions, for example, between tube potential and filtration and between tube loading and filtration. The study shows that factorial experiments can be used to predict the influence of various parameters on image quality and radiation dose. (authors)

  19. Visualization of the influence of the air conditioning system to the high-power laser beam quality with the modulation coherent imaging method.

    Science.gov (United States)

    Tao, Hua; Veetil, Suhas P; Pan, Xingchen; Liu, Cheng; Zhu, Jianqiang

    2015-08-01

    Air conditioning systems can lead to dynamic phase change in the laser beams of high-power laser facilities for the inertial confinement fusion, and this kind of phase change cannot be measured by most of the commonly employed Hartmann wavefront sensor or interferometry due to some uncontrollable factors, such as too large laser beam diameters and the limited space of the facility. It is demonstrated that this problem can be solved using a scheme based on modulation coherent imaging, and thus the influence of the air conditioning system on the performance of the high-power facility can be evaluated directly.

  20. SU-E-J-47: Development of a High-Precision, Image-Guided Radiotherapy, Multi- Purpose Radiation Isocenter Quality-Assurance Calibration and Checking System

    International Nuclear Information System (INIS)

    Liu, C; Yan, G; Helmig, R; Lebron, S; Kahler, D

    2014-01-01

    Purpose: To develop a system that can define the radiation isocenter and correlate this information with couch coordinates, laser alignment, optical distance indicator (ODI) settings, optical tracking system (OTS) calibrations, and mechanical isocenter walkout. Methods: Our team developed a multi-adapter, multi-purpose quality assurance (QA) and calibration device that uses an electronic portal imaging device (EPID) and in-house image-processing software to define the radiation isocenter, thereby allowing linear accelerator (Linac) components to be verified and calibrated. Motivated by the concept that each Linac component related to patient setup for image-guided radiotherapy based on cone-beam CT should be calibrated with respect to the radiation isocenter, we designed multiple concentric adapters of various materials and shapes to meet the needs of MV and KV radiation isocenter definition, laser alignment, and OTS calibration. The phantom's ability to accurately define the radiation isocenter was validated on 4 Elekta Linacs using a commercial ball bearing (BB) phantom as a reference. Radiation isocenter walkout and the accuracy of couch coordinates, ODI, and OTS were then quantified with the device. Results: The device was able to define the radiation isocenter within 0.3 mm. Radiation isocenter walkout was within ±1 mm at 4 cardinal angles. By switching adapters, we identified that the accuracy of the couch position digital readout, ODI, OTS, and mechanical isocenter walkout was within sub-mm. Conclusion: This multi-adapter, multi-purpose isocenter phantom can be used to accurately define the radiation isocenter and represents a potential paradigm shift in Linac QA. Moreover, multiple concentric adapters allowed for sub-mm accuracy for the other relevant components. This intuitive and user-friendly design is currently patent pending

  1. The mobile image quality survey game

    Science.gov (United States)

    Rasmussen, D. René

    2012-01-01

    In this paper we discuss human assessment of the quality of photographic still images, that are degraded in various manners relative to an original, for example due to compression or noise. In particular, we examine and present results from a technique where observers view images on a mobile device, perform pairwise comparisons, identify defects in the images, and interact with the display to indicate the location of the defects. The technique measures the response time and accuracy of the responses. By posing the survey in a form similar to a game, providing performance feedback to the observer, the technique attempts to increase the engagement of the observers, and to avoid exhausting observers, a factor that is often a problem for subjective surveys. The results are compared with the known physical magnitudes of the defects and with results from similar web-based surveys. The strengths and weaknesses of the technique are discussed. Possible extensions of the technique to video quality assessment are also discussed.

  2. The Image Quality of a Digital Chest X-Ray Radiography System: Comparison of Quantitative Image Quality Analysis and Radiologists' Visual Scoring

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Ji Ho [Dept. of Radiology Oncology, Yongsan Hospital, Pusan National University College of Medicine, Yongsan (Korea, Republic of); Chung, Myung Jin [Dept. of Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Park, Darl; Kim, Won Taek; Kim, Yong Ho; Ki, Yong Kan; Kim, DFong Hyun; Lee, Ju Hee; Kim, Dong Won [Dept. of Radiology Oncology, Yongsan Hospital, Pusan National University College of Medicine, Yongsan (Korea, Republic of); Jeon, Ho Sang [Reserach Institue for Convergence of Biomedical Science and Technology, Yongsan Hospital, Pusan National University College of Medicine, Yongsan (Korea, Republic of)

    2011-11-15

    To evaluate the performance of imaging devices, which should be periodically monitored to maintain high quality images to the radiologists. Additionally, this evaluation may prevent patients from radiation over-exposure. The most suitable engineering standard for imaging performance evaluation of digital X-ray thoracic images was determined. IEC 62220-1 standards were used to evaluate the performance of the images. In succession, the visibilities of overall image, pneumothorax, and humerus head in anthropomorphic thoracic phantom images were used to evaluate the image qualities by radiologists. The rank correlation coefficient (p) of visual scoring by radiologists with system spatial resolution is not meaningful (p-value, p = 0.295), but is significant with image noise (p-value, p -0.9267). Finally, the noise equivalent quanta (NEQ) presents a high rank correlation for visual scoring of radiologists (p-value, p = 0.9320). Image quality evaluation of radiologists were mainly affected by imaging noise. Hence, the engineered standard for evaluating image noise is the most important index to effectively monitor the performance of X-ray images. Additionally, the NEQ can be used to evaluate the performance of radiographic systems, because it theoretically corresponds to the synthetic image quality of systems.

  3. Robust image registration for multiple exposure high dynamic range image synthesis

    Science.gov (United States)

    Yao, Susu

    2011-03-01

    Image registration is an important preprocessing technique in high dynamic range (HDR) image synthesis. This paper proposed a robust image registration method for aligning a group of low dynamic range images (LDR) that are captured with different exposure times. Illumination change and photometric distortion between two images would result in inaccurate registration. We propose to transform intensity image data into phase congruency to eliminate the effect of the changes in image brightness and use phase cross correlation in the Fourier transform domain to perform image registration. Considering the presence of non-overlapped regions due to photometric distortion, evolutionary programming is applied to search for the accurate translation parameters so that the accuracy of registration is able to be achieved at a hundredth of a pixel level. The proposed algorithm works well for under and over-exposed image registration. It has been applied to align LDR images for synthesizing high quality HDR images..

  4. Investigation of grid performance using simple image quality tests

    Directory of Open Access Journals (Sweden)

    Dogan Bor

    2016-01-01

    Full Text Available Antiscatter grids improve the X-ray image contrast at a cost of patient radiation doses. The choice of appropriate grid or its removal requires a good knowledge of grid characteristics, especially for pediatric digital imaging. The aim of this work is to understand the relation between grid performance parameters and some numerical image quality metrics for digital radiological examinations. The grid parameters such as bucky factor (BF, selectivity (Σ, Contrast improvement factor (CIF, and signal-to-noise improvement factor (SIF were determined following the measurements of primary, scatter, and total radiations with a digital fluoroscopic system for the thicknesses of 5, 10, 15, 20, and 25 cm polymethyl methacrylate blocks at the tube voltages of 70, 90, and 120 kVp. Image contrast for low- and high-contrast objects and high-contrast spatial resolution were measured with simple phantoms using the same scatter thicknesses and tube voltages. BF and SIF values were also calculated from the images obtained with and without grids. The correlation coefficients between BF values obtained using two approaches (grid parameters and image quality metrics were in good agreement. Proposed approach provides a quick and practical way of estimating grid performance for different digital fluoroscopic examinations.

  5. Clinical efficiency, image quality and dosimetric considerations

    Energy Technology Data Exchange (ETDEWEB)

    Arreola, M. [Director of Clinical Radiological Physics, Shands Hospital at the University of Florida College of Medicine, Gainesville, FL (United States)

    2000-07-01

    Three decades have passed since the first clinical use of the famous EMI Computed Axial Tomography (Cat) scanner. At the time, the prospects for clinical success of this innovative idea were not very good. Time, however, has proven otherwise as what is now simply known as Computed tomography (CT) has been boosted in each one of these decades for different reasons. In the 1970s, technological progress augmented by the realization of the importance of tomographic imaging got everything started; in the 1980s, the boom in health care demand in the US solidified its position and in the 1990s the technological explosion in computers and the imperative need to lower costs in the health care industry have prompted the most dramatic changes in the wy CT is utilized in the year 2000. Thus, different motivations have led the way of progress in CT at various times, and in spite of amazing developments in other crucial imaging modalities, such as ultrasound, Doppler ultrasound, digital subtraction angiography and magnetic resonance imaging, CT maintains its rightful place as the premiere imaging modality in the modern radiology department. This work covers the basic principles of tomographic image reconstruction, and how axial CT scanners progressed historically in the first two decades. Developments in X-ray tubes, and detection systems are highlighted, as well as the impact of clinical efficiency, image quality and patient doses. The basic construction of translate-rotate (1st and 2nd generation), rotate-rotate (3rd generation) and detector ring (4th generation) scanners are described. The so-called 5th generation scanner, the electron beam scanner, is also described, with its clinical and technical advantages and its inherent financial and maintenance disadvantages, which brought the advent of spiral and multi-slice scanners. These most recent developments in CT technology have opened a new era in the clinical use of CT; and although image quality has reached an expected

  6. Clinical efficiency, image quality and dosimetric considerations

    International Nuclear Information System (INIS)

    Arreola, M.

    2000-01-01

    Three decades have passed since the first clinical use of the famous EMI Computed Axial Tomography (Cat) scanner. At the time, the prospects for clinical success of this innovative idea were not very good. Time, however, has proven otherwise as what is now simply known as Computed tomography (CT) has been boosted in each one of these decades for different reasons. In the 1970s, technological progress augmented by the realization of the importance of tomographic imaging got everything started; in the 1980s, the boom in health care demand in the US solidified its position and in the 1990s the technological explosion in computers and the imperative need to lower costs in the health care industry have prompted the most dramatic changes in the wy CT is utilized in the year 2000. Thus, different motivations have led the way of progress in CT at various times, and in spite of amazing developments in other crucial imaging modalities, such as ultrasound, Doppler ultrasound, digital subtraction angiography and magnetic resonance imaging, CT maintains its rightful place as the premiere imaging modality in the modern radiology department. This work covers the basic principles of tomographic image reconstruction, and how axial CT scanners progressed historically in the first two decades. Developments in X-ray tubes, and detection systems are highlighted, as well as the impact of clinical efficiency, image quality and patient doses. The basic construction of translate-rotate (1st and 2nd generation, rotate-rotate (3rd generation) and detector ring (4th generation) scanners are described. The so-called 5th generation scanner, the electron beam scanner, is also described, with its clinical and technical advantages and its inherent financial and maintenance disadvantages, which brought the advent of spiral and multi-slice scanners. These most recent developments in CT technology have opened a new era in the clinical use of CT; and although image quality has reached an expected

  7. Image quality testing of assembled IR camera modules

    Science.gov (United States)

    Winters, Daniel; Erichsen, Patrik

    2013-10-01

    Infrared (IR) camera modules for the LWIR (8-12_m) that combine IR imaging optics with microbolometer focal plane array (FPA) sensors with readout electronics are becoming more and more a mass market product. At the same time, steady improvements in sensor resolution in the higher priced markets raise the requirement for imaging performance of objectives and the proper alignment between objective and FPA. This puts pressure on camera manufacturers and system integrators to assess the image quality of finished camera modules in a cost-efficient and automated way for quality control or during end-of-line testing. In this paper we present recent development work done in the field of image quality testing of IR camera modules. This technology provides a wealth of additional information in contrast to the more traditional test methods like minimum resolvable temperature difference (MRTD) which give only a subjective overall test result. Parameters that can be measured are image quality via the modulation transfer function (MTF) for broadband or with various bandpass filters on- and off-axis and optical parameters like e.g. effective focal length (EFL) and distortion. If the camera module allows for refocusing the optics, additional parameters like best focus plane, image plane tilt, auto-focus quality, chief ray angle etc. can be characterized. Additionally, the homogeneity and response of the sensor with the optics can be characterized in order to calculate the appropriate tables for non-uniformity correction (NUC). The technology can also be used to control active alignment methods during mechanical assembly of optics to high resolution sensors. Other important points that are discussed are the flexibility of the technology to test IR modules with different form factors, electrical interfaces and last but not least the suitability for fully automated measurements in mass production.

  8. High visibility temporal ghost imaging with classical light

    Science.gov (United States)

    Liu, Jianbin; Wang, Jingjing; Chen, Hui; Zheng, Huaibin; Liu, Yanyan; Zhou, Yu; Li, Fu-li; Xu, Zhuo

    2018-03-01

    High visibility temporal ghost imaging with classical light is possible when superbunching pseudothermal light is employed. In the numerical simulation, the visibility of temporal ghost imaging with pseudothermal light, equaling (4 . 7 ± 0 . 2)%, can be increased to (75 ± 8)% in the same scheme with superbunching pseudothermal light. The reasons for that the retrieved images are different for superbunching pseudothermal light with different values of degree of second-order coherence are discussed in detail. It is concluded that high visibility and high quality temporal ghost image can be obtained by collecting sufficient number of data points. The results are helpful to understand the difference between ghost imaging with classical light and entangled photon pairs. The superbunching pseudothermal light can be employed to improve the image quality in ghost imaging applications.

  9. Quality of intensive care chest imaging

    International Nuclear Information System (INIS)

    Adam, G.; Wein, B.; Keulers, P.; Stargardt, A.; Guenther, R.W.

    1989-01-01

    The authors have evaluated the image quality of a stimulable phosphorous plate system in intensive care chest radiography. Four radiologists examined 308 chest radiographs (200 conventional, 108 digital) according to the following criteria: visibility of catheters, tubes (artificial objects), bronchi, central and peripheral vessels, diaphragm, trachea, and retrocardial lung parenchyma. Detectability of these structures was classified as good, poor, or impossible to see. In addition, optical density was measured in the region of liver, heart, and lung. Results were evaluated by Student and υ test

  10. Improvement of material decomposition and image quality in dual-energy radiography by reducing image noise

    International Nuclear Information System (INIS)

    Lee, D.; Choi, S.; Kim, H.; Kim, H.-J.; Kim, Y.-S.; Choi, S.; Lee, H.; Jo, B.D.; Jeon, P.-H.; Kim, H.; Kim, D.

    2016-01-01

    Although digital radiography has been widely used for screening human anatomical structures in clinical situations, it has several limitations due to anatomical overlapping. To resolve this problem, dual-energy imaging techniques, which provide a method for decomposing overlying anatomical structures, have been suggested as alternative imaging techniques. Previous studies have reported several dual-energy techniques, each resulting in different image qualities. In this study, we compared three dual-energy techniques: simple log subtraction (SLS), simple smoothing of a high-energy image (SSH), and anti-correlated noise reduction (ACNR) with respect to material thickness quantification and image quality. To evaluate dual-energy radiography, we conducted Monte Carlo simulation and experimental phantom studies. The Geant 4 Application for Tomographic Emission (GATE) v 6.0 and tungsten anode spectral model using interpolation polynomials (TASMIP) codes were used for simulation studies and digital radiography, and human chest phantoms were used for experimental studies. The results of the simulation study showed improved image contrast-to-noise ratio (CNR) and coefficient of variation (COV) values and bone thickness estimation accuracy by applying the ACNR and SSH methods. Furthermore, the chest phantom images showed better image quality with the SSH and ACNR methods compared to the SLS method. In particular, the bone texture characteristics were well-described by applying the SSH and ACNR methods. In conclusion, the SSH and ACNR methods improved the accuracy of material quantification and image quality in dual-energy radiography compared to SLS. Our results can contribute to better diagnostic capabilities of dual-energy images and accurate material quantification in various clinical situations.

  11. Fundamental image quality limits for microcomputed tomography in small animals

    International Nuclear Information System (INIS)

    Ford, N.L.; Thornton, M.M.; Holdsworth, D.W.

    2003-01-01

    resolution to improve, by decreasing the detector element size to tens of microns or less, high quality images will be limited by the x-ray dose administered. For the highest quality images, these doses will approach the lethal dose or LD50 for the animals. Approaching the lethal dose will affect the way experiments are planned, and may reduce opportunities for experiments involving imaging the same animal over time. Dose considerations will become much more important for live small-animal imaging as the limits of resolution are tested

  12. Image quality preferences among radiographers and radiologists. A conjoint analysis

    International Nuclear Information System (INIS)

    Ween, Borgny; Kristoffersen, Doris Tove; Hamilton, Glenys A.; Olsen, Dag Rune

    2005-01-01

    Purpose: The aim of this study was to investigate the image quality preferences among radiographers and radiologists. The radiographers' preferences are mainly related to technical parameters, whereas radiologists assess image quality based on diagnostic value. Methods: A conjoint analysis was undertaken to survey image quality preferences; the study included 37 respondents: 19 radiographers and 18 radiologists. Digital urograms were post-processed into 8 images with different properties of image quality for 3 different patients. The respondents were asked to rank the images according to their personally perceived subjective image quality. Results: Nearly half of the radiographers and radiologists were consistent in their ranking of the image characterised as 'very best image quality'. The analysis showed, moreover, that chosen filtration level and image intensity were responsible for 72% and 28% of the preferences, respectively. The corresponding figures for each of the two professions were 76% and 24% for the radiographers, and 68% and 32% for the radiologists. In addition, there were larger variations in image preferences among the radiologists, as compared to the radiographers. Conclusions: Radiographers revealed a more consistent preference than the radiologists with respect to image quality. There is a potential for image quality improvement by developing sets of image property criteria

  13. Fingerprint matching algorithm for poor quality images

    Directory of Open Access Journals (Sweden)

    Vedpal Singh

    2015-04-01

    Full Text Available The main aim of this study is to establish an efficient platform for fingerprint matching for low-quality images. Generally, fingerprint matching approaches use the minutiae points for authentication. However, it is not such a reliable authentication method for low-quality images. To overcome this problem, the current study proposes a fingerprint matching methodology based on normalised cross-correlation, which would improve the performance and reduce the miscalculations during authentication. It would decrease the computational complexities. The error rate of the proposed method is 5.4%, which is less than the two-dimensional (2D dynamic programming (DP error rate of 5.6%, while Lee's method produces 5.9% and the combined method has 6.1% error rate. Genuine accept rate at 1% false accept rate is 89.3% but at 0.1% value it is 96.7%, which is higher. The outcome of this study suggests that the proposed methodology has a low error rate with minimum computational effort as compared with existing methods such as Lee's method and 2D DP and the combined method.

  14. Image Quality Characteristics of Handheld Display Devices for Medical Imaging

    Science.gov (United States)

    Yamazaki, Asumi; Liu, Peter; Cheng, Wei-Chung; Badano, Aldo

    2013-01-01

    Handheld devices such as mobile phones and tablet computers have become widespread with thousands of available software applications. Recently, handhelds are being proposed as part of medical imaging solutions, especially in emergency medicine, where immediate consultation is required. However, handheld devices differ significantly from medical workstation displays in terms of display characteristics. Moreover, the characteristics vary significantly among device types. We investigate the image quality characteristics of various handheld devices with respect to luminance response, spatial resolution, spatial noise, and reflectance. We show that the luminance characteristics of the handheld displays are different from those of workstation displays complying with grayscale standard target response suggesting that luminance calibration might be needed. Our results also demonstrate that the spatial characteristics of handhelds can surpass those of medical workstation displays particularly for recent generation devices. While a 5 mega-pixel monochrome workstation display has horizontal and vertical modulation transfer factors of 0.52 and 0.47 at the Nyquist frequency, the handheld displays released after 2011 can have values higher than 0.63 at the respective Nyquist frequencies. The noise power spectra for workstation displays are higher than 1.2×10−5 mm2 at 1 mm−1, while handheld displays have values lower than 3.7×10−6 mm2. Reflectance measurements on some of the handheld displays are consistent with measurements for workstation displays with, in some cases, low specular and diffuse reflectance coefficients. The variability of the characterization results among devices due to the different technological features indicates that image quality varies greatly among handheld display devices. PMID:24236113

  15. Image quality assessment for selfies with and without super resolution

    Science.gov (United States)

    Kubota, Aya; Gohshi, Seiichi

    2018-04-01

    With the advent of cellphone cameras, in particular, on smartphones, many people now take photos of themselves alone and with others in the frame; such photos are popularly known as "selfies". Most smartphones are equipped with two cameras: the front-facing and rear cameras. The camera located on the back of the smartphone is referred to as the "out-camera," whereas the one located on the front of the smartphone is called the "in-camera." In-cameras are mainly used for selfies. Some smartphones feature high-resolution cameras. However, the original image quality cannot be obtained because smartphone cameras often have low-performance lenses. Super resolution (SR) is one of the recent technological advancements that has increased image resolution. We developed a new SR technology that can be processed on smartphones. Smartphones with new SR technology are currently available in the market have already registered sales. However, the effective use of new SR technology has not yet been verified. Comparing the image quality with and without SR on smartphone display is necessary to confirm the usefulness of this new technology. Methods that are based on objective and subjective assessments are required to quantitatively measure image quality. It is known that the typical object assessment value, such as Peak Signal to Noise Ratio (PSNR), does not go together with how we feel when we assess image/video. When digital broadcast started, the standard was determined using subjective assessment. Although subjective assessment usually comes at high cost because of personnel expenses for observers, the results are highly reproducible when they are conducted under right conditions and statistical analysis. In this study, the subjective assessment results for selfie images are reported.

  16. High-picture quality industrial CT scanner

    International Nuclear Information System (INIS)

    Shoji, Takao; Nishide, Akihiko; Fujii, Masashi.

    1989-01-01

    Industrial X-ray-CT-scanners, which provide cross-sectional images of a tested sample without destroying it, are attracting attention as a new nondestructive inspection device. In 1982, Toshiba commenced the development of industrial CT scanners, and introduced the 'TOSCANER' -3000 and-4000 series. Now, the state of the art 'TOSCANER'-20000 series of CT systems has been developed incorporating the latest computer tomography and image processing technology, such as the T9506 image processor. One of the advantages of this system is its applicability to a wide range of X-ray energy . The 'TOSCANER'-20000 series can be utilized for inspecting castings and other materials with relatively low-transparency to X-rays, as well as ceramics, composite materials and other materials with high X-ray transparency. A further feature of the new system is its high-picture quality, with a high-spatial resolution resulting from a pixel size of 0.2x0.2(mm). (author)

  17. Image quality optimization and evaluation of linearly mixed images in dual-source, dual-energy CT

    International Nuclear Information System (INIS)

    Yu Lifeng; Primak, Andrew N.; Liu Xin; McCollough, Cynthia H.

    2009-01-01

    In dual-source dual-energy CT, the images reconstructed from the low- and high-energy scans (typically at 80 and 140 kV, respectively) can be mixed together to provide a single set of non-material-specific images for the purpose of routine diagnostic interpretation. Different from the material-specific information that may be obtained from the dual-energy scan data, the mixed images are created with the purpose of providing the interpreting physician a single set of images that have an appearance similar to that in single-energy images acquired at the same total radiation dose. In this work, the authors used a phantom study to evaluate the image quality of linearly mixed images in comparison to single-energy CT images, assuming the same total radiation dose and taking into account the effect of patient size and the dose partitioning between the low-and high-energy scans. The authors first developed a method to optimize the quality of the linearly mixed images such that the single-energy image quality was compared to the best-case image quality of the dual-energy mixed images. Compared to 80 kV single-energy images for the same radiation dose, the iodine CNR in dual-energy mixed images was worse for smaller phantom sizes. However, similar noise and similar or improved iodine CNR relative to 120 kV images could be achieved for dual-energy mixed images using the same total radiation dose over a wide range of patient sizes (up to 45 cm lateral thorax dimension). Thus, for adult CT practices, which primarily use 120 kV scanning, the use of dual-energy CT for the purpose of material-specific imaging can also produce a set of non-material-specific images for routine diagnostic interpretation that are of similar or improved quality relative to single-energy 120 kV scans.

  18. Automated daily quality control analysis for mammography in a multi-unit imaging center.

    Science.gov (United States)

    Sundell, Veli-Matti; Mäkelä, Teemu; Meaney, Alexander; Kaasalainen, Touko; Savolainen, Sauli

    2018-01-01

    Background The high requirements for mammography image quality necessitate a systematic quality assurance process. Digital imaging allows automation of the image quality analysis, which can potentially improve repeatability and objectivity compared to a visual evaluation made by the users. Purpose To develop an automatic image quality analysis software for daily mammography quality control in a multi-unit imaging center. Material and Methods An automated image quality analysis software using the discrete wavelet transform and multiresolution analysis was developed for the American College of Radiology accreditation phantom. The software was validated by analyzing 60 randomly selected phantom images from six mammography systems and 20 phantom images with different dose levels from one mammography system. The results were compared to a visual analysis made by four reviewers. Additionally, long-term image quality trends of a full-field digital mammography system and a computed radiography mammography system were investigated. Results The automated software produced feature detection levels comparable to visual analysis. The agreement was good in the case of fibers, while the software detected somewhat more microcalcifications and characteristic masses. Long-term follow-up via a quality assurance web portal demonstrated the feasibility of using the software for monitoring the performance of mammography systems in a multi-unit imaging center. Conclusion Automated image quality analysis enables monitoring the performance of digital mammography systems in an efficient, centralized manner.

  19. The effect of image quality, repeated study, and assessment method on anatomy learning.

    Science.gov (United States)

    Fenesi, Barbara; Mackinnon, Chelsea; Cheng, Lucia; Kim, Joseph A; Wainman, Bruce C

    2017-06-01

    The use of two-dimensional (2D) images is consistently used to prepare anatomy students for handling real specimen. This study examined whether the quality of 2D images is a critical component in anatomy learning. The visual clarity and consistency of 2D anatomical images was systematically manipulated to produce low-quality and high-quality images of the human hand and human eye. On day 0, participants learned about each anatomical specimen from paper booklets using either low-quality or high-quality images, and then completed a comprehension test using either 2D images or three-dimensional (3D) cadaveric specimens. On day 1, participants relearned each booklet, and on day 2 participants completed a final comprehension test using either 2D images or 3D cadaveric specimens. The effect of image quality on learning varied according to anatomical content, with high-quality images having a greater effect on improving learning of hand anatomy than eye anatomy (high-quality vs. low-quality for hand anatomy P = 0.018; high-quality vs. low-quality for eye anatomy P = 0.247). Also, the benefit of high-quality images on hand anatomy learning was restricted to performance on short-answer (SA) questions immediately after learning (high-quality vs. low-quality on SA questions P = 0.018), but did not apply to performance on multiple-choice (MC) questions (high-quality vs. low-quality on MC questions P = 0.109) or after participants had an additional learning opportunity (24 hours later) with anatomy content (high vs. low on SA questions P = 0.643). This study underscores the limited impact of image quality on anatomy learning, and questions whether investment in enhancing image quality of learning aids significantly promotes knowledge development. Anat Sci Educ 10: 249-261. © 2016 American Association of Anatomists. © 2016 American Association of Anatomists.

  20. Effect of quality control implementation on image quality of radiographic films and irradiation doses to patients

    International Nuclear Information System (INIS)

    Cheng Yuxi; Zhou Qipu; Ge Lijuan; Hou Changsong; Qi Xuesong; Yue Baorong; Wang Zuoling; Wei Kedao

    1999-01-01

    Objective: To study the changes in the image quality of radiographic films and the irradiation doses to patients after quality control (QC) implementation. Methods: The entrance surface doses (ESD) to patients measured with TLD and the image quality of radiographic films were evaluated on the basis of CEC image quality criteria. Results: The ESD to patients were significantly reduced after QC implementation (P 0.05), but the post-QC image quality was significantly improved in chest PA, lumbar spine AP and pelvis AP(P0.01 or P<0.05). Conclusion: Significantly reduced irradiation dose with improved image quality can be obtained by QC implementation

  1. Image Processing for Quality Inspection of Mango Fruit

    OpenAIRE

    Ahmad, Usman

    2002-01-01

    Indonesia has many kinds of tropical fruits, including mango, that can be exported besides to suplly the demand on the fruits in the country. To ensure the quality of mango, it is important to do sortation and grading on them, especially those for export, based on the quality requirement. In this case, the use of high technology such as image processing in necesary to put into practise with the aim to increase the consistance of sortation and grading processes as compare to the result of manu...

  2. Image quality of digital mammography images produced using wet and dry laser imaging systems

    International Nuclear Information System (INIS)

    Al Khalifah, K.; Brindhaban, A.; AlArfaj, R.; Jassim, O.

    2006-01-01

    Introduction: A study was carried out to compare the quality of digital mammographic images printed or processed by a wet laser imaging system and a dedicated mammographic dry laser imaging system. Material and methods: Digital images of a tissue equivalent breast phantom were obtained using a GE Senographe 2000D digital mammography system and different target/filter combinations of the X-ray tube. These images were printed on films using the Fuji FL-IM D wet laser imaging system and the Kodak DryView 8600 dry laser imaging system. The quality of images was assessed in terms of detectability of microcalcifications and simulated tumour masses by five radiologists. In addition, the contrast index and speed index of the two systems were measured using the step wedge in the phantom. The unpaired, unequal variance t-test was used to test any statistically significant differences. Results: There were no significant (p < 0.05) differences between the images printed using the two systems in terms of microcalcification and tumour mass detectability. The wet system resulted in slightly higher contrast index while the dry system showed significantly higher speed index. Conclusion: Both wet and dry laser imaging systems can produce mammography images of good quality on which 0.2 mm microcalcifications and 2 mm tumour masses can be detected. Dry systems are preferable due to the absence of wet chemical processing and solid or liquid chemical waste. The wet laser imaging systems, however, still represent a useful alternative to dry laser imaging systems for mammography studies

  3. Noise Estimation and Quality Assessment of Gaussian Noise Corrupted Images

    Science.gov (United States)

    Kamble, V. M.; Bhurchandi, K.

    2018-03-01

    Evaluating the exact quantity of noise present in an image and quality of an image in the absence of reference image is a challenging task. We propose a near perfect noise estimation method and a no reference image quality assessment method for images corrupted by Gaussian noise. The proposed methods obtain initial estimate of noise standard deviation present in an image using the median of wavelet transform coefficients and then obtains a near to exact estimate using curve fitting. The proposed noise estimation method provides the estimate of noise within average error of +/-4%. For quality assessment, this noise estimate is mapped to fit the Differential Mean Opinion Score (DMOS) using a nonlinear function. The proposed methods require minimum training and yields the noise estimate and image quality score. Images from Laboratory for image and Video Processing (LIVE) database and Computational Perception and Image Quality (CSIQ) database are used for validation of the proposed quality assessment method. Experimental results show that the performance of proposed quality assessment method is at par with the existing no reference image quality assessment metric for Gaussian noise corrupted images.

  4. Image quality transfer and applications in diffusion MRI

    DEFF Research Database (Denmark)

    Alexander, Daniel C.; Zikic, Darko; Ghosh, Aurobrata

    2017-01-01

    This paper introduces a new computational imaging technique called image quality transfer (IQT). IQT uses machine learning to transfer the rich information available from one-off experimental medical imaging devices to the abundant but lower-quality data from routine acquisitions. The procedure u...

  5. How the task of evaluating image quality influences viewing behavior

    NARCIS (Netherlands)

    Alers, H.; Bos, Lennart; Heynderickx, I.E.J.

    2011-01-01

    Image quality scores collected in subjective experiments are widely used in image quality research, particularly in the design of objective quality assessment algorithms. It is therefore of vital importance to make sure that the collected scores reflect viewers' opinions in real-life situations.

  6. Performance evaluation of objective quality metrics for HDR image compression

    Science.gov (United States)

    Valenzise, Giuseppe; De Simone, Francesca; Lauga, Paul; Dufaux, Frederic

    2014-09-01

    Due to the much larger luminance and contrast characteristics of high dynamic range (HDR) images, well-known objective quality metrics, widely used for the assessment of low dynamic range (LDR) content, cannot be directly applied to HDR images in order to predict their perceptual fidelity. To overcome this limitation, advanced fidelity metrics, such as the HDR-VDP, have been proposed to accurately predict visually significant differences. However, their complex calibration may make them difficult to use in practice. A simpler approach consists in computing arithmetic or structural fidelity metrics, such as PSNR and SSIM, on perceptually encoded luminance values but the performance of quality prediction in this case has not been clearly studied. In this paper, we aim at providing a better comprehension of the limits and the potentialities of this approach, by means of a subjective study. We compare the performance of HDR-VDP to that of PSNR and SSIM computed on perceptually encoded luminance values, when considering compressed HDR images. Our results show that these simpler metrics can be effectively employed to assess image fidelity for applications such as HDR image compression.

  7. Quality Improvement of Liver Ultrasound Images Using Fuzzy Techniques.

    Science.gov (United States)

    Bayani, Azadeh; Langarizadeh, Mostafa; Radmard, Amir Reza; Nejad, Ahmadreza Farzaneh

    2016-12-01

    Liver ultrasound images are so common and are applied so often to diagnose diffuse liver diseases like fatty liver. However, the low quality of such images makes it difficult to analyze them and diagnose diseases. The purpose of this study, therefore, is to improve the contrast and quality of liver ultrasound images. In this study, a number of image contrast enhancement algorithms which are based on fuzzy logic were applied to liver ultrasound images - in which the view of kidney is observable - using Matlab2013b to improve the image contrast and quality which has a fuzzy definition; just like image contrast improvement algorithms using a fuzzy intensification operator, contrast improvement algorithms applying fuzzy image histogram hyperbolization, and contrast improvement algorithms by fuzzy IF-THEN rules. With the measurement of Mean Squared Error and Peak Signal to Noise Ratio obtained from different images, fuzzy methods provided better results, and their implementation - compared with histogram equalization method - led both to the improvement of contrast and visual quality of images and to the improvement of liver segmentation algorithms results in images. Comparison of the four algorithms revealed the power of fuzzy logic in improving image contrast compared with traditional image processing algorithms. Moreover, contrast improvement algorithm based on a fuzzy intensification operator was selected as the strongest algorithm considering the measured indicators. This method can also be used in future studies on other ultrasound images for quality improvement and other image processing and analysis applications.

  8. Imaging quality evaluation method of pixel coupled electro-optical imaging system

    Science.gov (United States)

    He, Xu; Yuan, Li; Jin, Chunqi; Zhang, Xiaohui

    2017-09-01

    With advancements in high-resolution imaging optical fiber bundle fabrication technology, traditional photoelectric imaging system have become ;flexible; with greatly reduced volume and weight. However, traditional image quality evaluation models are limited by the coupling discrete sampling effect of fiber-optic image bundles and charge-coupled device (CCD) pixels. This limitation substantially complicates the design, optimization, assembly, and evaluation image quality of the coupled discrete sampling imaging system. Based on the transfer process of grayscale cosine distribution optical signal in the fiber-optic image bundle and CCD, a mathematical model of coupled modulation transfer function (coupled-MTF) is established. This model can be used as a basis for following studies on the convergence and periodically oscillating characteristics of the function. We also propose the concept of the average coupled-MTF, which is consistent with the definition of traditional MTF. Based on this concept, the relationships among core distance, core layer radius, and average coupled-MTF are investigated.

  9. Image quality comparison between single energy and dual energy CT protocols for hepatic imaging

    International Nuclear Information System (INIS)

    Yao, Yuan; Pelc, Norbert J.; Ng, Joshua M.; Megibow, Alec J.

    2016-01-01

    increased with increasing kVp while for post-contrast imaging 90 kVp or lower yielded higher CNR images, depending on the differential iodine concentration of each tissue. Similar trends were seen in DE blended CNR and those from SE protocols. In the presence of differential iodine concentration (i.e., post-contrast), the CNR curves maximize at lower kVps (80–120), with the peak shifted rightward for larger patients. The combined pre- and post-contrast composite CNR study demonstrated that an optimal SE protocol has better performance than blended DE images, and the optimal tube potential for SE scan is around 90 kVp for a medium size patients and between 90 and 120 kVp for large size patients (although low kVp imaging requires high x-ray tube power to avoid photon starvation). Also, a tin filter added to the high kVp beam is not only beneficial for material decomposition but it improves the CNR of the DE blended images as well. The dose adjusted CNR of the clinical images also showed the same trend and radiologists favored the SE scans over blended DE images. Conclusions: Our simulation showed that an optimized SE protocol produces up to 5% higher CNR for a range of clinical tasks. The clinical study also suggested 120 kVp SE scans have better image quality than blended DE images. Hence, blended DE images do not have a fundamental CNR advantage over optimized SE images.

  10. Image quality of cone beam CT on respiratory motion

    International Nuclear Information System (INIS)

    Zhang Ke; Li Minghui; Dai Jianrong; Wang Shi

    2011-01-01

    In this study,the influence of respiratory motion on Cone Beam CT (CBCT) image quality was investigated by a motion simulating platform, an image quality phantom, and a kV X-ray CBCT. A total of 21 motion states in the superior-inferior direction and the anterior-posterior direction, separately or together, was simulated by considering different respiration amplitudes, periods and hysteresis. The influence of motion on CBCT image quality was evaluated with the quality indexes of low contrast visibility, geometric accuracy, spatial resolution and uniformity of CT values. The results showed that the quality indexes were affected by the motion more prominently in AP direction than in SI direction, and the image quality was affected by the respiration amplitude more prominently than the respiration period and the hysteresis. The CBCT image quality and its characteristics influenced by the respiration motion, and may be exploited in finding solutions. (authors)

  11. RADARSAT-1 Image Quality Excellence in the Extended Mission

    National Research Council Canada - National Science Library

    Srivastava, S. K; Cote, S; Le Dantec, P; Hawkins, R. K

    2005-01-01

    ... after its launch on November 4, 1995. Both single beams and ScanSAR imagery are still monitored routinely for radiometric calibration performance based on images of the Amazon Rainforest, and for image quality performance using imagery...

