Alignment issues, correlation techniques and their assessment for a visible light imaging-based 3D printer quality control system

NASA Astrophysics Data System (ADS)

Straub, Jeremy

2016-05-01

Quality control is critical to manufacturing. Frequently, techniques are used to define object conformity bounds, based on historical quality data. This paper considers techniques for bespoke and small batch jobs that are not statistical model based. These techniques also serve jobs where 100% validation is needed due to the mission or safety critical nature of particular parts. One issue with this type of system is alignment discrepancies between the generated model and the physical part. This paper discusses and evaluates techniques for characterizing and correcting alignment issues between the projected and perceived data sets to prevent errors attributable to misalignment.

A joint FED watermarking system using spatial fusion for verifying the security issues of teleradiology.

PubMed

Viswanathan, P; Krishna, P Venkata

2014-05-01

Teleradiology allows transmission of medical images for clinical data interpretation to provide improved e-health care access, delivery, and standards. The remote transmission raises various ethical and legal issues like image retention, fraud, privacy, malpractice liability, etc. A joint FED watermarking system means a joint fingerprint/encryption/dual watermarking system is proposed for addressing these issues. The system combines a region based substitution dual watermarking algorithm using spatial fusion, stream cipher algorithm using symmetric key, and fingerprint verification algorithm using invariants. This paper aims to give access to the outcomes of medical images with confidentiality, availability, integrity, and its origin. The watermarking, encryption, and fingerprint enrollment are conducted jointly in protection stage such that the extraction, decryption, and verification can be applied independently. The dual watermarking system, introducing two different embedding schemes, one used for patient data and other for fingerprint features, reduces the difficulty in maintenance of multiple documents like authentication data, personnel and diagnosis data, and medical images. The spatial fusion algorithm, which determines the region of embedding using threshold from the image to embed the encrypted patient data, follows the exact rules of fusion resulting in better quality than other fusion techniques. The four step stream cipher algorithm using symmetric key for encrypting the patient data with fingerprint verification system using algebraic invariants improves the robustness of the medical information. The experiment result of proposed scheme is evaluated for security and quality analysis in DICOM medical images resulted well in terms of attacks, quality index, and imperceptibility.

"Big Data" in Rheumatology: Intelligent Data Modeling Improves the Quality of Imaging Data.

PubMed

Landewé, Robert B M; van der Heijde, Désirée

2018-05-01

Analysis of imaging data in rheumatology is a challenge. Reliability of scores is an issue for several reasons. Signal-to-noise ratio of most imaging techniques is rather unfavorable (too little signal in relation to too much noise). Optimal use of all available data may help to increase credibility of imaging data, but knowledge of complicated statistical methodology and the help of skilled statisticians are required. Clinicians should appreciate the merits of sophisticated data modeling and liaise with statisticians to increase the quality of imaging results, as proper imaging studies in rheumatology imply more than a supersensitive imaging technique alone. Copyright © 2018 Elsevier Inc. All rights reserved.

Importance of methodology on (99m)technetium dimercapto-succinic acid scintigraphic image quality: imaging pilot study for RIVUR (Randomized Intervention for Children With Vesicoureteral Reflux) multicenter investigation.

PubMed

Ziessman, Harvey A; Majd, Massoud

2009-07-01

We reviewed our experience with (99m)technetium dimercapto-succinic acid scintigraphy obtained during an imaging pilot study for a multicenter investigation (Randomized Intervention for Children With Vesicoureteral Reflux) of the effectiveness of daily antimicrobial prophylaxis for preventing recurrent urinary tract infection and renal scarring. We analyzed imaging methodology and its relation to diagnostic image quality. (99m)Technetium dimercapto-succinic acid imaging guidelines were provided to participating sites. High-resolution planar imaging with parallel hole or pinhole collimation was required. Two core reviewers evaluated all submitted images. Analysis included appropriate views, presence or lack of patient motion, adequate magnification, sufficient counts and diagnostic image quality. Inter-reader agreement was evaluated. We evaluated 70, (99m)technetium dimercapto-succinic acid studies from 14 institutions. Variability was noted in methodology and image quality. Correlation (r value) between dose administered and patient age was 0.780. For parallel hole collimator imaging good correlation was noted between activity administered and counts (r = 0.800). For pinhole imaging the correlation was poor (r = 0.110). A total of 10 studies (17%) were rejected for quality issues of motion, kidney overlap, inadequate magnification, inadequate counts and poor quality images. The submitting institution was informed and provided with recommendations for improving quality, and resubmission of another study was required. Only 4 studies (6%) were judged differently by the 2 reviewers, and the differences were minor. Methodology and image quality for (99m)technetium dimercapto-succinic acid scintigraphy varied more than expected between institutions. The most common reason for poor image quality was inadequate count acquisition with insufficient attention to the tradeoff between administered dose, length of image acquisition, start time of imaging and resulting image quality. Inter-observer core reader agreement was high. The pilot study ensured good diagnostic quality standardized images for the Randomized Intervention for Children With Vesicoureteral Reflux investigation.

Fusion and quality analysis for remote sensing images using contourlet transform

NASA Astrophysics Data System (ADS)

Choi, Yoonsuk; Sharifahmadian, Ershad; Latifi, Shahram

2013-05-01

Recent developments in remote sensing technologies have provided various images with high spatial and spectral resolutions. However, multispectral images have low spatial resolution and panchromatic images have low spectral resolution. Therefore, image fusion techniques are necessary to improve the spatial resolution of spectral images by injecting spatial details of high-resolution panchromatic images. The objective of image fusion is to provide useful information by improving the spatial resolution and the spectral information of the original images. The fusion results can be utilized in various applications, such as military, medical imaging, and remote sensing. This paper addresses two issues in image fusion: i) image fusion method and ii) quality analysis of fusion results. First, a new contourlet-based image fusion method is presented, which is an improvement over the wavelet-based fusion. This fusion method is then applied to a case study to demonstrate its fusion performance. Fusion framework and scheme used in the study are discussed in detail. Second, quality analysis for the fusion results is discussed. We employed various quality metrics in order to analyze the fusion results both spatially and spectrally. Our results indicate that the proposed contourlet-based fusion method performs better than the conventional wavelet-based fusion methods.

Gloss uniformity measurement update for ISO/IEC 19751

NASA Astrophysics Data System (ADS)

Ng, Yee S.; Cui, Chengwu; Kuo, Chunghui; Maggard, Eric; Mashtare, Dale; Morris, Peter

2005-01-01

To address the standardization issues of perceptually based image quality for printing systems, ISO/IEC JTC1/SC28, the standardization committee for office equipment chartered the W1.1 project with the responsibility of drafting a proposal for an international standard for the evaluation of printed image quality1. An ISO draft Standard2, ISO/WD 19751-1, Office Equipment - Appearance-based image quality standards for printers - Part 1: Overview, Procedure and Common Methods, 2004 describes the overview of this multi-part appearance-based image quality standard. One of the ISO 19751 multi-part Standard"s tasks is to address the appearance-based gloss and gloss uniformity issues (in ISO 19751-2). This paper summarizes the current status and technical progress since the last two updates3, 4. In particular, we will be discussion our attempt to include 75 degree gloss (G75) objective measurement5 in differential gloss and within-page gloss uniformity. The result for a round-robin experiment involving objective measurement of differential gloss using G60 and G75 gloss measurement geometry is described. The results for two perceptual-based round-robin experiments relating to haze effect on the perception of gloss, and gloss artifacts (gloss streaks/bands, gloss graininess/mottle) are discussed.