  12. Image quality influences the assessment of left ventricular function

    DEFF Research Database (Denmark)

    Grossgasteiger, Manuel; Hien, Maximilian D; Graser, Bastian

    2014-01-01

    divided by the total endocardial border. These ratings were used to generate groups of poor (0%-40%), fair (41%-70%), and good (71%-100%) image quality. The ejection fraction (EF), end-diastolic volume, and end-systolic volume were analyzed by the Simpson method of disks (biplane and monoplane), eyeball...... method yield better correlations with poor image quality. The eyeball method was unaffected by image quality....

  13. Effects of characteristics of image quality in an immersive environment

    Science.gov (United States)

    Duh, Henry Been-Lirn; Lin, James J W.; Kenyon, Robert V.; Parker, Donald E.; Furness, Thomas A.

    2002-01-01

    Image quality issues such as field of view (FOV) and resolution are important for evaluating "presence" and simulator sickness (SS) in virtual environments (VEs). This research examined effects on postural stability of varying FOV, image resolution, and scene content in an immersive visual display. Two different scenes (a photograph of a fountain and a simple radial pattern) at two different resolutions were tested using six FOVs (30, 60, 90, 120, 150, and 180 deg.). Both postural stability, recorded by force plates, and subjective difficulty ratings varied as a function of FOV, scene content, and image resolution. Subjects exhibited more balance disturbance and reported more difficulty in maintaining posture in the wide-FOV, high-resolution, and natural scene conditions.

  14. Image quality and dose differences caused by vendor-specific image processing of neonatal radiographs.

    Science.gov (United States)

    Sensakovic, William F; O'Dell, M Cody; Letter, Haley; Kohler, Nathan; Rop, Baiywo; Cook, Jane; Logsdon, Gregory; Varich, Laura

    2016-10-01

    Image processing plays an important role in optimizing image quality and radiation dose in projection radiography. Unfortunately commercial algorithms are black boxes that are often left at or near vendor default settings rather than being optimized. We hypothesize that different commercial image-processing systems, when left at or near default settings, create significant differences in image quality. We further hypothesize that image-quality differences can be exploited to produce images of equivalent quality but lower radiation dose. We used a portable radiography system to acquire images on a neonatal chest phantom and recorded the entrance surface air kerma (ESAK). We applied two image-processing systems (Optima XR220amx, by GE Healthcare, Waukesha, WI; and MUSICA(2) by Agfa HealthCare, Mortsel, Belgium) to the images. Seven observers (attending pediatric radiologists and radiology residents) independently assessed image quality using two methods: rating and matching. Image-quality ratings were independently assessed by each observer on a 10-point scale. Matching consisted of each observer matching GE-processed images and Agfa-processed images with equivalent image quality. A total of 210 rating tasks and 42 matching tasks were performed and effective dose was estimated. Median Agfa-processed image-quality ratings were higher than GE-processed ratings. Non-diagnostic ratings were seen over a wider range of doses for GE-processed images than for Agfa-processed images. During matching tasks, observers matched image quality between GE-processed images and Agfa-processed images acquired at a lower effective dose (11 ± 9 μSv; P < 0.0001). Image-processing methods significantly impact perceived image quality. These image-quality differences can be exploited to alter protocols and produce images of equivalent image quality but lower doses. Those purchasing projection radiography systems or third-party image-processing software should be aware that image

  15. A very high energy imaging for radioactive wastes processing

    International Nuclear Information System (INIS)

    Moulin, V.; Pettier, J.L.

    2004-01-01

    The X imaging occurs at a lot of steps of the radioactive wastes processing: selection for conditioning, physical characterization with a view to radiological characterization, quality control of the product before storage, transport or disposal. Size and volume of the objects considered here necessitate to work with very high energy systems. Here is shown, through some examples, in which conditions this X imaging is carried out as well as the contribution of the obtained images. (O.M.)

  16. Blind CT image quality assessment via deep learning strategy: initial study

    Science.gov (United States)

    Li, Sui; He, Ji; Wang, Yongbo; Liao, Yuting; Zeng, Dong; Bian, Zhaoying; Ma, Jianhua

    2018-03-01

    Computed Tomography (CT) is one of the most important medical imaging modality. CT images can be used to assist in the detection and diagnosis of lesions and to facilitate follow-up treatment. However, CT images are vulnerable to noise. Actually, there are two major source intrinsically causing the CT data noise, i.e., the X-ray photo statistics and the electronic noise background. Therefore, it is necessary to doing image quality assessment (IQA) in CT imaging before diagnosis and treatment. Most of existing CT images IQA methods are based on human observer study. However, these methods are impractical in clinical for their complex and time-consuming. In this paper, we presented a blind CT image quality assessment via deep learning strategy. A database of 1500 CT images is constructed, containing 300 high-quality images and 1200 corresponding noisy images. Specifically, the high-quality images were used to simulate the corresponding noisy images at four different doses. Then, the images are scored by the experienced radiologists by the following attributes: image noise, artifacts, edge and structure, overall image quality, and tumor size and boundary estimation with five-point scale. We trained a network for learning the non-liner map from CT images to subjective evaluation scores. Then, we load the pre-trained model to yield predicted score from the test image. To demonstrate the performance of the deep learning network in IQA, correlation coefficients: Pearson Linear Correlation Coefficient (PLCC) and Spearman Rank Order Correlation Coefficient (SROCC) are utilized. And the experimental result demonstrate that the presented deep learning based IQA strategy can be used in the CT image quality assessment.

  17. Automatic analysis of image quality control for Image Guided Radiation Therapy (IGRT) devices in external radiotherapy

    International Nuclear Information System (INIS)

    Torfeh, Tarraf

    2009-01-01

    On-board imagers mounted on a radiotherapy treatment machine are very effective devices that improve the geometric accuracy of radiation delivery. However, a precise and regular quality control program is required in order to achieve this objective. Our purpose consisted of developing software tools dedicated to an automatic image quality control of IGRT devices used in external radiotherapy: 2D-MV mode for measuring patient position during the treatment using high energy images, 2D-kV mode (low energy images) and 3D Cone Beam Computed Tomography (CBCT) MV or kV mode, used for patient positioning before treatment. Automated analysis of the Winston and Lutz test was also proposed. This test is used for the evaluation of the mechanical aspects of treatment machines on which additional constraints are carried out due to the on-board imagers additional weights. Finally, a technique of generating digital phantoms in order to assess the performance of the proposed software tools is described. Software tools dedicated to an automatic quality control of IGRT devices allow reducing by a factor of 100 the time spent by the medical physics team to analyze the results of controls while improving their accuracy by using objective and reproducible analysis and offering traceability through generating automatic monitoring reports and statistical studies. (author) [fr

  18. Comparison of dose and image quality of a Flat-panel detector and an image intensifier

    International Nuclear Information System (INIS)

    Lazzaro, M.; Friedrich, B.Q.; Luz, R.M. da; Silva, A.M.M. da

    2016-01-01

    With the development of new technologies, have emerged new conversion methods of X-ray image, such as flat panel detectors. The aim of this work is the comparison of entrance surface air kerma (ESAK) and image quality between an image intensifier type of detector (A) and a flat panel (B). The ESAK was obtained by placing a ionization chamber under PMMA simulators of 10, 20 and 30 cm and the image quality was obtained by using the TOR "1"8FG simulator. The ESAK to the equipment A is higher when compared to the equipment B. The high contrast resolution is better for the equipment A for all thicknesses of simulators. The equipment A has low contrast resolution with a better viewing threshold for thicknesses of 10 and 20 cm, and a worse performance for 30 cm. It is concluded that the equipment B has ESAK smaller and despite having lower resolution, in almost all cases, have appropriate image quality for diagnosis. (author)

  19. The relationship between image quality and trial slits CT-1010

    International Nuclear Information System (INIS)

    Yoshinaga, Toshihiko; Nakamura, Sumio; Kakoi, Iwao; Ohkubo, Mitsuo; Tomiyoshi, Tsukasa

    1980-01-01

    We had used trial slits for EMI scanner CT-1010 and CT images of good quality almost free artifacts could be obtained when the slice thickness decreased to 5 mm. In this study, we experimented changes of MTF (modulation transfer function) as the slice thickness changed. As a result, MTF got worse as the slice thickness decreased, but got better as the exposure dose increased. The high accuracy high definitions of a 10 mm slice thickness and a 5 mm one were nearly equal in MTF. (author)

  20. Faraday imaging at high temperatures

    Science.gov (United States)

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  1. Faraday imaging at high temperatures

    International Nuclear Information System (INIS)

    Hackel, L.A.; Reichert, P.

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs

  2. Objective and Subjective Assessment of Digital Pathology Image Quality

    Directory of Open Access Journals (Sweden)

    Prarthana Shrestha

    2015-03-01

    Full Text Available The quality of an image produced by the Whole Slide Imaging (WSI scanners is of critical importance for using the image in clinical diagnosis. Therefore, it is very important to monitor and ensure the quality of images. Since subjective image quality assessments by pathologists are very time-consuming, expensive and difficult to reproduce, we propose a method for objective assessment based on clinically relevant and perceptual image parameters: sharpness, contrast, brightness, uniform illumination and color separation; derived from a survey of pathologists. We developed techniques to quantify the parameters based on content-dependent absolute pixel performance and to manipulate the parameters in a predefined range resulting in images with content-independent relative quality measures. The method does not require a prior reference model. A subjective assessment of the image quality is performed involving 69 pathologists and 372 images (including 12 optimal quality images and their distorted versions per parameter at 6 different levels. To address the inter-reader variability, a representative rating is determined as a one-tailed 95% confidence interval of the mean rating. The results of the subjective assessment support the validity of the proposed objective image quality assessment method to model the readers’ perception of image quality. The subjective assessment also provides thresholds for determining the acceptable level of objective quality per parameter. The images for both the subjective and objective quality assessment are based on the HercepTestTM slides scanned by the Philips Ultra Fast Scanners, developed at Philips Digital Pathology Solutions. However, the method is applicable also to other types of slides and scanners.

  3. Limiting liability via high resolution image processing

    Energy Technology Data Exchange (ETDEWEB)

    Greenwade, L.E.; Overlin, T.K.

    1996-12-31

    The utilization of high resolution image processing allows forensic analysts and visualization scientists to assist detectives by enhancing field photographs, and by providing the tools and training to increase the quality and usability of field photos. Through the use of digitized photographs and computerized enhancement software, field evidence can be obtained and processed as `evidence ready`, even in poor lighting and shadowed conditions or darkened rooms. These images, which are most often unusable when taken with standard camera equipment, can be shot in the worst of photographic condition and be processed as usable evidence. Visualization scientists have taken the use of digital photographic image processing and moved the process of crime scene photos into the technology age. The use of high resolution technology will assist law enforcement in making better use of crime scene photography and positive identification of prints. Valuable court room and investigation time can be saved and better served by this accurate, performance based process. Inconclusive evidence does not lead to convictions. Enhancement of the photographic capability helps solve one major problem with crime scene photos, that if taken with standard equipment and without the benefit of enhancement software would be inconclusive, thus allowing guilty parties to be set free due to lack of evidence.

  4. Development and validation of a psychometric scale for assessing PA chest image quality: A pilot study

    International Nuclear Information System (INIS)

    Mraity, H.; England, A.; Akhtar, I.; Aslam, A.; De Lange, R.; Momoniat, H.; Nicoulaz, S.; Ribeiro, A.; Mazhir, S.; Hogg, P.

    2014-01-01

    Purpose: To develop and validate a psychometric scale for assessing image quality perception for chest X-ray images. Methods: Bandura's theory was used to guide scale development. A review of the literature was undertaken to identify items/factors which could be used to evaluate image quality using a perceptual approach. A draft scale was then created (22 items) and presented to a focus group (student and qualified radiographers). Within the focus group the draft scale was discussed and modified. A series of seven postero-anterior chest images were generated using a phantom with a range of image qualities. Image quality perception was confirmed for the seven images using signal-to-noise ratio (SNR 17.2–36.5). Participants (student and qualified radiographers and radiology trainees) were then invited to independently score each of the seven images using the draft image quality perception scale. Cronbach alpha was used to test interval reliability. Results: Fifty three participants used the scale to grade image quality perception on each of the seven images. Aggregated mean scale score increased with increasing SNR from 42.1 to 87.7 (r = 0.98, P < 0.001). For each of the 22 individual scale items there was clear differentiation of low, mid and high quality images. A Cronbach alpha coefficient of >0.7 was obtained across each of the seven images. Conclusion: This study represents the first development of a chest image quality perception scale based on Bandura's theory. There was excellent correlation between the image quality perception scores derived using the scale and the SNR. Further research will involve a more detailed item and factor analysis

  5. Automated image quality assessment for chest CT scans.

    Science.gov (United States)

    Reeves, Anthony P; Xie, Yiting; Liu, Shuang

    2018-02-01

    Medical image quality needs to be maintained at standards sufficient for effective clinical reading. Automated computer analytic methods may be applied to medical images for quality assessment. For chest CT scans in a lung cancer screening context, an automated quality assessment method is presented that characterizes image noise and image intensity calibration. This is achieved by image measurements in three automatically segmented homogeneous regions of the scan: external air, trachea lumen air, and descending aorta blood. Profiles of CT scanner behavior are also computed. The method has been evaluated on both phantom and real low-dose chest CT scans and results show that repeatable noise and calibration measures may be realized by automated computer algorithms. Noise and calibration profiles show relevant differences between different scanners and protocols. Automated image quality assessment may be useful for quality control for lung cancer screening and may enable performance improvements to automated computer analysis methods. © 2017 American Association of Physicists in Medicine.

  6. Dynamic flat panel detector versus image intensifier in cardiac imaging: dose and image quality

    Science.gov (United States)

    Vano, E.; Geiger, B.; Schreiner, A.; Back, C.; Beissel, J.

    2005-12-01

    The practical aspects of the dosimetric and imaging performance of a digital x-ray system for cardiology procedures were evaluated. The system was configured with an image intensifier (II) and later upgraded to a dynamic flat panel detector (FD). Entrance surface air kerma (ESAK) to phantoms of 16, 20, 24 and 28 cm of polymethyl methacrylate (PMMA) and the image quality of a test object were measured. Images were evaluated directly on the monitor and with numerical methods (noise and signal-to-noise ratio). Information contained in the DICOM header for dosimetry audit purposes was also tested. ESAK values per frame (or kerma rate) for the most commonly used cine and fluoroscopy modes for different PMMA thicknesses and for field sizes of 17 and 23 cm for II, and 20 and 25 cm for FD, produced similar results in the evaluated system with both technologies, ranging between 19 and 589 µGy/frame (cine) and 5 and 95 mGy min-1 (fluoroscopy). Image quality for these dose settings was better for the FD version. The 'study dosimetric report' is comprehensive, and its numerical content is sufficiently accurate. There is potential in the future to set those systems with dynamic FD to lower doses than are possible in the current II versions, especially for digital cine runs, or to benefit from improved image quality.

  7. PLEIADES-HR INNOVATIVE TECHNIQUES FOR RADIOMETRIC IMAGE QUALITY COMMISSIONING

    Directory of Open Access Journals (Sweden)

    G. Blanchet

    2012-07-01

    Full Text Available The first Pleiades-HR satellite, part of a constellation of two, has been launched on December 17, 2011. This satellite produces high resolution optical images. In order to achieve good image quality, Pleiades-HR should first undergo an important 6 month commissioning phase period. This phase consists in calibrating and assessing the radiometric and geometric image quality to offer the best images to end users. This new satellite has benefited from technology improvements in various fields which make it stand out from other Earth observation satellites. In particular, its best-in-class agility performance enables new calibration and assessment techniques. This paper is dedicated to presenting these innovative techniques that have been tested for the first time for the Pleiades- HR radiometric commissioning. Radiometric activities concern compression, absolute calibration, detector normalization, and refocusing operations, MTF (Modulation Transfer Function assessment, signal-to-noise ratio (SNR estimation, and tuning of the ground processing parameters. The radiometric performances of each activity are summarized in this paper.

  8. Effects on MR images compression in tissue classification quality

    International Nuclear Information System (INIS)

    Santalla, H; Meschino, G; Ballarin, V

    2007-01-01

    It is known that image compression is required to optimize the storage in memory. Moreover, transmission speed can be significantly improved. Lossless compression is used without controversy in medicine, though benefits are limited. If we compress images lossy, where image can not be totally recovered; we can only recover an approximation. In this point definition of 'quality' is essential. What we understand for 'quality'? How can we evaluate a compressed image? Quality in images is an attribute whit several definitions and interpretations, which actually depend on the posterior use we want to give them. This work proposes a quantitative analysis of quality for lossy compressed Magnetic Resonance (MR) images, and their influence in automatic tissue classification, accomplished with these images

  9. Quality assurance in digital dental imaging: a systematic review.

    Science.gov (United States)

    Metsälä, Eija; Henner, Anja; Ekholm, Marja

    2014-07-01

    Doses induced by individual dental examinations are low. However, dental radiography accounts for nearly one third of the total number of radiological examinations in the European Union. Therefore, special attention is needed with regard to radiation protection. In order to lower patient doses, the staff performing dental examinations must have competence in imaging as well as in radiation protection issues. This paper presents a systematic review about the core competencies needed by the healthcare staff in performing digital dental radiological imaging quality assurance. The following databases were searched: Pubmed, Cinahl, Pro Quest and IEEXplore digital library. Also volumes of some dental imaging journals and doctoral theses of the Finnish universities educating dentists were searched. The search was performed using both MeSH terms and keywords using the option 'search all text'. The original keywords were: dental imaging, digital, x-ray, panoramic, quality, assurance, competence, competency, skills, knowledge, radiographer, radiologist technician, dentist, oral hygienist, radiation protection and their Finnish synonyms. Core competencies needed by the healthcare staff performing digital dental radiological imaging quality assurance described in the selected studies were: management of dental imaging equipment, competence in image quality and factors associated with it, dose optimization and quality assurance. In the future there will be higher doses in dental imaging due to increasing use of CBCT and digital imaging. The staff performing dental imaging must have competence in dental imaging quality assurance issues found in this review. They also have to practice ethical radiation safety culture in clinical practice.

  10. Exposure reduction and image quality in orthodontic radiology: a review of the literature

    International Nuclear Information System (INIS)

    Taylor, T.S.; Ackerman, R.J. Jr.; Hardman, P.K.

    1988-01-01

    This article summarizes the use of rare earth screen technology to achieve high-quality panoramic and cephalometric radiographs with sizable reductions in patient radiation dosage. Collimation, shielding, quality control, and darkroom procedures are reviewed to further reduce patient risk and improve image quality. 34 references

  11. QUALITY AWARDS: AN IMAGE OF BUSINESS EXCELLENCE

    Directory of Open Access Journals (Sweden)

    Ilies Liviu

    2015-07-01

    Full Text Available Across the world, increasingly more governmental organizations and industrial are doing everything possible to promote quality and to survive, the basic principle remains customer satisfaction and even more than that, it speaks of the principle of customer delight. In this sense, quality has become the source of sustained competitive advantage that provides organizations the supremacy of the global markets characterized by competition which becoming more and more intensified. Juran, one of the highest quality gurus say that “just as the twentieth century was the century of productivity, the twenty-first century will be the quality century” which is a very relevant and comprehensive statement of the economic reality of the past and a profound forecast for future business of the twenty-first century. In this regard, in order to achieve this competitive advantage, quality must be managed and this is accomplished through Total Quality Management (TQM. Quality awards models are instruments of total quality management through which quality can be assessed and improved, thus, knowing the quality awards models is critical for findings the new ways to improve the quality and performance of the organizations. The present paper aims to illustrate the best practices on quality improvement in this respect we intend to present the general framework of the quality awards for business excellence. In this sense we present the most important international quality awards, namely: "Malcolm Baldrige National Quality Award", "European Quality Award" and “Romanian Quality Award J. M. Juran". For this purpose we used as main sources of analyzing the structure and the operation mode of these three important quality awards, Juran's work (which is probably the most important work in the field of quality and other relevant sources in total quality management which treats issues related to quality awards and also we used as sources of updated information the official

  12. The relationship between compression force, image quality and ...

    African Journals Online (AJOL)

    Theoretically, an increase in breast compression gives a reduction in thickness without changing the density, resulting in improved image quality and reduced radiation dose. Aim. This study investigates the relationship between compression force, phantom thickness, image quality and radiation dose. The existence of a ...

  13. High dynamic range coding imaging system

    Science.gov (United States)

    Wu, Renfan; Huang, Yifan; Hou, Guangqi

    2014-10-01

    We present a high dynamic range (HDR) imaging system design scheme based on coded aperture technique. This scheme can help us obtain HDR images which have extended depth of field. We adopt Sparse coding algorithm to design coded patterns. Then we utilize the sensor unit to acquire coded images under different exposure settings. With the guide of the multiple exposure parameters, a series of low dynamic range (LDR) coded images are reconstructed. We use some existing algorithms to fuse and display a HDR image by those LDR images. We build an optical simulation model and get some simulation images to verify the novel system.

  14. Comparison of dose and image quality in protocols abdominal CT using high an low KVP; Comparacion de dosis y calidad de imagen en protocolos abdominales de TC utilizando alto y bajo kilovoltaje

    Energy Technology Data Exchange (ETDEWEB)

    Mas Munoz, I.; Alejo Luque, L.; Corredoira Silva, E.; Sanchez Munoz, F. J.; Serrada Hierro, A.

    2013-07-01

    This paper compares quantitatively low kV Protocol with the conventional Protocol of abdomen, analysing the image quality with objective physical parameters and calculating the corresponding dummy dose reduction. (Author)

  15. Comparison of quality of ultrasonographic image of the pancreas: Tissue harmonic image vs. Fundamental image

    International Nuclear Information System (INIS)

    Seo, Young Lan; Choi, Chul Soon; Kim, Ho Chul; Yoon, Dae Young; Han, Dae Hee; Bae, Sang Hoon

    2002-01-01

    To compare the quality of ultrasonographic (US) images, tissue harmonic image (THI) versus fundamental image (FI), of the pancreas. During a recent 2 month period, forty one patients with the normal pancreas on US were included. All of them were free of abnormal clinical and laboratory findings suggestive of pancreatic disease, US was performed by an abdominal radiologist with a 2.5-5 MHz convex-array transducer (Sequoia 512: Acuson, Mountain View, Calif.U.S.A.). Comparison of THI and FI of the pancreas was done for the following parameters:conspicuity, intermal architecture, and delineation range. Grading was made by the consensus of two abdominal radiologist witha three-point scale. Statistical analysis was done using Wilcox signed rank sum test. For the evaluation of the US image quality of the pancreas THI showed better conspicuity (p=0.0130), clearer internal architecture (p=0.0029) and superior delineation range (p=0.0191) than those of FI. THI appears to show a superior image quality than FI in evaluation of the pancreas.

  16. Using image quality measures and features to choose good images for classification of ISAR imagery

    CSIR Research Space (South Africa)

    Steyn, JM

    2014-10-01

    Full Text Available the quality measures and to determine the minimum dwell-time for ISAR image formation. Keywords—ISAR (inverse synthetic aperture radar), Dwell-time, Quality Measure, Image Contrast, Image Entropy, SNR (signal-to-noise ratio), Maritime Vessels ...

  17. Approaches for improving image quality in magnetic induction tomography

    International Nuclear Information System (INIS)

    Maimaitijiang, Y; Roula, M A; Kahlert, J

    2010-01-01

    Magnetic induction tomography (MIT) is a contactless and non-invasive method for imaging the passive electrical properties of objects. Measuring the weak signal produced by eddy currents within biological soft tissues can be challenging in the presence of noise and the large signals resulting from the direct excitation–detection coil coupling. To detect haemorrhagic stroke in the brain, for instance, high measurement accuracy is required to enable images with enough contrast to differentiate between normal and haemorrhaged brain tissues. The reconstructed images are often very sensitive to inevitable measurement noise from the environment, system instabilities and patient-related artefacts such as movement and sweating. We propose methods for mitigating signal noise and improving image reconstruction. We evaluated and compared the use of a range wavelet transforms for signal denoising. Adaptive regularization methods including L-curve, generalized cross validation (GCV) and noise estimation were also compared. We evaluated all these described methods with measurements of in vitro tissues resembling a peripheral haemorrhagic cerebral stroke created by placing a bio-membrane package filled with 10 ml blood in a swine brain of 100 ml. We show that wavelet packet denoising combined with adaptive regularization can improve the quality of reconstructed images

  18. Acquired image quality in digital industrial radiographic equipments

    International Nuclear Information System (INIS)

    Oliveira, Cristiane de Queiroz; Lopes, Ricardo Tadeu; Oliveira, Davi F.

    2008-01-01

    The computerized radiographic application in the industrial area is a recent event. The imaging plate is the equipment used as imaging receiver during the exposition radiographic technique, which consists of a flexible photostimulable phosphor screen, capable of storing the photons energy of the incident X and γ rays and of a reading unit which uses a laser device to stimulate a visible light. As two types of phosphor screen are manufactured, one for general use (General Plate - GP) and another one for specific using (High Resolution-HR), one of the objectives of this study was to evaluate the spatial resolution capability in both plates using the Kodak equipment. Furthermore, equipment from different makers, Kodak and General Electric Company - GE, were compared. Two phosphor screen HR were used as the main objective of this study. Imaging Quality Indicators - IQI were used to evaluate the spatial resolution of the images in accordance with ASME and DIN standard. The results show that after evaluating the GP and HR Kodak plates, the HR plate was capable of showing a larger resolution of details. However, after evaluating the performance of the HR Kodak plate and GE plate, over the same acquisition condition and with the same size of the laser focal set of 87 μm, the results show a superiority in the GE equipment used for industrial radiographic, mainly for processed images in each specific ambient of digital processing and its performance in meeting satisfactorily the ASME code and the DIN standard. (author)

  19. The study of surgical image quality evaluation system by subjective quality factor method

    Science.gov (United States)

    Zhang, Jian J.; Xuan, Jason R.; Yang, Xirong; Yu, Honggang; Koullick, Edouard

    2016-03-01

    GreenLightTM procedure is an effective and economical way of treatment of benign prostate hyperplasia (BPH); there are almost a million of patients treated with GreenLightTM worldwide. During the surgical procedure, the surgeon or physician will rely on the monitoring video system to survey and confirm the surgical progress. There are a few obstructions that could greatly affect the image quality of the monitoring video, like laser glare by the tissue and body fluid, air bubbles and debris generated by tissue evaporation, and bleeding, just to name a few. In order to improve the physician's visual experience of a laser surgical procedure, the system performance parameter related to image quality needs to be well defined. However, since image quality is the integrated set of perceptions of the overall degree of excellence of an image, or in other words, image quality is the perceptually weighted combination of significant attributes (contrast, graininess …) of an image when considered in its marketplace or application, there is no standard definition on overall image or video quality especially for the no-reference case (without a standard chart as reference). In this study, Subjective Quality Factor (SQF) and acutance are used for no-reference image quality evaluation. Basic image quality parameters, like sharpness, color accuracy, size of obstruction and transmission of obstruction, are used as subparameter to define the rating scale for image quality evaluation or comparison. Sample image groups were evaluated by human observers according to the rating scale. Surveys of physician groups were also conducted with lab generated sample videos. The study shows that human subjective perception is a trustworthy way of image quality evaluation. More systematic investigation on the relationship between video quality and image quality of each frame will be conducted as a future study.

  20. Image quality assessment for CT used on small animals

    Energy Technology Data Exchange (ETDEWEB)

    Cisneros, Isabela Paredes, E-mail: iparedesc@unal.edu.co; Agulles-Pedrós, Luis, E-mail: lagullesp@unal.edu.co [Universidad Nacional de Colombia, Departamento de Física, Grupo de Física Médica (Colombia)

    2016-07-07

    Image acquisition on a CT scanner is nowadays necessary in almost any kind of medical study. Its purpose, to produce anatomical images with the best achievable quality, implies the highest diagnostic radiation exposure to patients. Image quality can be measured quantitatively based on parameters such as noise, uniformity and resolution. This measure allows the determination of optimal parameters of operation for the scanner in order to get the best diagnostic image. A human Phillips CT scanner is the first one minded for veterinary-use exclusively in Colombia. The aim of this study was to measure the CT image quality parameters using an acrylic phantom and then, using the computational tool MATLAB, determine these parameters as a function of current value and window of visualization, in order to reduce dose delivery by keeping the appropriate image quality.

  1. The effect of image sharpness on quantitative eye movement data and on image quality evaluation while viewing natural images

    Science.gov (United States)

    Vuori, Tero; Olkkonen, Maria

    2006-01-01

    The aim of the study is to test both customer image quality rating (subjective image quality) and physical measurement of user behavior (eye movements tracking) to find customer satisfaction differences in imaging technologies. Methodological aim is to find out whether eye movements could be quantitatively used in image quality preference studies. In general, we want to map objective or physically measurable image quality to subjective evaluations and eye movement data. We conducted a series of image quality tests, in which the test subjects evaluated image quality while we recorded their eye movements. Results show that eye movement parameters consistently change according to the instructions given to the user, and according to physical image quality, e.g. saccade duration increased with increasing blur. Results indicate that eye movement tracking could be used to differentiate image quality evaluation strategies that the users have. Results also show that eye movements would help mapping between technological and subjective image quality. Furthermore, these results give some empirical emphasis to top-down perception processes in image quality perception and evaluation by showing differences between perceptual processes in situations when cognitive task varies.

  2. How does image noise affect actual and predicted human gaze allocation in assessing image quality?

    Science.gov (United States)

    Röhrbein, Florian; Goddard, Peter; Schneider, Michael; James, Georgina; Guo, Kun

    2015-07-01

    A central research question in natural vision is how to allocate fixation to extract informative cues for scene perception. With high quality images, psychological and computational studies have made significant progress to understand and predict human gaze allocation in scene exploration. However, it is unclear whether these findings can be generalised to degraded naturalistic visual inputs. In this eye-tracking and computational study, we methodically distorted both man-made and natural scenes with Gaussian low-pass filter, circular averaging filter and Additive Gaussian white noise, and monitored participants' gaze behaviour in assessing perceived image qualities. Compared with original high quality images, distorted images attracted fewer numbers of fixations but longer fixation durations, shorter saccade distance and stronger central fixation bias. This impact of image noise manipulation on gaze distribution was mainly determined by noise intensity rather than noise type, and was more pronounced for natural scenes than for man-made scenes. We furthered compared four high performing visual attention models in predicting human gaze allocation in degraded scenes, and found that model performance lacked human-like sensitivity to noise type and intensity, and was considerably worse than human performance measured as inter-observer variance. Furthermore, the central fixation bias is a major predictor for human gaze allocation, which becomes more prominent with increased noise intensity. Our results indicate a crucial role of external noise intensity in determining scene-viewing gaze behaviour, which should be considered in the development of realistic human-vision-inspired attention models. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Optimising cardiac/angiographic digital images using a Butternut as the image quality phantom

    International Nuclear Information System (INIS)

    Bibbo, G.; Balman, D.

    2008-01-01

    Full text: Digital images, whether produced by image intensifiers, flat panels or computed radiography imaging plates, have a broad dynamic range and, thus, there is a need to adjust the exposure parameters of the imaging protocols to obtain diagnostic images without over exposing patients. The default exposure techniques of protocols delivered with the imaging equipment are in general set to produce high quality images at the expense of high radiation doses to patients. Ideally, these protocols should be optimised for best possible image quality at the lowest possible patient dose, particularly for paediatric patients. Manufacturers of equipment do not generally supply paediatric protocols and, thus, the default settings of the adult protocols have to be adjusted for paediatric patients. Optimising imaging protocols is not a trivial matter and, without a suitable phantom, it is difficult and time consuming. Commercial phantoms are commonly used to optimise adult protocols, but these are made of dry materials such as perspex, Teflon, aluminium, dry bone as in dry skulls, or a combination of these materials. The problem with these phantoms is that the features on their images are artificial, not simulating any characteristics of patients' anatomic details. In optimising paediatric protocols for our new cardiac/angiographic Siemens Biplane Digital Imaging System, we searched for a paediatric phantom with moisture content, and found that the humble butternut pumpkin (cucurbita moschate) from the squash family makes a good paediatric phantom, particularly, when it is injected with contrast. The part of the butternut that is useful as a phantom is the pulp, i.e., the part that contains the seeds. This is also the part where the contrast is injected. The image of the pulp contains structures that are natural as the butternut is the fruit of a living plant. The image of the seeds is suitable for low-level contrast detectability while fine structures enhanced by the

  4. Relationship between image plates physical structure and quality of digital radiographic images in weld inspections

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Davi F.; Silva, Aline S.S.; Machado, Alessandra S.; Gomes, Celio S.; Nascimento, Joseilson; Lopes, Ricardo T., E-mail: davi@lin.ufrj.br.br, E-mail: aline@lin.ufrj.br, E-mail: celio@lin.ufrj.br, E-mail: alemachado@lin.ufrj.br, E-mail: joseilson@lin.ufrj.br, E-mail: ricardo@lin.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Instrumentacao Nuclear

    2015-07-01

    In the last decades a new type of detector which is based on photostimulable luminescence was developed. There are currently many kinds of image plates (IPs) available on the market, originating from different manufacturers. Each kind of plate distinguishes itself from the others by its peculiar physical structure and composition, two factors which have a direct influence upon the quality of the digital radiographic images obtained through them. For this study, several kinds of IPs were tested in order to determine in which way such influence takes place. For this purpose, each kind of IP has been characterized and correlated to its response in the final image. The aim of this work was to evaluate procedures for employing Computed Radiography (CR) to welding inspections in laboratory conditions using the Simple Wall Simple Image Technique (SWSI). Tests were performed in steel welded joins of thickness 5.33, 12.70 and 25.40 mm, using CR scanner and IPs available on the market. It was used an X-Ray equipment as radiation source. The image quality parameters Basic Spatial Resolution (BSR), Normalized Signal-to-Noise Ratio (SNR{sub N}), contrast and detectability were evaluated. In order to determine in which way the IPs' properties are correlated to its response in the final image, the thickness of the sensitive layer was determined and the grain size and the elemental composition of this layer were evaluated. Based on the results drawn from this study, it is possible to conclude that the physical characteristics of image plates are essential for determining the quality of the digital radiography images acquired with them. Regarding the chemical composition of the plates, it was possible to determine that, apart from the chemical elements that were expected to be found (Ba, I and Br), only two plates, with high resolution, do not have fluorine in their composition; the presence of Strontium was also detected in the chemical composition of the plates supplied by a

  5. Relationship between image plates physical structure and quality of digital radiographic images in weld inspections

    International Nuclear Information System (INIS)

    Oliveira, Davi F.; Silva, Aline S.S.; Machado, Alessandra S.; Gomes, Celio S.; Nascimento, Joseilson; Lopes, Ricardo T.

    2015-01-01

    In the last decades a new type of detector which is based on photostimulable luminescence was developed. There are currently many kinds of image plates (IPs) available on the market, originating from different manufacturers. Each kind of plate distinguishes itself from the others by its peculiar physical structure and composition, two factors which have a direct influence upon the quality of the digital radiographic images obtained through them. For this study, several kinds of IPs were tested in order to determine in which way such influence takes place. For this purpose, each kind of IP has been characterized and correlated to its response in the final image. The aim of this work was to evaluate procedures for employing Computed Radiography (CR) to welding inspections in laboratory conditions using the Simple Wall Simple Image Technique (SWSI). Tests were performed in steel welded joins of thickness 5.33, 12.70 and 25.40 mm, using CR scanner and IPs available on the market. It was used an X-Ray equipment as radiation source. The image quality parameters Basic Spatial Resolution (BSR), Normalized Signal-to-Noise Ratio (SNR N ), contrast and detectability were evaluated. In order to determine in which way the IPs' properties are correlated to its response in the final image, the thickness of the sensitive layer was determined and the grain size and the elemental composition of this layer were evaluated. Based on the results drawn from this study, it is possible to conclude that the physical characteristics of image plates are essential for determining the quality of the digital radiography images acquired with them. Regarding the chemical composition of the plates, it was possible to determine that, apart from the chemical elements that were expected to be found (Ba, I and Br), only two plates, with high resolution, do not have fluorine in their composition; the presence of Strontium was also detected in the chemical composition of the plates supplied by a

  6. Effect of image quality on calcification detection in digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C. [National Co-ordinating Centre for the Physics of Mammography, Royal Surrey County Hospital NHS Foundation Trust, Guildford GU2 7XX, United Kingdom and Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, GU2 7XH (United Kingdom); Jarvis Breast Screening and Diagnostic Centre, Guildford GU1 1LJ (United Kingdom); Department of Radiology, St. George' s Healthcare NHS Trust, Tooting, London SW17 0QT (United Kingdom); Cambridge Breast Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge CB2 0QQ, United Kingdom and NIHR Cambridge Biomedical Research Centre, Cambridge CB2 0QQ (United Kingdom); Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15210 (United States); National Co-ordinating Centre for the Physics of Mammography, Royal Surrey County Hospital NHS Foundation Trust, Guildford GU2 7XX, United Kingdom and Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom); University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); National Co-ordinating Centre for the Physics of Mammography, Royal Surrey County Hospital NHS Foundation Trust, Guildford GU2 7XX, United Kingdom and Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2012-06-15

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  7. Radiation dose optimization in pediatric temporal bone computed tomography: influence of tube tension on image contrast and image quality.