Gloss uniformity measurement update for ISO/IEC 19751

NASA Astrophysics Data System (ADS)

Ng, Yee S.; Cui, Chengwu; Kuo, Chunghui; Maggard, Eric; Mashtare, Dale; Morris, Peter

2004-10-01

To address the standardization issues of perceptually based image quality for printing systems, ISO/IEC JTC1/SC28, the standardization committee for office equipment chartered the W1.1 project with the responsibility of drafting a proposal for an international standard for the evaluation of printed image quality1. An ISO draft Standard2, ISO/WD 19751-1, Office Equipment - Appearance-based image quality standards for printers - Part 1: Overview, Procedure and Common Methods, 2004 describes the overview of this multi-part appearance-based image quality standard. One of the ISO 19751 multi-part Standard"s tasks is to address the appearance-based gloss and gloss uniformity issues (in ISO 19751-2). This paper summarizes the current status and technical progress since the last two updates3, 4. In particular, we will be discussion our attempt to include 75 degree gloss (G75) objective measurement5 in differential gloss and within-page gloss uniformity. The result for a round-robin experiment involving objective measurement of differential gloss using G60 and G75 gloss measurement geometry is described. The results for two perceptual-based round-robin experiments relating to haze effect on the perception of gloss, and gloss artifacts (gloss streaks/bands, gloss graininess/mottle) are discussed.

Learning a No-Reference Quality Assessment Model of Enhanced Images With Big Data.

PubMed

Gu, Ke; Tao, Dacheng; Qiao, Jun-Fei; Lin, Weisi

2018-04-01

In this paper, we investigate into the problem of image quality assessment (IQA) and enhancement via machine learning. This issue has long attracted a wide range of attention in computational intelligence and image processing communities, since, for many practical applications, e.g., object detection and recognition, raw images are usually needed to be appropriately enhanced to raise the visual quality (e.g., visibility and contrast). In fact, proper enhancement can noticeably improve the quality of input images, even better than originally captured images, which are generally thought to be of the best quality. In this paper, we present two most important contributions. The first contribution is to develop a new no-reference (NR) IQA model. Given an image, our quality measure first extracts 17 features through analysis of contrast, sharpness, brightness and more, and then yields a measure of visual quality using a regression module, which is learned with big-data training samples that are much bigger than the size of relevant image data sets. The results of experiments on nine data sets validate the superiority and efficiency of our blind metric compared with typical state-of-the-art full-reference, reduced-reference and NA IQA methods. The second contribution is that a robust image enhancement framework is established based on quality optimization. For an input image, by the guidance of the proposed NR-IQA measure, we conduct histogram modification to successively rectify image brightness and contrast to a proper level. Thorough tests demonstrate that our framework can well enhance natural images, low-contrast images, low-light images, and dehazed images. The source code will be released at https://sites.google.com/site/guke198701/publications.

WE-B-BRC-03: Risk in the Context of Medical Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samei, E.

Prospective quality management techniques, long used by engineering and industry, have become a growing aspect of efforts to improve quality management and safety in healthcare. These techniques are of particular interest to medical physics as scope and complexity of clinical practice continue to grow, thus making the prescriptive methods we have used harder to apply and potentially less effective for our interconnected and highly complex healthcare enterprise, especially in imaging and radiation oncology. An essential part of most prospective methods is the need to assess the various risks associated with problems, failures, errors, and design flaws in our systems. Wemore » therefore begin with an overview of risk assessment methodologies used in healthcare and industry and discuss their strengths and weaknesses. The rationale for use of process mapping, failure modes and effects analysis (FMEA) and fault tree analysis (FTA) by TG-100 will be described, as well as suggestions for the way forward. This is followed by discussion of radiation oncology specific risk assessment strategies and issues, including the TG-100 effort to evaluate IMRT and other ways to think about risk in the context of radiotherapy. Incident learning systems, local as well as the ASTRO/AAPM ROILS system, can also be useful in the risk assessment process. Finally, risk in the context of medical imaging will be discussed. Radiation (and other) safety considerations, as well as lack of quality and certainty all contribute to the potential risks associated with suboptimal imaging. The goal of this session is to summarize a wide variety of risk analysis methods and issues to give the medical physicist access to tools which can better define risks (and their importance) which we work to mitigate with both prescriptive and prospective risk-based quality management methods. Learning Objectives: Description of risk assessment methodologies used in healthcare and industry Discussion of radiation oncology-specific risk assessment strategies and issues Evaluation of risk in the context of medical imaging and image quality E. Samei: Research grants from Siemens and GE.« less

Recent advances in MRI technology: Implications for image quality and patient safety

PubMed Central

Sobol, Wlad T.

2012-01-01

Recent advances in MRI technology are presented, with emphasis on how this new technology impacts clinical operations (better image quality, faster exam times, and improved throughput). In addition, implications for patient safety are discussed with emphasis on the risk of patient injury due to either high local specific absorption rate (SAR) or large cumulative energy doses delivered during long exam times. Patient comfort issues are examined as well. PMID:23961024

A digital gigapixel large-format tile-scan camera.

PubMed

Ben-Ezra, M

2011-01-01

Although the resolution of single-lens reflex (SLR) and medium-format digital cameras has increased in recent years, applications for cultural-heritage preservation and computational photography require even higher resolutions. Addressing this issue, a large-format cameras' large image planes can achieve very high resolution without compromising pixel size and thus can provide high-quality, high-resolution images.This digital large-format tile scan camera can acquire high-quality, high-resolution images of static scenes. It employs unique calibration techniques and a simple algorithm for focal-stack processing of very large images with significant magnification variations. The camera automatically collects overlapping focal stacks and processes them into a high-resolution, extended-depth-of-field image.

Technical aspects of cardiac PET/MRI.

PubMed

Masuda, Atsuro; Nemoto, Ayaka; Takeishi, Yasuchika

2018-06-01

PET/MRI is a novel modality that enables to combine PET and MR images, and has significant potential to evaluate various cardiac diseases through the combination of PET molecular imaging and MRI functional imaging. Precise management of technical issues, however, is necessary for cardiac PET/MRI. This article describes several technical points, including patient preparation, MR attenuation correction, parallel acquisition of PET with MRI, clinical aspects, and image quality control.

Impact of image quality on reliability of the measurements of left ventricular systolic function and global longitudinal strain in 2D echocardiography

PubMed Central

Nagata, Yasufumi; Kado, Yuichiro; Onoue, Takeshi; Otani, Kyoko; Nakazono, Akemi; Otsuji, Yutaka; Takeuchi, Masaaki

2018-01-01

Background Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) play important roles in diagnosis and management of cardiac diseases. However, the issue of the accuracy and reliability of LVEF and GLS remains to be solved. Image quality is one of the most important factors affecting measurement variability. The aim of this study was to investigate whether improved image quality could reduce observer variability. Methods Two sets of three apical images were acquired using relatively old- and new-generation ultrasound imaging systems (Vivid 7 and Vivid E95) in 308 subjects. Image quality was assessed by endocardial border delineation index (EBDI) using a 3-point scoring system. Three observers measured the LVEF and GLS, and these values and inter-observer variability were investigated. Results Image quality was significantly better with Vivid E95 (EBDI: 26.8 ± 5.9) than that with Vivid 7 (22.8 ± 6.3, P < 0.0001). Regarding the inter-observer variability of LVEF, the r-value, bias, 95% limit of agreement and intra-class correlation coefficient for Vivid 7 were comparable to those for Vivid E95. The % variabilities were significantly lower for Vivid E95 (5.3–6.5%) than those for Vivid 7 (6.5–7.5%). Regarding GLS, all observer variability parameters were better for Vivid E95 than for Vivid 7. Improvements in image quality yielded benefits to both LVEF and GLS measurement reliability. Multivariate analysis showed that image quality was indeed an important factor of observer variability in the measurement of LVEF and GLS. Conclusions The new-generation ultrasound imaging system offers improved image quality and reduces inter-observer variability in the measurement of LVEF and GLS. PMID:29432198

Impact of image quality on reliability of the measurements of left ventricular systolic function and global longitudinal strain in 2D echocardiography.

PubMed

Nagata, Yasufumi; Kado, Yuichiro; Onoue, Takeshi; Otani, Kyoko; Nakazono, Akemi; Otsuji, Yutaka; Takeuchi, Masaaki

2018-03-01

Left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) play important roles in diagnosis and management of cardiac diseases. However, the issue of the accuracy and reliability of LVEF and GLS remains to be solved. Image quality is one of the most important factors affecting measurement variability. The aim of this study was to investigate whether improved image quality could reduce observer variability. Two sets of three apical images were acquired using relatively old- and new-generation ultrasound imaging systems (Vivid 7 and Vivid E95) in 308 subjects. Image quality was assessed by endocardial border delineation index (EBDI) using a 3-point scoring system. Three observers measured the LVEF and GLS, and these values and inter-observer variability were investigated. Image quality was significantly better with Vivid E95 (EBDI: 26.8 ± 5.9) than that with Vivid 7 (22.8 ± 6.3, P  < 0.0001). Regarding the inter-observer variability of LVEF, the r -value, bias, 95% limit of agreement and intra-class correlation coefficient for Vivid 7 were comparable to those for Vivid E95. The % variabilities were significantly lower for Vivid E95 (5.3-6.5%) than those for Vivid 7 (6.5-7.5%). Regarding GLS, all observer variability parameters were better for Vivid E95 than for Vivid 7. Improvements in image quality yielded benefits to both LVEF and GLS measurement reliability. Multivariate analysis showed that image quality was indeed an important factor of observer variability in the measurement of LVEF and GLS. The new-generation ultrasound imaging system offers improved image quality and reduces inter-observer variability in the measurement of LVEF and GLS. © 2018 The authors.

WE-B-BRC-01: Current Methodologies in Risk Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rath, F.

Prospective quality management techniques, long used by engineering and industry, have become a growing aspect of efforts to improve quality management and safety in healthcare. These techniques are of particular interest to medical physics as scope and complexity of clinical practice continue to grow, thus making the prescriptive methods we have used harder to apply and potentially less effective for our interconnected and highly complex healthcare enterprise, especially in imaging and radiation oncology. An essential part of most prospective methods is the need to assess the various risks associated with problems, failures, errors, and design flaws in our systems. Wemore » therefore begin with an overview of risk assessment methodologies used in healthcare and industry and discuss their strengths and weaknesses. The rationale for use of process mapping, failure modes and effects analysis (FMEA) and fault tree analysis (FTA) by TG-100 will be described, as well as suggestions for the way forward. This is followed by discussion of radiation oncology specific risk assessment strategies and issues, including the TG-100 effort to evaluate IMRT and other ways to think about risk in the context of radiotherapy. Incident learning systems, local as well as the ASTRO/AAPM ROILS system, can also be useful in the risk assessment process. Finally, risk in the context of medical imaging will be discussed. Radiation (and other) safety considerations, as well as lack of quality and certainty all contribute to the potential risks associated with suboptimal imaging. The goal of this session is to summarize a wide variety of risk analysis methods and issues to give the medical physicist access to tools which can better define risks (and their importance) which we work to mitigate with both prescriptive and prospective risk-based quality management methods. Learning Objectives: Description of risk assessment methodologies used in healthcare and industry Discussion of radiation oncology-specific risk assessment strategies and issues Evaluation of risk in the context of medical imaging and image quality E. Samei: Research grants from Siemens and GE.« less

WE-B-BRC-00: Concepts in Risk-Based Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Prospective quality management techniques, long used by engineering and industry, have become a growing aspect of efforts to improve quality management and safety in healthcare. These techniques are of particular interest to medical physics as scope and complexity of clinical practice continue to grow, thus making the prescriptive methods we have used harder to apply and potentially less effective for our interconnected and highly complex healthcare enterprise, especially in imaging and radiation oncology. An essential part of most prospective methods is the need to assess the various risks associated with problems, failures, errors, and design flaws in our systems. Wemore » therefore begin with an overview of risk assessment methodologies used in healthcare and industry and discuss their strengths and weaknesses. The rationale for use of process mapping, failure modes and effects analysis (FMEA) and fault tree analysis (FTA) by TG-100 will be described, as well as suggestions for the way forward. This is followed by discussion of radiation oncology specific risk assessment strategies and issues, including the TG-100 effort to evaluate IMRT and other ways to think about risk in the context of radiotherapy. Incident learning systems, local as well as the ASTRO/AAPM ROILS system, can also be useful in the risk assessment process. Finally, risk in the context of medical imaging will be discussed. Radiation (and other) safety considerations, as well as lack of quality and certainty all contribute to the potential risks associated with suboptimal imaging. The goal of this session is to summarize a wide variety of risk analysis methods and issues to give the medical physicist access to tools which can better define risks (and their importance) which we work to mitigate with both prescriptive and prospective risk-based quality management methods. Learning Objectives: Description of risk assessment methodologies used in healthcare and industry Discussion of radiation oncology-specific risk assessment strategies and issues Evaluation of risk in the context of medical imaging and image quality E. Samei: Research grants from Siemens and GE.« less

WE-B-BRC-02: Risk Analysis and Incident Learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fraass, B.

Prospective quality management techniques, long used by engineering and industry, have become a growing aspect of efforts to improve quality management and safety in healthcare. These techniques are of particular interest to medical physics as scope and complexity of clinical practice continue to grow, thus making the prescriptive methods we have used harder to apply and potentially less effective for our interconnected and highly complex healthcare enterprise, especially in imaging and radiation oncology. An essential part of most prospective methods is the need to assess the various risks associated with problems, failures, errors, and design flaws in our systems. Wemore » therefore begin with an overview of risk assessment methodologies used in healthcare and industry and discuss their strengths and weaknesses. The rationale for use of process mapping, failure modes and effects analysis (FMEA) and fault tree analysis (FTA) by TG-100 will be described, as well as suggestions for the way forward. This is followed by discussion of radiation oncology specific risk assessment strategies and issues, including the TG-100 effort to evaluate IMRT and other ways to think about risk in the context of radiotherapy. Incident learning systems, local as well as the ASTRO/AAPM ROILS system, can also be useful in the risk assessment process. Finally, risk in the context of medical imaging will be discussed. Radiation (and other) safety considerations, as well as lack of quality and certainty all contribute to the potential risks associated with suboptimal imaging. The goal of this session is to summarize a wide variety of risk analysis methods and issues to give the medical physicist access to tools which can better define risks (and their importance) which we work to mitigate with both prescriptive and prospective risk-based quality management methods. Learning Objectives: Description of risk assessment methodologies used in healthcare and industry Discussion of radiation oncology-specific risk assessment strategies and issues Evaluation of risk in the context of medical imaging and image quality E. Samei: Research grants from Siemens and GE.« less

Miniature Wide-Angle Lens for Small-Pixel Electronic Camera

NASA Technical Reports Server (NTRS)

Mouroulils, Pantazis; Blazejewski, Edward

2009-01-01

A proposed wideangle lens is shown that would be especially well suited for an electronic camera in which the focal plane is occupied by an image sensor that has small pixels. The design of the lens is intended to satisfy requirements for compactness, high image quality, and reasonably low cost, while addressing issues peculiar to the operation of small-pixel image sensors. Hence, this design is expected to enable the development of a new generation of compact, high-performance electronic cameras. The lens example shown has a 60 degree field of view and a relative aperture (f-number) of 3.2. The main issues affecting the design are also shown.

Evaluation of Effective Parameters on Quality of Magnetic Resonance Imaging-computed Tomography Image Fusion in Head and Neck Tumors for Application in Treatment Planning.