    Science.gov (United States)

    Nauer, Claude Bertrand; Zubler, Christoph; Weisstanner, Christian; Stieger, Christof; Senn, Pascal; Arnold, Andreas

    2012-03-01

    The purpose of this experimental study was to investigate the effect of tube tension reduction on image contrast and image quality in pediatric temporal bone computed tomography (CT). Seven lamb heads with infant-equivalent sizes were scanned repeatedly, using four tube tensions from 140 to 80 kV while the CT-Dose Index (CTDI) was held constant. Scanning was repeated with four CTDI values from 30 to 3 mGy. Image contrast was calculated for the middle ear as the Hounsfield unit (HU) difference between bone and air and for the inner ear as the HU difference between bone and fluid. The influence of tube tension on high-contrast detail delineation was evaluated using a phantom. The subjective image quality of eight middle and inner ear structures was assessed using a 4-point scale (scores 1-2 = insufficient; scores 3-4 = sufficient). Middle and inner ear contrast showed a near linear increase with tube tension reduction (r = -0.94/-0.88) and was highest at 80 kV. Tube tension had no influence on spatial resolution. Subjective image quality analysis showed significantly better scoring at lower tube tensions, with highest image quality at 80 kV. However, image quality improvement was most relevant for low-dose scans. Image contrast in the temporal bone is significantly higher at low tube tensions, leading to a better subjective image quality. Highest contrast and best quality were found at 80 kV. This image quality improvement might be utilized to further reduce the radiation dose in pediatric low-dose CT protocols.

  8. Radiation dose optimization in pediatric temporal bone computed tomography: influence of tube tension on image contrast and image quality

    International Nuclear Information System (INIS)

    Nauer, Claude Bertrand; Zubler, Christoph; Weisstanner, Christian; Stieger, Christof; Senn, Pascal; Arnold, Andreas

    2012-01-01

    The purpose of this experimental study was to investigate the effect of tube tension reduction on image contrast and image quality in pediatric temporal bone computed tomography (CT). Seven lamb heads with infant-equivalent sizes were scanned repeatedly, using four tube tensions from 140 to 80 kV while the CT-Dose Index (CTDI) was held constant. Scanning was repeated with four CTDI values from 30 to 3 mGy. Image contrast was calculated for the middle ear as the Hounsfield unit (HU) difference between bone and air and for the inner ear as the HU difference between bone and fluid. The influence of tube tension on high-contrast detail delineation was evaluated using a phantom. The subjective image quality of eight middle and inner ear structures was assessed using a 4-point scale (scores 1-2 = insufficient; scores 3-4 = sufficient). Middle and inner ear contrast showed a near linear increase with tube tension reduction (r = -0.94/-0.88) and was highest at 80 kV. Tube tension had no influence on spatial resolution. Subjective image quality analysis showed significantly better scoring at lower tube tensions, with highest image quality at 80 kV. However, image quality improvement was most relevant for low-dose scans. Image contrast in the temporal bone is significantly higher at low tube tensions, leading to a better subjective image quality. Highest contrast and best quality were found at 80 kV. This image quality improvement might be utilized to further reduce the radiation dose in pediatric low-dose CT protocols. (orig.)

  9. Availability of high quality weather data measurements

    DEFF Research Database (Denmark)

    Andersen, Elsa; Johansen, Jakob Berg; Furbo, Simon

    In the period 2016-2017 the project “Availability of high quality weather data measurements” is carried out at Department of Civil Engineering at the Technical University of Denmark. The aim of the project is to establish measured high quality weather data which will be easily available...... for the building energy branch and the solar energy branch in their efforts to achieve energy savings and for researchers and students carrying out projects where measured high quality weather data are needed....

  10. Effect of image quality on calcification detection in digital mammography.

    Science.gov (United States)

    Warren, Lucy M; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M; Wallis, Matthew G; Chakraborty, Dev P; Dance, David R; Bosmans, Hilde; Young, Kenneth C

    2012-06-01

    This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC (AFROC) area decreased from

  11. Effect of image quality on calcification detection in digital mammography

    International Nuclear Information System (INIS)

    Warren, Lucy M.; Mackenzie, Alistair; Cooke, Julie; Given-Wilson, Rosalind M.; Wallis, Matthew G.; Chakraborty, Dev P.; Dance, David R.; Bosmans, Hilde; Young, Kenneth C.

    2012-01-01

    Purpose: This study aims to investigate if microcalcification detection varies significantly when mammographic images are acquired using different image qualities, including: different detectors, dose levels, and different image processing algorithms. An additional aim was to determine how the standard European method of measuring image quality using threshold gold thickness measured with a CDMAM phantom and the associated limits in current EU guidelines relate to calcification detection. Methods: One hundred and sixty two normal breast images were acquired on an amorphous selenium direct digital (DR) system. Microcalcification clusters extracted from magnified images of slices of mastectomies were electronically inserted into half of the images. The calcification clusters had a subtle appearance. All images were adjusted using a validated mathematical method to simulate the appearance of images from a computed radiography (CR) imaging system at the same dose, from both systems at half this dose, and from the DR system at quarter this dose. The original 162 images were processed with both Hologic and Agfa (Musica-2) image processing. All other image qualities were processed with Agfa (Musica-2) image processing only. Seven experienced observers marked and rated any identified suspicious regions. Free response operating characteristic (FROC) and ROC analyses were performed on the data. The lesion sensitivity at a nonlesion localization fraction (NLF) of 0.1 was also calculated. Images of the CDMAM mammographic test phantom were acquired using the automatic setting on the DR system. These images were modified to the additional image qualities used in the observer study. The images were analyzed using automated software. In order to assess the relationship between threshold gold thickness and calcification detection a power law was fitted to the data. Results: There was a significant reduction in calcification detection using CR compared with DR: the alternative FROC

  12. Evaluation of image quality of lumbar spine images: A comparison between FFE and VGA

    International Nuclear Information System (INIS)

    Tingberg, A.; Baath, M.; Haakansson, M.; Medin, J.; Besjakov, J.; Sandborg, M.; Alm-Carlsson, G.; Mattsson, S.; Maansson, L. G.

    2005-01-01

    Purpose: The aim of the present study is to compare two different methods for evaluation of the quality of clinical X-ray images. Methods: Based on fifteen lumbar spine radiographs, two new sets of images were created. A hybrid image set was created by adding two distributions of artificial lesions to each original image. The image quality parameters spatial resolution and noise were manipulated and a total of 210 hybrid images were created. A set of 105 disease-free images was created by applying the same combinations of spatial resolution and noise to the original images. The hybrid images were evaluated with the free-response forced error experiment (FFE) and the normal images with visual grading analysis (VGA) by nine experienced radiologists. Results: In the VGA study, images with low noise were preferred over images with higher noise levels. The alteration of the MTF had a limited influence on the VGA score. For the FFE study, the visibility of the lesions was independent of the sharpness and the noise level. No correlation was found between the two image quality measures. Conclusions: FFE is a precise method for evaluation of image quality, but the results are only valid for the type of lesion used in the study, whereas VGA is a more general method for clinical image quality assessment. The results of the FFE study indicate that there might be a potential to lower the dose levels in lumbar spine radiography without losing important diagnostic information. (authors)

  13. 1024 matrix image reconstruction: usefulness in high resolution chest CT

    International Nuclear Information System (INIS)

    Jeong, Sun Young; Chung, Myung Jin; Chong, Se Min; Sung, Yon Mi; Lee, Kyung Soo

    2006-01-01

    We tried to evaluate whether high resolution chest CT with a 1,024 matrix has a significant advantage in image quality compared to a 512 matrix. Each set of 512 and 1024 matrix high resolution chest CT scans with both 0.625 mm and 1.25 mm slice thickness were obtained from 26 patients. Seventy locations that contained twenty-four low density lesions without sharp boundary such as emphysema, and forty-six sharp linear densities such as linear fibrosis were selected; these were randomly displayed on a five mega pixel LCD monitor. All the images were masked for information concerning the matrix size and slice thickness. Two chest radiologists scored the image quality of each ar rowed lesion as follows: (1) undistinguishable, (2) poorly distinguishable, (3) fairly distinguishable, (4) well visible and (5) excellently visible. The scores were compared from the aspects of matrix size, slice thickness and the different observers by using ANOVA tests. The average and standard deviation of image quality were 3.09 (± .92) for the 0.625 mm x 512 matrix, 3.16 (± .84) for the 0.625 mm x 1024 matrix, 2.49 (± 1.02) for the 1.25 mm x 512 matrix, and 2.35 (± 1.02) for the 1.25 mm x 1024 matrix, respectively. The image quality on both matrices of the high resolution chest CT scans with a 0.625 mm slice thickness was significantly better than that on the 1.25 mm slice thickness (ρ < 0.001). However, the image quality on the 1024 matrix high resolution chest CT scans was not significantly different from that on the 512 matrix high resolution chest CT scans (ρ = 0.678). The interobserver variation between the two observers was not significant (ρ = 0.691). We think that 1024 matrix image reconstruction for high resolution chest CT may not be clinical useful

  14. Super-resolution convolutional neural network for the improvement of the image quality of magnified images in chest radiographs

    Science.gov (United States)

    Umehara, Kensuke; Ota, Junko; Ishimaru, Naoki; Ohno, Shunsuke; Okamoto, Kentaro; Suzuki, Takanori; Shirai, Naoki; Ishida, Takayuki

    2017-02-01

    Single image super-resolution (SR) method can generate a high-resolution (HR) image from a low-resolution (LR) image by enhancing image resolution. In medical imaging, HR images are expected to have a potential to provide a more accurate diagnosis with the practical application of HR displays. In recent years, the super-resolution convolutional neural network (SRCNN), which is one of the state-of-the-art deep learning based SR methods, has proposed in computer vision. In this study, we applied and evaluated the SRCNN scheme to improve the image quality of magnified images in chest radiographs. For evaluation, a total of 247 chest X-rays were sampled from the JSRT database. The 247 chest X-rays were divided into 93 training cases with non-nodules and 152 test cases with lung nodules. The SRCNN was trained using the training dataset. With the trained SRCNN, the HR image was reconstructed from the LR one. We compared the image quality of the SRCNN and conventional image interpolation methods, nearest neighbor, bilinear and bicubic interpolations. For quantitative evaluation, we measured two image quality metrics, peak signal-to-noise ratio (PSNR) and structural similarity (SSIM). In the SRCNN scheme, PSNR and SSIM were significantly higher than those of three interpolation methods (pmethods without any obvious artifacts. These preliminary results indicate that the SRCNN scheme significantly outperforms conventional interpolation algorithms for enhancing image resolution and that the use of the SRCNN can yield substantial improvement of the image quality of magnified images in chest radiographs.

  15. Free-breathing motion-corrected late-gadolinium-enhancement imaging improves image quality in children

    International Nuclear Information System (INIS)

    Olivieri, Laura; O'Brien, Kendall J.; Cross, Russell; Xue, Hui; Kellman, Peter; Hansen, Michael S.

    2016-01-01

    -enhancement imaging with motion-corrected averaging is feasible in children, robust at high heart rates and with variable R-R intervals, and can be performed without breath-holding with higher image quality ratings than standard breath-held techniques. Use of free-breathing single-shot motion-corrected technique does not compromise LGE image quality in children who can hold their breath, and it can significantly improve image quality in children who cannot hold their breath or who have significant arrhythmia. (orig.)

  16. Image quality of conventional images of dual-layer SPECTRAL CT: a phantom study.

    Science.gov (United States)

    van Ommen, F; Bennink, E; Vlassenbroek, A; Dankbaar, J W; Schilham, A M R; Viergever, M A; de Jong, H W A M

    2018-05-10

    Spectral CT using a dual layer detector offers the possibility of retrospectively introducing spectral information to conventional CT images. In theory, the dual-layer technology should not come with a dose or image quality penalty for conventional images. In this study, we evaluate the influence of a dual-layer detector (IQon Spectral CT, Philips) on the image quality of conventional CT images, by comparing these images with those of a conventional but otherwise technically comparable single-layer CT scanner (Brilliance iCT, Philips), by means of phantom experiments. For both CT scanners conventional CT images were acquired using four adult scanning protocols: i) body helical, ii) body axial, iii) head helical and iv) head axial. A CATPHAN 600 phantom was scanned to conduct an assessment of image quality metrics at equivalent (CTDI) dose levels. Noise was characterized by means of noise power spectra (NPS) and standard deviation (SD) of a uniform region, and spatial resolution was evaluated with modulation transfer functions (MTF) of a tungsten wire. In addition, contrast-to-noise ratio (CNR), image uniformity, CT number linearity, slice thickness, slice spacing, and spatial linearity were measured and evaluated. Additional measurements of CNR, resolution and noise were performed in two larger phantoms. The resolution levels at 50%, 10% and 5% MTF of the iCT and IQon showed small but significant differences up to 0.25 lp/cm for body scans, and up to 0.2 lp/cm for head scans in favor of the IQon. The iCT and IQon showed perfect CT linearity for body scans, but for head scans both scanners showed an underestimation of the CT numbers of materials with a high opacity. Slice thickness was slightly overestimated for both scanners. Slice spacing was comparable and reconstructed correctly. In addition, spatial linearity was excellent for both scanners, with a maximum error of 0.11 mm. CNR was higher on the IQon compared to the iCT for both normal and larger phantoms with

  17. Free-breathing motion-corrected late-gadolinium-enhancement imaging improves image quality in children

    Energy Technology Data Exchange (ETDEWEB)

    Olivieri, Laura; O' Brien, Kendall J. [Children' s National Health System, Division of Cardiology, Washington, DC (United States); National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD (United States); Cross, Russell [Children' s National Health System, Division of Cardiology, Washington, DC (United States); Xue, Hui; Kellman, Peter; Hansen, Michael S. [National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD (United States)

    2016-06-15

    -enhancement imaging with motion-corrected averaging is feasible in children, robust at high heart rates and with variable R-R intervals, and can be performed without breath-holding with higher image quality ratings than standard breath-held techniques. Use of free-breathing single-shot motion-corrected technique does not compromise LGE image quality in children who can hold their breath, and it can significantly improve image quality in children who cannot hold their breath or who have significant arrhythmia. (orig.)

  18. Optimization of image quality in diagnostic radiology associated with exposure

    International Nuclear Information System (INIS)

    Fulea, C.; Ramboiu, S.

    1996-01-01

    Optimal parameters for a high quality image and minimal radiation risk for the patients were established. The characteristics that affect image quality speed, contrast factor, latitude, base density, fog density, reciprocity law failure and latent image fading were analyzed. Base density on the radiographic image was measured for Azoix film and it is 0.1 log units. Fog density is a function of development time and it will increase with 20% through the increase with 2 minutes of development time. The curve Hurter-Driffield was used to characterize photographic emulsion for Azoix film. The value of latitude of 0.7 log units is in the normally useful range of densities found in radiographs. The speed of Azoix film, as a function of the time interval between exposure and development, increase with 10% for the first 24 hours. The reduction in the patient exposure that could be effected by delaying the development of Azoix is so small, that it is far outweighed by the possible disadvantage of a delay in the acquisition of diagnostic information. Therefore, latent image fading is not very important from the point of view of patient exposure. The speeds evaluated for exposure times 0.08s, 0.16s, 0.64s were unmodified, that is reciprocity law failure was unimportant for Azoix film Perlux screen. The romania films Azoix used with Perlux screen and processed with original solutions are determined an optical density of 1.0 (average density of medical radiograph) with a minimum radiation exposure for the patient (59·10 -7 C/kg). (author)

  19. Quality image and incident air kerma evaluation in X-ray chest exams

    International Nuclear Information System (INIS)

    Campos de O, P. M.; Do Carmo S, P.; De Sousa L, M. A.; Da Silva, T. A.

    2017-10-01

    The procedures optimization for obtaining diagnostic quality images is an important factor to the patients radiation levels submitted to diagnostic radiology examinations was the lowest as reasonably practicable. Two methodologies for image quality parameters evaluation were applied in the routine of three diagnostic radiology clinics (A, B and C), two with digital image processing and one with chemical processing in Belo Horizonte, Brazil. The incident air kerma was evaluated for the radiographic techniques used in the clinic routine chest exams, approved in accordance with European Image Quality Criteria. It was possible to determine that the Fluke Biomedical X-ray Phantom test objects coupled to the Leeds Test Objects (TOR CDR) obtained better results than Gammex s Radiographic Survey Phantom (RSV), because the low and high contrast structures present in the RSV were not visualized in lower energies. The three clinics presented very similar results in all image quality parameters in the evaluation with the TOR CDR test object. However, clinic C presented an low contrast structures result 28.1 % lower than clinical B, although the average Ka,i to obtain their images was 33.4 % superior. The clinic A results present the best relation between image quality and radiation dose in patients. It was verified the optimization doses possibility in diagnostic radiology services with digital processing system, without significant reduction in image quality. Patients submitted to the highest radiation levels belonged to the clinic that presented the worst results in the image quality parameters evaluated. (Author)

  20. Evaluating phantom image quality parameters to optimise patient radiation dose in dental digital radiology.

    Science.gov (United States)

    Gonzalez, Luciano; Vano, Eliseo; Fernandez, Ramon; Ziraldo, Viviana; Delgado, Jaime; Delgado, Victor; Moro, Javier; Ubeda, Carlos

    2012-08-01

    Our objective was to obtain images of a predictable level of quality using an intraoral X-ray system with digital imaging, avoiding patient overexposure. A polymethylmethacrylate (PMMA) physical test phantom was imaged at different exposure times and at various PMMA thicknesses using a dental imaging coupled charge device. Two identical regions of interest (ROIs) were chosen in every image file, and quality was numerically evaluated by measuring high-contrast spatial resolutions, low-contrast thresholds and signal-to-noise ratios. In addition, three practitioners proposed personal quality scores by image inspection. Numerical contents in the ROIs, related to the image quality, were plotted against exposure time. From here, a simple expression linking the exposure time with the thickness to obtain images of comparable quality was deduced. As a result, the optimum exposure time for imaging with a predictable level of quality can be inferred. The potential effect could imply savings above 1000 man Sv, roughly 20 % of the collective dose due to dental imaging, over a population of 1540 millions.

  1. Image quality characteristics of a novel colour scanning digital ophthalmoscope (SDO) compared with fundus photography.

    Science.gov (United States)

    Strauss, Rupert W; Krieglstein, Tina R; Priglinger, Siegfried G; Reis, Werner; Ulbig, Michael W; Kampik, Anselm; Neubauer, Aljoscha S

    2007-11-01

    To establish a set of quality parameters for grading image quality and apply those to evaluate the fundus image quality obtained by a new scanning digital ophthalmoscope (SDO) compared with standard slide photography. On visual analogue scales a total of eight image characteristics were defined: overall quality, contrast, colour brilliance, focus (sharpness), resolution and details, noise, artefacts and validity of clinical assessment. Grading was repeated after 4 months to assess repeatability. Fundus images of 23 patients imaged digitally by SDO and by Zeiss 450FF fundus camera using Kodak film were graded side-by-side by three graders. Lens opacity was quantified with the Interzeag Lens Opacity Meter 701. For all of the eight scales of image quality, good repeatability within the graders (mean Kendall's W 0.69) was obtained after 4 months. Inter-grader agreement ranged between 0.31 and 0.66. Despite the SDO's limited nominal image resolution of 720 x 576 pixels, the Zeiss FF 450 camera performed better in only two of the subscales - noise (p = 0.001) and artefacts (p = 0.01). Lens opacities significantly influenced only the two subscales 'resolution' and 'details', which deteriorated with increasing media opacities for both imaging systems. Distinct scales to grade image characteristics of different origin were developed and validated. Overall SDO digital imaging was found to provide fundus pictures of a similarly high level of quality as expert photography on slides.

  2. Image processing system performance prediction and product quality evaluation

    Science.gov (United States)

    Stein, E. K.; Hammill, H. B. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. A new technique for image processing system performance prediction and product quality evaluation was developed. It was entirely objective, quantitative, and general, and should prove useful in system design and quality control. The technique and its application to determination of quality control procedures for the Earth Resources Technology Satellite NASA Data Processing Facility are described.

  3. Multidetector CT of the coronary imaging: assessment of image quality and accuracy in detecting stenoses

    International Nuclear Information System (INIS)

    Huang Meiping; Liu Qishun; Liu Hui; Liang Changhong; Zhang Shaobin

    2006-01-01

    Objective: To evaluate the image quality of 64-multi detector computed tomography (MDCT) and the clinical accuracy in detecting coronary artery lesions. Methods: One hundred and five patients were studied by MDCT. The results were compared with invasive coronary angiography (ICA). Patients were excluded for atrial fibrillation, but not for high heart rate, coronary calcification, or obesity. MDCT was analyzed with regard to image quality and presence of coronary artery lesions. Results: The data evaluation of the image quality was based on a total of 1365 segments (13 coronary segments for each patient), of which 1144 segments were considered to have diagnostic image quality, but 221 segments (16.2%) could not be sufficiently evaluated because of severe calcifications (153 segments) and motion artifacts (68 segments). The median calcium score [Agatston score equivalent (ASE)] was 154 (range 0--1983). 87 of the 105 patients had an ASE of less than 1,000 [median 105 (range 0-994)], and 18 patients had an ASE greater than 1000 [median 1477 (range 1115-1983)]. For detecting lesions with 50% or greater narrowing (without any exclusion criteria), the overall sensitivity, specificity, positive predictive value, and negative predictive value were 85.7%, 97.9%, 93.0%, and 95.5%, respectively. When limiting the number of patients to those with a calcium score of less than 1000 ASE, the threshold- corrected sensitivity for lesions with 50% or greater narrowing was 96.0%; specificity, 98.9%; positive predictive value, 95.3%; and negative predictive value, 99.0%. Conclusion: Our results indicate high quantitative and qualitative diagnostic accuracy of 64-slice MSCT in comparison to QCA in a broad spectrum of patients. (authors)

  4. Performance comparison of different graylevel image fusion schemes through a universal image quality index

    NARCIS (Netherlands)

    Toet, A.; Hogervorst, M.A.

    2003-01-01

    We applied a recently introduced universal image quality index Q that quantifies the distortion of a processed image relative to its original version, to assess the performance of different graylevel image fusion schemes. The method is as follows. First, we adopt an original test image as the

  5. Image Quality Assessment of 2D versus 3D T2WI and Evaluation of Ultra-high b-Value (b=2,000 mm/s2) DWI for Response Assessment in Rectal Cancer.

    Science.gov (United States)

    Hausmann, Daniel; Liu, Jing; Budjan, Johannes; Reichert, Miriam; Ong, Melissa; Meyer, Mathias; Smakic, Arman; Grimm, Robert; Strecker, Ralph; Schoenberg, Stefan O; Wang, Xiaoying; Attenberger, Ulrike I

    2018-02-01

    The purpose of this IRB-approved, retrospective study was to compare image quality between 2D and high-resolution 3D, T2-weighted (T2WI) magnetic resonance imaging (MRI) sequences and to investigate the additional value of ultra-high b-value diffusion-weighted imaging (DWI; b=2,000 mm/s 2 ) for both rectal cancer staging and evaluating treatment response. From 12 February to 24 August 2016, 26 consecutive patients (22 males, four females; mean age: 61.9±14.0 years) with histologically-proven rectal cancer. In total 31 examinations [12 prior to and 19 after chemoradiation (CRT)] were included. The patients underwent pelvic MRI on a 3.0-T scanner (Magnetom Skyra, Erlangen, Germany). Three radiologists (3, 4, and 5 years of experience in MRI, respectively) independently assessed all images and rated the image quality of DWI (b=800 mm/s 2 ), apparent diffusion coefficient map, DWI (b=2,000 mm/s 2 ), 3D sagittal T2WI, 3D axial T2WI, 2D sagittal T2WI, and 2D axial T2WI of each patient, respectively. In addition, signal intensity ratios (SIR) were calculated between rectal cancer and obturator internus muscle (background) in all patients after CRT on DWI (b=2,000 mm/s 2 ) and correlated with histopathological regression grade (RG). Tumor delineation was significantly better by 2D T2WI than 3D T2WI both before and after CRT (before CRT: Z=-3.2, p=0.02; after CRT: Z=-4.408, p3D sagittal: 4.00±0.48; 2D sagittal: 4.03±0.34, p=0.713; 3D axial: 3.85±0.61, 2D axial: 3.78±0.64, p=0.537). Independent t-test showed significantly higher SIR between those with RG 1 or 2 (moderate response: mean score=2.02) and those with RG 3+4 (good response: mean score=0.8) (t=3.044, p=0.011). In those with RG 4 (complete response), SIR of b2000 was 0.946 compared to a 1.41 average of the whole cohort. In two patients, tumor was invisible on b2000 following CRT (RG 3 and 4, respectively). Interobserver agreement was mostly good (κ≥0.6) regarding image quality assessment, except for poor

  6. Decision theory applied to image quality control in radiology.

    Science.gov (United States)

    Lessa, Patrícia S; Caous, Cristofer A; Arantes, Paula R; Amaro, Edson; de Souza, Fernando M Campello

    2008-11-13

    The present work aims at the application of the decision theory to radiological image quality control (QC) in diagnostic routine. The main problem addressed in the framework of decision theory is to accept or reject a film lot of a radiology service. The probability of each decision of a determined set of variables was obtained from the selected films. Based on a radiology service routine a decision probability function was determined for each considered group of combination characteristics. These characteristics were related to the film quality control. These parameters were also framed in a set of 8 possibilities, resulting in 256 possible decision rules. In order to determine a general utility application function to access the decision risk, we have used a simple unique parameter called r. The payoffs chosen were: diagnostic's result (correct/incorrect), cost (high/low), and patient satisfaction (yes/no) resulting in eight possible combinations. Depending on the value of r, more or less risk will occur related to the decision-making. The utility function was evaluated in order to determine the probability of a decision. The decision was made with patients or administrators' opinions from a radiology service center. The model is a formal quantitative approach to make a decision related to the medical imaging quality, providing an instrument to discriminate what is really necessary to accept or reject a film or a film lot. The method presented herein can help to access the risk level of an incorrect radiological diagnosis decision.

  7. Enhancement of digital radiography image quality using a convolutional neural network.

    Science.gov (United States)

    Sun, Yuewen; Li, Litao; Cong, Peng; Wang, Zhentao; Guo, Xiaojing

    2017-01-01

    Digital radiography system is widely used for noninvasive security check and medical imaging examination. However, the system has a limitation of lower image quality in spatial resolution and signal to noise ratio. In this study, we explored whether the image quality acquired by the digital radiography system can be improved with a modified convolutional neural network to generate high-resolution images with reduced noise from the original low-quality images. The experiment evaluated on a test dataset, which contains 5 X-ray images, showed that the proposed method outperformed the traditional methods (i.e., bicubic interpolation and 3D block-matching approach) as measured by peak signal to noise ratio (PSNR) about 1.3 dB while kept highly efficient processing time within one second. Experimental results demonstrated that a residual to residual (RTR) convolutional neural network remarkably improved the image quality of object structural details by increasing the image resolution and reducing image noise. Thus, this study indicated that applying this RTR convolutional neural network system was useful to improve image quality acquired by the digital radiography system.

  8. Improving the quality of brain CT image from Wavelet filters

    International Nuclear Information System (INIS)

    Pita Machado, Reinaldo; Perez Diaz, Marlen; Bravo Pino, Rolando

    2012-01-01

    An algorithm to reduce Poisson noise is described using Wavelet filters. Five tomographic images of patients and a head anthropomorphic phantom were used. They were acquired with two different CT machines. Due to the original images contain the acquisition noise; some simulated free noise lesions were added to the images and after that the whole images were contaminated with noise. Contaminated images were filtered with 9 Wavelet filters at different decomposition levels and thresholds. Image quality of filtered and unfiltered images was graded using the Signal to Noise ratio, Normalized Mean Square Error and the Structural Similarity Index, as well as, by the subjective JAFROC methods with 5 observers. Some filters as Bior 3.7 and dB45 improved in a significant way head CT image quality (p<0.05) producing an increment in SNR without visible structural distortions

  9. Semiconductor crystal high resolution imager

    Science.gov (United States)

    Levin, Craig S. (Inventor); Matteson, James (Inventor)

    2011-01-01

    A radiation imaging device (10). The radiation image device (10) comprises a subject radiation station (12) producing photon emissions (14), and at least one semiconductor crystal detector (16) arranged in an edge-on orientation with respect to the emitted photons (14) to directly receive the emitted photons (14) and produce a signal. The semiconductor crystal detector (16) comprises at least one anode and at least one cathode that produces the signal in response to the emitted photons (14).

  10. Perceived image quality for autostereoscopic holograms in healthcare training

    Science.gov (United States)

    Goldiez, Brian; Abich, Julian; Carter, Austin; Hackett, Matthew

    2017-03-01

    The current state of dynamic light field holography requires further empirical investigation to ultimately advance this developing technology. This paper describes a user-centered design approach for gaining insight into the features most important to clinical personnel using emerging dynamic holographic displays. The approach describes the generation of a high quality holographic model of a simulated traumatic amputation above the knee using 3D scanning. Using that model, a set of static holographic prints will be created varying in color or monochrome, contrast ratio, and polygon density. Leveraging methods from image quality research, the goal for this paper is to describe an experimental approach wherein participants are asked to provide feedback regarding the elements previously mentioned in order to guide the ongoing evolution of holographic displays.

  11. Section on High Resolution Optical Imaging (HROI)

    Data.gov (United States)

    Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

  12. No-reference visual quality assessment for image inpainting

    Science.gov (United States)

    Voronin, V. V.; Frantc, V. A.; Marchuk, V. I.; Sherstobitov, A. I.; Egiazarian, K.

    2015-03-01

    Inpainting has received a lot of attention in recent years and quality assessment is an important task to evaluate different image reconstruction approaches. In many cases inpainting methods introduce a blur in sharp transitions in image and image contours in the recovery of large areas with missing pixels and often fail to recover curvy boundary edges. Quantitative metrics of inpainting results currently do not exist and researchers use human comparisons to evaluate their methodologies and techniques. Most objective quality assessment methods rely on a reference image, which is often not available in inpainting applications. Usually researchers use subjective quality assessment by human observers. It is difficult and time consuming procedure. This paper focuses on a machine learning approach for no-reference visual quality assessment for image inpainting based on the human visual property. Our method is based on observation that Local Binary Patterns well describe local structural information of the image. We use a support vector regression learned on assessed by human images to predict perceived quality of inpainted images. We demonstrate how our predicted quality value correlates with qualitative opinion in a human observer study. Results are shown on a human-scored dataset for different inpainting methods.

  13. High-speed reconstruction of compressed images

    Science.gov (United States)

    Cox, Jerome R., Jr.; Moore, Stephen M.

    1990-07-01

    A compression scheme is described that allows high-definition radiological images with greater than 8-bit intensity resolution to be represented by 8-bit pixels. Reconstruction of the images with their original intensity resolution can be carried out by means of a pipeline architecture suitable for compact, high-speed implementation. A reconstruction system is described that can be fabricated according to this approach and placed between an 8-bit display buffer and the display's video system thereby allowing contrast control of images at video rates. Results for 50 CR chest images are described showing that error-free reconstruction of the original 10-bit CR images can be achieved.

  14. A quantitative image quality comparison of four different image guided radiotherapy devices

    International Nuclear Information System (INIS)

    Stuetzel, Julia; Oelfke, Uwe; Nill, Simeon

    2008-01-01

    Purpose: A study to quantitatively compare the image quality of four different image guided radiotherapy (IGRT) devices based on phantom measurements with respect to the additional dose delivered to the patient. Methods: Images of three different head-sized phantoms (diameter 16-18 cm) were acquired with the following four IGRT-CT solutions: (i) the Siemens Primatom single slice fan beam computed tomography (CT) scanner with an acceleration voltage of 130 kV, (ii) a Tomotherapy HI-ART II unit using a fan beam scanner with an energy of 3.5 MeV and (iii) the Siemens Artiste prototype, providing the possibility to perform kV (121 kV) and MV (6 MV) cone beam (CB) CTs. For each device three scan protocols (named low, normal, high) were selected to yield the same weighted computed tomography dose index (CTDI w ). Based on the individual inserts of the different phantoms the image quality achieved with each device at a certain dose level was characterized in terms of homogeneity, spatial resolution, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and electron density-to-CT-number conversion. Results: Based on the current findings for head-sized phantoms all devices show an electron density-to-CT-number conversion almost independent of the imaging parameters and hence can be suited for treatment planning purposes. The evaluation of the image quality, however, points out clear differences due to the different energies and geometries. The Primatom standard CT scanner shows throughout the best performance, especially for soft tissue contrast and spatial resolution with low imaging doses. Reasonable soft tissue contrast can be obtained with slightly higher doses compared to the CT scanner with the kVCB and the Tomotherapy unit. In order to get similar results with the MVCB system a much higher dose needs to be applied to the patient. Conclusion: Considering the entire investigations, especially in terms of contrast and spatial resolution, a rough tendency for

  15. Prospectively ECG-triggered high-pitch coronary angiography with third-generation dual-source CT at 70 kVp tube voltage: feasibility, image quality, radiation dose, and effect of iterative reconstruction.

    Science.gov (United States)

    Hell, Michaela M; Bittner, Daniel; Schuhbaeck, Annika; Muschiol, Gerd; Brand, Michael; Lell, Michael; Uder, Michael; Achenbach, Stephan; Marwan, Mohamed

    2014-01-01

    Low tube voltage reduces radiation exposure in coronary CT angiography (CTA). Using 70 kVp tube potential has so far not been possible because CT systems were unable to provide sufficiently high tube current with low voltage. We evaluated feasibility, image quality (IQ), and radiation dose of coronary CTA using a third-generation dual-source CT system capable of producing 450 mAs tube current at 70 kVp tube voltage. Coronary CTA was performed in 26 consecutive patients with suspected coronary artery disease, selected for body weight Image noise was lower in IR vs FBP (60 ± 10 HU vs 74 ± 8 HU; P < .001). In patients <100 kg and with a regular heart rate <60 beats/min, third-generation dual-source CT using high-pitch spiral acquisition and 70 kVp tube voltage is feasible and provides both robust IQ and very low radiation exposure. Copyright © 2014 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  16. Sensitometric properties and image quality of radiographic film and paper

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1985-01-01

    When using X-ray film or radiographic paper for industrial applications one is interested in knowing not only their sensitometric properties (such as speed and contrast) but also the image quality obtainable with a particular brand of film or paper. Although standard methods for testing sensitometric properties and image quality separately are available, it is desirable to find a method by the use of which all the relevant properties could be tested together. The sensitometric properties are usually determined at constant kilovoltage and filtration at the X-ray tube, whereas the radiographic image quality is tested at different kilovoltages and for different material thicknesses

  17. Image quality control in radiodiagnostic in an University Hospital

    International Nuclear Information System (INIS)

    Almeida, Claudio Domingues de; Mota, Helvecio C.; Almeida, Carlos Eduardo de

    1996-01-01

    The image quality criteria proposed for European Union (UE) has been used to evaluate the chest x-ray examinations in a typical Department of Radiology of an University Hospital in Rio de Janeiro. The study includes information on x-ray beam parameters, film-screen combination, doses to the patients, film processing and image quality. Lateral and PA chest examinations of 63 patients were investigated. Only 10% of the patients presented entrance doses greater than the reference level proposed for UE and adopted by International Atomic Energy Agency and World Health Organization. The image quality has been approved for 87% of the examinations. (author)

  18. Optical studies of high quality synthetic diamond

    International Nuclear Information System (INIS)

    Sharp, S.J.

    1999-01-01

    This thesis is concerned with the study of fundamental and defect induced optical properties of synthetic diamond grown using high pressure, high temperature (HPHT) synthesis or chemical vapour deposition (CVD). The primary technique used for investigation is cathodoluminescence (including imaging and decay-time measurements) in addition to other forms of optical spectroscopy. This thesis is timely in that the crystallinity and purity of synthetic diamond has increased ten fold over the last few years. The diamond exciton emission, which is easily quenched by the presence of defects, is studied in high quality samples in detail. In addition the ability now exists to engineer the isotopic content of synthetic diamond to a high degree of accuracy. The experimental chapters are divided as follows: Chapter 2: High resolution, low temperature spectra reveal a splitting of the free-exciton phonon recombination emission peaks and the bound-exciton zero phonon line. Included are measurements of the variation in intensity and decay-time as a function of temperature. Chapter 3: The shift in energy of the phonon-assisted free-exciton phonon replicas with isotopic content has been measured. The shift is in agreement with the results of interatomic force model for phonon scattering due to isotope disorder. Chapter 4: A study of the shift in energy with isotopic content of the diamond of the GR1 band due to the neutral vacancy has allowed a verification of the theoretical predictions due to the Jahn Teller effect. Chapter 5: The spatial distribution of the free-exciton luminescence is studied in HPHT synthetic and CVD diamond. A variation in intensity with distance from the surface is interpreted as a significant non-radiative loss of excitons to the surface. Chapter 6: The decay-times of all known self-interstitial related centres have been measured in order to calculate the concentration of these centres present in electron irradiated diamond. (author)

  19. Zerodur polishing process for high surface quality and high efficiency

    International Nuclear Information System (INIS)

    Tesar, A.; Fuchs, B.