PubMed

Shirvani, Atefeh; Jabbari, Keyvan; Amouheidari, Alireza

2017-01-01

In radiation therapy, computed tomography (CT) simulation is used for treatment planning to define the location of tumor. Magnetic resonance imaging (MRI)-CT image fusion leads to more efficient tumor contouring. This work tried to identify the practical issues for the combination of CT and MRI images in real clinical cases. The effect of various factors is evaluated on image fusion quality. In this study, the data of thirty patients with brain tumors were used for image fusion. The effect of several parameters on possibility and quality of image fusion was evaluated. These parameters include angles of the patient's head on the bed, slices thickness, slice gap, and height of the patient's head. According to the results, the first dominating factor on quality of image fusion was the difference slice gap between CT and MRI images (cor = 0.86, P < 0.005) and second factor was the angle between CT and MRI slice in the sagittal plane (cor = 0.75, P < 0.005). In 20% of patients, this angle was more than 28° and image fusion was not efficient. In 17% of patients, difference slice gap in CT and MRI was >4 cm and image fusion quality was <25%. The most important problem in image fusion is that MRI images are taken without regard to their use in treatment planning. In general, parameters related to the patient position during MRI imaging should be chosen to be consistent with CT images of the patient in terms of location and angle.

Basic Principles of Magnetic Resonance Imaging—An Update

PubMed Central

Scherzinger, Ann L.; Hendee, William R.

1985-01-01

Magnetic resonance (MR) imaging technology has undergone many technologic advances over the past few years. Many of these advances were stimulated by the wealth of information emerging from nuclear magnetic resonance research in the areas of new and optimal scanning methods and radio-frequency coil design. Other changes arose from the desire to improve image quality, ease siting restrictions and generally facilitate the clinical use of MR equipment. Many questions, however, remain unanswered. Perhaps the most controversial technologic question involves the optimal field strength required for imaging or spectroscopic applications or both. Other issues include safety and clinical efficacy. Technologic issues affect all aspects of MR use including the choice of equipment, examination procedure and image interpretation. Thus, an understanding of recent changes and their theoretic basis is necessary. ImagesFigure 9. PMID:3911591

Quality: from imperatives to innovations.

PubMed

Dunbar, S

1987-05-01

I have outlined the quality issues facing critical care nurses today and have also presented some challenges for the future. Critical care nurses must now enter a new era characterized by unification, collaboration and involvement, increased professional autonomy, and caring to meet the customer's expectations for quality in fact and quality in perception. Through innovation, critical care nurses can control the pace of change and influence quality in critical care. Recall the kaleidoscope and remember that its intent is to make the whole seem more than the sum of its parts. The image on the horizon is a dynamic and powerful nursing profession as a whole, with critical care nurses assuming an essential and more important role. In fact, the image on the horizon looks bright to me.

The use of noise equivalent count rate and the NEMA phantom for PET image quality evaluation.

PubMed

Yang, Xin; Peng, Hao

2015-03-01

PET image quality is directly associated with two important parameters among others: count-rate performance and image signal-to-noise ratio (SNR). The framework of noise equivalent count rate (NECR) was developed back in the 1990s and has been widely used since then to evaluate count-rate performance for PET systems. The concept of NECR is not entirely straightforward, however, and among the issues requiring clarification are its original definition, its relationship to image quality, and its consistency among different derivation methods. In particular, we try to answer whether a higher NECR measurement using a standard NEMA phantom actually corresponds to better imaging performance. The paper includes the following topics: 1) revisiting the original analytical model for NECR derivation; 2) validating three methods for NECR calculation based on the NEMA phantom/standard; and 3) studying the spatial dependence of NECR and quantitative relationship between NECR and image SNR. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

21 CFR 900.22 - Standards for certification agencies.

Code of Federal Regulations, 2010 CFR

2010-04-01

... accreditation bodies for issues related to mammography image quality and clinical practice. The certification... interest. The certification agency shall establish and implement measures that FDA has approved in...

Selection and quality assessment of Landsat data for the North American forest dynamics forest history maps of the US

USGS Publications Warehouse

Schleeweis, Karen; Goward, Samuel N.; Huang, Chengquan; Dwyer, John L.; Dungan, Jennifer L.; Lindsey, Mary A.; Michaelis, Andrew; Rishmawi, Khaldoun; Masek, Jeffery G.

2016-01-01

Using the NASA Earth Exchange platform, the North American Forest Dynamics (NAFD) project mapped forest history wall-to-wall, annually for the contiguous US (1986–2010) using the Vegetation Change Tracker algorithm. As with any effort to identify real changes in remotely sensed time-series, data gaps, shifts in seasonality, misregistration, inconsistent radiometry and cloud contamination can be sources of error. We discuss the NAFD image selection and processing stream (NISPS) that was designed to minimize these sources of error. The NISPS image quality assessments highlighted issues with the Landsat archive and metadata including inadequate georegistration, unreliability of the pre-2009 L5 cloud cover assessments algorithm, missing growing-season imagery and paucity of clear views. Assessment maps of Landsat 5–7 image quantities and qualities are presented that offer novel perspectives on the growing-season archive considered for this study. Over 150,000+ Landsat images were considered for the NAFD project. Optimally, one high quality cloud-free image in each year or a total of 12,152 images would be used. However, to accommodate data gaps and cloud/shadow contamination 23,338 images were needed. In 220 specific path-row image years no acceptable images were found resulting in data gaps in the annual national map products.

Warped document image correction method based on heterogeneous registration strategies

NASA Astrophysics Data System (ADS)

Tong, Lijing; Zhan, Guoliang; Peng, Quanyao; Li, Yang; Li, Yifan

2013-03-01

With the popularity of digital camera and the application requirement of digitalized document images, using digital cameras to digitalize document images has become an irresistible trend. However, the warping of the document surface impacts on the quality of the Optical Character Recognition (OCR) system seriously. To improve the warped document image's vision quality and the OCR rate, this paper proposed a warped document image correction method based on heterogeneous registration strategies. This method mosaics two warped images of the same document from different viewpoints. Firstly, two feature points are selected from one image. Then the two feature points are registered in the other image base on heterogeneous registration strategies. At last, image mosaics are done for the two images, and the best mosaiced image is selected by OCR recognition results. As a result, for the best mosaiced image, the distortions are mostly removed and the OCR results are improved markedly. Experimental results show that the proposed method can resolve the issue of warped document image correction more effectively.

Display challenges resulting from the use of wide field of view imaging devices

NASA Astrophysics Data System (ADS)

Petty, Gregory J.; Fulton, Jack; Nicholson, Gail; Seals, Ean

2012-06-01

As focal plane array technologies advance and imagers increase in resolution, display technology must outpace the imaging improvements in order to adequately represent the complete data collection. Typical display devices tend to have an aspect ratio similar to 4:3 or 16:9, however a breed of Wide Field of View (WFOV) imaging devices exist that skew from the norm with aspect ratios as high as 5:1. This particular quality, when coupled with a high spatial resolution, presents a unique challenge for display devices. Standard display devices must choose between resizing the image data to fit the display and displaying the image data in native resolution and truncating potentially important information. The problem compounds when considering the applications; WFOV high-situationalawareness imagers are sought for space-limited military vehicles. Tradeoffs between these issues are assessed to the image quality of the WFOV sensor.

Body Image, Self-esteem, and Quality of Life in Patients with Psoriasis.

PubMed

Nazik, Hulya; Nazik, Selcuk; Gul, Feride C

2017-01-01

Psoriasis is a chronic inflammatory disease of the skin that may affect the visible areas of body. Hence, the quality of life, self-esteem, and body image can be affected in psoriasis patients. We aimed in the present study to assess the effects of psoriasis on the quality of life, self-esteem, and body image. The study included 92 patients with psoriasis, along with 98 control participants. The sociodemographic characteristics of the patients were assessed, their Psoriasis Area Severity Index (PASI) scores were calculated to determine the clinical severity of the psoriasis, and the values were recorded. In addition, Dermatology Life Quality Index (DLQI), Body Image Scale, and Rosenberg Self-Esteem Scale results were evaluated. When the control and psoriasis groups were evaluated regarding the DLQI, self-esteem, and body image, quality of life was found to be more negatively affected in the psoriasis group than the controls, which was statistically significant ( P < 0.001), and self-esteem ( P < 0.001) and body image ( P < 0.001) were found to be significantly lower. Educational status significantly affected self-esteem ( P < 0.001) and body image ( P = 0.021), however, quality of life was not significantly affected by this parameter ( P = 0.345). PASI was positively correlated with the quality of life ( r = 0.703) and self-esteem ( r = 0.448), however, it was negatively correlated with the body image ( r = -0.423). Psoriasis may negatively affect quality of life, self-esteem, and body image, and may also cause psychosocial problems. An assessment of new approaches on this issue may contribute to developments in the treatment of and rehabilitation from this disease.