    1992-08-01

    Zerodur is a glass-ceramic composite importance in applications where temperature instabilities influence optical and mechanical performance, such as in earthbound and spaceborne telescope mirror substrates. Polished Zerodur surfaces of high quality have been required for laser gyro mirrors. Polished surface quality of substrates affects performance of high reflection coatings. Thus, the interest in improving Zerodur polished surface quality has become more general. Beyond eliminating subsurface damage, high quality surfaces are produced by reducing the amount of hydrated material redeposited on the surface during polishing. With the proper control of polishing parameters, such surfaces exhibit roughnesses of < l Angstrom rms. Zerodur polishing was studied to recommend a high surface quality polishing process which could be easily adapted to standard planetary continuous polishing machines and spindles. This summary contains information on a polishing process developed at LLNL which reproducibly provides high quality polished Zerodur surfaces at very high polishing efficiencies

  20. Study of quality perception in medical images based on comparison of contrast enhancement techniques in mammographic images

    Science.gov (United States)

    Matheus, B.; Verçosa, L. B.; Barufaldi, B.; Schiabel, H.

    2014-03-01

    With the absolute prevalence of digital images in mammography several new tools became available for radiologist; such as CAD schemes, digital zoom and contrast alteration. This work focuses in contrast variation and how the radiologist reacts to these changes when asked to evaluated image quality. Three contrast enhancing techniques were used in this study: conventional equalization, CCB Correction [1] - a digitization correction - and value subtraction. A set of 100 images was used in tests from some available online mammographic databases. The tests consisted of the presentation of all four versions of an image (original plus the three contrast enhanced images) to the specialist, requested to rank each one from the best up to worst quality for diagnosis. Analysis of results has demonstrated that CCB Correction [1] produced better images in almost all cases. Equalization, which mathematically produces a better contrast, was considered the worst for mammography image quality enhancement in the majority of cases (69.7%). The value subtraction procedure produced images considered better than the original in 84% of cases. Tests indicate that, for the radiologist's perception, it seems more important to guaranty full visualization of nuances than a high contrast image. Another result observed is that the "ideal" scanner curve does not yield the best result for a mammographic image. The important contrast range is the middle of the histogram, where nodules and masses need to be seen and clearly distinguished.

  1. Brain imaging with synthetic MR in children: clinical quality assessment

    Energy Technology Data Exchange (ETDEWEB)

    Betts, Aaron M.; Serai, Suraj [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Leach, James L.; Jones, Blaise V. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); University of Cincinnati College of Medicine, Cincinnati, OH (United States); Zhang, Bin [Cincinnati Children' s Hospital Medical Center, Biostatistics and Epidemiology, Cincinnati, OH (United States)

    2016-10-15

    Synthetic magnetic resonance imaging is a quantitative imaging technique that measures inherent T1-relaxation, T2-relaxation, and proton density. These inherent tissue properties allow synthesis of various imaging sequences from a single acquisition. Clinical use of synthetic MR imaging has been described in adult populations. However, use of synthetic MR imaging has not been previously reported in children. The purpose of this study is to report our assessment of diagnostic image quality using synthetic MR imaging in children. Synthetic MR acquisition was obtained in a sample of children undergoing brain MR imaging. Image quality assessments were performed on conventional and synthetic T1-weighted, T2-weighted, and FLAIR images. Standardized linear measurements were performed on conventional and synthetic T2 images. Estimates of patient age based upon myelination patterns were also performed. Conventional and synthetic MR images were evaluated on 30 children. Using a 4-point assessment scale, conventional imaging performed better than synthetic imaging for T1-weighted, T2-weighted, and FLAIR images. When the assessment was simplified to a dichotomized scale, the conventional and synthetic T1-weighted and T2-weighted images performed similarly. However, the superiority of conventional FLAIR images persisted in the dichotomized assessment. There were no statistically significant differences between linear measurements made on T2-weighted images. Estimates of patient age based upon pattern of myelination were also similar between conventional and synthetic techniques. Synthetic MR imaging may be acceptable for clinical use in children. However, users should be aware of current limitations that could impact clinical utility in the software version used in this study. (orig.)

  2. Feasibility, safety and image quality of cardiac FDG studies during hyperinsulinaemic-euglycaemic clamping

    International Nuclear Information System (INIS)

    Bax, Jeroen J.; Visser, Frans C.; Lingen, Arthur van; Visser, Cees A.; Poldermans, Don; Elhendy, Abdou; Boersma, Eric

    2002-01-01

    Fluorine-18 fluorodeoxyglucose (FDG) imaging for the assessment of myocardial viability has become an integral part of the diagnostic and prognostic work-up of patients with ischaemic cardiomyopathy. To ensure good image quality, in particular in patients with diabetes mellitus, hyperinsulinaemic-euglycaemic clamping has been proposed. In this study we evaluated the safety and the image quality of cardiac FDG imaging during clamping in a large group of patients, including a subgroup with diabetes mellitus. The incidence of viability (on both a segment and a patient basis) was also determined for patients with and without diabetes mellitus. The safety and image quality of cardiac FDG studies during clamping were evaluated in 131 patients, including 19 with diabetes mellitus. Image quality was assessed visually and quantitatively using heart-to-lung (H/L), heart-to-liver (H/Li) and myocardium-to-background (M/B) ratios. Blood samples were drawn at baseline and at the time of FDG injection to determine levels of glucose, free fatty acids and insulin. The metabolic circumstances were optimal for FDG imaging: high insulin levels, low free fatty acid levels and glucose levels in the normal range (levels of substrates were comparable between patients with and patients without diabetes mellitus). No serious side-effects occurred in any patient. Image quality (assessed visually) was good in all patients. The quantitative parameters of image quality (H/L, H/Li and M/B) were comparable between patients with and patients without diabetes mellitus. The incidence of viability was high: 38% of patients without and 58% of patients with diabetes mellitus had substantial viability despite contractile dysfunction. It is concluded that cardiac FDG imaging during clamping is safe and provides excellent image quality, including in patients with diabetes mellitus. The incidence of viability is high, in particular in patients with diabetes mellitus. (orig.)

  3. SEGMENTATION AND QUALITY ANALYSIS OF LONG RANGE CAPTURED IRIS IMAGE

    Directory of Open Access Journals (Sweden)

    Anand Deshpande

    2016-05-01

    Full Text Available The iris segmentation plays a major role in an iris recognition system to increase the performance of the system. This paper proposes a novel method for segmentation of iris images to extract the iris part of long range captured eye image and an approach to select best iris frame from the iris polar image sequences by analyzing the quality of iris polar images. The quality of iris image is determined by the frequency components present in the iris polar images. The experiments are carried out on CASIA-long range captured iris image sequences. The proposed segmentation method is compared with Hough transform based segmentation and it has been determined that the proposed method gives higher accuracy for segmentation than Hough transform.

  4. Engineering high quality medical software

    CERN Document Server

    Coronato, Antonio

    2018-01-01

    This book focuses on high-confidence medical software in the growing field of e-health, telecare services and health technology. It covers the development of methodologies and engineering tasks together with standards and regulations for medical software.

  5. Evaluating Picture Quality of Image Plates in Digital CR Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Byung Joon [Dept. of Radiological Tecnology, Choonhae College of Health Science, Ulsan (Korea, Republic of); Ji Tae Jeong [Dept. of Radiological Science, Kaya University, Kimhae (Korea, Republic of)

    2011-12-15

    Lab effectively supplemented the effects of outside radiation on image plates in the process of image acquisition of CR (computed radiography) systems and conducted for effective utilization in the case of clinical application. For this, Lab classified the storage places and time periods of image plates and compared and analyzed the differences between small dark spots. Lab also assessed the concentration distribution within the boundaries of images. Lab compared and measured the number of dark spots in a light room and a dark room depending on the storage places of image plates and found that dark spots slightly increased in an image plate when stored in a light room on the first and second days. Dark spots increased in proportion to the length of time stored. In the case of the image plate stored in a dark room, the number of dark spots remarkably decreased. With regard to picture quality as related to the location of image plates, the damage to picture quality could be reduced by locating regions of interest in the center. With regard to differences in sharpness following changes in the thickness of subjects, fewer scatter rays occurred and sharpness improved by reducing the thickness of subjects as much as possible. To get medical images of excellent quality, image plates should be managed effectively and it is desirable to keep images plates in dark iron plate boxes and not to expose them to outside radiation for a long time.

  6. Evaluating Picture Quality of Image Plates in Digital CR Systems

    International Nuclear Information System (INIS)

    Kwak, Byung Joon; Ji Tae Jeong

    2011-01-01

    Lab effectively supplemented the effects of outside radiation on image plates in the process of image acquisition of CR (computed radiography) systems and conducted for effective utilization in the case of clinical application. For this, Lab classified the storage places and time periods of image plates and compared and analyzed the differences between small dark spots. Lab also assessed the concentration distribution within the boundaries of images. Lab compared and measured the number of dark spots in a light room and a dark room depending on the storage places of image plates and found that dark spots slightly increased in an image plate when stored in a light room on the first and second days. Dark spots increased in proportion to the length of time stored. In the case of the image plate stored in a dark room, the number of dark spots remarkably decreased. With regard to picture quality as related to the location of image plates, the damage to picture quality could be reduced by locating regions of interest in the center. With regard to differences in sharpness following changes in the thickness of subjects, fewer scatter rays occurred and sharpness improved by reducing the thickness of subjects as much as possible. To get medical images of excellent quality, image plates should be managed effectively and it is desirable to keep images plates in dark iron plate boxes and not to expose them to outside radiation for a long time.

  7. Highly integrated image sensors enable low-cost imaging systems

    Science.gov (United States)

    Gallagher, Paul K.; Lake, Don; Chalmers, David; Hurwitz, J. E. D.

    1997-09-01

    The highest barriers to wide scale implementation of vision systems have been cost. This is closely followed by the level of difficulty of putting a complete imaging system together. As anyone who has every been in the position of creating a vision system knows, the various bits and pieces supplied by the many vendors are not under any type of standardization control. In short, unless you are an expert in imaging, electrical interfacing, computers, digital signal processing, and high speed storage techniques, you will likely spend more money trying to do it yourself rather than to buy the exceedingly expensive systems available. Another alternative is making headway into the imaging market however. The growing investment in highly integrated CMOS based imagers is addressing both the cost and the system integration difficulties. This paper discusses the benefits gained from CMOS based imaging, and how these benefits are already being applied.

  8. Correlation between image quality of CT scan and amount of intravenous contrast media

    International Nuclear Information System (INIS)

    Yoon, Dae Young; Choi, Dae Seob; Kim, Seung Hyup; Han, Joon Koo; Choi, Byung Ihn; Im, Jung Gi; Han, Moon Hee; Chang, Kee Hyun; Kim, Jong Hyo; Han, Man Chung

    1993-01-01

    A blind, comparative clinical study was performed prospectively to examine the correlation between image quality of CT scan in terms of contrast enhancement effect and amount of intravenous contrast media. A total of 357 patients were randomized into two groups. Ionic high-osmolality contrast media (68% meglumine ioglicate) was administered intravenously as 100 ml bolus in one group and as 50 ml bolus in the other group. Statistically significant differences of image quality were found in CT scans of the brain, head and neck, chest and abdomen (p 0.05). We suggest that amount of contrast media may be reduced in pelvis CT without significant degradation of image quality

  9. Dose performance and image quality: Dual source CT versus single source CT in cardiac CT angiography

    International Nuclear Information System (INIS)

    Wang Min; Qi Hengtao; Wang Ximing; Wang Tao; Chen, Jiu-Hong; Liu Cheng

    2009-01-01

    Objective: To evaluate dose performance and image quality of 64-slice dual source CT (DSCT) in comparison to 64-slice single source CT (SSCT) in cardiac CT angiography (CTA). Methods: 100 patients examined by DSCT and 60 patients scanned by SSCT were included in this study. Objective indices such as image noise, contrast-to-noise ratio and signal-to-noise ratio were analyzed. Subjective image quality was assessed by two cardiovascular radiologists in consensus using a four-point scale (1 = excellent to 4 = not acceptable). Estimation of effective dose was performed on the basis of dose length product (DLP). Results: At low heart rates ( 0.05), but, at high heart rates (>70 bpm), DSCT provided robust image quality (P 70 bpm), DSCT is able to provide robust diagnostic image quality at doses far below that of SSCT.

  10. High sensitivity optical molecular imaging system

    Science.gov (United States)

    An, Yu; Yuan, Gao; Huang, Chao; Jiang, Shixin; Zhang, Peng; Wang, Kun; Tian, Jie

    2018-02-01

    Optical Molecular Imaging (OMI) has the advantages of high sensitivity, low cost and ease of use. By labeling the regions of interest with fluorescent or bioluminescence probes, OMI can noninvasively obtain the distribution of the probes in vivo, which play the key role in cancer research, pharmacokinetics and other biological studies. In preclinical and clinical application, the image depth, resolution and sensitivity are the key factors for researchers to use OMI. In this paper, we report a high sensitivity optical molecular imaging system developed by our group, which can improve the imaging depth in phantom to nearly 5cm, high resolution at 2cm depth, and high image sensitivity. To validate the performance of the system, special designed phantom experiments and weak light detection experiment were implemented. The results shows that cooperated with high performance electron-multiplying charge coupled device (EMCCD) camera, precision design of light path system and high efficient image techniques, our OMI system can simultaneously collect the light-emitted signals generated by fluorescence molecular imaging, bioluminescence imaging, Cherenkov luminance and other optical imaging modality, and observe the internal distribution of light-emitting agents fast and accurately.

  11. Quality assessment in radiological imaging methods

    International Nuclear Information System (INIS)

    Herstel, W.

    1985-01-01

    The equipment used in diagnostic radiology is becoming more and more complicated. In the imaging process four components are distinguished, each of which can introduce loss in essential information: the X-ray source, the human body, the imaging system and the observer. In nearly all imaging methods the X-ray quantum fluctuations are a limitation to observation. But there are also technical factors. As an illustration it is shown how in a television scanning process the resolution is restricted by the system parameters. A short review is given of test devices and the results are given of an image comparison based on regular bar patterns. Although this method has the disadvantage of measuring mainly the limiting resolution, the results of the test correlate reasonably well with the subjective appreciations of radiographs of bony structures made by a group of trained radiologists. Fluoroscopic systems should preferably be tested using moving structures under dynamic conditions. (author)

  12. Optimization of shearography image quality analysis

    International Nuclear Information System (INIS)

    Rafhayudi Jamro

    2005-01-01

    Shearography is an optical technique based on speckle pattern to measure the deformation of the object surface in which the fringe pattern is obtained through the correlation analysis from the speckle pattern. Analysis of fringe pattern for engineering application is limited for qualitative measurement. Therefore, for further analysis that lead to qualitative data, series of image processing mechanism are involved. In this paper, the fringe pattern for qualitative analysis is discussed. In principal field of applications is qualitative non-destructive testing such as detecting discontinuity, defect in the material structure, locating fatigue zones and etc and all these required image processing application. In order to performed image optimisation successfully, the noise in the fringe pattern must be minimised and the fringe pattern itself must be maximise. This can be achieved by applying a filtering method with a kernel size ranging from 2 X 2 to 7 X 7 pixels size and also applying equalizer in the image processing. (Author)

  13. Testing the quality of images for permanent magnet desktop MRI systems using specially designed phantoms.

    Science.gov (United States)

    Qiu, Jianfeng; Wang, Guozhu; Min, Jiao; Wang, Xiaoyan; Wang, Pengcheng

    2013-12-21

    Our aim was to measure the performance of desktop magnetic resonance imaging (MRI) systems using specially designed phantoms, by testing imaging parameters and analysing the imaging quality. We designed multifunction phantoms with diameters of 18 and 60 mm for desktop MRI scanners in accordance with the American Association of Physicists in Medicine (AAPM) report no. 28. We scanned the phantoms with three permanent magnet 0.5 T desktop MRI systems, measured the MRI image parameters, and analysed imaging quality by comparing the data with the AAPM criteria and Chinese national standards. Image parameters included: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, signal-to-noise ratio (SNR), and image uniformity. The image parameters of three desktop MRI machines could be measured using our specially designed phantoms, and most parameters were in line with MRI quality control criterion, including: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, image uniformity and slice position accuracy. However, SNR was significantly lower than in some references. The imaging test and quality control are necessary for desktop MRI systems, and should be performed with the applicable phantom and corresponding standards.

  14. Testing the quality of images for permanent magnet desktop MRI systems using specially designed phantoms

    International Nuclear Information System (INIS)

    Qiu, Jianfeng; Wang, Guozhu; Min, Jiao; Wang, Xiaoyan; Wang, Pengcheng

    2013-01-01

    Our aim was to measure the performance of desktop magnetic resonance imaging (MRI) systems using specially designed phantoms, by testing imaging parameters and analysing the imaging quality. We designed multifunction phantoms with diameters of 18 and 60 mm for desktop MRI scanners in accordance with the American Association of Physicists in Medicine (AAPM) report no. 28. We scanned the phantoms with three permanent magnet 0.5 T desktop MRI systems, measured the MRI image parameters, and analysed imaging quality by comparing the data with the AAPM criteria and Chinese national standards. Image parameters included: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, signal-to-noise ratio (SNR), and image uniformity. The image parameters of three desktop MRI machines could be measured using our specially designed phantoms, and most parameters were in line with MRI quality control criterion, including: resonance frequency, high contrast spatial resolution, low contrast object detectability, slice thickness, geometrical distortion, image uniformity and slice position accuracy. However, SNR was significantly lower than in some references. The imaging test and quality control are necessary for desktop MRI systems, and should be performed with the applicable phantom and corresponding standards. (paper)

  15. Comparison of the perceived image quality between two digital imaging systems for neonatal bedside radiography – A case study

    International Nuclear Information System (INIS)

    Zyl, S.A. van; Kekana, R.M.

    2015-01-01

    Background: Chest X-rays are performed daily in the neonatal intensive care and high care units. The skill of the radiographer is critical for obtaining the best image quality and limiting the patient's radiation exposure. The literature states that indirect flat panel detectors produce images of superior quality in comparison to computed radiography systems. At Steve Biko Academic Hospital a decision was made to revert from the direct digital radiography (DR) system to the computed radiography (CR) system, due to poor image quality experienced. Method: The case study objective was to conduct a comparative analysis describing key technical factors contributing to image quality. The analysis entailed retrospectively comparing the images obtained during 2010 and 2011. An image analysis form was utilised in evaluating the technical aspects of the image. A total of 160 images were viewed by 16 participants sampled from the radiography, radiology and paediatric departments. The participants were asked to re-evaluate two of their allotted images after five days to determine their reliability. Results: Findings were that the DR system provides significantly better image quality than the CR system (p < 0.05) for all the technical factors evaluated. However technical improvements are recommended. A wide variance in intra-observer reliability was also found. Conclusion: This case study demonstrated that DR images were considered to be superior to CR images. Recommendations include: a standardised technique for imaging the neonates; optimisation of the imaging software for the digital detectors, improved feedback systems in terms of exposure index values, and the training of radiographers and referring physicians in technical image analysis. - Highlights: • DR system provides better image quality than the CR system for all technical factors evaluated. • The average values obtained from the VAS showed that the DR system still needs to be optimised. • There is need

  16. TH-A-16A-01: Image Quality for the Radiation Oncology Physicist: Review of the Fundamentals and Implementation

    International Nuclear Information System (INIS)

    Seibert, J; Imbergamo, P

    2014-01-01

    The expansion and integration of diagnostic imaging technologies such as On Board Imaging (OBI) and Cone Beam Computed Tomography (CBCT) into radiation oncology has required radiation oncology physicists to be responsible for and become familiar with assessing image quality. Unfortunately many radiation oncology physicists have had little or no training or experience in measuring and assessing image quality. Many physicists have turned to automated QA analysis software without having a fundamental understanding of image quality measures. This session will review the basic image quality measures of imaging technologies used in the radiation oncology clinic, such as low contrast resolution, high contrast resolution, uniformity, noise, and contrast scale, and how to measure and assess them in a meaningful way. Additionally a discussion of the implementation of an image quality assurance program in compliance with Task Group recommendations will be presented along with the advantages and disadvantages of automated analysis methods. Learning Objectives: Review and understanding of the fundamentals of image quality. Review and understanding of the basic image quality measures of imaging modalities used in the radiation oncology clinic. Understand how to implement an image quality assurance program and to assess basic image quality measures in a meaningful way

  17. Automatic analysis of quality of images from X-ray digital flat detectors

    International Nuclear Information System (INIS)

    Le Meur, Y.

    2009-04-01

    Since last decade, medical imaging has grown up with the development of new digital imaging techniques. In the field of X-ray radiography, new detectors replace progressively older techniques, based on film or x-ray intensifiers. These digital detectors offer a higher sensibility and reduced overall dimensions. This work has been prepared with Trixell, the world leading company in flat detectors for medical radiography. It deals with quality control on digital images stemming from these detectors. High quality standards of medical imaging impose a close analysis of the defects that can appear on the images. This work describes a complete process for quality analysis of such images. A particular focus is given on the detection task of the defects, thanks to methods well adapted to our context of spatially correlated defects in noise background. (author)

  18. Near-infrared hyperspectral imaging for quality analysis of agricultural and food products

    Science.gov (United States)

    Singh, C. B.; Jayas, D. S.; Paliwal, J.; White, N. D. G.

    2010-04-01

    Agricultural and food processing industries are always looking to implement real-time quality monitoring techniques as a part of good manufacturing practices (GMPs) to ensure high-quality and safety of their products. Near-infrared (NIR) hyperspectral imaging is gaining popularity as a powerful non-destructive tool for quality analysis of several agricultural and food products. This technique has the ability to analyse spectral data in a spatially resolved manner (i.e., each pixel in the image has its own spectrum) by applying both conventional image processing and chemometric tools used in spectral analyses. Hyperspectral imaging technique has demonstrated potential in detecting defects and contaminants in meats, fruits, cereals, and processed food products. This paper discusses the methodology of hyperspectral imaging in terms of hardware, software, calibration, data acquisition and compression, and development of prediction and classification algorithms and it presents a thorough review of the current applications of hyperspectral imaging in the analyses of agricultural and food products.

  19. Liver imaging with MDCT and high concentration contrast media

    International Nuclear Information System (INIS)

    Spielmann, Audrey L.

    2003-01-01

    Liver imaging has advanced greatly over the last 10 years with helical CT capability and more recently the addition of multidetector-row CT (MDCT). Multidetector CT technology facilitates imaging at faster speeds with improved image quality and less breathing artifact [Abdom. Imaging 25 (2000) 643]. Exquisite three-dimensional data sets can be obtained with thin collimation providing improved lesion detection, multiplanar imaging, and the ability to perform CT angiography of the liver and mesenteric vessels. New challenges arise with this advance in technology including safety considerations. The radiation dose to the patient has increased with MDCT and this is compounded by the ability to perform multi-phase liver imaging. Furthermore, issues of contrast media administration require reconsideration including optimal timing and rate of administration, the total volume of contrast needed and the ideal iodine concentration of the contrast media. Recently, the use of high concentration contrast media (HCCM) has been explored and study results to date will be reviewed

  20. Using Adobe Acrobat to create high-resolution line art images.

    Science.gov (United States)

    Woo, Hyoun Sik; Lee, Jeong Min

    2009-08-01

    The purpose of this article is to introduce a method for using Adobe Acrobat to make high-resolution and high-quality line art images. High-resolution and high-quality line art images for radiology journal submission can be generated using Adobe Acrobat as a steppingstone, and the customized PDF conversion settings can be used for converting hybrid images, including both bitmap and vector components.

  1. X-ray Computed Tomography Image Quality Indicator (IQI) Development

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase one of the program is to identify suitable x-ray Computed Tomography (CT) Image Quality Indicator (IQI) design(s) that can be used to adequately capture CT...

  2. Image quality measurements for X-ray television chains

    International Nuclear Information System (INIS)

    Mohr, M.

    1986-01-01

    Image quality measurements were carried out for 36 television chains during 3 years. For the parameters sensitivity, resolution, contrast-detail diagram, minimal contrast and dose rate average values and experiences on their long-term stability are reported. (author)

  3. Survey of image quality and patient dose for computed tomography

    International Nuclear Information System (INIS)

    Augusto, Fernando Mecca

    2009-01-01

    The aim of this work is to evaluate the dose index and the image quality in seventeen computed tomography scanners installed in radiology departments at the city of Rio de Janeiro. The American College of Radiology (ACR) accreditation phantom (Gammex, 464) was used for the image quality evaluation. The following parameters were investigated according to the procedure manual of the ACR phantom: CT number calibration, exactitude of the slice thickness, low and high contrast resolution, uniformity, noise and artifacts. Despite of the CT number accuracy, only one scanner passed in the test. The low contrast resolution and the uniformity criteria were not accomplished in two different scanners. The conformity for the criteria established for slice width and high contrast was not verified in 16% and 11 % of the equipment respectively. The noise, expressed as a standard deviation measured in the center of the image in an adult abdomen protocol, ranged from 2.8 to 9.5. The ACR criteria of the accreditation program were not accomplished in the sample evaluated. Some parameters failed are essential to assure the diagnostic accuracy. For the head scans CTDI 100,VOL values varied between 9 and 109 mGy and the DLP from 160 to 2000 mGy cm for adults. Values for abdomen scans varied between 8 and 94 mGy and the DLP from 180 to 3700 mGy cm for adults, and CTDI 100,VOL from 3 to 54 mGy and DLP from 46 to 1300 mGy cm for children. Similar ranges were found for hi-resolution chest scans. These results are compatibles with those from reported literature and indicate a large potential for optimization and dose reduction, specially in pediatric patients. (author)

  4. Dosimetry and image quality assessment in a direct radiography system

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Bruno Beraldo; Paixao, Lucas; Nogueira, Maria do Socorro, E-mail: boliveira.mg@gmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Oliveira, Marcio Alves de [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Fac. de Medicina. Dept. de Anatomia e Imagem; Teixeira, Maria Helena Araujo [Clinica Dra. Maria Helena Araujo Teixeira, Belo Horizonte, MG (Brazil)

    2014-11-15

    Objective: to evaluate the mean glandular dose with a solid state detector and the image quality in a direct radiography system, utilizing phantoms. Materials and methods: Irradiations were performed with automatic exposure control and polymethyl methacrylate slabs with different thicknesses to calculate glandular dose values. The image quality was evaluated by means of the structures visualized on the images of the phantoms. Results: considering the uncertainty of the measurements, the mean glandular dose results are in agreement with the values provided by the equipment and with internationally adopted reference levels. Results obtained from images of the phantoms were in agreement with the reference values. Conclusion: the present study contributes to verify the equipment conformity as regards dose values and image quality. (author)

  5. High contrast two-photon imaging of fingermarks

    Science.gov (United States)

    Stoltzfus, Caleb R.; Rebane, Aleksander

    2016-04-01

    Optically-acquired fingermarks are widely used as evidence across law enforcement agencies as well as in the courts of law. A common technique for visualizing latent fingermarks on nonporous surfaces consists of cyanoacrylate fuming of the fingerprint material, followed by impregnation with a fluorescent dye, which under ultra violet (UV) illumination makes the fingermarks visible and thus accessible for digital recording. However, there exist critical circumstances, when the image quality is compromised due to high background scattering, high auto-fluorescence of the substrate material, or other detrimental photo-physical and photo-chemical effects such as light-induced damage to the sample. Here we present a novel near-infrared (NIR), two-photon induced fluorescence imaging modality, which significantly enhances the quality of the fingermark images, especially when obtained from highly reflective and/or scattering surfaces, while at the same time reducing photo-damage to sensitive forensic samples.

  6. Image processor for high resolution video

    International Nuclear Information System (INIS)

    Pessoa, P.P.; Assis, J.T.; Cardoso, S.B.; Lopes, R.T.

    1989-01-01

    In this paper, we discuss an image presentation and processing system developed in Turbo Pascal 5.0 Language. Our system allows the visualization and processing of images in 16 different colors, taken at a time from a set of 64 possible ones. Digital filters of the mean, mediam Laplacian, gradient and histograms equalization type have been implemented, so as to allow a better image quality. Possible applications of our system are also discussed e.g., satellites, computerized tomography, medicine, microscopes. (author) [pt

  7. Naturalness and image quality : saturation and lightness variation in color images of natural scenes

    NARCIS (Netherlands)

    Ridder, de H.

    1996-01-01

    The relation between perceived image quality and naturalness was investigated by varying the colorfulness of natural images at various lightness levels. At each lightness level, subjects assessed perceived colorfulness, naturalness, and quality as a function of average saturation by means of direct

  8. MATLAB-based Applications for Image Processing and Image Quality Assessment – Part II: Experimental Results

    Directory of Open Access Journals (Sweden)

    L. Krasula

    2012-04-01

    Full Text Available The paper provides an overview of some possible usage of the software described in the Part I. It contains the real examples of image quality improvement, distortion simulations, objective and subjective quality assessment and other ways of image processing that can be obtained by the individual applications.

  9. Relationship among RR interval, optimal reconstruction phase, temporal resolution, and image quality of end-systolic reconstruction of coronary CT angiography in patients with high heart rates. In search of the optimal acquisition protocol

    International Nuclear Information System (INIS)

    Sano, Tomonari; Matsutani, Hideyuki; Kondo, Takeshi; Fujimoto, Shinichiro; Sekine, Takako; Arai, Takehiro; Morita, Hitomi; Takase, Shinichi

    2011-01-01

    The purpose of this study is to elucidate the relationship among RR interval (RR), the optimal reconstruction phase, and adequate temporal resolution (TR) to obtain coronary CT angiography images of acceptable quality using 64-multi detector-row CT (MDCT) (Aquilion 64) of end-systolic reconstruction in 407 patients with high heart rates. Image quality was classified into 3 groups [rank A (excellent): 161, rank B (acceptable): 207, and rank C (unacceptable): 39 patients]. The optimal absolute phase (OAP) significantly correlated with RR [OAP (ms)=119-0.286 RR (ms), r=0.832, p<0.0001], and the optimal relative phase (ORP) also significantly correlated with RR [ORP (%)=62-0.023 RR (ms), r=0.656, p<0.0001], and the correlation coefficient of OAP was significantly (p<0.0001) higher than that of ORP. The OAP range (±2 standard deviation (SD)) in which it is highly possible to get a static image was from [119-0.286 RR (ms)-46] to [119-0.286 RR (ms)+46]. The TR was significantly different among ranks A (97±22 ms), B (111±31 ms) and C (135±34 ms). The TR significantly correlated with RR in ranks A (TR=-16+0.149 RR, r=0.767, p<0.0001), B (TR=-15+0.166 RR, r=0.646, p<0.0001), and C (TR=52+0.117 RR, r=0.425, p=0.0069). Rank C was distinguished from ranks A or B by linear discriminate analysis (TR=-46+0.21 RR), and the discriminate rate was 82.6%. In conclusion, both the OAP and adequate TR depend on RR, and the OAP range (±2 SD) can be calculated using the formula [119-0.286 RR (ms)-46] to [119-0.286 RR (ms) +46], and an adequate TR value would be less than (-46+0.21 RR). (author)

  10. Improved radionuclide bone imaging agent injection needle withdrawal method can improve image quality

    International Nuclear Information System (INIS)

    Qin Yongmei; Wang Laihao; Zhao Lihua; Guo Xiaogang; Kong Qingfeng

    2009-01-01

    Objective: To investigate the improvement of radionuclide bone imaging agent injection needle withdrawal method on whole body bone scan image quality. Methods: Elbow vein injection syringe needle directly into the bone imaging agent in the routine group of 117 cases, with a cotton swab needle injection method for the rapid pull out the needle puncture point pressing, pressing moment. Improvement of 117 cases of needle injection method to put two needles into the skin swabs and blood vessels, pull out the needle while pressing two or more entry point 5min. After 2 hours underwent whole body bone SPECT imaging plane. Results: The conventional group at the injection site imaging agents uptake rate was 16.24%, improved group was 2.56%. Conclusion: The modified bone imaging agent injection needle withdrawal method, injection-site imaging agent uptake were significantly decreased whole body bone imaging can improve image quality. (authors)

  11. Applying image quality in cell phone cameras: lens distortion

    Science.gov (United States)

    Baxter, Donald; Goma, Sergio R.; Aleksic, Milivoje

    2009-01-01

    This paper describes the framework used in one of the pilot studies run under the I3A CPIQ initiative to quantify overall image quality in cell-phone cameras. The framework is based on a multivariate formalism which tries to predict overall image quality from individual image quality attributes and was validated in a CPIQ pilot program. The pilot study focuses on image quality distortions introduced in the optical path of a cell-phone camera, which may or may not be corrected in the image processing path. The assumption is that the captured image used is JPEG compressed and the cellphone camera is set to 'auto' mode. As the used framework requires that the individual attributes to be relatively perceptually orthogonal, in the pilot study, the attributes used are lens geometric distortion (LGD) and lateral chromatic aberrations (LCA). The goal of this paper is to present the framework of this pilot project starting with the definition of the individual attributes, up to their quantification in JNDs of quality, a requirement of the multivariate formalism, therefore both objective and subjective evaluations were used. A major distinction in the objective part from the 'DSC imaging world' is that the LCA/LGD distortions found in cell-phone cameras, rarely exhibit radial behavior, therefore a radial mapping/modeling cannot be used in this case.

  12. Blind image quality assessment based on aesthetic and statistical quality-aware features

    Science.gov (United States)

    Jenadeleh, Mohsen; Masaeli, Mohammad Masood; Moghaddam, Mohsen Ebrahimi

    2017-07-01

    The main goal of image quality assessment (IQA) methods is the emulation of human perceptual image quality judgments. Therefore, the correlation between objective scores of these methods with human perceptual scores is considered as their performance metric. Human judgment of the image quality implicitly includes many factors when assessing perceptual image qualities such as aesthetics, semantics, context, and various types of visual distortions. The main idea of this paper is to use a host of features that are commonly employed in image aesthetics assessment in order to improve blind image quality assessment (BIQA) methods accuracy. We propose an approach that enriches the features of BIQA methods by integrating a host of aesthetics image features with the features of natural image statistics derived from multiple domains. The proposed features have been used for augmenting five different state-of-the-art BIQA methods, which use statistical natural scene statistics features. Experiments were performed on seven benchmark image quality databases. The experimental results showed significant improvement of the accuracy of the methods.

  13. Decision theory on the quality evaluation of medical images

    International Nuclear Information System (INIS)

    Lessa, Patricia Silva

    2001-10-01

    The problem of quality has been a constant issue in every organization.One is always seeking to produce more, to do it at a lower cost, and to do it with better quality. However, in this country, there is no radiographic film quality control system for radiographic services. The tittle that actually gets done is essentially ad hoc and superficial. The implications of this gap, along with some other shortcomings that exist in process as a whole (the state of the x-ray equipment, the adequate to use in order to obtain a radiography, the quality of the film, the processing of the film, the brightness and homogeneity of the viewing boxes, the ability of the radiologist), have a very negative impact on the quality of the medical image, and, as result, to the quality of the medical diagnosis and therapy. It frequently happens that many radiographs have to be repeated, which leads to an increase of the patient's exposure to radiation, as well as of the cost of the procedure for the patient. Low quality radiographs that are not repeated greatly increase the probability of a wrong diagnosis, and consequently, of inadequate therapeutical procedures, thus producing increased incidence of bad outcomes and higher costs. The paradigm proposed in order to establish a system for the measurement of the image's quality is Decision Theory. The problem of the assessment of the image is studied by proposing a Decision Theory approach. The review of the literature reveals a great concern with the quality of the image, along with an absence of an adequate paradigm and several essentially empirical procedures. Image parameters are developed in order to formalize the problem in terms of Decision Theory, and various aspects of image digitalisation are exposed. Finally, a solution is presented, including a protocol for quality control. (author)

  14. High frame rate synthetic aperture duplex imaging

    DEFF Research Database (Denmark)

    Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Pihl, Michael Johannes

    2013-01-01

    aperture flow imaging as demonstrated in this paper. Synthetic aperture, directional beamforming, and cross-correlation are used to produce B-mode and vector velocity images at high frame rates. The frame rate equals the effective pulse repetition frequency of each imaging mode. Emissions for making the B...... estimation is −1.8% and the relative standard deviation 5.4%. The approach can thus estimate both high and low velocities with equal accuracy and thereby makes it possible to present vector flow images with a high dynamic range. Measurements are made using the SARUS research scanner, a linear array......Conventional color flow images are limited in velocity range and can either show the high velocities in systole or be optimized for the lower diastolic velocities. The full dynamics of the flow is, thus, hard to visualize. The dynamic range can be significantly increased by employing synthetic...

  15. Source position error influence on industry CT image quality

    International Nuclear Information System (INIS)

    Cong Peng; Li Zhipeng; Wu Haifeng

    2004-01-01

    Based on the emulational exercise, the influence of source position error on industry CT (ICT) image quality was studied and the valuable parameters were obtained for the design of ICT. The vivid container CT image was also acquired from the CT testing system. (authors)

  16. An image quality comparison study between XVI and OBI CBCT systems.

    Science.gov (United States)

    Kamath, Srijit; Song, William; Chvetsov, Alexei; Ozawa, Shuichi; Lu, Haibin; Samant, Sanjiv; Liu, Chihray; Li, Jonathan G; Palta, Jatinder R

    2011-02-04

    The purpose of this study is to evaluate and compare image quality characteristics for two commonly used and commercially available CBCT systems: the X-ray Volumetric Imager and the On-Board Imager. A commonly used CATPHAN image quality phantom was used to measure various image quality parameters, namely, pixel value stability and accuracy, noise, contrast to noise ratio (CNR), high-contrast resolution, low contrast resolution and image uniformity. For the XVI unit, we evaluated the image quality for four manufacturer-supplied protocols as a function of mAs. For the OBI unit, we did the same for the full-fan and half-fan scanning modes, which were respectively used with the full bow-tie and half bow-tie filters. For XVI, the mean pixel values of regions of interest were found to generally decrease with increasing mAs for all protocols, while they were relatively stable with mAs for OBI. Noise was slightly lower on XVI and was seen to decrease with increasing mAs, while CNR increased with mAs for both systems. For XVI and OBI, the high-contrast resolution was approximately limited by the pixel resolution of the reconstructed image. On OBI images, up to 6 and 5 discs of 1% and 0.5% contrast, respectively, were visible for a high mAs setting using the full-fan mode, while none of the discs were clearly visible on the XVI images for various mAs settings when the medium resolution reconstruction was used. In conclusion, image quality parameters for XVI and OBI have been quantified and compared for clinical protocols under various mAs settings. These results need to be viewed in the context of a recent study that reported the dose-mAs relationship for the two systems and found that OBI generally delivered higher imaging doses than XVI.

  17. Quality control in diagnostic mammography: myths, realities and their importance in the final image quality

    International Nuclear Information System (INIS)

    Mora Rodriguez, Patricia

    2011-01-01

    Mammography is the most used tool for early detection of breast cancer and reduce mortality from this cause. Studies with ionizing radiation it is important that be justified and provide a quality image to make the diagnosis, to get more benefits and fewer risks. The problem is the difficult to obtain an image of the breast. Therefore, the commitment to quality mammography is to maximize the contrast, definition, resolution and reliability, thus minimizing noise and dose. A mammogram performed without quality don't detect early breast cancer and the study doesn't have sense. Quality mammography requires trained and experienced staff, modern equipment and in good conditions, correct positioning, right technical factors and appropriate viewing conditions. In addition, quality programs are required to reach to ensure quality, control in testing techniques and image quality. (author) [es

  18. Quality Assurance By Laser Scanning And Imaging Techniques

    Science.gov (United States)

    SchmalfuB, Harald J.; Schinner, Karl Ludwig

    1989-03-01

    Laser scanning systems are well established in the world of fast industrial in-process quality inspection systems. The materials inspected by laser scanning systems are e.g. "endless" sheets of steel, paper, textile, film or foils. The web width varies from 50 mm up to 5000 mm or more. The web speed depends strongly on the production process and can reach several hundred meters per minute. The continuous data flow in one of different channels of the optical receiving system exceeds ten Megapixels/sec. Therefore it is clear that the electronic evaluation system has to process these data streams in real time and no image storage is possible. But sometimes (e.g. first installation of the system, change of the defect classification) it would be very helpful to have the possibility for a visual look on the original, i.e. not processed sensor data. At first we show the principle set up of a standard laser scanning system. Then we will introduce a large image memory especially designed for the needs of high-speed inspection sensors. This image memory co-operates with the standard on-line evaluation electronics and provides therefore an easy comparison between processed and non-processed data. We will discuss the basic system structure and we will show the first industrial results.

  19. The Image Quality Translator – A Way to Support Specification of Imaging Requirements

    DEFF Research Database (Denmark)

    Kejser, Ulla Bøgvad; Bech, Mogens

    2015-01-01

    Archives, libraries, and museums run numerous imaging projects to digitize physical works and collections of cultural heritage. This study presents a tool called the 'Image Quality Translator' that is being designed at the Royal Library to support the planning of digitization projects and to make...... the process of specifying and controlling imaging requirements more efficient. The tool seeks to translate between the language used by collection managers and curators to express needs for image quality, and the more technical terms and metrics used by imaging experts and photographers to express...

  20. Image quality analysis of vibration effects In C-arm-flat panel X-ray imaging

    NARCIS (Netherlands)

    Snoeren, R.M.; Kroon, J.N.; With, de P.H.N.

    2011-01-01

    The motion of C-arm scanning X-ray systems may result in vibrations of the imaging sub-system. In this paper, we connect C-arm system vibrations to Image Quality (IQ) deterioration for 2D angiography and 3D cone beam X-ray imaging, using large Flat Panel detectors. Vibrations will affect the

  1. Naturalness and image quality : chroma and hue variation in color images of natural scenes

    NARCIS (Netherlands)

    Ridder, de H.; Blommaert, F.J.J.; Fedorovskaya, E.A.; Rogowitz, B.E.; Allebach, J.P.

    1995-01-01

    The relation between perceptual image quality and naturalness was investigated by varying the colorfulness and hue of color images of natural scenes. These variations were created by digitizing the images, subsequently determining their color point distributions in the CIELUV color space and finally

  2. Naturalness and image quality: Chroma and hue variation in color images of natural scenes

    NARCIS (Netherlands)

    Ridder, de H.; Blommaert, F.J.J.; Fedorovskaya, E.A.; Eschbach, R.; Braun, K.

    1997-01-01

    The relation between perceptual image quality and natural ness was investigated by varying the colorfulness and hue of color images of natural scenes. These variations were created by digitizing the images, subsequently determining their color point distributions in the CIELUV color space and

  3. Quality management manual for production of high quality cassava flour

    DEFF Research Database (Denmark)

    Dziedzoave, Nanam Tay; Abass, Adebayo Busura; Amoa-Awua, Wisdom K.

    The high quality cassava flour (HQCF) industry has just started to evolve in Africa and elsewhere. The sustainability of the growing industry, the profitability of small- and medium-scale enterprises (SMEs) that are active in the industry and good-health of consumers can best be guaranteed through...... the adoption of proper quality and food safety procedures. Cassava processing enterprises involved in the productionof HQCF must therefore be commited to the quality and food safety of the HQCF. They must have the right technology, appropriate processing machhinery, standard testing instruments...... and the necessary technical expertise. This quality manual was therefore developed to guide small- to medium-scale cassava in the design and implematation of Hazard Analysis Critical Control Point (HACCP) system and Good manufacturing Practices (GMP) plans for HQCF production. It describes the HQCF production...

  4. Deep learning for objective quality assessment of 3D images

    NARCIS (Netherlands)

    Mocanu, D.C.; Exarchakos, G.; Liotta, A.

    2014-01-01

    Improving the users' Quality of Experience (QoE) in modern 3D Multimedia Systems is a challenging proposition, mainly due to our limited knowledge of 3D image Quality Assessment algorithms. While subjective QoE methods would better reflect the nature of human perception, these are not suitable in

  5. Inter-observer variation in masked and unmasked images for quality evaluation of clinical radiographs

    International Nuclear Information System (INIS)

    Tingberg, A.; Eriksson, F.; Medin, J.; Besjakov, J.; Baarth, M.; Haakansson, M.; Sandborg, M.; Almen, A.; Lanhede, B.; Alm-Carlsson, G.; Mattsson, S.; Maansson, L. G.

    2005-01-01

    Purpose: To investigate the influence of masking on the inter-observer variation in image quality evaluation of clinical radiographs of chest and lumbar spine. Background: Inter-observer variation is a big problem in image quality evaluation since this variation is often much bigger than the variation in image quality between, for example, two radiographic systems. In this study, we have evaluated the effect of masking on the inter-observer variation. The idea of the masking was to force every observer to view exactly the same part of the image and to avoid the effect of the overall 'first impression' of the image. A discussion with a group of European expert radiologists before the study indicated that masking might be a good way to reduce the inter-observer variation. Methods: Five chest and five lumbar spine radiographs were collected together with detailed information regarding exposure conditions. The radiographs were digitised with a high-performance scanner and five different manipulations were performed, simulating five different exposure conditions. The contrast, noise and spatial resolution were manipulated by this method. The images were printed onto the film and the individual masks were produced for each film, showing only the parts of the images that were necessary for the image quality evaluation. The quality of the images was evaluated on ordinary viewing boxes by a large group of experienced radiologists. The images were examined with and without the masks with a set of image criteria (if fulfilled, 1 point; and not fulfilled, 0 point), and the mean score was calculated for each simulated exposure condition. Results: The results of this study indicate that - contrary to what was supposed - the inter-observer variation increased when the images were masked. In some cases, especially for chest, this increase was statistically significant. Conclusions: Based on the results of this study, image masking in studies of fulfilment of image criteria cannot

  6. High spatial resolution free-breathing 3D late gadolinium enhancement cardiac magnetic resonance imaging in ischaemic and non-ischaemic cardiomyopathy: quantitative assessment of scar mass and image quality.

    Science.gov (United States)

    Bizino, Maurice B; Tao, Qian; Amersfoort, Jacob; Siebelink, Hans-Marc J; van den Bogaard, Pieter J; van der Geest, Rob J; Lamb, Hildo J

    2018-04-06

    To compare breath-hold (BH) with navigated free-breathing (FB) 3D late gadolinium enhancement cardiac MRI (LGE-CMR) MATERIALS AND METHODS: Fifty-one patients were retrospectively included (34 ischaemic cardiomyopathy, 14 non-ischaemic cardiomyopathy, three discarded). BH and FB 3D phase sensitive inversion recovery sequences were performed at 3T. FB datasets were reformatted into normal resolution (FB-NR, 1.46x1.46x10mm) and high resolution (FB-HR, isotropic 0.91-mm voxels). Scar mass, scar edge sharpness (SES), SNR and CNR were compared using paired-samples t-test, Pearson correlation and Bland-Altman analysis. Scar mass was similar in BH and FB-NR (mean ± SD: 15.5±18.0 g vs. 15.5±16.9 g, p=0.997), with good correlation (r=0.953), and no bias (mean difference ± SD: 0.00±5.47 g). FB-NR significantly overestimated scar mass compared with FB-HR (15.5±16.9 g vs 14.4±15.6 g; p=0.007). FB-NR and FB-HR correlated well (r=0.988), but Bland-Altman demonstrated systematic bias (1.15±2.84 g). SES was similar in BH and FB-NR (p=0.947), but significantly higher in FB-HR than FB-NR (pFB-NR (pFB-HR than FB-NR (p<0.01). Navigated free-breathing 3D LGE-CMR allows reliable scar mass quantification comparable to breath-hold. During free-breathing, spatial resolution can be increased resulting in improved sharpness and reduced scar mass. • Navigated free-breathing 3D late gadolinium enhancement is reliable for myocardial scar quantification. • High-resolution 3D late gadolinium enhancement increases scar sharpness • Ischaemic and non-ischaemic cardiomyopathy patients can be imaged using free-breathing LGE CMR.

  7. High quality-factor optical resonators

    International Nuclear Information System (INIS)

    Henriet, Rémi; Salzenstein, Patrice; Coillet, Aurélien; Saleh, Khaldoun; Chembo, Yanne K; Ristic, Davor; Ferrari, Maurizio; Mortier, Michel; Rasoloniaina, Alphonse; Dumeige, Yannick; Féron, Patrice; Cibiel, Gilles; Llopis, Olivier

    2014-01-01

    Various resonators are investigated for microwave photonic applications. Micro-sphere, disk and fiber ring resonators were designed, realized and characterized. Obtained quality factors are as high as Q = 10 10 . (paper)

  8. Cone beam computed tomography radiation dose and image quality assessments.

    Science.gov (United States)

    Lofthag-Hansen, Sara

    2010-01-01

    Diagnostic radiology has undergone profound changes in the last 30 years. New technologies are available to the dental field, cone beam computed tomography (CBCT) as one of the most important. CBCT is a catch-all term for a technology comprising a variety of machines differing in many respects: patient positioning, volume size (FOV), radiation quality, image capturing and reconstruction, image resolution and radiation dose. When new technology is introduced one must make sure that diagnostic accuracy is better or at least as good as the one it can be expected to replace. The CBCT brand tested was two versions of Accuitomo (Morita, Japan): 3D Accuitomo with an image intensifier as detector, FOV 3 cm x 4 cm and 3D Accuitomo FPD with a flat panel detector, FOVs 4 cm x 4 cm and 6 cm x 6 cm. The 3D Accuitomo was compared with intra-oral radiography for endodontic diagnosis in 35 patients with 46 teeth analyzed, of which 41 were endodontically treated. Three observers assessed the images by consensus. The result showed that CBCT imaging was superior with a higher number of teeth diagnosed with periapical lesions (42 vs 32 teeth). When evaluating 3D Accuitomo examinations in the posterior mandible in 30 patients, visibility of marginal bone crest and mandibular canal, important anatomic structures for implant planning, was high with good observer agreement among seven observers. Radiographic techniques have to be evaluated concerning radiation dose, which requires well-defined and easy-to-use methods. Two methods: CT dose index (CTDI), prevailing method for CT units, and dose-area product (DAP) were evaluated for calculating effective dose (E) for both units. An asymmetric dose distribution was revealed when a clinical situation was simulated. Hence, the CTDI method was not applicable for these units with small FOVs. Based on DAP values from 90 patient examinations effective dose was estimated for three diagnostic tasks: implant planning in posterior mandible and

  9. Mammography practice in Serbia: Evaluation and optimisation of image quality and the technical aspects of the mammographic imaging chain

    International Nuclear Information System (INIS)

    Kosutic, D.; Ciraj-Bjelac, O.; Arandjic, D.

    2010-01-01

    The purpose of this work was to assess mammography practice in Serbia and its appropriateness for both diagnostic service and potential screening by implementing quality control (QC) protocol in three large teaching hospitals. Corrective actions were suggested, accordingly. In addition to technical aspects of QC, image quality was assessed using image grading before and after the introduction of corrective measures. The survey demonstrated considerable variations in technical parameters that affect image quality and patients doses. Average glandular doses ranged from 1.8 to 2.8 mGy, while reference optical density (OD) ranged from 1.0 to 2.6. Image grading resulted in a very high percentage of images with poor quality (12-70% for cranio-caudal projection and 8-66% for medio-lateral oblique projection). Main problems were associated with film processing, viewing conditions and OD control. Following introduction of corrective measures, the image grading results were improved in some hospitals, so the percentage of images without any remarks has been increased. (authors)

  10. Pre-analytic process control: projecting a quality image.

    Science.gov (United States)

    Serafin, Mark D

    2006-09-26

    Within the health-care system, the term "ancillary department" often describes the laboratory. Thus, laboratories may find it difficult to define their image and with it, customer perception of department quality. Regulatory requirements give laboratories who so desire an elegant way to address image and perception issues--a comprehensive pre-analytic system solution. Since large laboratories use such systems--laboratory service manuals--I describe and illustrate the process for the benefit of smaller facilities. There exist resources to help even small laboratories produce a professional service manual--an elegant solution to image and customer perception of quality.

  11. Image quality in CT perfusion imaging of the brain. The role of iodine concentration

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, Matthias; Bueltmann, Eva; Bode-Schnurbus, Lucas; Koenen, Dirk; Mielke, Eckhart; Heuser, Lothar [Knappschaftskrankenhaus Langendreer, Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Ruhr-University Bochum, Bochum (Germany)

    2007-01-15

    The purpose of this study was to evaluate the impact of various iodine contrast concentrations on image quality in computed tomography (CT) perfusion studies. Twenty-one patients with suspicion of cerebral ischemia underwent perfusion CT using two different iodine contrast concentrations: 11 patients received iomeprol 300 (iodine concentration: 300 mg/ml) while ten received the same volume of iomeprol 400 (iodine concentration: 400 mg/ml). Scan parameters were kept constant for both groups. Maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and time to peak (TTP) were calculated from two adjacent slices. Quantitative comparisons were based on measurements of the maximum enhancement [Hounsfield units (HU)] and signal-to-noise index (SNI) on CBF, CBV, and TTP images. Determinations of grey-to-white-matter delineation for each iodine concentration were performed by two blinded readers. Only data from the non-ischemic hemispheres were considered. Both maximum enhancement and SNI values were higher after iomeprol 400, resulting in significantly better image quality in areas of low perfusion. No noteworthy differences were found for normal values of CBF, CBV, and TTP. Qualitative assessment of grey/white matter contrast on CBF and CBV maps revealed better performance for iomeprol 400. For brain perfusion studies, highly concentrated contrast media such as iomeprol 400 is superior to iomeprol 300. (orig.)

  12. MRI quality assurance using the ACR phantom in a multi-unit imaging center

    International Nuclear Information System (INIS)

    Ihalainen, Toni M.; Kuusela, Linda J.; Savolainen, Sauli E.; Loennroth, Nadja T.; Peltonen, Juha I.; Uusi-Simola, Jouni K.; Timonen, Marjut H.; Sipilae, Outi E.

    2011-01-01

    Background. Magnetic resonance imaging (MRI) instrumentation is vulnerable to technical and image quality problems, and quality assurance is essential. In the studied regional imaging center the long-term quality assurance has been based on MagNET phantom measurements. American College of Radiology (ACR) has an accreditation program including a standardized image quality measurement protocol and phantom. The ACR protocol includes recommended acceptance criteria for clinical sequences and thus provides possibility to assess the clinical relevance of quality assurance. The purpose of this study was to test the ACR MRI phantom in quality assurance of a multi-unit imaging center. Material and methods. The imaging center operates 11 MRI systems of three major manufacturers with field strengths of 3.0 T, 1.5 T and 1.0 T. Images of the ACR phantom were acquired using a head coil following the ACR scanning instructions. Both ACR T1- and T2-weighted sequences as well as T1- and T2-weighted brain sequences in clinical use at each site were acquired. Measurements were performed twice. The images were analyzed and the results were compared with the ACR acceptance levels. Results. The acquisition procedure with the ACR phantom was faster than with the MagNET phantoms. On the first and second measurement rounds 91% and 73% of the systems passed the ACR test. Measured slice thickness accuracies were not within the acceptance limits in site T2 sequences. Differences in the high contrast spatial resolution between the ACR and the site sequences were observed. In 3.0 T systems the image intensity uniformity was slightly lower than the ACR acceptance limit. Conclusion. The ACR method was feasible in quality assurance of a multi-unit imaging center and the ACR protocol could replace the MagNET phantom tests. An automatic analysis of the images will further improve cost-effectiveness and objectiveness of the ACR protocol

  13. Selecting optimal monochromatic level with spectral CT imaging for improving imaging quality in hepatic venography

    International Nuclear Information System (INIS)

    Sun Jun; Luo Xianfu; Wang Shou'an; Wang Jun; Sun Jiquan; Wang Zhijun; Wu Jingtao

    2013-01-01

    Objective: To investigate the effect of spectral CT monochromatic images for improving imaging quality in hepatic venography. Methods: Thirty patients underwent spectral CT examination on a GE Discovery CT 750 HD scanner. During portal phase, 1.25 mm slice thickness polychromatic images and optimal monochromatic images were obtained, and volume rendering and maximum intensity projection were created to show the hepatic veins respectively. The overall imaging quality was evaluated on a five-point scale by two radiologists. Inter-observer agreement in subjective image quality grading was assessed by Kappa statistics. Paired-sample t test were used to compare hepatic vein attenuation, hepatic parenchyma attenuation, CT value difference between the hepatic vein and the liver parenchyma, image noise, vein-to-liver contrast-to-noise ratio (CNR), the image quality score of hepatic venography between the two image data sets. Results: The monochromatic images at 50 keV were found to demonstrate the best CNR for hepatic vein.The hepatic vein attenuation [(329 ± 47) HU], hepatic parenchyma attenuation [(178 ± 33) HU], CT value difference between the hepatic vein and the liver parenchyma [(151 ± 33) HU], image noise (17.33 ± 4.18), CNR (9.13 ± 2.65), the image quality score (4.2 ± 0.6) of optimal monochromatic images were significantly higher than those of polychromatic images [(149 ± 18) HU], [(107 ± 14) HU], [(43 ±11) HU], 12.55 ± 3.02, 3.53 ± 1.03, 3.1 ± 0.8 (t values were 24.79, 13.95, 18.85, 9.07, 13.25 and 12.04, respectively, P < 0.01). In the comparison of image quality, Kappa value was 0.81 with optimal monochromatic images and 0.69 with polychromatic images. Conclusion: Monochromatic images of spectral CT could improve CNR for displaying hepatic vein and improve the image quality compared to the conventional polychromatic images. (authors)

  14. Classification of high resolution satellite images

    OpenAIRE

    Karlsson, Anders

    2003-01-01

    In this thesis the Support Vector Machine (SVM)is applied on classification of high resolution satellite images. Sveral different measures for classification, including texture mesasures, 1st order statistics, and simple contextual information were evaluated. Additionnally, the image was segmented, using an enhanced watershed method, in order to improve the classification accuracy.

  15. Quality control of the interpretation monitors of digital radiological images

    International Nuclear Information System (INIS)

    Favero, Mariana S.; Goulart, Adriano Oliveira S.

    2016-01-01

    The performance monitors has great importance in image quality of digital radiographic systems. In environments without films, it became necessary to implement acceptance testing and quality control monitors used for interpretation of medical images. The monitors dedicated to radiodiagnostic should provide information that represent slight differences in x-ray attenuation or minor differences in some anatomical region of interest. This should also result in small differences in luminance of an image represented. Factors affecting the quality of medical imaging are contrast, noise, resolution, artifacts and distortions. Therefore, a monitor must have specific characteristics, making it possible for the observer to carry out an assessment that leads to better diagnosis. Based on the need to evaluate diagnostic monitors in various radiological applications, this paper presents a summary for implementation and standardization of tests that are recommended by the publication AAPM Report 03. (author)

  16. Standardization of Image Quality Analysis – ISO 19264

    DEFF Research Database (Denmark)

    Wüller, Dietmar; Kejser, Ulla Bøgvad

    2016-01-01

    There are a variety of image quality analysis tools available for the archiving world, which are based on different test charts and analysis algorithms. ISO has formed a working group in 2012 to harmonize these approaches and create a standard way of analyzing the image quality for archiving...... systems. This has resulted in three documents that have been or are going to be published soon. ISO 19262 defines the terms used in the area of image capture to unify the language. ISO 19263 describes the workflow issues and provides detailed information on how the measurements are done. Last...... but not least ISO 19264 describes the measurements in detail and provides aims and tolerance levels for the different aspects. This paper will present the new ISO 19264 technical specification to analyze image quality based on a single capture of a multi-pattern test chart, and discuss the reasoning behind its...

  17. MYTHS vesus reality in computed radiography image quality

    International Nuclear Information System (INIS)

    Mango, Steve; Castro, Luiz

    2009-01-01

    As NDE operation - particularly radiographic testing - ransition form analog to digital technologies such as computed radiography (CR), users are learning that there's more to digital image quality than meets the eye. In fact, there are ultiple factors that determine the final perceived image quality of a computed radiograph. Many of these factors are misunderstood, and some are touted as the ''key parameter'' or ''magic bullet'' in producing optiumum image quality, In reality, such claims are oversimplified, and are more marketing hype than reality. The truth?. Perceived image quality results form the cascaded effects of many factor - such as sharpness, system noise, spot size and pixel size, subject contrast, bit depth, radiographic technique, and so on. Many of these factors are within the control of rdiographers or designers of equipment and media. This paper will explain some of these key factors, dispel some of the myths surrounding them, and will show that qualities such as bigger, smaller, more, or less are not always better when it comes to CR image quality. (authors)

  18. Investigation of Photographic Image Quality Estimators

    Science.gov (United States)

    1980-04-01

    Bibeman (1973) describes acutance as being "expressed in terms of the mean square of the gradient of . . . density (in a photographic image) with...the density difference AD. for each interval from the (smoothed) microdensitometer trace (calibrated in density units). 4. Compute the gradient -77...resolution." Rotacion Effects: The conditions were: Target: Shutter Speed: I- requency: Arplitude: Medium contrast, variable aspect 250 milliseconds

  19. The influence of software filtering in digital mammography image quality

    Science.gov (United States)

    Michail, C.; Spyropoulou, V.; Kalyvas, N.; Valais, I.; Dimitropoulos, N.; Fountos, G.; Kandarakis, I.; Panayiotakis, G.

    2009-05-01

    Breast cancer is one of the most frequently diagnosed cancers among women. Several techniques have been developed to help in the early detection of breast cancer such as conventional and digital x-ray mammography, positron and single-photon emission mammography, etc. A key advantage in digital mammography is that images can be manipulated as simple computer image files. Thus non-dedicated commercially available image manipulation software can be employed to process and store the images. The image processing tools of the Photoshop (CS 2) software usually incorporate digital filters which may be used to reduce image noise, enhance contrast and increase spatial resolution. However, improving an image quality parameter may result in degradation of another. The aim of this work was to investigate the influence of three sharpening filters, named hereafter sharpen, sharpen more and sharpen edges on image resolution and noise. Image resolution was assessed by means of the Modulation Transfer Function (MTF).In conclusion it was found that the correct use of commercial non-dedicated software on digital mammograms may improve some aspects of image quality.

  20. The influence of software filtering in digital mammography image quality

    International Nuclear Information System (INIS)

    Michail, C; Spyropoulou, V; Valais, I; Panayiotakis, G; Kalyvas, N; Fountos, G; Kandarakis, I; Dimitropoulos, N

    2009-01-01

    Breast cancer is one of the most frequently diagnosed cancers among women. Several techniques have been developed to help in the early detection of breast cancer such as conventional and digital x-ray mammography, positron and single-photon emission mammography, etc. A key advantage in digital mammography is that images can be manipulated as simple computer image files. Thus non-dedicated commercially available image manipulation software can be employed to process and store the images. The image processing tools of the Photoshop (CS 2) software usually incorporate digital filters which may be used to reduce image noise, enhance contrast and increase spatial resolution. However, improving an image quality parameter may result in degradation of another. The aim of this work was to investigate the influence of three sharpening filters, named hereafter sharpen, sharpen more and sharpen edges on image resolution and noise. Image resolution was assessed by means of the Modulation Transfer Function (MTF).In conclusion it was found that the correct use of commercial non-dedicated software on digital mammograms may improve some aspects of image quality.

  1. THE INFLUENCE OF PERCEIVED QUALITY, BRAND IMAGE, AND EMOTIONAL VALUE TOWARDS PURCHASE INTENTION OF CONSINA BACKPACK

    Directory of Open Access Journals (Sweden)

    Basrah Saidani

    2017-05-01

    Full Text Available This study was conducted to determine the descriptive and empirical impact of perceived quality, brand image and emotional value toward purchase intention. The object of this research was respondents of backpack users in East Jakarta. Methods of data collection using survey methods. Data analysis using SPSS to process and analyze the research data. The results of descriptive test explained that perceived quality, brand image and emotional value of backpack Consina is good according most respondents answer, so they have quite high purchase intention. The hypothesis test shows, perceived quality has positive and significant effect on purchase intention, brand image has positive and significant effect on purchase intention, emotional value has positive and significant effect on purchase intention, perceived quality, brand image and emotional value have simultaneous effect on purchase intention.

  2. Improving lateral resolution and image quality of optical coherence tomography by the multi-frame superresolution technique for 3D tissue imaging.

    Science.gov (United States)

    Shen, Kai; Lu, Hui; Baig, Sarfaraz; Wang, Michael R

    2017-11-01

    The multi-frame superresolution technique is introduced to significantly improve the lateral resolution and image quality of spectral domain optical coherence tomography (SD-OCT). Using several sets of low resolution C-scan 3D images with lateral sub-spot-spacing shifts on different sets, the multi-frame superresolution processing of these sets at each depth layer reconstructs a higher resolution and quality lateral image. Layer by layer processing yields an overall high lateral resolution and quality 3D image. In theory, the superresolution processing including deconvolution can solve the diffraction limit, lateral scan density and background noise problems together. In experiment, the improved lateral resolution by ~3 times reaching 7.81 µm and 2.19 µm using sample arm optics of 0.015 and 0.05 numerical aperture respectively as well as doubling the image quality has been confirmed by imaging a known resolution test target. Improved lateral resolution on in vitro skin C-scan images has been demonstrated. For in vivo 3D SD-OCT imaging of human skin, fingerprint and retina layer, we used the multi-modal volume registration method to effectively estimate the lateral image shifts among different C-scans due to random minor unintended live body motion. Further processing of these images generated high lateral resolution 3D images as well as high quality B-scan images of these in vivo tissues.

  3. Image quality and dose in mammographic images obtained in Mexico City hospitals

    International Nuclear Information System (INIS)

    Ruiz-Trejo, C.; Brandan, M.-E.; Verdejo, M.; Flores, A.; Guevara, M.; Martin, J.; Madero-Preciado, L.

    2001-01-01

    The performance of three mammographic systems in large Mexican hospitals has been evaluated, as well as the image quality and associated dose. Quality control tests include examination of X-ray equipment, darkroom conditions, film processor, and viewboxes. Systems referred to as '1', '2', and '3' passed 50%, 75% and 75% of these tests, respectively. Quality image is assessed using five images obtained under similar nominal conditions in each X-ray equipment. System 1 generates no image of acceptable quality, while equipment 2 and 3 produce one and two, respectively. The mean glandular dose for the best images obtained in each service with an accreditation phantom has been measured, and the values are 1.4 mGy, 1.6 mGy, and 1.0 mGy, respectively. (author)

  4. Physical image quality of computed radiography in mammography system

    International Nuclear Information System (INIS)

    Norriza Mohd Isa; Muhammad Jamal Isa; Wan Muhamad Saridan Wan Hassan; Fatimah Othman

    2013-01-01

    Full-text: Mammography is a screening procedure that mostly used for early detection of breast cancer. In digital imaging system, Computed Radiography is a cost-effective technology that applied indirect conversion detector. The paper presents physical image quality parameter measurements namely modulation transfer function (MTF), normalized noise power spectrum (NNPS) and detective quantum efficiency (DQE) of Computed Radiography in mammography system. MTF was calculated from two different orientations of slanted images of an edge test device and NNPS was estimated using flat-field image. Both images were acquired using a standard mammography beam quality. DQE was determined by applying the MTF and NNPS values into our developed software program. Both orientations have similar DQE characteristics. (author)

  5. Comparison of image quality in head CT studies with different dose-reduction strategies

    DEFF Research Database (Denmark)

    Johansen, Jeppe; Nielsen, Rikke; Fink-Jensen, Vibeke

    The number of multi-detector CT examinations is increasing rapidly. They allow high quality reformatted images providing accurate and precise diagnosis at maximum speed. Brain examinations are the most commonly requested studies, and although they come at a lower effective dose than body CT, can...... account to a considerable radiation dose as many patients undergo repeated studies. Therefore, various dose-reduction strategies are applied such as automated tube current and voltage modulation and recently different iterative reconstruction algorithms. However, the trade-off of all dose......-reduction maneuvers is reduction of image quality due to image noise or artifacts. The aim of our study was therefore to find the best diagnostic images with lowest possible dose. We present results of dose- and image quality optimizing strategies of brain CT examinations at our institution. We compare sequential...

  6. Automated Region of Interest Retrieval of Metallographic Images for Quality Classification in Industry

    Directory of Open Access Journals (Sweden)

    Petr Kotas

    2012-01-01

    Full Text Available The aim of the research is development and testing of new methods to classify the quality of metallographic samples of steels with high added value (for example grades X70 according API. In this paper, we address the development of methods to classify the quality of slab samples images with the main emphasis on the quality of the image center called as segregation area. For this reason, we introduce an alternative method for automated retrieval of region of interest. In the first step, the metallographic image is segmented using both spectral method and thresholding. Then, the extracted macrostructure of the metallographic image is automatically analyzed by statistical methods. Finally, automatically extracted region of interests are compared with results of human experts.  Practical experience with retrieval of non-homogeneous noised digital images in industrial environment is discussed as well.

  7. A Methodology for Anatomic Ultrasound Image Diagnostic Quality Assessment

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Lange, Theis; Brandt, Andreas Hjelm

    2017-01-01

    are presented. Earlier uses of the methodology has shown that it ensures validity of the assessment, as it separates the influences between developer, investigator, and assessor once a research protocol has been established. This separation reduces confounding influences on the result from the developer......This paper discusses methods for assessment of ultrasound image quality based on our experiences with evaluating new methods for anatomic imaging. It presents a methodology to ensure a fair assessment between competing imaging methods using clinically relevant evaluations. The methodology...... to properly reveal the clinical value. The paper exemplifies the methodology using recent studies of Synthetic Aperture Sequential Beamforming tissue harmonic imaging....

  8. High Fidelity Raman Chemical Imaging of Materials

    Science.gov (United States)

    Bobba, Venkata Nagamalli Koteswara Rao

    The development of high fidelity Raman imaging systems is important for a number of application areas including material science, bio-imaging, bioscience and healthcare, pharmaceutical analysis, and semiconductor characterization. The use of Raman imaging as a characterization tool for detecting the amorphous and crystalline regions in the biopolymer poly-L-lactic acid (PLLA) is the precis of my thesis. In the first chapter, a brief insight about the basics of Raman spectroscopy, Raman chemical imaging, Raman mapping, and Raman imaging techniques has been provided. The second chapter contains details about the successful development of tailored sample of PLLA. Biodegradable polymers are used in areas of tissue engineering, agriculture, packaging, and in medical field for drug delivery, implant devices, and surgical sutures. Detailed information about the sample preparation and characterization of these cold-drawn PLLA polymer substrates has been provided. Wide-field Raman hyperspectral imaging using an acousto-optic tunable filter (AOTF) was demonstrated in the early 1990s. The AOTF contributed challenges such as image walk, distortion, and image blur. A wide-field AOTF Raman imaging system has been developed as part of my research and methods to overcome some of the challenges in performing AOTF wide-field Raman imaging are discussed in the third chapter. This imaging system has been used for studying the crystalline and amorphous regions on the cold-drawn sample of PLLA. Of all the different modalities that are available for performing Raman imaging, Raman point-mapping is the most extensively used method. The ease of obtaining the Raman hyperspectral cube dataset with a high spectral and spatial resolution is the main motive of performing this technique. As a part of my research, I have constructed a Raman point-mapping system and used it for obtaining Raman hyperspectral image data of various minerals, pharmaceuticals, and polymers. Chapter four offers

  9. Simulation of High Quality Ultrasound Imaging

    DEFF Research Database (Denmark)

    Hemmsen, Martin Christian; Kortbek, Jacob; Nikolov, Svetoslav Ivanov

    2010-01-01

    ), and at Full Width at One-Hundredth Maximum (FWOHM) of 9 points spread functions resulting from evenly distributed point targets at depths ranging from 10 mm to 90 mm. The results are documented for a 64 channel system, using a 192 element linear array transducer model. A physical BK Medical 8804 transducer...... amplitude and phase compensation, the LR at FWOHM improves from 6.3 mm to 4.7 mm and is a factor of 2.2 better than DRF. This study has shown that individual element impulse response, phase, and amplitude deviations are important to include in simulated system performance evaluations. Furthermore...

  10. The quality assurance in diagnostic radiology and their effect in the quality image and radiological protection of the patient

    International Nuclear Information System (INIS)

    Gaona, Enrique

    2002-01-01

    The quality assurance in diagnostic radiology in Mexico before 1997 was virtually nonexistent except in few academic institutions and hospitals. The purpose of this study was to carry out an exploratory survey of the issue of quality control parameters of general and fluoroscopy x-ray systems in the Mexican Republic and their effects in the quality image and radiological protection of the patient. A general result of the survey is that there is not significant difference in the observed frequencies among public and private radiology departments for α = 0.05, then the results are valid for both departments. 37% of x-ray systems belong to public radiology departments. In the radiology departments that didn't agree with the Mexican regulations in: light field to mach the x-ray field, light field intensity, kV, time and output. In those cases, we found a repeat rate of radiography studies >30% with non necessary dose to patient, low quality image and high operating costs of the radiology service. We found in x-ray fluoroscopy systems that 62% had a low quality image due to electronic noise in the television chain. In general the x-ray systems that didn't agree with Mexican regulations are 35% and they can affect in a way or other the quality image and the dose to patient

  11. Image Quality Improvement after Implementation of a CT Accreditation Program

    International Nuclear Information System (INIS)

    Kim, You Sung; Jung, Seung Eun; Choi, Byung Gil; Shin, Yu Ri; Hwang, Seong Su; Ku, Young Mi; Lim, Yeon Soo; Lee, Jae Mun

    2010-01-01

    The purpose of this study was to evaluate any improvement in the quality of abdominal CTs after the utilization of the nationally based accreditation program. Approval was obtained from the Institutional Review Board, and informed consent was waived. We retrospectively analyzed 1,011 outside abdominal CTs, from 2003 to 2007. We evaluated images using a fill-up sheet form of the national accreditation program, and subjectively by grading for the overall CT image quality. CT scans were divided into two categories according to time periods; before and after the implementation of the accreditation program. We compared CT scans between two periods according to parameters pertaining to the evaluation of images. We determined whether there was a correlation between the results of a subjective assessment of the image quality and the evaluation scores of the clinical image. The following parameters were significantly different after the implementation of the accreditation program: identifying data, display parameters, scan length, spatial and contrast resolution, window width and level, optimal contrast enhancement, slice thickness, and total score. The remaining parameters were not significantly different between scans obtained from the two different periods: scan parameters, film quality, and artifacts. After performing the CT accreditation program, the quality of the outside abdominal CTs show marked improvement, especially for the parameters related to the scanning protocol

  12. Body image and quality of life in a Spanish population

    Directory of Open Access Journals (Sweden)

    Ignacio Jáuregui Lobera

    2011-01-01

    Full Text Available Ignacio Jáuregui Lobera1, Patricia Bolaños Ríos21Department of Nutrition and Bromatology, Pablo de Olavide University, Seville, Spain; 2Behavior Science Institute, Seville, SpainPurpose: The aim of the current study was to analyze the psychometric properties, factor structure, and internal consistency of the Spanish version of the Body Image Quality of Life Inventory (BIQLI-SP as well as its test–retest reliability. Further objectives were to analyze different relationships with key dimensions of psychosocial functioning (ie, self-esteem, presence of psychopathological symptoms, eating and body image-related problems, and perceived stress and to evaluate differences in body image quality of life due to gender.Patients and methods: The sample comprised 417 students without any psychiatric history, recruited from the Pablo de Olavide University and the University of Seville. There were 140 men (33.57% and 277 women (66.43%, and the mean age was 21.62 years (standard deviation = 5.12. After obtaining informed consent from all participants, the following questionnaires were administered: BIQLI, Eating Disorder Inventory-2 (EDI-2, Perceived Stress Questionnaire (PSQ, Self-Esteem Scale (SES, and Symptom Checklist-90-Revised (SCL-90-R.Results: The BIQLI-SP shows adequate psychometric properties, and it may be useful to determine the body image quality of life in different physical conditions. A more positive body image quality of life is associated with better self-esteem, better psychological wellbeing, and fewer eating-related dysfunctional attitudes, this being more evident among women.Conclusion: The BIQLI-SP may be useful to determine the body image quality of life in different contexts with regard to dermatology, cosmetic and reconstructive surgery, and endocrinology, among others. In these fields of study, a new trend has emerged to assess body image-related quality of life.Keywords: body appreciation, wellbeing, self-esteem, social

  13. Analysis of an image quality assurance program

    International Nuclear Information System (INIS)

    Goethlin, J.H.; Alders, B.