IRQN award paper: Operational rounds: a practical administrative process to improve safety and clinical services in radiology.

PubMed

Donnelly, Lane F; Dickerson, Julie M; Lehkamp, Todd W; Gessner, Kevin E; Moskovitz, Jay; Hutchinson, Sally

2008-11-01

As part of a patient safety program in the authors' department of radiology, operational rounds have been instituted. This process consists of radiology leaders' visiting imaging divisions at the site of imaging and discussing frontline employees' concerns about patient safety, the quality of care, and patient and family satisfaction. Operational rounds are executed at a time to optimize the number of attendees. Minutes that describe the issues identified, persons responsible for improvement, and updated improvement plan status are available to employees online. Via this process, multiple patient safety and other issues have been identified and remedied. The authors believe that the process has improved patient safety, the quality of care, and the efficiency of operations. Since the inception of the safety program, the mean number of days between serious safety events involving radiology has doubled. The authors review the background around such walk rounds, describe their particular program, and give multiple illustrative examples of issues identified and improvement plans put in place.

Quality-control issues on high-resolution diagnostic monitors.

PubMed

Parr, L F; Anderson, A L; Glennon, B K; Fetherston, P

2001-06-01

Previous literature indicates a need for more data collection in the area of quality control of high-resolution diagnostic monitors. Throughout acceptance testing, which began in June 2000, stability of monitor calibration was analyzed. Although image quality on all monitors was found to be acceptable upon initial acceptance testing using VeriLUM software by Image Smiths, Inc (Germantown, MD), it was determined to be unacceptable during the clinical phase of acceptance testing. High-resolution monitors were evaluated for quality assurance on a weekly basis from installation through acceptance testing and beyond. During clinical utilization determination (CUD), monitor calibration was identified as a problem and the manufacturer returned and recalibrated all workstations. From that time through final acceptance testing, high-resolution monitor calibration and monitor failure rate remained a problem. The monitor vendor then returned to the site to address these areas. Monitor defocus was still noticeable and calibration checks were increased to three times per week. White and black level drift on medium-resolution monitors had been attributed to raster size settings. Measurements of white and black level at several different size settings were taken to determine the effect of size on white and black level settings. Black level remained steady with size change. White level appeared to increase by 2.0 cd/m2 for every 0.1 inches decrease in horizontal raster size. This was determined not to be the cause of the observed brightness drift. Frequency of calibration/testing is an issue in a clinical environment. The increased frequency required at our site cannot be sustained. The medical physics division cannot provide dedicated personnel to conduct the quality-assurance testing on all monitors at this interval due to other physics commitments throughout the hospital. Monitor access is also an issue due to radiologists' need to read images. Some workstations are in use 7 AM to 11 PM daily. An appropriate monitor calibration frequency must be established during acceptance testing to ensure unacceptable drift is not masked by excessive calibration frequency. Standards for acceptable black level and white level drift also need to be determined. The monitor vendor and hospital staff agree that currently, very small printed text is an acceptable method of determining monitor blur, however, a better method of determining monitor blur is being pursued. Although monitors may show acceptable quality during initial acceptance testing, they need to show sustained quality during the clinical acceptance-testing phase. Defocus, black level, and white level are image quality concerns, which need to be evaluated during the clinical phase of acceptance testing. Image quality deficiencies can have a negative impact on patient care and raise serious medical-legal concerns. The attention to quality control required of the hospital staff needs to be realistic and not have a significant impact on radiology workflow.

TU-AB-207A-03: Image Quality, Dose, and Clinical Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, F.

Practicing medical physicists are often time charged with the tasks of evaluating and troubleshooting complex image quality issues related to CT scanners. This course will equip them with a solid and practical understanding of common CT imaging chain and its major components with emphasis on acquisition physics and hardware, reconstruction, artifacts, image quality, dose, and advanced clinical applications. The core objective is to explain the effects of these major system components on the image quality. This course will not focus on the rapid-changing advanced technologies given the two-hour time limit, but the fundamental principles discussed in this course may facilitatemore » better understanding of those more complicated technologies. The course will begin with an overview of CT acquisition physics and geometry. X-ray tube and CT detector are important acquisition hardware critical to the overall image quality. Each of these two subsystems consists of several major components. An in-depth description of the function and failure modes of these components will be provided. Examples of artifacts related to these failure modes will be presented: off-focal radiation, tube arcing, heel effect, oil bubble, offset drift effect, cross-talk effect, and bad pixels. The fundamentals of CT image reconstruction will first be discussed on an intuitive level. Approaches that do not require rigorous derivation of mathematical formulations will be presented. This is followed by a detailed derivation of the Fourier slice theorem: the foundation of the FBP algorithm. FBP for parallel-beam, fan-beam, and cone-beam geometries will be discussed. To address the issue of radiation dose related to x-ray CT, recent advances in iterative reconstruction, their advantages, and clinical applications will also be described. Because of the nature of fundamental physics and mathematics, limitations in data acquisition, and non-ideal conditions of major system components, image artifact often arise 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.« less

A Novel Texture-Quantization-Based Reversible Multiple Watermarking Scheme Applied to Health Information System.

PubMed

Turuk, Mousami; Dhande, Ashwin

2018-04-01

The recent innovations in information and communication technologies have appreciably changed the panorama of health information system (HIS). These advances provide new means to process, handle, and share medical images and also augment the medical image security issues in terms of confidentiality, reliability, and integrity. Digital watermarking has emerged as new era that offers acceptable solutions to the security issues in HIS. Texture is a significant feature to detect the embedding sites in an image, which further leads to substantial improvement in the robustness. However, considering the perspective of digital watermarking, this feature has received meager attention in the reported literature. This paper exploits the texture property of an image and presents a novel hybrid texture-quantization-based approach for reversible multiple watermarking. The watermarked image quality has been accessed by peak signal to noise ratio (PSNR), structural similarity measure (SSIM), and universal image quality index (UIQI), and the obtained results are superior to the state-of-the-art methods. The algorithm has been evaluated on a variety of medical imaging modalities (CT, MRA, MRI, US) and robustness has been verified, considering various image processing attacks including JPEG compression. The proposed scheme offers additional security using repetitive embedding of BCH encoded watermarks and ADM encrypted ECG signal. Experimental results achieved a maximum of 22,616 bits hiding capacity with PSNR of 53.64 dB.

Magnetic resonance imaging of the subthalamic nucleus for deep brain stimulation.

PubMed

Chandran, Arjun S; Bynevelt, Michael; Lind, Christopher R P

2016-01-01

The subthalamic nucleus (STN) is one of the most important stereotactic targets in neurosurgery, and its accurate imaging is crucial. With improving MRI sequences there is impetus for direct targeting of the STN. High-quality, distortion-free images are paramount. Image reconstruction techniques appear to show the greatest promise in balancing the issue of geometrical distortion and STN edge detection. Existing spin echo- and susceptibility-based MRI sequences are compared with new image reconstruction methods. Quantitative susceptibility mapping is the most promising technique for stereotactic imaging of the STN.

Contrast medium administration and image acquisition parameters in renal CT angiography: what radiologists need to know.

PubMed

Saade, Charbel; Deeb, Ibrahim Alsheikh; Mohamad, Maha; Al-Mohiy, Hussain; El-Merhi, Fadi

2016-01-01

Over the last decade, exponential advances in computed tomography (CT) technology have resulted in improved spatial and temporal resolution. Faster image acquisition enabled renal CT angiography to become a viable and effective noninvasive alternative in diagnosing renal vascular pathologies. However, with these advances, new challenges in contrast media administration have emerged. Poor synchronization between scanner and contrast media administration have reduced the consistency in image quality with poor spatial and contrast resolution. Comprehensive understanding of contrast media dynamics is essential in the design and implementation of contrast administration and image acquisition protocols. This review includes an overview of the parameters affecting renal artery opacification and current protocol strategies to achieve optimal image quality during renal CT angiography with iodinated contrast media, with current safety issues highlighted.