    1985-01-01

    Reject film analysis before and after the introduction of a quality assurance program showed a 45% decrease in rejected films. The main changes in equipment and routines were: 1. Increased control of film processors and X-ray generators. 2. New film casettes and screens. 3. Decreased number of film sizes. 4. Information to and supervision of radiographing personnel. Savings in costs and increased income from an increased amount of out-patients corresponded to about 4.5% of the total cost of operating and maintaining the department. (orig.)

  14. Image quality in non-gated versus gated reconstruction of tongue motion using magnetic resonance imaging: a comparison using automated image processing

    Energy Technology Data Exchange (ETDEWEB)

    Alvey, Christopher; Orphanidou, C.; Coleman, J.; McIntyre, A.; Golding, S.; Kochanski, G. [University of Oxford, Oxford (United Kingdom)

    2008-11-15

    The use of gated or ECG triggered MR is a well-established technique and developments in coil technology have enabled this approach to be applied to areas other than the heart. However, the image quality of gated (ECG or cine) versus non-gated or real-time has not been extensively evaluated in the mouth. We evaluate two image sequences by developing an automatic image processing technique which compares how well the image represents known anatomy. Four subjects practised experimental poly-syllabic sentences prior to MR scanning. Using a 1.5 T MR unit, we acquired comparable gated (using an artificial trigger) and non-gated sagittal images during speech. We then used an image processing algorithm to model the image grey along lines that cross the airway. Each line involved an eight parameter non-linear equation to model of proton densities, edges, and dimensions. Gated and non-gated images show similar spatial resolution, with non-gated images being slightly sharper (10% better resolution, less than 1 pixel). However, the gated sequences generated images of substantially lower inherent noise, and substantially better discrimination between air and tissue. Additionally, the gated sequences demonstrate a very much greater temporal resolution. Overall, image quality is better with gated imaging techniques, especially given their superior temporal resolution. Gated techniques are limited by the repeatability of the motions involved, and we have shown that speech to a metronome can be sufficiently repeatable to allow high-quality gated magnetic resonance imaging images. We suggest that gated sequences may be useful for evaluating other types of repetitive movement involving the joints and limb motions. (orig.)

  15. Image quality in non-gated versus gated reconstruction of tongue motion using magnetic resonance imaging: a comparison using automated image processing

    International Nuclear Information System (INIS)

    Alvey, Christopher; Orphanidou, C.; Coleman, J.; McIntyre, A.; Golding, S.; Kochanski, G.

    2008-01-01

    The use of gated or ECG triggered MR is a well-established technique and developments in coil technology have enabled this approach to be applied to areas other than the heart. However, the image quality of gated (ECG or cine) versus non-gated or real-time has not been extensively evaluated in the mouth. We evaluate two image sequences by developing an automatic image processing technique which compares how well the image represents known anatomy. Four subjects practised experimental poly-syllabic sentences prior to MR scanning. Using a 1.5 T MR unit, we acquired comparable gated (using an artificial trigger) and non-gated sagittal images during speech. We then used an image processing algorithm to model the image grey along lines that cross the airway. Each line involved an eight parameter non-linear equation to model of proton densities, edges, and dimensions. Gated and non-gated images show similar spatial resolution, with non-gated images being slightly sharper (10% better resolution, less than 1 pixel). However, the gated sequences generated images of substantially lower inherent noise, and substantially better discrimination between air and tissue. Additionally, the gated sequences demonstrate a very much greater temporal resolution. Overall, image quality is better with gated imaging techniques, especially given their superior temporal resolution. Gated techniques are limited by the repeatability of the motions involved, and we have shown that speech to a metronome can be sufficiently repeatable to allow high-quality gated magnetic resonance imaging images. We suggest that gated sequences may be useful for evaluating other types of repetitive movement involving the joints and limb motions. (orig.)

  16. No-reference image quality assessment for horizontal-path imaging scenarios

    Science.gov (United States)

    Rios, Carlos; Gladysz, Szymon

    2013-05-01

    There exist several image-enhancement algorithms and tasks associated with imaging through turbulence that depend on defining the quality of an image. Examples include: "lucky imaging", choosing the width of the inverse filter for image reconstruction, or stopping iterative deconvolution. We collected a number of image quality metrics found in the literature. Particularly interesting are the blind, "no-reference" metrics. We discuss ways of evaluating the usefulness of these metrics, even when a fully objective comparison is impossible because of the lack of a reference image. Metrics are tested on simulated and real data. Field data comes from experiments performed by the NATO SET 165 research group over a 7 km distance in Dayton, Ohio.

  17. Fabrication of high-quality brazed joints

    International Nuclear Information System (INIS)

    Orlov, A.V.

    1980-01-01

    Problem of ensuring of joint high-quality when brazing different parts in power engineering is considered. To obtain high-quality joints it is necessary to correctly design brazed joint and to choose a gap width, overlap length and fillet radius; to clean up carefully the surfaces to be brazed and fix them properly one relative to another; to apply a solder so as to provide its flowing into the gap and sticking in it; to exactly regulate thermal conditions of brazing. High quality and reliability of brazed joints are ensured by the application of solders based on noble metals, and cheap solders based on nickel, manganese and copper. Joints brazed with nickel base solders may operate at temperatures as high as 888 deg C

  18. TOTAL QUALITY MANAGEMENT IN HIGH EDUCATION

    Directory of Open Access Journals (Sweden)

    Hasan SERİN, Alper AYTEKİN

    2009-01-01

    Full Text Available The approach of Total Quality Management (TQM has been even more common and most recently its use in high education has been discussed. Likewise the enterprises producing various products, universities have also inputs, processes, and outputs. Due to conditions of competition, universities have to improve the qualities of these inputs, processes, and outputs, according to satisfaction, demands, and expectations of internal and external customers. If the TQM has been implemented in the universities with a manner that aims for customer satisfaction (students, lecturers, public and private establishments, and families, supports constant development, ensures participatory approach, and encourages working in groups, it will provide universities with effectiveness, efficiency, dynamics, and economics. In this study, common problems of universities, definitions of quality and TQM in high education, customer concept at universities, and factors affecting the quality of education have been explained. Besides, in order TQM approach to be successfully implemented in the universities, various suggestions have been presented.

  19. Remote Cherenkov imaging-based quality assurance of a magnetic resonance image-guided radiotherapy system.

    Science.gov (United States)

    Andreozzi, Jacqueline M; Mooney, Karen E; Brůža, Petr; Curcuru, Austen; Gladstone, David J; Pogue, Brian W; Green, Olga

    2018-06-01

    Tools to perform regular quality assurance of magnetic resonance image-guided radiotherapy (MRIgRT) systems should ideally be independent of interference from the magnetic fields. Remotely acquired optical Cherenkov imaging-based dosimetry measurements in water were investigated for this purpose, comparing measures of dose accuracy, temporal dynamics, and overall integrated IMRT delivery. A 40 × 30.5 × 37.5 cm 3 water tank doped with 1 g/L of quinine sulfate was imaged using an intensified charge-coupled device (ICCD) to capture the Cherenkov emission while being irradiated by a commercial MRIgRT system (ViewRay™). The ICCD was placed down-bore at the end of the couch, 4 m from treatment isocenter and behind the 5-Gauss line of the 0.35-T MRI. After establishing optimal camera acquisition settings, square beams of increasing size (4.2 × 4.2 cm 2 , 10.5 × 10.5 cm 2 , and 14.7 × 14.7 cm 2 ) were imaged at 0.93 frames per second, from an individual cobalt-60 treatment head, to develop projection measures related to percent depth dose (PDD) curves and cross beam profiles (CPB). These Cherenkov-derived measurements were compared to ionization chamber (IC) and radiographic film dosimetry data, as well as simulation data from the treatment planning system (TPS). An intensity-modulated radiotherapy (IMRT) commissioning plan from AAPM TG-119 (C4:C-Shape) was also imaged at 2.1 frames per second, and the single linear sum image from 509 s of plan delivery was compared to the dose volume prediction generated by the TPS using gamma index analysis. Analysis of standardized test target images (1024 × 1024 pixels) yielded a pixel resolution of 0.37 mm/pixel. The beam width measured from the Cherenkov image-generated projection CBPs was within 1 mm accuracy when compared to film measurements for all beams. The 502 point measurements (i.e., pixels) of the Cherenkov image-based projection percent depth dose curves (pPDDs) were compared to p

  20. An approach for quantitative image quality analysis for CT

    Science.gov (United States)

    Rahimi, Amir; Cochran, Joe; Mooney, Doug; Regensburger, Joe

    2016-03-01

    An objective and standardized approach to assess image quality of Compute Tomography (CT) systems is required in a wide variety of imaging processes to identify CT systems appropriate for a given application. We present an overview of the framework we have developed to help standardize and to objectively assess CT image quality for different models of CT scanners used for security applications. Within this framework, we have developed methods to quantitatively measure metrics that should correlate with feature identification, detection accuracy and precision, and image registration capabilities of CT machines and to identify strengths and weaknesses in different CT imaging technologies in transportation security. To that end we have designed, developed and constructed phantoms that allow for systematic and repeatable measurements of roughly 88 image quality metrics, representing modulation transfer function, noise equivalent quanta, noise power spectra, slice sensitivity profiles, streak artifacts, CT number uniformity, CT number consistency, object length accuracy, CT number path length consistency, and object registration. Furthermore, we have developed a sophisticated MATLAB based image analysis tool kit to analyze CT generated images of phantoms and report these metrics in a format that is standardized across the considered models of CT scanners, allowing for comparative image quality analysis within a CT model or between different CT models. In addition, we have developed a modified sparse principal component analysis (SPCA) method to generate a modified set of PCA components as compared to the standard principal component analysis (PCA) with sparse loadings in conjunction with Hotelling T2 statistical analysis method to compare, qualify, and detect faults in the tested systems.

  1. High Throughput Neuro-Imaging Informatics

    Directory of Open Access Journals (Sweden)

    Michael I Miller

    2013-12-01

    Full Text Available This paper describes neuroinformatics technologies at 1 mm anatomical scale based on high throughput 3D functional and structural imaging technologies of the human brain. The core is an abstract pipeline for converting functional and structural imagery into their high dimensional neuroinformatic representations index containing O(E3-E4 discriminating dimensions. The pipeline is based on advanced image analysis coupled to digital knowledge representations in the form of dense atlases of the human brain at gross anatomical scale. We demonstrate the integration of these high-dimensional representations with machine learning methods, which have become the mainstay of other fields of science including genomics as well as social networks. Such high throughput facilities have the potential to alter the way medical images are stored and utilized in radiological workflows. The neuroinformatics pipeline is used to examine cross-sectional and personalized analyses of neuropsychiatric illnesses in clinical applications as well as longitudinal studies. We demonstrate the use of high throughput machine learning methods for supporting (i cross-sectional image analysis to evaluate the health status of individual subjects with respect to the population data, (ii integration of image and non-image information for diagnosis and prognosis.

  2. Optimage central organised image quality control including statistics and reporting

    International Nuclear Information System (INIS)

    Jahnen, A.; Schilz, C.; Shannoun, F.; Schreiner, A.; Hermen, J.; Moll, C.

    2008-01-01

    Quality control of medical imaging systems is performed using dedicated phantoms. As the imaging systems are more and more digital, adequate image processing methods might help to save evaluation time and to receive objective results. The developed software package OPTIMAGE is focusing on this with a central approach: On one hand, OPTIMAGE provides a framework, which includes functions like database integration, DICOM data sources, multilingual user interface and image processing functionality. On the other hand, the test methods are implemented using modules which are able to process the images automatically for the common imaging systems. The integration of statistics and reporting into this environment is paramount: This is the only way to provide these functions in an interactive, user-friendly way. These features enable the users to discover degradation in performance quickly and document performed measurements easily. (authors)

  3. Feasibility study and quality assessment of unmanned aircraft system-derived multispectral images

    Science.gov (United States)

    Chang, Kuo-Jen

    2017-04-01

    The purpose of study is to explore the precision and the applicability of UAS-derived multispectral images. In this study, the Micro-MCA6 multispectral camera was mounted on quadcopter. The Micro-MCA6 shoot images synchronized of each single band. By means of geotagged images and control points, the orthomosaic images of each single band generated firstly by 14cm resolution. The multispectral image was merged complete with 6 bands. In order to improve the spatial resolution, the 6 band image fused with 9cm resolution image taken from RGB camera. Quality evaluation of the image is verified of the each single band by using control points and check points. The standard deviations of errors are within 1 to 2 pixel resolution of each band. The quality of the multispectral image is compared with 3 cm resolution orthomosaic RGB image gathered from UAV in the same mission, as well. The standard deviations of errors are within 2 to 3 pixel resolution. The result shows that the errors resulting from the blurry and the band dislocation of the objects edge identification. To the end, the normalized difference vegetation index (NDVI) extracted from the image to explore the condition of vegetation and the nature of the environment. This study demonstrates the feasibility and the capability of the high resolution multispectral images.

  4. Body image quality of life in eating disorders

    Directory of Open Access Journals (Sweden)

    Ignacio Jáuregui Lobera

    2011-03-01

    Full Text Available Ignacio Jáuregui Lobera1, Patricia Bolaños Ríos21Department of Nutrition and Bromatology, Pablo de Olavide University, Seville, Spain; 2Behavior Sciences Institute, Seville, SpainPurpose: The objective was to examine how body image affects quality of life in an eating-disorder (ED clinical sample, a non-ED clinical sample, and a nonclinical sample. We hypothesized that ED patients would show the worst body image quality of life. We also hypothesized that body image quality of life would have a stronger negative association with specific ED-related variables than with other psychological and psychopathological variables, mainly among ED patients. On the basis of previous studies, the influence of gender on the results was explored, too.Patients and methods: The final sample comprised 70 ED patients (mean age 22.65 ± 7.76 years; 59 women and 11 men; 106 were patients with other psychiatric disorders (mean age 28.20 ± 6.52; 67 women and 39 men, and 135 were university students (mean age 21.57 ± 2.58; 81 women and 54 men, with no psychiatric history. After having obtained informed consent, the following questionnaires were administered: Body Image Quality of Life Inventory-Spanish version (BIQLI-SP, Eating Disorders Inventory-2 (EDI-2, Perceived Stress Questionnaire (PSQ, Self-Esteem Scale (SES, and Symptom Checklist-90-Revised (SCL-90-R.Results: The ED patients' ratings on the BIQLI-SP were the lowest and negatively scored (BIQLI-SP means: +20.18, +5.14, and —6.18, in the student group, the non-ED patient group, and the ED group, respectively. The effect of body image on quality of life was more negative in the ED group in all items of the BIQLI-SP. Body image quality of life was negatively associated with specific ED-related variables, more than with other psychological and psychopathological variables, but not especially among ED patients.Conclusion: Body image quality of life was affected not only by specific pathologies related to body

  5. Impact of orthodontic appliances on the quality of craniofacial anatomical magnetic resonance imaging and real-time speech imaging.

    Science.gov (United States)

    Wylezinska, Marzena; Pinkstone, Marie; Hay, Norman; Scott, Andrew D; Birch, Malcolm J; Miquel, Marc E

    2015-12-01

    The aim of this work was to investigate the effects of commonly used orthodontic appliances on the magnetic resonance (MR) image quality of the craniofacial region, with special interest in the soft palate and velopharyngeal wall using real-time speech imaging sequences and anatomical imaging of the temporomandibular joints (TMJ) and pituitaries. Common orthodontic appliances were studied on 1.5 T scanner using standard spin and gradient echo sequences (based on the American Society for Testing and Materials standard test method) and sequences previously applied for high-resolution anatomical and dynamic real-time imaging during speech. Images were evaluated for the presence and size of artefacts. Metallic orthodontic appliances had different effects on image quality. The most extensive individual effects were associated with the presence of stainless steel archwire, particularly if combined with stainless steel brackets and stainless steel molar bands. With those appliances, diagnostic quality of magnetic resonance imaging speech and palate images will be most likely severely degraded, or speech imaging and imaging of pituitaries and TMJ will be not possible. All non-metallic, non-metallic with Ni/Cr reinforcement or Ni/Ti alloys appliances were of little concern. The results in the study are only valid at 1.5 T and for the sequences and devices used and cannot necessarily be extrapolated to all sequences and devices. Furthermore, both geometry and size of some appliances are subject dependent, and consequently, the effects on the image quality can vary between subjects. Therefore, the results presented in this article should be treated as a guide when assessing the risks of image quality degradation rather than an absolute evaluation of possible artefacts. Appliances manufactured from stainless steel cause extensive artefacts, which may render image non-diagnostic. The presence and type of orthodontic appliances should be always included in the patient

  6. Indicators of image quality and doses in mammography

    International Nuclear Information System (INIS)

    Gaona, E.; Franco E, J.G.; Azorin N, J.; Diaz G, J.A.I.; Arreola, M.

    2007-01-01

    Full text: The purpose of the study was to determine the values of the image quality indicators and their relationship with the dose in mammography of screen-film that they allowed the detection of a bigger number of objects in the images obtained with the mannequin (phantom) authorized of the ACR/FDA. The study was carried out in four mammography services in a period of 12 months. The indicators of the image quality are the half optic density (DOM), contrast (differences of densities), the number of observed objects in the images and the dose for image. The minimum acceptable values by the ACR/FDA are a half optical density of 1.4, contrast of 0.4 and the one numbers minimum of objects observed in the image of the mannequin of mammography of 10 (4 fibers, 3 groups of calcifications and 3 masses), with a maximum dose by image of 3 mGy. The found results are half optical density of 1.9, contrast of 0.56 and the average number of objects observed in the images of 12, with a dose in the interval of 1.6 mGy to 2.4 mGy. The doses were measured by thermoluminescent dosimetry and ionization chamber. Once carried out the analysis of the tendencies of the indicators of image quality and their distributions is found that for a p < 0.05, the bigger number of objects observed in the images is in the interval from 1.8 to 1.9 of DOM. When comparing both mammography system, the system screen-film has a lower variability in the distribution of objects associated to a DOM. (Author)

  7. High Contrast Imaging of Exoplanets and Exoplanetary Systems with JWST

    Science.gov (United States)

    Hinkley, Sasha; Skemer, Andrew; Biller, Beth; Baraffe, I.; Bonnefoy, M.; Bowler, B.; Carter, A.; Chen, C.; Choquet, E.; Currie, T.; Danielski, C.; Fortney, J.; Grady, C.; Greenbaum, A.; Hines, D.; Janson, M.; Kalas, P.; Kennedy, G.; Kraus, A.; Lagrange, A.; Liu, M.; Marley, M.; Marois, C.; Matthews, B.; Mawet, D.; Metchev, S.; Meyer, M.; Millar-Blanchaer, M.; Perrin, M.; Pueyo, L.; Quanz, S.; Rameau, J.; Rodigas, T.; Sallum, S.; Sargent, B.; Schlieder, J.; Schneider, G.; Stapelfeldt, K.; Tremblin, P.; Vigan, A.; Ygouf, M.

    2017-11-01

    JWST will transform our ability to characterize directly imaged planets and circumstellar debris disks, including the first spectroscopic characterization of directly imaged exoplanets at wavelengths beyond 5 microns, providing a powerful diagnostic of cloud particle properties, atmospheric structure, and composition. To lay the groundwork for these science goals, we propose a 39-hour ERS program to rapidly establish optimal strategies for JWST high contrast imaging. We will acquire: a) coronagraphic imaging of a newly discovered exoplanet companion, and a well-studied circumstellar debris disk with NIRCam & MIRI; b) spectroscopy of a wide separation planetary mass companion with NIRSPEC & MIRI; and c) deep aperture masking interferometry with NIRISS. Our primary goals are to: 1) generate representative datasets in modes to be commonly used by the exoplanet and disk imaging communities; 2) deliver science enabling products to empower a broad user base to develop successful future investigations; and 3) carry out breakthrough science by characterizing exoplanets for the first time over their full spectral range from 2-28 microns, and debris disk spectrophotometry out to 15 microns sampling the 3 micron water ice feature. Our team represents the majority of the community dedicated to exoplanet and disk imaging and has decades of experience with high contrast imaging algorithms and pipelines. We have developed a collaboration management plan and several organized working groups to ensure we can rapidly and effectively deliver high quality Science Enabling Products to the community.

  8. The influence factors in image quality of multi-slice spiral CT coronary angiography (MSCTA)

    International Nuclear Information System (INIS)

    Zeng Huiliang; Zhu Xinjin; Liang Jianhao; Zhong Yingze; Chen Xueguang; Ou Weiqian; Wen Haomao; Li Peiwen

    2007-01-01

    Objective: To evaluate the influence of heart rate on image quality of multi-slice spiral CT coronary angiography(MSCTA) and the optimization of image reconstruction windows. Methods: Retrospectively ECG-gated MSCT coronary angiography were performed in 67 cases. The cases were divided into four groups by heart rate, groupl with heart rate less than 60 beats per minute(bpm), group 2 with heart rate 61-70 bpm, group 3 with heart rate 71-80 bpm and group 4 with heart rate over 81 bpm. The impact of heart rate on image quality of MSCTA and the optimization of image reconstruction windows were evaluated. Results: 4 coronary (RCA,LM,LAD,LCX) segments were analyzed in each patients with regard to image quality. 86.7%(112/128) of the coronary segments were sufficient for analysis in patients with heart rate less than 60 bpm,62.5%(55/88) with 61-70 bpm,40%(8/20) with 71-80 bpm and 12.5%(2/16) with heart rate over 81 bpm, respectively. There were statistically significances between every coronary segments of group 1 and 2, group 3 and 4 (P<0.05). All coronary segments of group 1 were optimally visualized on the image reconstructed at 75% image reconstruction window of' cardiac cycle; 89.5% cases at 75% in group 2; for group 3.55% of coronary artery were best presented at 75% image reconstruction window, 45% of coronary artery at 45%; All coronary segments of group 4 were optimally visualized on the image reconstructed at 45% image reconstruction window. Conclusion: Image quality of MSCT coronary angiography is highly dependent on heart rate. Coronary artery is usually best shown at 75% image reconstruction window of cardiac cycle for those with heart rate less than 70 bpm. 30%-90% image reconstruction should be performed when heart rate is over 71 bpm. (authors)

  9. Image quality enhancement for skin cancer optical diagnostics

    Science.gov (United States)

    Bliznuks, Dmitrijs; Kuzmina, Ilona; Bolocko, Katrina; Lihachev, Alexey

    2017-12-01

    The research presents image quality analysis and enhancement proposals in biophotonic area. The sources of image problems are reviewed and analyzed. The problems with most impact in biophotonic area are analyzed in terms of specific biophotonic task - skin cancer diagnostics. The results point out that main problem for skin cancer analysis is the skin illumination problems. Since it is often not possible to prevent illumination problems, the paper proposes image post processing algorithm - low frequency filtering. Practical results show diagnostic results improvement after using proposed filter. Along that, filter do not reduces diagnostic results' quality for images without illumination defects. Current filtering algorithm requires empirical tuning of filter parameters. Further work needed to test the algorithm in other biophotonic applications and propose automatic filter parameter selection.

  10. Storage phosphor radiography of wrist fractures: a subjective comparison of image quality at varying exposure levels

    Energy Technology Data Exchange (ETDEWEB)

    Peer, Regina; Giacomuzzi, Salvatore M.; Bodner, Gerd; Jaschke, Werner; Peer, Siegfried [Innsbruck Univ. (Austria). Inst. fuer Radiologie; Lanser, Anton [Academy of Radiology Technicians, Innsbruck (Austria); Pechlaner, Sigurd [Department of Traumatology, University Hospital, Innsbruck (Austria); Kuenzel, Karl Heinz; Gaber, O. [Department of Anatomy and Histology, University Hospital, Innsbruck (Austria)

    2002-06-01

    Image quality of storage phosphor radiographs acquired at different exposure levels was compared to define the minimal radiation dose needed to achieve images which allow for reliable detection of wrist fractures. In a study on 33 fractured anatomical wrist specimens image quality of storage phosphor radiographs was assessed on a diagnostic PACS workstation by three observers. Images were acquired at exposure levels corresponding to a speed classes 100, 200, 400 and 800. Cortical bone surface, trabecular bone, soft tissues and fracture delineation were judged on a subjective basis. Image quality was rated according to a standard protocol and statistical evaluation was performed based on an analysis of variance (ANOVA). Images at a dose reduction of 37% were rated sufficient quality without loss in diagnostic accuracy. Sufficient trabecular and cortical bone presentation was still achieved at a dose reduction of 62%. The latter images, however, were considered unacceptable for fracture detection. To achieve high-quality storage phosphor radiographs, which allow for a reliable evaluation of wrist fractures, a minimum exposure dose equivalent to a speed class of 200 is needed. For general-purpose skeletal radiography, however, a dose reduction of up to 62% can be achieved. A choice of exposure settings according to the clinical situation (ALARA principle) is recommended to achieve possible dose reductions. (orig.)

  11. Image quality of multiplanar reconstruction of pulmonary CT scans using adaptive statistical iterative reconstruction.

    Science.gov (United States)

    Honda, O; Yanagawa, M; Inoue, A; Kikuyama, A; Yoshida, S; Sumikawa, H; Tobino, K; Koyama, M; Tomiyama, N

    2011-04-01

    We investigated the image quality of multiplanar reconstruction (MPR) using adaptive statistical iterative reconstruction (ASIR). Inflated and fixed lungs were scanned with a garnet detector CT in high-resolution mode (HR mode) or non-high-resolution (HR) mode, and MPR images were then reconstructed. Observers compared 15 MPR images of ASIR (40%) and ASIR (80%) with those of ASIR (0%), and assessed image quality using a visual five-point scale (1, definitely inferior; 5, definitely superior), with particular emphasis on normal pulmonary structures, artefacts, noise and overall image quality. The mean overall image quality scores in HR mode were 3.67 with ASIR (40%) and 4.97 with ASIR (80%). Those in non-HR mode were 3.27 with ASIR (40%) and 3.90 with ASIR (80%). The mean artefact scores in HR mode were 3.13 with ASIR (40%) and 3.63 with ASIR (80%), but those in non-HR mode were 2.87 with ASIR (40%) and 2.53 with ASIR (80%). The mean scores of the other parameters were greater than 3, whereas those in HR mode were higher than those in non-HR mode. There were significant differences between ASIR (40%) and ASIR (80%) in overall image quality (pASIR did not suppress the severe artefacts of contrast medium. In general, MPR image quality with ASIR (80%) was superior to that with ASIR (40%). However, there was an increased incidence of artefacts by ASIR when CT images were obtained in non-HR mode.

  12. Association Between Echocardiography Laboratory Accreditation and the Quality of Imaging and Reporting for Valvular Heart Disease.

    Science.gov (United States)

    Thaden, Jeremy J; Tsang, Michael Y; Ayoub, Chadi; Padang, Ratnasari; Nkomo, Vuyisile T; Tucker, Stephen F; Cassidy, Cynthia S; Bremer, Merri; Kane, Garvan C; Pellikka, Patricia A

    2017-08-01

    It is presumed that echocardiographic laboratory accreditation leads to improved quality, but there are few data. We sought to compare the quality of echocardiographic examinations performed at accredited versus nonaccredited laboratories for the evaluation of valvular heart disease. We enrolled 335 consecutive valvular heart disease subjects who underwent echocardiography at our institution and an external accredited or nonaccredited institution within 6 months. Completeness and quality of echocardiographic reports and images were assessed by investigators blinded to the external laboratory accreditation status and echocardiographic results. Compared with nonaccredited laboratories, accredited sites more frequently reported patient sex (94% versus 78%; P heart disease. Future quality improvement initiatives should highlight the importance of high-quality color Doppler imaging and echocardiographic quantification to improve the accuracy, reproducibility, and quality of echocardiographic studies for valvular heart disease. © 2017 American Heart Association, Inc.

  13. Evaluation of motion and its effect on brain magnetic resonance image quality in children

    Energy Technology Data Exchange (ETDEWEB)

    Afacan, Onur; Erem, Burak; Roby, Diona P.; Prabhu, Sanjay P.; Warfield, Simon K. [Boston Children' s Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States); Roth, Noam; Roth, Amir [Robin Medical Inc., Baltimore, MD (United States)

    2016-11-15

    Motion artifacts pose significant problems for the acquisition of MR images in pediatric populations. To evaluate temporal motion metrics in MRI scanners and their effect on image quality in pediatric populations in neuroimaging studies. We report results from a large pediatric brain imaging study that shows the effect of motion on MRI quality. We measured motion metrics in 82 pediatric patients, mean age 13.4 years, in a T1-weighted brain MRI scan. As a result of technical difficulties, 5 scans were not included in the subsequent analyses. A radiologist graded the images using a 4-point scale ranging from clinically non-diagnostic because of motion artifacts to no motion artifacts. We used these grades to correlate motion parameters such as maximum motion, mean displacement from a reference point, and motion-free time with image quality. Our results show that both motion-free time (as a ratio of total scan time) and average displacement from a position at a fixed time (when the center of k-space was acquired) were highly correlated with image quality, whereas maximum displacement was not as good a predictor. Among the 77 patients whose motion was measured successfully, 17 had average displacements of greater than 0.5 mm, and 11 of those (14.3%) resulted in non-diagnostic images. Similarly, 14 patients (18.2%) had less than 90% motion-free time, which also resulted in non-diagnostic images. We report results from a large pediatric study to show how children and young adults move in the MRI scanner and the effect that this motion has on image quality. The results will help the motion-correction community in better understanding motion patterns in pediatric populations and how these patterns affect MR image quality. (orig.)

  14. Evaluation of motion and its effect on brain magnetic resonance image quality in children

    International Nuclear Information System (INIS)

    Afacan, Onur; Erem, Burak; Roby, Diona P.; Prabhu, Sanjay P.; Warfield, Simon K.; Roth, Noam; Roth, Amir

    2016-01-01

    Motion artifacts pose significant problems for the acquisition of MR images in pediatric populations. To evaluate temporal motion metrics in MRI scanners and their effect on image quality in pediatric populations in neuroimaging studies. We report results from a large pediatric brain imaging study that shows the effect of motion on MRI quality. We measured motion metrics in 82 pediatric patients, mean age 13.4 years, in a T1-weighted brain MRI scan. As a result of technical difficulties, 5 scans were not included in the subsequent analyses. A radiologist graded the images using a 4-point scale ranging from clinically non-diagnostic because of motion artifacts to no motion artifacts. We used these grades to correlate motion parameters such as maximum motion, mean displacement from a reference point, and motion-free time with image quality. Our results show that both motion-free time (as a ratio of total scan time) and average displacement from a position at a fixed time (when the center of k-space was acquired) were highly correlated with image quality, whereas maximum displacement was not as good a predictor. Among the 77 patients whose motion was measured successfully, 17 had average displacements of greater than 0.5 mm, and 11 of those (14.3%) resulted in non-diagnostic images. Similarly, 14 patients (18.2%) had less than 90% motion-free time, which also resulted in non-diagnostic images. We report results from a large pediatric study to show how children and young adults move in the MRI scanner and the effect that this motion has on image quality. The results will help the motion-correction community in better understanding motion patterns in pediatric populations and how these patterns affect MR image quality. (orig.)

  15. Structural similarity image quality reliability: Determining parameters and window size

    OpenAIRE

    Silvestre-Blanes, Javier

    2011-01-01

    The need to obtain objective values of the quality of distorted images with respect to the original is fundamental in multimedia and image processing applications. It is generally required that this value correlates well with the human vision system (HVS). In spite of the properties and the general use of the mean square error (MSE) measurement, this has a poor correlation with HSV, which has led to the development of methods such as structural similarity (SSIM). This metric improves the corr...

  16. PET/CT Atlas on Quality Control and Image Artefacts

    International Nuclear Information System (INIS)

    2014-01-01

    Combined positron emission tomography (PET)/computed tomography (CT) imaging has become a routine procedure in diagnostic radiology and nuclear medicine. The clinical review of both PET and PET/CT images requires a thorough understanding of the basics of image formation as well as an appreciation of variations of inter-patient and intra-patient image appearance. Such variations may be caused by variations in tracer accumulation and metabolism, and, perhaps more importantly, by image artefacts related to methodological pitfalls of the two modalities. This atlas on quality control (QC) and PET/CT artefacts provides guidance on typical image distortions in clinical PET/CT usage scenarios. A number of cases are presented to provide nuclear medicine and radiology professionals with an assortment of examples of possible image distortions and errors in order to support the correct interpretation of images. About 70 typical PET and PET/CT cases, comprised of image sets and cases, have been collected in this book, and all have been catalogued and have explanations as to the causes of and solutions to each individual image problem. This atlas is intended to be used as a guide on how to take proper QC measures, on performing situation and problem analysis, and on problem prevention. This book will be especially useful to medical physicists, physicians, technologists and service engineers in the clinical field

  17. The dose and image quality in mammography in Macedonia

    International Nuclear Information System (INIS)

    Gershan, V.

    2007-01-01

    Complete test of publication follows. Mean Glandular Dose (MGD), dose distribution, phantom and quality of the real mammogram were studied for the first time in Macedonia. The study was conducted to review the condition of mammography equipment, to access the dose and image quality in mammography practices in Macedonia.. The purpose was to find out the weak points in the mammography practices in order to suggest improvements in the practices and establish quality control procedures. Under evaluation were 12 monographic machines. MGD was estimated using Entrance Surface Air KERMA at the breast surface K f measured free in air and appropriate conversion factors. Dose survey was curried by measurement and calculated of the HVLs and radiation output for 25-32 kVp and keeping record of the clinical parameters (breast thickness, kVp, mAs). Image quality was evaluated using the Mammographic Accreditation Phantom Gammex 156, PMMA plates and test tool for film processing.

  18. Collimation effects on the radiation detectors in the iCT image quality

    International Nuclear Information System (INIS)

    Carvalho, Diego Vergacas de Sousa; Kirita, Rodrigo; Mesquita, Carlos Henrique de; Hamada, Margarida Mizue; Ferreira, Erick Oliveira; Dantas, Carlos Costa

    2013-01-01

    This work studies the collimation effect in radiation detectors on the image quality of the iCT scanner, in which the path traversed by radiation beams is similar to a fan. The collimators were made of lead, 5 cm deep and 12 cm high, with rectangular holes (slits) of 2 x 5 mm, 4 x 10 mm (width x height) and circular hole of 5 mm diameter. The matrix images reconstructed from the data obtained with these collimation holes are presented. The spatial resolution of the image depends on the geometry of the collimator. One of the major advantages of narrow beam transmission tomography is the so-called hard field property. This property is capable of producing high quality images, though it decreases the count value and it takes a longer time. In contrast, a large collimation diameter produces a fuzzy image but with a faster scanning time. Moreover, the enlargement of the aperture from 2 x 5 mm to 4 x 10 mm barely affects the image quality. The aperture from 4 x 10 mm and 5 mm diameter presented similar quality image. (author)

  19. Collimation effects on the radiation detectors in the iCT image quality

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Diego Vergacas de Sousa; Kirita, Rodrigo; Mesquita, Carlos Henrique de; Hamada, Margarida Mizue, E-mail: dvcarvalho@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ferreira, Erick Oliveira; Dantas, Carlos Costa [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear

    2013-07-01

    This work studies the collimation effect in radiation detectors on the image quality of the iCT scanner, in which the path traversed by radiation beams is similar to a fan. The collimators were made of lead, 5 cm deep and 12 cm high, with rectangular holes (slits) of 2 x 5 mm, 4 x 10 mm (width x height) and circular hole of 5 mm diameter. The matrix images reconstructed from the data obtained with these collimation holes are presented. The spatial resolution of the image depends on the geometry of the collimator. One of the major advantages of narrow beam transmission tomography is the so-called hard field property. This property is capable of producing high quality images, though it decreases the count value and it takes a longer time. In contrast, a large collimation diameter produces a fuzzy image but with a faster scanning time. Moreover, the enlargement of the aperture from 2 x 5 mm to 4 x 10 mm barely affects the image quality. The aperture from 4 x 10 mm and 5 mm diameter presented similar quality image. (author)

  20. Dual-source CT coronary imaging in heart transplant recipients: image quality and optimal reconstruction interval

    International Nuclear Information System (INIS)

    Bastarrika, Gorka; Arraiza, Maria; Pueyo, Jesus C.; Cecco, Carlo N. de; Ubilla, Matias; Mastrobuoni, Stefano; Rabago, Gregorio

    2008-01-01

    The image quality and optimal reconstruction interval for coronary arteries in heart transplant recipients undergoing non-invasive dual-source computed tomography (DSCT) coronary angiography was evaluated. Twenty consecutive heart transplant recipients who underwent DSCT coronary angiography were included (19 male, one female; mean age 63.1±10.7 years). Data sets were reconstructed in 5% steps from 30% to 80% of the R-R interval. Two blinded independent observers assessed the image quality of each coronary segments using a five-point scale (from 0 = not evaluative to 4=excellent quality). A total of 289 coronary segments in 20 heart transplant recipients were evaluated. Mean heart rate during the scan was 89.1±10.4 bpm. At the best reconstruction interval, diagnostic image quality (score ≥2) was obtained in 93.4% of the coronary segments (270/289) with a mean image quality score of 3.04± 0.63. Systolic reconstruction intervals provided better image quality scores than diastolic reconstruction intervals (overall mean quality scores obtained with the systolic and diastolic reconstructions 3.03±1.06 and 2.73±1.11, respectively; P<0.001). Different systolic reconstruction intervals (35%, 40%, 45% of RR interval) did not yield to significant differences in image quality scores for the coronary segments (P=0.74). Reconstructions obtained at the systolic phase of the cardiac cycle allowed excellent diagnostic image quality coronary angiograms in heart transplant recipients undergoing DSCT coronary angiography. (orig.)