Image size invariant visual cryptography for general access structures subject to display quality constraints.

PubMed

Lee, Kai-Hui; Chiu, Pei-Ling

2013-10-01

Conventional visual cryptography (VC) suffers from a pixel-expansion problem, or an uncontrollable display quality problem for recovered images, and lacks a general approach to construct visual secret sharing schemes for general access structures. We propose a general and systematic approach to address these issues without sophisticated codebook design. This approach can be used for binary secret images in non-computer-aided decryption environments. To avoid pixel expansion, we design a set of column vectors to encrypt secret pixels rather than using the conventional VC-based approach. We begin by formulating a mathematic model for the VC construction problem to find the column vectors for the optimal VC construction, after which we develop a simulated-annealing-based algorithm to solve the problem. The experimental results show that the display quality of the recovered image is superior to that of previous papers.

Integrated Imaging and Vision Techniques for Industrial Inspection: A Special Issue on Machine Vision and Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zheng; Ukida, H.; Ramuhalli, Pradeep

2010-06-05

Imaging- and vision-based techniques play an important role in industrial inspection. The sophistication of the techniques assures high- quality performance of the manufacturing process through precise positioning, online monitoring, and real-time classification. Advanced systems incorporating multiple imaging and/or vision modalities provide robust solutions to complex situations and problems in industrial applications. A diverse range of industries, including aerospace, automotive, electronics, pharmaceutical, biomedical, semiconductor, and food/beverage, etc., have benefited from recent advances in multi-modal imaging, data fusion, and computer vision technologies. Many of the open problems in this context are in the general area of image analysis methodologies (preferably in anmore » automated fashion). This editorial article introduces a special issue of this journal highlighting recent advances and demonstrating the successful applications of integrated imaging and vision technologies in industrial inspection.« less

Evaluation of Effective Parameters on Quality of Magnetic Resonance Imaging-computed Tomography Image Fusion in Head and Neck Tumors for Application in Treatment Planning

PubMed Central

Shirvani, Atefeh; Jabbari, Keyvan; Amouheidari, Alireza

2017-01-01

Background: In radiation therapy, computed tomography (CT) simulation is used for treatment planning to define the location of tumor. Magnetic resonance imaging (MRI)-CT image fusion leads to more efficient tumor contouring. This work tried to identify the practical issues for the combination of CT and MRI images in real clinical cases. The effect of various factors is evaluated on image fusion quality. Materials and Methods: In this study, the data of thirty patients with brain tumors were used for image fusion. The effect of several parameters on possibility and quality of image fusion was evaluated. These parameters include angles of the patient's head on the bed, slices thickness, slice gap, and height of the patient's head. Results: According to the results, the first dominating factor on quality of image fusion was the difference slice gap between CT and MRI images (cor = 0.86, P < 0.005) and second factor was the angle between CT and MRI slice in the sagittal plane (cor = 0.75, P < 0.005). In 20% of patients, this angle was more than 28° and image fusion was not efficient. In 17% of patients, difference slice gap in CT and MRI was >4 cm and image fusion quality was <25%. Conclusion: The most important problem in image fusion is that MRI images are taken without regard to their use in treatment planning. In general, parameters related to the patient position during MRI imaging should be chosen to be consistent with CT images of the patient in terms of location and angle. PMID:29387672

Application of Terahertz Imaging and Backscatter Radiography to Space Shuttle Foam Inspection

NASA Technical Reports Server (NTRS)

Ussery, Warren

2008-01-01

Two state of the art technologies have been developed for External Fuel Tank foam inspections. Results of POD tests have shown Backscatter Radiography and Terahertz imaging detect critical defects with no false positive issue. These techniques are currently in use on the External Tank program as one component in the foam quality assurance program.

A range/depth modulation transfer function (RMTF) framework for characterizing 3D imaging LADAR performance

NASA Astrophysics Data System (ADS)

Staple, Bevan; Earhart, R. P.; Slaymaker, Philip A.; Drouillard, Thomas F., II; Mahony, Thomas

2005-05-01

3D imaging LADARs have emerged as the key technology for producing high-resolution imagery of targets in 3-dimensions (X and Y spatial, and Z in the range/depth dimension). Ball Aerospace & Technologies Corp. continues to make significant investments in this technology to enable critical NASA, Department of Defense, and national security missions. As a consequence of rapid technology developments, two issues have emerged that need resolution. First, the terminology used to rate LADAR performance (e.g., range resolution) is inconsistently defined, is improperly used, and thus has become misleading. Second, the terminology does not include a metric of the system"s ability to resolve the 3D depth features of targets. These two issues create confusion when translating customer requirements into hardware. This paper presents a candidate framework for addressing these issues. To address the consistency issue, the framework utilizes only those terminologies proposed and tested by leading LADAR research and standards institutions. We also provide suggestions for strengthening these definitions by linking them to the well-known Rayleigh criterion extended into the range dimension. To address the inadequate 3D image quality metrics, the framework introduces the concept of a Range/Depth Modulation Transfer Function (RMTF). The RMTF measures the impact of the spatial frequencies of a 3D target on its measured modulation in range/depth. It is determined using a new, Range-Based, Slanted Knife-Edge test. We present simulated results for two LADAR pulse detection techniques and compare them to a baseline centroid technique. Consistency in terminology plus a 3D image quality metric enable improved system standardization.

Image quality assessment for teledermatology: from consumer devices to a dedicated medical device

NASA Astrophysics Data System (ADS)

Amouroux, Marine; Le Cunff, Sébastien; Haudrechy, Alexandre; Blondel, Walter

2017-03-01

Aging population as well as growing incidence of type 2 diabetes induce a growing incidence of chronic skin disorders. In the meantime, chronic shortage of dermatologists leaves some areas underserved. Remote triage and assistance to homecare nurses (known as "teledermatology") appear to be promising solutions to provide dermatological valuation in a decent time to patients wherever they live. Nowadays, teledermatology is often based on consumer devices (digital tablets, smartphones, webcams) whose photobiological and electrical safety levels do not match with medical devices' levels. The American Telemedicine Association (ATA) has published recommendations on quality standards for teledermatology. This "quick guide" does not address the issue of image quality which is critical in domestic environments where lighting is rarely reproducible. Standardized approaches of image quality would allow clinical trial comparison, calibration, manufacturing quality control and quality insurance during clinical use. Therefore, we defined several critical metrics using calibration charts (color and resolution charts) in order to assess image quality such as resolution, lighting uniformity, color repeatability and discrimination of key couples of colors. Using such metrics, we compared quality of images produced by several medical devices (handheld and video-dermoscopes) as well as by consumer devices (digital tablet and cameras) widely spread among dermatologists practice. Since diagnosis accuracy may be impaired by "low quality-images", this study highlights that, from an optical point of view, teledermatology should only be performed using medical devices. Furthermore, a dedicated medical device should probably be developed for the time follow-up of skin lesions often managed in teledermatology such as chronic wounds that require i) noncontact imaging of ii) large areas of skin surfaces, both criteria that cannot be matched using dermoscopes.

IOT Overview: Wide-Field Imaging

NASA Astrophysics Data System (ADS)

Selman, F. J.

The Wide Field Imager (WFI) instrument at La Silla has been the workhorse of wide-field imaging instruments at ESO for several years. In this contribution I will summarize the issues relating to its productivity for the community both in terms of the quality and quantity of data that has come out of it. Although only surveys of limited scope have been completed using WFI, it is ESO's stepping-stone to the new generation of survey telescopes.

Contrast medium administration and image acquisition parameters in renal CT angiography: what radiologists need to know

PubMed Central

Saade, Charbel; Deeb, Ibrahim Alsheikh; Mohamad, Maha; Al-Mohiy, Hussain; El-Merhi, Fadi

2016-01-01

Over the last decade, exponential advances in computed tomography (CT) technology have resulted in improved spatial and temporal resolution. Faster image acquisition enabled renal CT angiography to become a viable and effective noninvasive alternative in diagnosing renal vascular pathologies. However, with these advances, new challenges in contrast media administration have emerged. Poor synchronization between scanner and contrast media administration have reduced the consistency in image quality with poor spatial and contrast resolution. Comprehensive understanding of contrast media dynamics is essential in the design and implementation of contrast administration and image acquisition protocols. This review includes an overview of the parameters affecting renal artery opacification and current protocol strategies to achieve optimal image quality during renal CT angiography with iodinated contrast media, with current safety issues highlighted. PMID:26728701

Smartphone-based grading of apple quality

NASA Astrophysics Data System (ADS)

Li, Xianglin; Li, Ting

2018-02-01

Apple quality grading is a critical issue in apple industry which is one economical pillar of many countries. Artificial grading is inefficient and of poor accuracy. Here we proposed to develop a portable, convenient, real-time, and low cost method aimed at grading apple. Color images of the apples were collected with a smartphone and the grade of sampled apple was assessed by a customized smartphone app, which offered the functions translating RGB color values of the apple to color grade and translating the edge of apple image to weight grade. The algorithms are based on modeling with a large number of apple image at different grades. The apple grade data evaluated by the smartphone are in accordance with the actual data. This study demonstrated the potential of smart phone in apple quality grading/online monitoring at gathering and transportation stage for apple industry.

Ultrasound tissue analysis and characterization

NASA Astrophysics Data System (ADS)

Kaufhold, John; Chan, Ray C.; Karl, William C.; Castanon, David A.

1999-07-01

On the battlefield of the future, it may become feasible for medics to perform, via application of new biomedical technologies, more sophisticated diagnoses and surgery than is currently practiced. Emerging biomedical technology may enable the medic to perform laparoscopic surgical procedures to remove, for example, shrapnel from injured soldiers. Battlefield conditions constrain the types of medical image acquisition and interpretation which can be performed. Ultrasound is the only viable biomedical imaging modality appropriate for deployment on the battlefield -- which leads to image interpretation issues because of the poor quality of ultrasound imagery. To help overcome these issues, we develop and implement a method of image enhancement which could aid non-experts in the rapid interpretation and use of ultrasound imagery. We describe an energy minimization approach to finding boundaries in medical images and show how prior information on edge orientation can be incorporated into this framework to detect tissue boundaries oriented at a known angle.

Distributing FIA Information onto Segmented Landsat Thematic Mapper Images Stratified with Industrial Ground Data

Treesearch

Tripp Lowe; Chris Cieszewski; Michael Zasada; Jarek Zawadzki

2005-01-01

The ability to evaluate the ecological and economical effects of proposed modifications to Georgia's best management practices is an important issue in the State. We have incorporated tabular FIA data with Landsat Thematic Mapper satellite images and other spatial data to model Georgia's forested land and assess the area, volume, age, and site quality...

Diffusion-weighted Breast MRI: Clinical Applications and Emerging Techniques

PubMed Central

Partridge, Savannah C.; Nissan, Noam; Rahbar, Habib; Kitsch, Averi E.; Sigmund, Eric E.

2016-01-01

Diffusion weighted MRI (DWI) holds potential to improve the detection and biological characterization of breast cancer. DWI is increasingly being incorporated into breast MRI protocols to address some of the shortcomings of routine clinical breast MRI. Potential benefits include improved differentiation of benign and malignant breast lesions, assessment and prediction of therapeutic efficacy, and non-contrast detection of breast cancer. The breast presents a unique imaging environment with significant physiologic and inter-subject variations, as well as specific challenges to achieving reliable high quality diffusion weighted MR images. Technical innovations are helping to overcome many of the image quality issues that have limited widespread use of DWI for breast imaging. Advanced modeling approaches to further characterize tissue perfusion, complexity, and glandular organization may expand knowledge and yield improved diagnostic tools. PMID:27690173

Lung Cancer Workshop XI: Tobacco-Induced Disease: Advances in Policy, Early Detection and Management.

PubMed

Mulshine, James L; Avila, Rick; Yankelevitz, David; Baer, Thomas M; Estépar, Raul San Jose; Ambrose, Laurie Fenton; Aldigé, Carolyn R

2015-05-01

The Prevent Cancer Foundation Lung Cancer Workshop XI: Tobacco-Induced Disease: Advances in Policy, Early Detection and Management was held in New York, NY on May 16 and 17, 2014. The two goals of the Workshop were to define strategies to drive innovation in precompetitive quantitative research on the use of imaging to assess new therapies for management of early lung cancer and to discuss a process to implement a national program to provide high quality computed tomography imaging for lung cancer and other tobacco-induced disease. With the central importance of computed tomography imaging for both early detection and volumetric lung cancer assessment, strategic issues around the development of imaging and ensuring its quality are critical to ensure continued progress against this most lethal cancer.

Perceptual full-reference quality assessment of stereoscopic images by considering binocular visual characteristics.

PubMed

Shao, Feng; Lin, Weisi; Gu, Shanbo; Jiang, Gangyi; Srikanthan, Thambipillai

2013-05-01

Perceptual quality assessment is a challenging issue in 3D signal processing research. It is important to study 3D signal directly instead of studying simple extension of the 2D metrics directly to the 3D case as in some previous studies. In this paper, we propose a new perceptual full-reference quality assessment metric of stereoscopic images by considering the binocular visual characteristics. The major technical contribution of this paper is that the binocular perception and combination properties are considered in quality assessment. To be more specific, we first perform left-right consistency checks and compare matching error between the corresponding pixels in binocular disparity calculation, and classify the stereoscopic images into non-corresponding, binocular fusion, and binocular suppression regions. Also, local phase and local amplitude maps are extracted from the original and distorted stereoscopic images as features in quality assessment. Then, each region is evaluated independently by considering its binocular perception property, and all evaluation results are integrated into an overall score. Besides, a binocular just noticeable difference model is used to reflect the visual sensitivity for the binocular fusion and suppression regions. Experimental results show that compared with the relevant existing metrics, the proposed metric can achieve higher consistency with subjective assessment of stereoscopic images.

Stochastic performance modeling and evaluation of obstacle detectability with imaging range sensors

NASA Technical Reports Server (NTRS)

Matthies, Larry; Grandjean, Pierrick

1993-01-01

Statistical modeling and evaluation of the performance of obstacle detection systems for Unmanned Ground Vehicles (UGVs) is essential for the design, evaluation, and comparison of sensor systems. In this report, we address this issue for imaging range sensors by dividing the evaluation problem into two levels: quality of the range data itself and quality of the obstacle detection algorithms applied to the range data. We review existing models of the quality of range data from stereo vision and AM-CW LADAR, then use these to derive a new model for the quality of a simple obstacle detection algorithm. This model predicts the probability of detecting obstacles and the probability of false alarms, as a function of the size and distance of the obstacle, the resolution of the sensor, and the level of noise in the range data. We evaluate these models experimentally using range data from stereo image pairs of a gravel road with known obstacles at several distances. The results show that the approach is a promising tool for predicting and evaluating the performance of obstacle detection with imaging range sensors.