  1. High-resolution CCD imaging alternatives

    Science.gov (United States)

    Brown, D. L.; Acker, D. E.

    1992-08-01

    High resolution CCD color cameras have recently stimulated the interest of a large number of potential end-users for a wide range of practical applications. Real-time High Definition Television (HDTV) systems are now being used or considered for use in applications ranging from entertainment program origination through digital image storage to medical and scientific research. HDTV generation of electronic images offers significant cost and time-saving advantages over the use of film in such applications. Further in still image systems electronic image capture is faster and more efficient than conventional image scanners. The CCD still camera can capture 3-dimensional objects into the computing environment directly without having to shoot a picture on film develop it and then scan the image into a computer. 2. EXTENDING CCD TECHNOLOGY BEYOND BROADCAST Most standard production CCD sensor chips are made for broadcast-compatible systems. One popular CCD and the basis for this discussion offers arrays of roughly 750 x 580 picture elements (pixels) or a total array of approximately 435 pixels (see Fig. 1). FOR. A has developed a technique to increase the number of available pixels for a given image compared to that produced by the standard CCD itself. Using an inter-lined CCD with an overall spatial structure several times larger than the photo-sensitive sensor areas each of the CCD sensors is shifted in two dimensions in order to fill in spatial gaps between adjacent sensors.

  2. Optimization of image quality and patient dose in mammography

    International Nuclear Information System (INIS)

    Shafqat Faaruq; Jaferi, R.A.; Nafeesa Nazlee

    2007-01-01

    Complete test of publication follows. Optimization of patient dose and image quality can be defined as to get the best image quality with minimum possible radiation dose to the patient by setting various parameters and modes of operation available in mammography machines. The optimization procedures were performed on two mammography units from M/S GE and Metaltronica, available at NORI, using standard mammographic accreditation phantom (Model: BR-156) and acrylic sheets of variable thicknesses. Quality assurance and quality control (QC) tests being the essential part of optimization. The QC tests as recommended by American College of Radiology, were first performed on both machines as well as X-ray film processor. In the second step, different affecting the image quality and radiation dose to patient, like film screen combination (FSC), phantom optical density (PD), kVp, mAs etc, were adjusted for various phantom thicknesses ranging from 3 cm to 6.5 cm in various modes of operation in the machines (semi-auto- and manual in GE, Auto-, semi-auto- and manual mode in Metaltronica). The image quality was studied for these optimized parameters on the basis of the number of test objects of the phantom visible in these images. Finally the linear relationship between mAs and skin entrance dose (mGy) was verified using ionization chamber with the phantom and the actual patients. Despite some practical limitations, the results of the quality assurance tests were within acceptable limits defined by ACR. The dose factor for GE was 68.0 y/mAs, while 76.0 mGy/mAs for Metaltronica at 25 kVp. Before the start of this study the only one mammography unit GE, was routinely used at NORI and normal mode of operation of this unit was semi-auto mode with fixed kVp independent of compressed breast thickness, but in this study it was concluded that selecting kVp according to beast thickness result in an appreciable dose reduction (4-5 times less) without any compromise in image quality. The

  3. TU-AB-207A-03: Image Quality, Dose, and Clinical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Dong, F. [The Cleveland Clinic (United States)

    2016-06-15

    in the reconstructed images. Because of the limited scope of this course, only major imaging artifacts, their appearance, and possible mitigation and corrections will be discussed. Assessment of the performance of a CT scanner is a complicated subject. Procedures to measure common image quality metrics such as high contrast spatial resolution, low contrast detectability, and slice profile will be described. The reason why these metrics used for FBP may not be sufficient for statistical iterative reconstruction will be explained. Optimizing radiation dose requires comprehension of CT dose metrics. This course will briefly describe various dose metrics, and interaction with acquisition parameters and patient habitus. CT is among the most frequently used imaging tools due to its superior image quality, easy to operate, and a broad range of applications. This course will present several interesting CT applications such as a mobile CT unit on an ambulance for stroke patients, low dose lung cancer screening, and single heartbeat cardiac CT. Learning Objectives: Understand the function and impact of major components of X-ray tube on the image quality. Understand the function and impact of major components of CT detector on the image quality. Be familiar with the basic procedure of CT image reconstruction. Understand the effect of image reconstruction on CT image quality and artifacts. Understand the root causes of common CT image artifacts. Be familiar with image quality metrics especially high and low contrast resolution, noise power spectrum, slice sensitivity profile, etc. Understand why basic image quality metrics used for FBP may not be sufficient to characterize the performance of advanced iterative reconstruction. Be familiar with various CT dose metrics and their interaction with acquisition parameters. New development in advanced CT clinical applications. JH: Employee of GE Healthcare. FD: No disclosure.; J. Hsieh, Jiang Hsieh is an employee of GE Healthcare.

  4. TU-AB-207A-03: Image Quality, Dose, and Clinical Applications

    International Nuclear Information System (INIS)

    Dong, F.

    2016-01-01

    in the reconstructed images. Because of the limited scope of this course, only major imaging artifacts, their appearance, and possible mitigation and corrections will be discussed. Assessment of the performance of a CT scanner is a complicated subject. Procedures to measure common image quality metrics such as high contrast spatial resolution, low contrast detectability, and slice profile will be described. The reason why these metrics used for FBP may not be sufficient for statistical iterative reconstruction will be explained. Optimizing radiation dose requires comprehension of CT dose metrics. This course will briefly describe various dose metrics, and interaction with acquisition parameters and patient habitus. CT is among the most frequently used imaging tools due to its superior image quality, easy to operate, and a broad range of applications. This course will present several interesting CT applications such as a mobile CT unit on an ambulance for stroke patients, low dose lung cancer screening, and single heartbeat cardiac CT. Learning Objectives: Understand the function and impact of major components of X-ray tube on the image quality. Understand the function and impact of major components of CT detector on the image quality. Be familiar with the basic procedure of CT image reconstruction. Understand the effect of image reconstruction on CT image quality and artifacts. Understand the root causes of common CT image artifacts. Be familiar with image quality metrics especially high and low contrast resolution, noise power spectrum, slice sensitivity profile, etc. Understand why basic image quality metrics used for FBP may not be sufficient to characterize the performance of advanced iterative reconstruction. Be familiar with various CT dose metrics and their interaction with acquisition parameters. New development in advanced CT clinical applications. JH: Employee of GE Healthcare. FD: No disclosure.; J. Hsieh, Jiang Hsieh is an employee of GE Healthcare.

  5. Quality assurance of imaging instruments for nuclear medicine

    International Nuclear Information System (INIS)

    Sera, T.; Csernay, L.

    1993-01-01

    Advanced quality control and assurance techniques for imaging instrumentation used in medical diagnosis are overviewed. The measurement systems for the homogeneity, linearity, geometrical resolution, energy resolution, sensitivity and pulse yield output of gamma camera detectors are presented in detail. The two most important quality control standards, the National Electrical Manufacturers' Association (NEMA) and the International Atomic Energy Agency standards and tests are described. Their use in gamma camera calibration is proposed. (R.P.) 22 refs.; 1 tabs

  6. Enhancement of positron emission tomography-computed tomography image quality using the principle of stochastic resonance

    International Nuclear Information System (INIS)

    Pandey, Anil Kumar; Sharma, Sanjay Kumar; Sharma, Punit; Singh, Harmandeep; Patel, Chetan; Sarkar, Kaushik; Kumar, Rakesh; Bal, Chandra Sekhar

    2014-01-01

    Acquisition of higher counts improves visual perception of positron emission tomography-computed tomography (PET-CT) image. Larger radiopharmaceutical doses (implies more radiation dose) are administered to acquire this count in a short time period. However, diagnostic information does not increase after a certain threshold of counts. This study was conducted to develop a post processing method based on principle of “stochastic resonance” to improve visual perception of the PET-CT image having a required threshold counts. PET-CT images (JPEG file format) with low, medium, and high counts in the image were included in this study. The image was corrupted with the addition of Poisson noise. The amplitude of the Poisson noise was adjusted by dividing each pixel by a constant 1, 2, 4, 8, 16, and 32. The best amplitude of the noise that gave best images quality was selected based on high value of entropy of the output image, high value of structural similarity index and feature similarity index. Visual perception of the image was evaluated by two nuclear medicine physicians. The variation in structural and feature similarity of the image was not appreciable visually, but statistically images deteriorated as the noise amplitude increases although maintaining structural (above 70%) and feature (above 80%) similarity of input images in all cases. We obtained the best image quality at noise amplitude “4” in which 88% structural and 95% feature similarity of the input images was retained. This method of stochastic resonance can be used to improve the visual perception of the PET-CT image. This can indirectly lead to reduction of radiation dose

  7. Analysis and Comparison of Objective Methods for Image Quality Assessment

    Directory of Open Access Journals (Sweden)

    P. S. Babkin

    2014-01-01

    Full Text Available The purpose of this work is research and modification of the reference objective methods for image quality assessment. The ultimate goal is to obtain a modification of formal assessments that more closely corresponds to the subjective expert estimates (MOS.In considering the formal reference objective methods for image quality assessment we used the results of other authors, which offer results and comparative analyzes of the most effective algorithms. Based on these investigations we have chosen two of the most successful algorithm for which was made a further analysis in the MATLAB 7.8 R 2009 a (PQS and MSSSIM. The publication focuses on the features of the algorithms, which have great importance in practical implementation, but are insufficiently covered in the publications by other authors.In the implemented modification of the algorithm PQS boundary detector Kirsch was replaced by the boundary detector Canny. Further experiments were carried out according to the method of the ITU-R VT.500-13 (01/2012 using monochrome images treated with different types of filters (should be emphasized that an objective assessment of image quality PQS is applicable only to monochrome images. Images were obtained with a thermal imaging surveillance system. The experimental results proved the effectiveness of this modification.In the specialized literature in the field of formal to evaluation methods pictures, this type of modification was not mentioned.The method described in the publication can be applied to various practical implementations of digital image processing.Advisability and effectiveness of using the modified method of PQS to assess the structural differences between the images are shown in the article and this will be used in solving the problems of identification and automatic control.

  8. Presence capture cameras - a new challenge to the image quality

    Science.gov (United States)

    Peltoketo, Veli-Tapani

    2016-04-01

    Commercial presence capture cameras are coming to the markets and a new era of visual entertainment starts to get its shape. Since the true presence capturing is still a very new technology, the real technical solutions are just passed a prototyping phase and they vary a lot. Presence capture cameras have still the same quality issues to tackle as previous phases of digital imaging but also numerous new ones. This work concentrates to the quality challenges of presence capture cameras. A camera system which can record 3D audio-visual reality as it is has to have several camera modules, several microphones and especially technology which can synchronize output of several sources to a seamless and smooth virtual reality experience. Several traditional quality features are still valid in presence capture cameras. Features like color fidelity, noise removal, resolution and dynamic range create the base of virtual reality stream quality. However, co-operation of several cameras brings a new dimension for these quality factors. Also new quality features can be validated. For example, how the camera streams should be stitched together with 3D experience without noticeable errors and how to validate the stitching? The work describes quality factors which are still valid in the presence capture cameras and defines the importance of those. Moreover, new challenges of presence capture cameras are investigated in image and video quality point of view. The work contains considerations how well current measurement methods can be used in presence capture cameras.

  9. A novel high-frequency encoding algorithm for image compression

    Science.gov (United States)

    Siddeq, Mohammed M.; Rodrigues, Marcos A.

    2017-12-01

    In this paper, a new method for image compression is proposed whose quality is demonstrated through accurate 3D reconstruction from 2D images. The method is based on the discrete cosine transform (DCT) together with a high-frequency minimization encoding algorithm at compression stage and a new concurrent binary search algorithm at decompression stage. The proposed compression method consists of five main steps: (1) divide the image into blocks and apply DCT to each block; (2) apply a high-frequency minimization method to the AC-coefficients reducing each block by 2/3 resulting in a minimized array; (3) build a look up table of probability data to enable the recovery of the original high frequencies at decompression stage; (4) apply a delta or differential operator to the list of DC-components; and (5) apply arithmetic encoding to the outputs of steps (2) and (4). At decompression stage, the look up table and the concurrent binary search algorithm are used to reconstruct all high-frequency AC-coefficients while the DC-components are decoded by reversing the arithmetic coding. Finally, the inverse DCT recovers the original image. We tested the technique by compressing and decompressing 2D images including images with structured light patterns for 3D reconstruction. The technique is compared with JPEG and JPEG2000 through 2D and 3D RMSE. Results demonstrate that the proposed compression method is perceptually superior to JPEG with equivalent quality to JPEG2000. Concerning 3D surface reconstruction from images, it is demonstrated that the proposed method is superior to both JPEG and JPEG2000.

  10. Dual Channel Pulse Coupled Neural Network Algorithm for Fusion of Multimodality Brain Images with Quality Analysis

    Directory of Open Access Journals (Sweden)

    Kavitha SRINIVASAN

    2014-09-01

    Full Text Available Background: In the review of medical imaging techniques, an important fact that emerged is that radiologists and physicians still are in a need of high-resolution medical images with complementary information from different modalities to ensure efficient analysis. This requirement should have been sorted out using fusion techniques with the fused image being used in image-guided surgery, image-guided radiotherapy and non-invasive diagnosis. Aim: This paper focuses on Dual Channel Pulse Coupled Neural Network (PCNN Algorithm for fusion of multimodality brain images and the fused image is further analyzed using subjective (human perception and objective (statistical measures for the quality analysis. Material and Methods: The modalities used in fusion are CT, MRI with subtypes T1/T2/PD/GAD, PET and SPECT, since the information from each modality is complementary to one another. The objective measures selected for evaluation of fused image were: Information Entropy (IE - image quality, Mutual Information (MI – deviation in fused to the source images and Signal to Noise Ratio (SNR – noise level, for analysis. Eight sets of brain images with different modalities (T2 with T1, T2 with CT, PD with T2, PD with GAD, T2 with GAD, T2 with SPECT-Tc, T2 with SPECT-Ti, T2 with PET are chosen for experimental purpose and the proposed technique is compared with existing fusion methods such as the Average method, the Contrast pyramid, the Shift Invariant Discrete Wavelet Transform (SIDWT with Harr and the Morphological pyramid, using the selected measures to ascertain relative performance. Results: The IE value and SNR value of the fused image derived from dual channel PCNN is higher than other fusion methods, shows that the quality is better with less noise. Conclusion: The fused image resulting from the proposed method retains the contrast, shape and texture as in source images without false information or information loss.

  11. Practical guide to quality assurance in medical imaging

    International Nuclear Information System (INIS)

    Moores, M.; Watkinson, S.; Pearcy, J.; Henshaw, E.T.

    1987-01-01

    This volume forms an important part of the response to a growing need to ensure the same and cost-effective use of ionizing radiations for the benefit of both staff and patients. The authors provide guidance to implementing and running quality assurance programs in medical imaging departments. The treatment provides an overview of all the tests which need to be carried out in medical imaging, and the text contains step-by-step guidance as to how to perform and interpret the results of medical imaging

  12. Effect of forage quality in faeces from different ruminant species fed high and low quality forage

    DEFF Research Database (Denmark)

    Jalali, A R; Nørgaard, P; Nielsen, M O

    2010-01-01

    Effect of forage quality in faeces from different ruminant species fed high and low quality forage......Effect of forage quality in faeces from different ruminant species fed high and low quality forage...

  13. Registration accuracy and quality of real-life images.

    Directory of Open Access Journals (Sweden)

    Wei-Yen Hsu

    Full Text Available BACKGROUND: A common registration problem for the application of consumer device is to align all the acquired image sequences into a complete scene. Image alignment requires a registration algorithm that will compensate as much as possible for geometric variability among images. However, images captured views from a real scene usually produce different distortions. Some are derived from the optic characteristics of image sensors, and others are caused by the specific scenes and objects. METHODOLOGY/PRINCIPAL FINDINGS: An image registration algorithm considering the perspective projection is proposed for the application of consumer devices in this study. It exploits a multiresolution wavelet-based method to extract significant features. An analytic differential approach is then proposed to achieve fast convergence of point matching. Finally, the registration accuracy is further refined to obtain subpixel precision by a feature-based modified Levenberg-Marquardt method. Due to its feature-based and nonlinear characteristic, it converges considerably faster than most other methods. In addition, vignette compensation and color difference adjustment are also performed to further improve the quality of registration results. CONCLUSIONS/SIGNIFICANCE: The performance of the proposed method is evaluated by testing the synthetic and real images acquired by a hand-held digital still camera and in comparison with two registration techniques in terms of the squared sum of intensity differences (SSD and correlation coefficient (CC. The results indicate that the proposed method is promising in registration accuracy and quality, which are statistically significantly better than other two approaches.

  14. Developing optimized CT scan protocols: Phantom measurements of image quality

    International Nuclear Information System (INIS)

    Zarb, Francis; Rainford, Louise; McEntee, Mark F.

    2011-01-01

    Purpose: The increasing frequency of computerized tomography (CT) examinations is well documented, leading to concern about potential radiation risks for patients. However, the consequences of not performing the CT examination and missing injuries and disease are potentially serious, impacting upon correct patient management. The ALARA principle of dose optimization must be employed for all justified CT examinations. Dose indicators displayed on the CT console as either CT dose index (CTDI) and/or dose length product (DLP), are used to indicate dose and can quantify improvements achieved through optimization. Key scan parameters contributing to dose have been identified in previous literature and in previous work by our group. The aim of this study was to optimize the scan parameters of mA; kV and pitch, whilst maintaining image quality and reducing dose. This research was conducted using psychophysical image quality measurements on a CT quality assurance (QA) phantom establishing the impact of dose optimization on image quality parameters. Method: Current CT scan parameters for head (posterior fossa and cerebrum), abdomen and chest examinations were collected from 57% of CT suites available nationally in Malta (n = 4). Current scan protocols were used to image a Catphan 600 CT QA phantom whereby image quality was assessed. Each scan parameter: mA; kV and pitch were systematically reduced until the contrast resolution (CR), spatial resolution (SR) and noise were significantly lowered. The Catphan 600 images, produced by the range of protocols, were evaluated by 2 expert observers assessing CR, SR and noise. The protocol considered as the optimization threshold was just above the setting that resulted in a significant reduction in CR and noise but not affecting SR at the 95% confidence interval. Results: The limit of optimization threshold was determined for each CT suite. Employing optimized parameters, CTDI and DLP were both significantly reduced (p ≤ 0.001) by

  15. DIANE stationary neutron radiography system image quality and industrial applications

    International Nuclear Information System (INIS)

    Cluzeau, S.; Huet, J.; Tourneur, P. le

    1994-01-01

    The SODERN neutron radiography laboratory has operated since February 1993 using a sealed tube generator (GENIE 46). An experimental programme of characterization (dosimetry, spectroscopy) has confirmed the expected performances concerning: neutron flux intensity, neutron energy range, residual gamma flux. Results are given in a specific report [2]. This paper is devoted to the image performance reporting. ASTM and specific indicators have been used to test the image quality with various converters and films. The corresponding modulation transfer functions are to be determined from image processing. Some industrial applications have demonstrated the capabilities of the system: corrosion detection in aircraft parts, ammunitions filling testing, detection of polymer lacks in sandwich steel sheets, detection of moisture in a probe for geophysics, residual ceramic cores imaging in turbine blades. Various computerized electronic imaging systems will be tested to improve the industrial capabilities. (orig.)

  16. Assuring quality in high-consequence engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hoover, Marcey L.; Kolb, Rachel R.

    2014-03-01

    In high-consequence engineering organizations, such as Sandia, quality assurance may be heavily dependent on staff competency. Competency-dependent quality assurance models are at risk when the environment changes, as it has with increasing attrition rates, budget and schedule cuts, and competing program priorities. Risks in Sandia's competency-dependent culture can be mitigated through changes to hiring, training, and customer engagement approaches to manage people, partners, and products. Sandia's technical quality engineering organization has been able to mitigate corporate-level risks by driving changes that benefit all departments, and in doing so has assured Sandia's commitment to excellence in high-consequence engineering and national service.

  17. Performance evaluation of no-reference image quality metrics for face biometric images

    Science.gov (United States)

    Liu, Xinwei; Pedersen, Marius; Charrier, Christophe; Bours, Patrick

    2018-03-01

    The accuracy of face recognition systems is significantly affected by the quality of face sample images. The recent established standardization proposed several important aspects for the assessment of face sample quality. There are many existing no-reference image quality metrics (IQMs) that are able to assess natural image quality by taking into account similar image-based quality attributes as introduced in the standardization. However, whether such metrics can assess face sample quality is rarely considered. We evaluate the performance of 13 selected no-reference IQMs on face biometrics. The experimental results show that several of them can assess face sample quality according to the system performance. We also analyze the strengths and weaknesses of different IQMs as well as why some of them failed to assess face sample quality. Retraining an original IQM by using face database can improve the performance of such a metric. In addition, the contribution of this paper can be used for the evaluation of IQMs on other biometric modalities; furthermore, it can be used for the development of multimodality biometric IQMs.

  18. Adapting protocols of CT imaging in a pediatric emergency department. Evaluation of image quality and dose

    International Nuclear Information System (INIS)

    Batista Arce, A.; Gonzalez Lopez, S.; Catalan Acosta, A.; Casares Magaz, O.; Hernandez Armas, O.; Hernandez Armas, J.

    2011-01-01

    The purpose of this study was to assess qualitatively the picture quality in relation to the radiation dose delivered in CT studies of computer tomograph Pediatric Emergency Department of Hospital Universitario de Canarias (HUC) in order to optimize the technical parameters used these radiological examinations so as to obtain optimal image quality at the lowest possible dose.

  19. Extracting a Good Quality Frontal Face Image from a Low-Resolution Video Sequence

    DEFF Research Database (Denmark)

    Nasrollahi, Kamal; Moeslund, Thomas B.

    2011-01-01

    Feeding low-resolution and low-quality images, from inexpensive surveillance cameras, to systems like, e.g., face recognition, produces erroneous and unstable results. Therefore, there is a need for a mechanism to bridge the gap between on one hand low-resolution and low-quality images......, we use a learning-based super-resolution algorithm applied to the result of the reconstruction-based part to improve the quality by another factor of two. This results in an improvement factor of four for the entire system. The proposed system has been tested on 122 low-resolution sequences from two...... different databases. The experimental results show that the proposed system can indeed produce a high-resolution and good quality frontal face image from low-resolution video sequences....

  20. Producing high-quality slash pine seeds

    Science.gov (United States)

    James Barnett; Sue Varela

    2003-01-01

    Slash pine is a desirable species. It serves many purposes and is well adapted to poorly drained flatwoods and seasonally flooded areas along the lower Coastal Plain of the Southeastern US. The use of high-quality seeds has been shown to produce uniform seedlings for outplanting, which is key to silvicultural success along the Coastal Plain and elsewhere. We present...

  1. Endorectal high dose rate brachytherapy quality assurance

    International Nuclear Information System (INIS)

    Devic, S.; Vuong, T.; Evans, M.; Podgorsak, E.

    2008-01-01

    We describe our quality assurance method for preoperative high dose rate (HDR) brachytherapy of endorectal tumours. Reproduction of the treatment planning dose distribution on a daily basis is crucial for treatment success. Due to the cylindrical symmetry, two types of adjustments are necessary: applicator rotation and dose distribution shift along the applicator axis. (author)

  2. [Development of image quality assurance support system using image recognition technology in radiography in lacked images of chest and abdomen].

    Science.gov (United States)

    Shibuya, Toru; Kato, Kyouichi; Eshima, Hidekazu; Sumi, Shinichirou; Kubo, Tadashi; Ishida, Hideki; Nakazawa, Yasuo

    2012-01-01

    In order to provide a precise radiography for diagnosis, it is required that we avoid radiography with defects by having enough evaluation. Conventionally, evaluation was performed only by observation of a radiological technologist (RT). The evaluation support system was developed for providing a high quality assurance without depending on RT observation only. The evaluation support system, called as the Image Quality Assurance Support System (IQASS), is characterized in that "image recognition technology" for the purpose of diagnostic radiography of chest and abdomen areas. The technique of the system used in this study. Of the 259 samples of posterior-anterior (AP) chest, lateral chest, and upright abdominal x-rays, the sensitivity and specificity was 93.1% and 91.8% in the chest AP, 93.3% and 93.6% in the chest lateral, and 95.0% and 93.8% in the upright abdominal x-rays. In the light of these results, it is suggested that AIQAS could be applied to practical usage for the RT.

  3. Quality control: comparison of images quality with screen film system and digital mammography CR

    International Nuclear Information System (INIS)

    Alvarenga, Frederico L.; Nogueira, Maria do Socorro

    2008-01-01

    The mammography screen film system should be used as part of processing chemicals, revelation process, equipment and this system has have a progressive replacing by the digital technology Full Field Digital Mammography FFDM, Computed Radiography (CR) Mammography and hardcopy. This new acquisition process of medical images has improved radiology section; however it is necessary efficient means for evaluating of the quality parameters. It should be considered taking into account the adaptation of the existent equipment and that procedures adopted for the exam, as well the adaptation of the new mammography films, the radiologist view box constitutes a part of the quality control program. This program aims at obtaining radiography with good quality that allows obtaining more information for the diagnosis and decreases the patient dose. For evaluation the quality image, this article is focused on presenting the differences regarding the acquired images through simulator mammography radiographic PMMA (Poly methyl methacrylate) in CR Mammography system and screen film system. The tests were accomplished at the same equipment of Mammography with the Automatic Exposure Control using a tension of 28 kV for both systems. The quality tests evaluated the spatial resolution, the own structures of the phantom, artifacts, optical density and contrast with conventional and laser films by mammography system. The installation for the accomplishment of the test has a quality control program. The evaluation was based on the pattern developed by the competent organ of the State of Minas Gerais. In this study, it was verified that the suitable Phantom Mama used by the Brazilian School of Radiology for conventional mammography did not obtain satisfactory result for Spatial Resolution in the digital mammography system CR. The final aim of this work is to obtain parameters to characterize the reference phantom quality image in an objective way. These parameters will be used to compare

  4. Precision crystal alignment for high-resolution electron microscope imaging

    International Nuclear Information System (INIS)

    Wood, G.J.; Beeching, M.J.

    1990-01-01

    One of the more difficult tasks involved in obtaining quality high-resolution electron micrographs is the precise alignment of a specimen into the required zone. The current accepted procedure, which involves changing to diffraction mode and searching for symmetric point diffraction pattern, is insensitive to small amounts of misalignment and at best qualitative. On-line analysis of the fourier space representation of the image, both for determining and correcting crystal tilt, is investigated. 8 refs., 42 figs

  5. Mammography in Norway: Image quality and total performance

    International Nuclear Information System (INIS)

    Olsen, J.B.; Skretting, A.; Widmark, A.

    1997-04-01

    This report describes a method for assessing the total performance in mammography based on Receiver Operating Characteristic (ROC) analysis. In the time period from December 1993 to March 1994 the method was applied to assess the total performance of all the 45 Norwegian mammography laboratories operative at that time. Image quality characteristics in each laboratory was established by use of well-known phantoms

  6. New Image Qualities in Education: A Comparative Study

    Science.gov (United States)

    Çankaya, Ibrahim

    2018-01-01

    The aim of this study is to compare Turkish and European Union Countries Educations in terms of the new image qualities such as data like access to online education, digital access, foreign languages learnt per pupil, research & development investments, human resources employed in science and technology, the study opportunities offered to…

  7. Beyond image quality : designing engaging interactions with digital products

    NARCIS (Netherlands)

    Ridder, de H.; Rozendaal, M.C.

    2008-01-01

    Ubiquitous computing (or Ambient Intelligence) promises a world in which information is available anytime anywhere and with which humans can interact in a natural, multimodal way. In such world, perceptual image quality remains an important criterion since most information will be displayed

  8. Beyond image quality : Designing engaging interactions with digital products

    NARCIS (Netherlands)

    De Ridder, H.; Rozendaal, M.C.

    2008-01-01

    Ubiquitous computing (or Ambient Intelligence) promises a world in which information is available anytime anywhere and with which humans can interact in a natural, multimodal way. In such world, perceptual image quality remains an important criterion since most information will be displayed

  9. Quality measures for HRR alignment based ISAR imaging algorithms

    CSIR Research Space (South Africa)

    Janse van Rensburg, V

    2013-05-01

    Full Text Available Some Inverse Synthetic Aperture Radar (ISAR) algorithms form the image in a two-step process of range alignment and phase conjugation. This paper discusses a comprehensive set of measures used to quantify the quality of range alignment, with the aim...

  10. A Reduction in Radiographic Exposure and Image Quality in Film ...

    African Journals Online (AJOL)

    Purpose: To develop a protocol for the optimization of diagnostic chest radiography examination, the effect of radiographic exposure reduction on image quality is investigated. Procedure: Fourty-eight adult patients presenting for posterior-anterior (PA) chest radiography in a tertiary health care centre were categorized into 3 ...

  11. Determining storage related egg quality changes via digital image ...

    African Journals Online (AJOL)

    Area and length measurements related to exterior and interior egg quality were determined by digital image analysis. In general, excluding the outer thin albumen area, all of the area measurements such as total egg content area and inner thick albumen area were larger in stored eggs than in fresh eggs (52.28 vs.

  12. A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager.

    Science.gov (United States)

    Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

    2011-10-01

    Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132×124 high sensitivity imager array with a 20.1 μm pixel pitch fabricated in a standard 0.5 μ CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm(2) at a wavelength of 450 nm while consuming 718 μA from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 μW/cm(2). Implementing 4×4 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm(2) while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt.

  13. Thermoluminescence dosimetry in quality imaging in CR mammography systems

    Energy Technology Data Exchange (ETDEWEB)

    Gaona, E.; Franco E, J.G. [UAM-Xochimilco, 04960 Mexico D.F. (Mexico); Azorin N, J. [UAM-Iztapalapa, 09340 Mexico D.F. (Mexico); Diaz G, J.A.I. [CICATA, Unidad Legaria, Av. Legaria 694, 11599 mexico D.F. (Mexico); Arreola, M. [Department of Radiology, Shands Hospital at UF, PO Box 100374, Gainesville, FL 32610-0374 (United States)

    2006-07-01

    The aim of this work is to estimate the average glandular dose with Thermoluminescence Dosimetry (TLD) and comparison with quality imaging in CR mammography. For measuring dose, FDA and ACR use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, Full Field Digital Mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one CR mammography system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium fluoro halide. We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated x-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose that overcomes 3.0 mGy and it doesn't improve the image quality and dose to the breast will be excessive. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement. (Author)

  14. Thermoluminescence dosimetry in quality imaging in CR mammography systems

    International Nuclear Information System (INIS)

    Gaona, E.; Franco E, J.G.; Azorin N, J.; Diaz G, J.A.I.; Arreola, M.

    2006-01-01

    The aim of this work is to estimate the average glandular dose with Thermoluminescence Dosimetry (TLD) and comparison with quality imaging in CR mammography. For measuring dose, FDA and ACR use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, Full Field Digital Mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one CR mammography system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium fluoro halide. We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated x-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose that overcomes 3.0 mGy and it doesn't improve the image quality and dose to the breast will be excessive. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement. (Author)

  15. Comparison of quality control software tools for diffusion tensor imaging.

    Science.gov (United States)

    Liu, Bilan; Zhu, Tong; Zhong, Jianhui

    2015-04-01

    Image quality of diffusion tensor imaging (DTI) is critical for image interpretation, diagnostic accuracy and efficiency. However, DTI is susceptible to numerous detrimental artifacts that may impair the reliability and validity of the obtained data. Although many quality control (QC) software tools are being developed and are widely used and each has its different tradeoffs, there is still no general agreement on an image quality control routine for DTIs, and the practical impact of these tradeoffs is not well studied. An objective comparison that identifies the pros and cons of each of the QC tools will be helpful for the users to make the best choice among tools for specific DTI applications. This study aims to quantitatively compare the effectiveness of three popular QC tools including DTI studio (Johns Hopkins University), DTIprep (University of North Carolina at Chapel Hill, University of Iowa and University of Utah) and TORTOISE (National Institute of Health). Both synthetic and in vivo human brain data were used to quantify adverse effects of major DTI artifacts to tensor calculation as well as the effectiveness of different QC tools in identifying and correcting these artifacts. The technical basis of each tool was discussed, and the ways in which particular techniques affect the output of each of the tools were analyzed. The different functions and I/O formats that three QC tools provide for building a general DTI processing pipeline and integration with other popular image processing tools were also discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Physics-based optimization of image quality in 3D X-ray flat-panel cone-beam imaging

    NARCIS (Netherlands)

    Snoeren, R.M.

    2012-01-01

    This thesis describes the techniques for modeling and control of 3D X-ray cardiovascular systems in terms of Image Quality and patient dose, aiming at optimizing the diagnostic quality. When aiming at maximum Image Quality (IQ), a cascaded system constituted from inter-dependent imaging components,

  17. Model-Based Referenceless Quality Metric of 3D Synthesized Images Using Local Image Description.

    Science.gov (United States)

    Gu, Ke; Jakhetiya, Vinit; Qiao, Jun-Fei; Li, Xiaoli; Lin, Weisi; Thalmann, Daniel

    2017-07-28

    New challenges have been brought out along with the emerging of 3D-related technologies such as virtual reality (VR), augmented reality (AR), and mixed reality (MR). Free viewpoint video (FVV), due to its applications in remote surveillance, remote education, etc, based on the flexible selection of direction and viewpoint, has been perceived as the development direction of next-generation video technologies and has drawn a wide range of researchers' attention. Since FVV images are synthesized via a depth image-based rendering (DIBR) procedure in the "blind" environment (without reference images), a reliable real-time blind quality evaluation and monitoring system is urgently required. But existing assessment metrics do not render human judgments faithfully mainly because geometric distortions are generated by DIBR. To this end, this paper proposes a novel referenceless quality metric of DIBR-synthesized images using the autoregression (AR)-based local image description. It was found that, after the AR prediction, the reconstructed error between a DIBR-synthesized image and its AR-predicted image can accurately capture the geometry distortion. The visual saliency is then leveraged to modify the proposed blind quality metric to a sizable margin. Experiments validate the superiority of our no-reference quality method as compared with prevailing full-, reduced- and no-reference models.

  18. Full-reference quality assessment of stereoscopic images by learning binocular receptive field properties.

    Science.gov (United States)

    Shao, Feng; Li, Kemeng; Lin, Weisi; Jiang, Gangyi; Yu, Mei; Dai, Qionghai

    2015-10-01

    Quality assessment of 3D images encounters more challenges than its 2D counterparts. Directly applying 2D image quality metrics is not the solution. In this paper, we propose a new full-reference quality assessment for stereoscopic images by learning binocular receptive field properties to be more in line with human visual perception. To be more specific, in the training phase, we learn a multiscale dictionary from the training database, so that the latent structure of images can be represented as a set of basis vectors. In the quality estimation phase, we compute sparse feature similarity index based on the estimated sparse coefficient vectors by considering their phase difference and amplitude difference, and compute global luminance similarity index by considering luminance changes. The final quality score is obtained by incorporating binocular combination based on sparse energy and sparse complexity. Experimental results on five public 3D image quality assessment databases demonstrate that in comparison with the most related existing methods, the devised algorithm achieves high consistency with subjective assessment.

  19. Latin American image quality survey in digital mammography studies

    International Nuclear Information System (INIS)

    Mora, Patricia; Khoury, Helen; Bitelli, Regina; Quintero, Ana Rosa; Garay, Fernando; Garcia Aguilar, Juan; Gamarra, Mirtha; Ubeda, Carlos

    2017-01-01

    Under International Atomic Energy Agency regional programme TSA3 Radiological Protection of Patients in Medical Exposures, Latin American countries evaluated the image quality and glandular doses for digital mammography equipment with the purpose of seeing the performance and compliance with international recommendations. Totally, 24 institutions participated from Brazil, Chile, Costa Rica, El Salvador, Mexico, Paraguay and Venezuela. Signal difference noise ratio results showed for CR poor compliance with tolerances; better results were obtained for full-field digital mammography equipment. Mean glandular dose results showed that the majority of units have values below the acceptable dose levels. This joint Latin American project identified common problems: difficulty in working with digital images and lack of specific training by medical physicists from the region. Image quality is a main issue not being satisfied in accordance with international recommendations; optimisation processes in which the doses are increased should be very carefully done in order to improve early detection of any cancer signs. (authors)

  20. Improving image quality of parallel phase-shifting digital holography

    International Nuclear Information System (INIS)

    Awatsuji, Yasuhiro; Tahara, Tatsuki; Kaneko, Atsushi; Koyama, Takamasa; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

    2008-01-01

    The authors propose parallel two-step phase-shifting digital holography to improve the image quality of parallel phase-shifting digital holography. The proposed technique can increase the effective number of pixels of hologram twice in comparison to the conventional parallel four-step technique. The increase of the number of pixels makes it possible to improve the image quality of the reconstructed image of the parallel phase-shifting digital holography. Numerical simulation and preliminary experiment of the proposed technique were conducted and the effectiveness of the technique was confirmed. The proposed technique is more practical than the conventional parallel phase-shifting digital holography, because the composition of the digital holographic system based on the proposed technique is simpler.

  1. Simultaneous analysis and quality assurance for diffusion tensor imaging.

    Directory of Open Access Journals (Sweden)

    Carolyn B Lauzon

    Full Text Available Diffusion tensor imaging (DTI enables non-invasive, cyto-architectural mapping of in vivo tissue microarchitecture through voxel-wise mathematical modeling of multiple magnetic resonance imaging (MRI acquisitions, each differently sensitized to water diffusion. DTI computations are fundamentally estimation processes and are sensitive to noise and artifacts. Despite widespread adoption in the neuroimaging community, maintaining consistent DTI data quality remains challenging given the propensity for patient motion, artifacts associated with fast imaging techniques, and the possibility of hardware changes/failures. Furthermore, the quantity of data acquired per voxel, the non-linear estimation process, and numerous potential use cases complicate traditional visual data inspection approaches. Currently, quality inspection of DTI data has relied on visual inspection and individual processing in DTI analysis software programs (e.g. DTIPrep, DTI-studio. However, recent advances in applied statistical methods have yielded several different metrics to assess noise level, artifact propensity, quality of tensor fit, variance of estimated measures, and bias in estimated measures. To date, these metrics have been largely studied in isolation. Herein, we select complementary metrics for integration into an automatic DTI analysis and quality assurance pipeline. The pipeline completes in 24 hours, stores statistical outputs, and produces a graphical summary quality analysis (QA report. We assess the utility of this streamlined approach for empirical quality assessment on 608 DTI datasets from pediatric neuroimaging studies. The efficiency and accuracy of quality analysis using the proposed pipeline is compared with quality analysis based on visual inspection. The unified pipeline is found to save a statistically significant amount of time (over 70% while improving the consistency of QA between a DTI expert and a pool of research associates. Projection of QA

  2. A quality-refinement process for medical imaging applications.

    Science.gov (United States)

    Neuhaus, J; Maleike, D; Nolden, M; Kenngott, H-G; Meinzer, H-P; Wolf, I

    2009-01-01

    To introduce and evaluate a process for refinement of software quality that is suitable to research groups. In order to avoid constraining researchers too much, the quality improvement process has to be designed carefully. The scope of this paper is to present and evaluate a process to advance quality aspects of existing research prototypes in order to make them ready for initial clinical studies. The proposed process is tailored for research environments and therefore more lightweight than traditional quality management processes. Focus on quality criteria that are important at the given stage of the software life cycle. Usage of tools that automate aspects of the process is emphasized. To evaluate the additional effort that comes along with the process, it was exemplarily applied for eight prototypical software modules for medical image processing. The introduced process has been applied to improve the quality of all prototypes so that they could be successfully used in clinical studies. The quality refinement yielded an average of 13 person days of additional effort per project. Overall, 107 bugs were found and resolved by applying the process. Careful selection of quality criteria and the usage of automated process tools lead to a lightweight quality refinement process suitable for scientific research groups that can be applied to ensure a successful transfer of technical software prototypes into clinical research workflows.

  3. Effects of task and image properties on visual-attention deployment in image-quality assessment

    Science.gov (United States)

    Alers, Hani; Redi, Judith; Liu, Hantao; Heynderickx, Ingrid

    2015-03-01

    It is important to understand how humans view images and how their behavior is affected by changes in the properties of the viewed images and the task they are given, particularly the task of scoring the image quality (IQ). This is a complex behavior that holds great importance for the field of image-quality research. This work builds upon 4 years of research work spanning three databases studying image-viewing behavior. Using eye-tracking equipment, it was possible to collect information on human viewing behavior of different kinds of stimuli and under different experimental settings. This work performs a cross-analysis on the results from all these databases using state-of-the-art similarity measures. The results strongly show that asking the viewers to score the IQ significantly changes their viewing behavior. Also muting the color saturation seems to affect the saliency of the images. However, a change in IQ was not consistently found to modify visual attention deployment, neither under free looking nor during scoring. These results are helpful in gaining a better understanding of image viewing behavior under different conditions. They also have important implications on work that collects subjective image-quality scores from human observers.

  4. Objective masurement of image quality in fluoroscopic x-ray equipment FluoroQuality

    CERN Document Server

    Tapiovaara, M

    2003-01-01

    The report describes FluoroQuality, a computer program that is developed in STUK and used for measuring the image quality in medical fluoroscopic equipment. The method is based on the statistical decision theory (SDT) and the main measurement result is given in terms of the accumulation rate of the signal-to-noise ratio squared (SNR sup 2 sub r sub a sub t sub e). In addition to this quantity several other quantities are measured. These quantities include the SNR of single image frames, the spatio-temporal noise power spectrum and the temporal lag. The measurement method can be used, for example, for specifying the image quality in fluoroscopic images, for optimising the image quality and dose rate in fluoroscopy and for quality control of fluoroscopic equipment. The theory behind the measurement method is reviewed and the measurement of the various quantities is explained. An example of using the method for optimising a specified fluoroscopic procedure is given. The User's Manual of the program is included a...

  5. High Quality Virtual Reality for Architectural Exhibitions

    DEFF Research Database (Denmark)

    Kreutzberg, Anette

    2016-01-01

    This paper will summarise the findings from creating and implementing a visually high quality Virtual Reality (VR) experiment as part of an international architecture exhibition. It was the aim to represent the architectural spatial qualities as well as the atmosphere created from combining natural...... and artificial lighting in a prominent not yet built project. The outcome is twofold: Findings concerning the integration of VR in an exhibition space and findings concerning the experience of the virtual space itself. In the exhibition, an important aspect was the unmanned exhibition space, requiring the VR...... experience to be self-explanatory. Observations of different visitor reactions to the unmanned VR experience compared with visitor reactions at guided tours with personal instructions are evaluated. Data on perception of realism, spatial quality and light in the VR model were collected with qualitative...

  6. Online hyperspectral imaging system for evaluating quality of agricultural products

    Science.gov (United States)

    Mo, Changyeun; Kim, Giyoung; Lim, Jongguk

    2017-06-01

    The consumption of fresh-cut agricultural produce in Korea has been growing. The browning of fresh-cut vegetables that occurs during storage and foreign substances such as worms and slugs are some of the main causes of consumers' concerns with respect to safety and hygiene. The purpose of this study is to develop an on-line system for evaluating quality of agricultural products using hyperspectral imaging technology. The online evaluation system with single visible-near infrared hyperspectral camera in the range of 400 nm to 1000 nm that can assess quality of both surfaces of agricultural products such as fresh-cut lettuce was designed. Algorithms to detect browning surface were developed for this system. The optimal wavebands for discriminating between browning and sound lettuce as well as between browning lettuce and the conveyor belt were investigated using the correlation analysis and the one-way analysis of variance method. The imaging algorithms to discriminate the browning lettuces were developed using the optimal wavebands. The ratio image (RI) algorithm of the 533 nm and 697 nm images (RI533/697) for abaxial surface lettuce and the ratio image algorithm (RI533/697) and subtraction image (SI) algorithm (SI538-697) for adaxial surface lettuce had the highest classification accuracies. The classification accuracy of browning and sound lettuce was 100.0% and above 96.0%, respectively, for the both surfaces. The overall results show that the online hyperspectral imaging system could potentially be used to assess quality of agricultural products.

  7. Quality Control of Mega Voltage Portal Imaging System

    International Nuclear Information System (INIS)

    Diklic, A.; Dundara Debeljuh, D.; Jurkovic, S.; Smilovic Radojcic, D.; Svabic Kolacio; Kasabasic, M.; Faj, D.

    2013-01-01

    The Electronic Portal Imaging Device (EPID) is a system used to verify either the correct positioning of the patient during radiotherapy treatment or the linear accelerator beam parameters. The correct position of the patient corresponds to the position at which the patient was scanned at the CT simulator and according to which the therapy plan was made and optimized. Regarding this, besides the advanced treatment planning system and optimized treatment planning techniques, the day-to-day reproduction of simulated conditions is of great importance for the treatment outcome. Therefore, to verify the patient set-up portal imaging should be applied prior to the first treatment session and repeated according to treatment prescriptions during the treatment. In order to achieve full functionality and precision of the EPID, it must be included in radiotherapy Quality Control (QC) programme. The QC of the Mega Voltage portal imaging system was separated in two parts. In the first, the QC of the detector parameters should be performed. For this purpose, the FC2 and QC3 phantoms should be used, along with the Portal Image Processing System program (PIPSpro) package for data analysis. The second part of the QC of the linear accelerator's portal imaging system should include the QC of the CBCT. In this part a set of predefined manufacturer's tests using two different phantoms, one for the geometry calibration and the other for the image quality evaluation, should be performed. Also, the treatment conditions should be simulated using anthropomorphic phantoms and dose distributions for particular EPID protocols should be measured. Procedures for quality control of the portal imaging system developed and implemented at University Hospital Rijeka are presented in this paper.(author)

  8. High Throughput Multispectral Image Processing with Applications in Food Science.

    Directory of Open Access Journals (Sweden)

    Panagiotis Tsakanikas

    Full Text Available Recently, machine vision is gaining attention in food science as well as in food industry concerning food quality assessment and monitoring. Into the framework of implementation of Process Analytical Technology (PAT in the food industry, image processing can be used not only in estimation and even prediction of food quality but also in detection of adulteration. Towards these applications on food science, we present here a novel methodology for automated image analysis of several kinds of food products e.g. meat, vanilla crème and table olives, so as to increase objectivity, data reproducibility, low cost information extraction and faster quality assessment, without human intervention. Image processing's outcome will be propagated to the downstream analysis. The developed multispectral image processing method is based on unsupervised machine learning approach (Gaussian Mixture Models and a novel unsupervised scheme of spectral band selection for segmentation process optimization. Through the evaluation we prove its efficiency and robustness against the currently available semi-manual software, showing that the developed method is a high throughput approach appropriate for massive data extraction from food samples.

  9. High Throughput Multispectral Image Processing with Applications in Food Science.

    Science.gov (United States)

    Tsakanikas, Panagiotis; Pavlidis, Dimitris; Nychas, George-John

    2015-01-01

    Recently, machine vision is gaining attention in food science as well as in food industry concerning food quality assessment and monitoring. Into the framework of implementation of Process Analytical Technology (PAT) in the food industry, image processing can be used not only in estimation and even prediction of food quality but also in detection of adulteration. Towards these applications on food science, we present here a novel methodology for automated image analysis of several kinds of food products e.g. meat, vanilla crème and table olives, so as to increase objectivity, data reproducibility, low cost information extraction and faster quality assessment, without human intervention. Image processing's outcome will be propagated to the downstream analysis. The developed multispectral image processing method is based on unsupervised machine learning approach (Gaussian Mixture Models) and a novel unsupervised scheme of spectral band selection for segmentation process optimization. Through the evaluation we prove its efficiency and robustness against the currently available semi-manual software, showing that the developed method is a high throughput approach appropriate for massive data extraction from food samples.

  10. Investigation of Collimator Influential Parameter on SPECT Image Quality: a Monte Carlo Study

    Directory of Open Access Journals (Sweden)

    Banari Bahnamiri Sh

    2015-03-01

    Full Text Available Background: Obtaining high quality images in Single Photon Emission Tomography (SPECT device is the most important goal in nuclear medicine. Because if image quality is low, the possibility of making a mistake in diagnosing and treating the patient will rise. Studying effective factors in spatial resolution of imaging systems is thus deemed to be vital. One of the most important factors in SPECT imaging in nuclear medicine is the use of an appropriate collimator for a certain radiopharmaceutical feature in order to create the best image as it can be effective in the quantity of Full Width at Half Maximum (FWHM which is the main parameter in spatial resolution. Method: In this research, the simulation of the detector and collimator of SPECT imaging device, Model HD3 made by Philips Co. and the investigation of important factors on the collimator were carried out using MCNP-4c code. Results: The results of the experimental measurments and simulation calculations revealed a relative difference of less than 5% leading to the confirmation of the accuracy of conducted simulation MCNP code calculation. Conclusion: This is the first essential step in the design and modelling of new collimators used for creating high quality images in nuclear medicine

  11. Image quality assessment based on multiscale geometric analysis.

    Science.gov (United States)

    Gao, Xinbo; Lu, Wen; Tao, Dacheng; Li, Xuelong

    2009-07-01

    Reduced-reference (RR) image quality assessment (IQA) has been recognized as an effective and efficient way to predict the visual quality of distorted images. The current standard is the wavelet-domain natural image statistics model (WNISM), which applies the Kullback-Leibler divergence between the marginal distributions of wavelet coefficients of the reference and distorted images to measure the image distortion. However, WNISM fails to consider the statistical correlations of wavelet coefficients in different subbands and the visual response characteristics of the mammalian cortical simple cells. In addition, wavelet transforms are optimal greedy approximations to extract singularity structures, so they fail to explicitly extract the image geometric information, e.g., lines and curves. Finally, wavelet coefficients are dense for smooth image edge contours. In this paper, to target the aforementioned problems in IQA, we develop a novel framework for IQA to mimic the human visual system (HVS) by incorporating the merits from multiscale geometric analysis (MGA), contrast sensitivity function (CSF), and the Weber's law of just noticeable difference (JND). In the proposed framework, MGA is utilized to decompose images and then extract features to mimic the multichannel structure of HVS. Additionally, MGA offers a series of transforms including wavelet, curvelet, bandelet, contourlet, wavelet-based contourlet transform (WBCT), and hybrid wavelets and directional filter banks (HWD), and different transforms capture different types of image geometric information. CSF is applied to weight coefficients obtained by MGA to simulate the appearance of images to observers by taking into account many of the nonlinearities inherent in HVS. JND is finally introduced to produce a noticeable variation in sensory experience. Thorough empirical studies are carried out upon the LIVE database against subjective mean opinion score (MOS) and demonstrate that 1) the proposed framework has

  12. Image and diagnosis quality of X-ray image transmission via cell phone camera: a project study evaluating quality and reliability.

    Directory of Open Access Journals (Sweden)

    Hans Goost

    Full Text Available INTRODUCTION: Developments in telemedicine have not produced any relevant benefits for orthopedics and trauma surgery to date. For the present project study, several parameters were examined during assessment of x-ray images, which had been photographed and transmitted via cell phone. MATERIALS AND METHODS: A total of 100 x-ray images of various body regions were photographed with a Nokia cell phone and transmitted via email or MMS. Next, the transmitted photographs were reviewed on a laptop computer by five medical specialists and assessed regarding quality and diagnosis. RESULTS: Due to their poor quality, the transmitted MMS images could not be evaluated and this path of transmission was therefore excluded. Mean size of transmitted x-ray email images was 394 kB (range: 265-590 kB, SD ± 59, average transmission time was 3.29 min ± 8 (CI 95%: 1.7-4.9. Applying a score from 1-10 (very poor - excellent, mean image quality was 5.8. In 83.2 ± 4% (mean value ± SD of cases (median 82; 80-89%, there was agreement between final diagnosis and assessment by the five medical experts who had received the images. However, there was a markedly low concurrence ratio in the thoracic area and in pediatric injuries. DISCUSSION: While the rate of accurate diagnosis and indication for surgery was high with a concurrence ratio of 83%, considerable differences existed between the assessed regions, with lowest values for thoracic images. Teleradiology is a cost-effective, rapid method which can be applied wherever wireless cell phone reception is available. In our opinion, this method is in principle suitable for clinical use, enabling the physician on duty to agree on appropriate measures with colleagues located elsewhere via x-ray image transmission on a cell phone.

  13. ESIM: Edge Similarity for Screen Content Image Quality Assessment.

    Science.gov (United States)

    Ni, Zhangkai; Ma, Lin; Zeng, Huanqiang; Chen, Jing; Cai, Canhui; Ma, Kai-Kuang

    2017-10-01

    In this paper, an accurate full-reference image quality assessment (IQA) model developed for assessing screen content images (SCIs), called the edge similarity (ESIM), is proposed. It is inspired by the fact that the human visual system (HVS) is highly sensitive to edges that are often encountered in SCIs; therefore, essential edge features are extracted and exploited for conducting IQA for the SCIs. The key novelty of the proposed ESIM lies in the extraction and use of three salient edge features-i.e., edge contrast, edge width, and edge direction. The first two attributes are simultaneously generated from the input SCI based on a parametric edge model, while the last one is derived directly from the input SCI. The extraction of these three features will be performed for the reference SCI and the distorted SCI, individually. The degree of similarity measured for each above-mentioned edge attribute is then computed independently, followed by combining them together using our proposed edge-width pooling strategy to generate the final ESIM score. To conduct the performance evaluation of our proposed ESIM model, a new and the largest SCI database (denoted as SCID) is established in our work and made to the public for download. Our database contains 1800 distorted SCIs that are generated from 40 reference SCIs. For each SCI, nine distortion types are investigated, and five degradation levels are produced for each distortion type. Extensive simulation results have clearly shown that the proposed ESIM model is more consistent with the perception of the HVS on the evaluation of distorted SCIs than the multiple state-of-the-art IQA methods.

  14. MO-DE-209-03: Assessing Image Quality

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, W. [Stony Brook Medicine (United States)

    2016-06-15

    Digital Breast Tomosynthesis (DBT) is rapidly replacing mammography as the standard of care in breast cancer screening and diagnosis. DBT is a form of computed tomography, in which a limited set of projection images are acquired over a small angular range and reconstructed into tomographic data. The angular range varies from 15° to 50° and the number of projections varies between 9 and 25 projections, as determined by the equipment manufacturer. It is equally valid to treat DBT as the digital analog of classical tomography – that is, linear tomography. In fact, the name “tomosynthesis” stands for “synthetic tomography.” DBT shares many common features with classical tomography, including the radiographic appearance, dose, and image quality considerations. As such, both the science and practical physics of DBT systems is a hybrid between computed tomography and classical tomographic methods. In this lecture, we will explore the continuum from radiography to computed tomography to illustrate the characteristics of DBT. This lecture will consist of four presentations that will provide a complete overview of DBT, including a review of the fundamentals of DBT acquisition, a discussion of DBT reconstruction methods, an overview of dosimetry for DBT systems, and summary of the underlying image theory of DBT thereby relating image quality and dose. Learning Objectives: To understand the fundamental principles behind tomosynthesis image acquisition. To understand the fundamentals of tomosynthesis image reconstruction. To learn the determinants of image quality and dose in DBT, including measurement techniques. To learn the image theory underlying tomosynthesis, and the relationship between dose and image quality. ADM is a consultant to, and holds stock in, Real Time Tomography, LLC. ADM receives research support from Hologic Inc., Analogic Inc., and Barco NV.; ADM is a member of the Scientific Advisory Board for Gamma Medica Inc.; A. Maidment, Research Support

  15. MO-DE-209-03: Assessing Image Quality

    International Nuclear Information System (INIS)

    Zhao, W.

    2016-01-01

    Digital Breast Tomosynthesis (DBT) is rapidly replacing mammography as the standard of care in breast cancer screening and diagnosis. DBT is a form of computed tomography, in which a limited set of projection images are acquired over a small angular range and reconstructed into tomographic data. The angular range varies from 15° to 50° and the number of projections varies between 9 and 25 projections, as determined by the equipment manufacturer. It is equally valid to treat DBT as the digital analog of classical tomography – that is, linear tomography. In fact, the name “tomosynthesis” stands for “synthetic tomography.” DBT shares many common features with classical tomography, including the radiographic appearance, dose, and image quality considerations. As such, both the science and practical physics of DBT systems is a hybrid between computed tomography and classical tomographic methods. In this lecture, we will explore the continuum from radiography to computed tomography to illustrate the characteristics of DBT. This lecture will consist of four presentations that will provide a complete overview of DBT, including a review of the fundamentals of DBT acquisition, a discussion of DBT reconstruction methods, an overview of dosimetry for DBT systems, and summary of the underlying image theory of DBT thereby relating image quality and dose. Learning Objectives: To understand the fundamental principles behind tomosynthesis image acquisition. To understand the fundamentals of tomosynthesis image reconstruction. To learn the determinants of image quality and dose in DBT, including measurement techniques. To learn the image theory underlying tomosynthesis, and the relationship between dose and image quality. ADM is a consultant to, and holds stock in, Real Time Tomography, LLC. ADM receives research support from Hologic Inc., Analogic Inc., and Barco NV.; ADM is a member of the Scientific Advisory Board for Gamma Medica Inc.; A. Maidment, Research Support

  16. Assessing the quality of restored images in optical long-baseline interferometry

    Science.gov (United States)

    Gomes, Nuno; Garcia, Paulo J. V.; Thiébaut, Éric

    2017-03-01

    Assessing the quality of aperture synthesis maps is relevant for benchmarking image reconstruction algorithms, for the scientific exploitation of data from optical long-baseline interferometers, and for the design/upgrade of new/existing interferometric imaging facilities. Although metrics have been proposed in these contexts, no systematic study has been conducted on the selection of a robust metric for quality assessment. This article addresses the question: what is the best metric to assess the quality of a reconstructed image? It starts by considering several metrics and selecting a few based on general properties. Then, a variety of image reconstruction cases are considered. The observational scenarios are phase closure and phase referencing at the Very Large Telescope Interferometer (VLTI), for a combination of two, three, four and six telescopes. End-to-end image reconstruction is accomplished with the MIRA software, and several merit functions are put to test. It is found that convolution by an effective point spread function is required for proper image quality assessment. The effective angular resolution of the images is superior to naive expectation based on the maximum frequency sampled by the array. This is due to the prior information used in the aperture synthesis algorithm and to the nature of the objects considered. The ℓ1-norm is the most robust of all considered metrics, because being linear it is less sensitive to image smoothing by high regularization levels. For the cases considered, this metric allows the implementation of automatic quality assessment of reconstructed images, with a performance similar to human selection.

  17. Quality assurance for MR stereotactic imaging for three Siemens scanners

    International Nuclear Information System (INIS)

    Kozubikova, P.; Novotny, J. Jr.; Kulhova, K.; Mihalova, P.; Tamasova, J.; Veselsk, T.

    2014-01-01

    Quality assurance of stereotactic imaging, especially with MRI (magnetic resonance imaging), is a complex issue. It can be divided in the basic verification and commissioning of a particular new scanner or a new scanning MRI protocol that is being implemented into a clinical practice and the routine quality assurance performed for each single radiosurgical case. The aim of this study was geometric distortion assessment in MRI with a special PTGR (Physikalisch-Technische Gesellschaft fuer Radiologie - GmbH, Tuebingen, Germany) target phantom. PTGR phantom consists of 21 three-dimensional cross-hairs filled with contrast medium. Cross hairs are positioned at known Leksell coordinates with a precision of better than 0.1 mm and covering the whole stereotactic space. The phantom can be fixed in the Leksell stereotactic frame and thus stereotactic imaging procedures can be reproduced following exactly the same steps as for a real patient, including also the stereotactic image definition in the Leksell GammaPlan. Since the geometric position (stereotactic coordinates) of each cross-hair is known based on the construction of the phantom, it can be compared with the actual measured Leksell coordinates based on the stereotactic MRI. Deviations between expected and actual coordinates provide information about the level of distortion. The measured distortions proved satisfactory accuracy precision for stereotactic localization at 1.5 T Siemens Magnetom Avanto scanner, Siemens Magnetom Symphony scanner and 3T Siemens Magnetom Skyra scanner (Na Homolce Hospital, Prague). The mean distortion for these MR scanners for standard imaging protocol (T1 weighted 3D images) were 0.8 mm, 1.1 mm and 1.1 mm and maximum distortions were 1.3 mm, 1.9 mm and 2.2 mm, respectively.There was detected dependence of the distortions on the slice orientation and the type of imaging protocol. Image distortions are also property of each particular scanner, the worst distortion were observed for 3T

  18. Correlation of bone quality in radiographic images with clinical bone quality classification

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Woo; Huh, Kyung Hoe; Kim, Jeong Hwa; Yi, Won Jin; Heo, Min Suk; Lee, Sam Sun; Choi, Soon Chul [Seoul National University, Seoul (Korea, Republic of); Park, Kwan Soo [Inje University, Seoul (Korea, Republic of)

    2006-03-15

    To investigate the validity of digital image processing on panoramic radiographs in estimating bone quality before endosseous dental implant installation by correlating bone quality in radiographic images with clinical bone quality classification. An experienced surgeon assessed and classified bone quality for implant sites with tactile sensation at the time of implant placement. Including fractal dimension eighteen morphologic features of trabecular pattern were examined in each anatomical sites on panoramic radiographs. Finally bone quality of 67 implant sites were evaluated in 42 patients. Pearson correlation analysis showed that three morphologic parameters had weak linear negative correlation with clinical bone quality classification showing correlation coefficients of -0.276, -0.280, and -0.289, respectively (p<0.05). And other three morphologic parameters had obvious linear negative correlation with clinical bone quality classification showing correlation coefficients of -0.346, -0.488, and -0.343 respectively (p<0.05). Fractal dimension also had a linear correlating with clinical bone quality classification with correlation coefficients -0.506 significantly (P<0.05). This study suggests that fractal and morphometric analysis using digital panoramic radiographs can be used to evaluate bone quality for implant recipient sites.

  19. SU-F-P-06: Moving From Computed Radiography to Digital Radiography: A Collaborative Approach to Improve Image Quality

    Energy Technology Data Exchange (ETDEWEB)

    Sandoval, D; Mlady, G; Selwyn, R [University of New Mexico School of Medicine, Albuquerque, NM (United States); Valenti, D; Bateman, T; Norris, V [University of New Mexico Hospital, Albuquerque, New Mexico (United States)

    2016-06-15

    Purpose: To bring together radiologists, technologists, and physicists to utilize post-processing techniques in digital radiography (DR) in order to optimize image acquisition and improve image quality. Methods: Sub-optimal images acquired on a new General Electric (GE) DR system were flagged for follow-up by radiologists and reviewed by technologists and medical physicists. Various exam types from adult musculoskeletal (n=35), adult chest (n=4), and pediatric (n=7) were chosen for review. 673 total images were reviewed. These images were processed using five customized algorithms provided by GE. An image score sheet was created allowing the radiologist to assign a numeric score to each of the processed images, this allowed for objective comparison to the original images. Each image was scored based on seven properties: 1) overall image look, 2) soft tissue contrast, 3) high contrast, 4) latitude, 5) tissue equalization, 6) edge enhancement, 7) visualization of structures. Additional space allowed for additional comments not captured in scoring categories. Radiologists scored the images from 1 – 10 with 1 being non-diagnostic quality and 10 being superior diagnostic quality. Scores for each custom algorithm for each image set were summed. The algorithm with the highest score for each image set was then set as the default processing. Results: Images placed into the PACS “QC folder” for image processing reasons decreased. Feedback from radiologists was, overall, that image quality for these studies had improved. All default processing for these image types was changed to the new algorithm. Conclusion: This work is an example of the collaboration between radiologists, technologists, and physicists at the University of New Mexico to add value to the radiology department. The significant amount of work required to prepare the processing algorithms, reprocessing and scoring of the images was eagerly taken on by all team members in order to produce better quality

  20. SU-F-P-06: Moving From Computed Radiography to Digital Radiography: A Collaborative Approach to Improve Image Quality

    International Nuclear Information System (INIS)

    Sandoval, D; Mlady, G; Selwyn, R; Valenti, D; Bateman, T; Norris, V

    2016-01-01

    Purpose: To bring together radiologists, technologists, and physicists to utilize post-processing techniques in digital radiography (DR) in order to optimize image acquisition and improve image quality. Methods: Sub-optimal images acquired on a new General Electric (GE) DR system were flagged for follow-up by radiologists and reviewed by technologists and medical physicists. Various exam types from adult musculoskeletal (n=35), adult chest (n=4), and pediatric (n=7) were chosen for review. 673 total images were reviewed. These images were processed using five customized algorithms provided by GE. An image score sheet was created allowing the radiologist to assign a numeric score to each of the processed images, this allowed for objective comparison to the original images. Each image was scored based on seven properties: 1) overall image look, 2) soft tissue contrast, 3) high contrast, 4) latitude, 5) tissue equalization, 6) edge enhancement, 7) visualization of structures. Additional space allowed for additional comments not captured in scoring categories. Radiologists scored the images from 1 – 10 with 1 being non-diagnostic quality and 10 being superior diagnostic quality. Scores for each custom algorithm for each image set were summed. The algorithm with the highest score for each image set was then set as the default processing. Results: Images placed into the PACS “QC folder” for image processing reasons decreased. Feedback from radiologists was, overall, that image quality for these studies had improved. All default processing for these image types was changed to the new algorithm. Conclusion: This work is an example of the collaboration between radiologists, technologists, and physicists at the University of New Mexico to add value to the radiology department. The significant amount of work required to prepare the processing algorithms, reprocessing and scoring of the images was eagerly taken on by all team members in order to produce better quality

  1. Sensitometric properties and image quality of radiographic film and paper

    International Nuclear Information System (INIS)

    Domanus, J.C.

    1985-09-01

    When using X-ray film or radiographic paper for industrial applications one is interested in knowing not only their sensitometric properties (such as speed and contrast) but also the image quality obtainable with a particular brand of film or paper. Although standard methods for testing both properties separately are available it is desirable that the method permits the assessment of all the relevant properties together. The sensitometric properties are usually determined at constant kilovoltage and filtration at the X-ray tube, whereas radiographic image thicknesses. The use of the constant exposure technique could be used to compare both the sensitometric properties as well as the image quality for different radiographic materials. It consist of exposing different film or paper brands at a chosen, constant mAmin exposure when testing radiographic image quality for different thicknesses of a given material. From the results obtained with the constant exposure technique conclusions are drawn about its applicability as a standard method for assessing radiographic film and paper. (author)

  2. Effect of exercise supplementation on dipyridamole thallium-201 image quality

    International Nuclear Information System (INIS)

    Stern, S.; Greenberg, I.D.; Corne, R.

    1991-01-01

    To determine the effect of different types of exercise supplementation on dipyridamole thallium image quality, 78 patients were prospectively randomized to one of three protocols: dipyridamole infusion alone, dipyridamole supplemented with isometric handgrip, and dipyridamole with low-level treadmill exercise. Heart-to-lung, heart-to-liver, and heart-to-adjacent infradiaphragmatic activity ratios were generated from anterior images acquired immediately following the test. Additionally, heart-to-total infradiaphragmatic activity was graded semiquantitatively. Results showed a significantly higher ratio of heart to subdiaphragmatic activity in the treadmill group as compared with dipyridamole alone (p less than 0.001) and dipyridamole supplemented with isometric handgrip exercise (p less than 0.001). No significant difference was observed between patients receiving the dipyridamole infusion, and dipyridamole supplemented with isometric handgrip exercise. The authors conclude that low-level treadmill exercise supplementation of dipyridamole infusion is an effective means of improving image quality. Supplementation with isometric handgrip does not improve image quality over dipyridamole alone

  3. Comparative study of image quality and radiation dose between prospective and retrospective ECG gating technique in coronary artery imaging with 64-slice spiral CT

    International Nuclear Information System (INIS)

    Liu Jianxin; Liu Jian; Dou Yanbin; Wang Jichen; Sun Hongyue

    2009-01-01

    Objective: To compare the image quality and radiation dose between prospective ECG-trigering and retrospective ECG gating technique in coronary artery imaging. Methods: 33 patients suspected coronary artery disease were included in this study and divided into experimental group (prospective ECG-triggering coronary artery imaging, heart rate 0.05). The mean DLP of experimental group (234.4 mGy · cm) was DLP of control group (974.4 mGy · cm) 24.1%. The mean effective dose of prospective ECG gating coronary artery imaging was 3.2 mSv. Effective dose reduced 76.47 %. Conclusions: Prospective ECG gating coronary artery imaging can obtain the similar image quality compared with prospective ECG gating coronary artery imaging but the effective dose reduced 76.47 %. Prospective ECG gating coronary artery imaging has clinical value to peoples who are able to not accept high radiation dose and with low heart rate. (authors)

  4. Radiographic imaging system for high energy radiation

    International Nuclear Information System (INIS)

    1975-01-01

    A radiographic imaging system for high energy radiation is described utilizing a detector of such radiation and a mask having regions relatively transparent to such radiation and interspersed among regions relatively opaque to such radiation. A relative motion is imparted between the mask and the detector, the detector providing a time varying signal in response to the incident radiation and in response to the relative motion. The time varying signal provides, with the aid of a decoder, an image of a source of such radiation

  5. Architecture Of High Speed Image Processing System

    Science.gov (United States)

    Konishi, Toshio; Hayashi, Hiroshi; Ohki, Tohru

    1988-01-01

    One of architectures for a high speed image processing system which corresponds to a new algorithm for a shape understanding is proposed. And the hardware system which is based on the archtecture was developed. Consideration points of the architecture are mainly that using processors should match with the processing sequence of the target image and that the developed system should be used practically in an industry. As the result, it was possible to perform each processing at a speed of 80 nano-seconds a pixel.

  6. Radiographic imaging system for high energy radiation

    International Nuclear Information System (INIS)

    Barrett, H.H.

    1976-01-01

    A radiographic imaging system for high energy radiation utilizing a detector of such radiation and a mask having regions relatively transparent to such radiation interspersed among regions relatively opaque to such radiation is described. A relative motion is imparted between the mask and the detector, the detector providing a time varying signal in response to the incident radiation and in response to the relative motion. The time varying signal provides, with the aid of a decoder, an image of a source of such radiation

  7. High dynamic range imaging sensors and architectures

    CERN Document Server

    Darmont, Arnaud

    2013-01-01

    Illumination is a crucial element in many applications, matching the luminance of the scene with the operational range of a camera. When luminance cannot be adequately controlled, a high dynamic range (HDR) imaging system may be necessary. These systems are being increasingly used in automotive on-board systems, road traffic monitoring, and other industrial, security, and military applications. This book provides readers with an intermediate discussion of HDR image sensors and techniques for industrial and non-industrial applications. It describes various sensor and pixel architectures capable

  8. TL dosimetry for quality control of CR mammography imaging systems

    Science.gov (United States)

    Gaona, E.; Nieto, J. A.; Góngora, J. A. I. D.; Arreola, M.; Enríquez, J. G. F.

    The aim of this work is to estimate the average glandular dose with thermoluminescent (TL) dosimetry and comparison with quality imaging in computed radiography (CR) mammography. For a measuring dose, the Food and Drug Administration (FDA) and the American College of Radiology (ACR) use a phantom, so that dose and image quality are assessed with the same test object. The mammography is a radiological image to visualize early biological manifestations of breast cancer. Digital systems have two types of image-capturing devices, full field digital mammography (FFDM) and CR mammography. In Mexico, there are several CR mammography systems in clinical use, but only one system has been approved for use by the FDA. Mammography CR uses a photostimulable phosphor detector (PSP) system. Most CR plates are made of 85% BaFBr and 15% BaFI doped with europium (Eu) commonly called barium flourohalideE We carry out an exploratory survey of six CR mammography units from three different manufacturers and six dedicated X-ray mammography units with fully automatic exposure. The results show three CR mammography units (50%) have a dose greater than 3.0 mGy without demonstrating improved image quality. The differences between doses averages from TLD system and dosimeter with ionization chamber are less than 10%. TLD system is a good option for average glandular dose measurement for X-rays with a HVL (0.35-0.38 mmAl) and kVp (24-26) used in quality control procedures with ACR Mammography Accreditation Phantom.

  9. The Importance of Store Image and Retail Service Quality in Private Brand Image-Building

    Directory of Open Access Journals (Sweden)

    Adi Alić

    2017-03-01

    Full Text Available Objective: The purpose of this research is to highlight the role which store image and retail service quality can play in private brand image-building in the context of an emerging market in South-Eastern Europe (i.e. Bosnia and Herzegovina. We propose to address this issue by seeking answers to the following questions: (1 Does a ‘halo effect’ take place between the store image and the private brand image? (2 How does consumer’s evaluation of the quality of the service delivered by a retailer affect the image of its private brand? Research Design & Methods: Data were collected through a field survey via the store-intercept method. The sample consisted of 699 customers of two large retail chains. The data were analysed using the Structural Equation Modelling technique. Findings: The findings of the present study suggest that store image and retail service quality are important factors in the formation of the image of product-branded products. Implications & Recommendations: This study offers some important insights for retailers who intend to develop their private brand. First, the image transfer from store brand to private brand suggests that retailers should consider the introduction of a private brand as a brand extension, with their stores as the parent brand. Second, we recommend that retailers put more emphasis on quality improvement initiatives related to the store environment attributes. Contribution & Value Added: This study enhances the discussion on the phenomenon of private branding by analysing the store-level factors which underpin the formation of private brand image in the context of less developed European markets.

  10. A method for the evaluation of image quality according to the recognition effectiveness of objects in the optical remote sensing image using machine learning algorithm.

    Directory of Open Access Journals (Sweden)

    Tao Yuan

    Full Text Available Objective and effective image quality assessment (IQA is directly related to the application of optical remot