No-reference image quality assessment based on natural scene statistics and gradient magnitude similarity

NASA Astrophysics Data System (ADS)

Jia, Huizhen; Sun, Quansen; Ji, Zexuan; Wang, Tonghan; Chen, Qiang

2014-11-01

The goal of no-reference/blind image quality assessment (NR-IQA) is to devise a perceptual model that can accurately predict the quality of a distorted image as human opinions, in which feature extraction is an important issue. However, the features used in the state-of-the-art "general purpose" NR-IQA algorithms are usually natural scene statistics (NSS) based or are perceptually relevant; therefore, the performance of these models is limited. To further improve the performance of NR-IQA, we propose a general purpose NR-IQA algorithm which combines NSS-based features with perceptually relevant features. The new method extracts features in both the spatial and gradient domains. In the spatial domain, we extract the point-wise statistics for single pixel values which are characterized by a generalized Gaussian distribution model to form the underlying features. In the gradient domain, statistical features based on neighboring gradient magnitude similarity are extracted. Then a mapping is learned to predict quality scores using a support vector regression. The experimental results on the benchmark image databases demonstrate that the proposed algorithm correlates highly with human judgments of quality and leads to significant performance improvements over state-of-the-art methods.

Performance evaluation of image segmentation algorithms on microscopic image data.

PubMed

Beneš, Miroslav; Zitová, Barbara

2015-01-01

In our paper, we present a performance evaluation of image segmentation algorithms on microscopic image data. In spite of the existence of many algorithms for image data partitioning, there is no universal and 'the best' method yet. Moreover, images of microscopic samples can be of various character and quality which can negatively influence the performance of image segmentation algorithms. Thus, the issue of selecting suitable method for a given set of image data is of big interest. We carried out a large number of experiments with a variety of segmentation methods to evaluate the behaviour of individual approaches on the testing set of microscopic images (cross-section images taken in three different modalities from the field of art restoration). The segmentation results were assessed by several indices used for measuring the output quality of image segmentation algorithms. In the end, the benefit of segmentation combination approach is studied and applicability of achieved results on another representatives of microscopic data category - biological samples - is shown. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Who owns the image? Archiving and retention issues in the digital age.

PubMed

Mezrich, Jonathan L; Siegel, Eliot

2014-04-01

Patients are often confused with respect to the ownership of radiologic images and the extent to which they may exert rights over their own imaging. In general, a facility that generates imaging maintains "ownership" rights. Patients have a right to inspect their images and obtain copies but they may not have the images or reports modified or stricken. Facilities may use images not only for treatment purposes but also have rights to use images with respect to educational training, quality control, and research, subject to HIPAA requirements. A facility has statutory obligations with respect to record retention and may face financial penalty and malpractice consequences for failure to retain images. Bankruptcy and state laws address issues of transfer of ownership of a patient's images in cases in which a facility goes out of business. Future questions remain as to whether the length of time a facility maintains images should increase as digital storage media improve and whether the use of inter-facility image sharing via "cloud" technology should alter obligations with respect to which facility must retain the images. Copyright © 2014 American College of Radiology. All rights reserved.

A practical approach to superresolution

NASA Astrophysics Data System (ADS)

Farsiu, Sina; Elad, Michael; Milanfar, Peyman

2006-01-01

Theoretical and practical limitations usually constrain the achievable resolution of any imaging device. Super-Resolution (SR) methods are developed through the years to go beyond this limit by acquiring and fusing several low-resolution (LR) images of the same scene, producing a high-resolution (HR) image. The early works on SR, although occasionally mathematically optimal for particular models of data and noise, produced poor results when applied to real images. In this paper, we discuss two of the main issues related to designing a practical SR system, namely reconstruction accuracy and computational efficiency. Reconstruction accuracy refers to the problem of designing a robust SR method applicable to images from different imaging systems. We study a general framework for optimal reconstruction of images from grayscale, color, or color filtered (CFA) cameras. The performance of our proposed method is boosted by using powerful priors and is robust to both measurement (e.g. CCD read out noise) and system noise (e.g. motion estimation error). Noting that the motion estimation is often considered a bottleneck in terms of SR performance, we introduce the concept of "constrained motions" for enhancing the quality of super-resolved images. We show that using such constraints will enhance the quality of the motion estimation and therefore results in more accurate reconstruction of the HR images. We also justify some practical assumptions that greatly reduce the computational complexity and memory requirements of the proposed methods. We use efficient approximation of the Kalman Filter (KF) and adopt a dynamic point of view to the SR problem. Novel methods for addressing these issues are accompanied by experimental results on real data.

Air Land Sea Bulletin. Issue No. 2013-1

DTIC Science & Technology

2013-01-01

face, finger- print, iris , DNA, and palm print. Biometric capabilities may achieve enabling effects such as the ability to separate, identify...to obtain forensic-quality fingerprints, latent fingerprints, iris images, photos, and other biometric data. Figure 1. SEEK II ALSB 2013-1 12...logical and biographical contextual data of POIs and matches fingerprints and iris images against an internal biomet- rics enrollment database. The

Photoacoustic image reconstruction via deep learning

NASA Astrophysics Data System (ADS)

Antholzer, Stephan; Haltmeier, Markus; Nuster, Robert; Schwab, Johannes

2018-02-01

Applying standard algorithms to sparse data problems in photoacoustic tomography (PAT) yields low-quality images containing severe under-sampling artifacts. To some extent, these artifacts can be reduced by iterative image reconstruction algorithms which allow to include prior knowledge such as smoothness, total variation (TV) or sparsity constraints. These algorithms tend to be time consuming as the forward and adjoint problems have to be solved repeatedly. Further, iterative algorithms have additional drawbacks. For example, the reconstruction quality strongly depends on a-priori model assumptions about the objects to be recovered, which are often not strictly satisfied in practical applications. To overcome these issues, in this paper, we develop direct and efficient reconstruction algorithms based on deep learning. As opposed to iterative algorithms, we apply a convolutional neural network, whose parameters are trained before the reconstruction process based on a set of training data. For actual image reconstruction, a single evaluation of the trained network yields the desired result. Our presented numerical results (using two different network architectures) demonstrate that the proposed deep learning approach reconstructs images with a quality comparable to state of the art iterative reconstruction methods.

Applications of hyperspectral imaging in chicken meat safety and quality detection and evaluation: a review.

PubMed

Xiong, Zhenjie; Xie, Anguo; Sun, Da-Wen; Zeng, Xin-An; Liu, Dan

2015-01-01

Currently, the issue of food safety and quality is a great public concern. In order to satisfy the demands of consumers and obtain superior food qualities, non-destructive and fast methods are required for quality evaluation. As one of these methods, hyperspectral imaging (HSI) technique has emerged as a smart and promising analytical tool for quality evaluation purposes and has attracted much interest in non-destructive analysis of different food products. With the main advantage of combining both spectroscopy technique and imaging technique, HSI technique shows a convinced attitude to detect and evaluate chicken meat quality objectively. Moreover, developing a quality evaluation system based on HSI technology would bring economic benefits to the chicken meat industry. Therefore, in recent years, many studies have been conducted on using HSI technology for the safety and quality detection and evaluation of chicken meat. The aim of this review is thus to give a detailed overview about HSI and focus on the recently developed methods exerted in HSI technology developed for microbiological spoilage detection and quality classification of chicken meat. Moreover, the usefulness of HSI technique for detecting fecal contamination and bone fragments of chicken carcasses are presented. Finally, some viewpoints on its future research and applicability in the modern poultry industry are proposed.

TRMM Microwave Imager (TMI) Updates for Final Data Version Release

NASA Technical Reports Server (NTRS)

Kroodsma, Rachael A; Bilanow, Stephen; Ji, Yimin; McKague, Darren

2017-01-01

The Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) dataset released by the Precipitation Processing System (PPS) will be updated to a final version within the next year. These updates are based on increased knowledge in recent years of radiometer calibration and sensor performance issues. In particular, the Global Precipitation Measurement (GPM) Microwave Imager (GMI) is used as a model for many of the TMI version updates. This paper discusses four aspects of the TMI data product that will be improved: spacecraft attitude, calibration and quality control, along-scan bias corrections, and sensor pointing accuracy. These updates will be incorporated into the final TMI data version, improving the quality of the data product and ensuring accurate geophysical parameters can be derived from TMI.

Body Image and Sexuality in Women Survivors of Breast Cancer in India: Qualitative Findings.

PubMed

Barthakur, Michelle S; Sharma, Mahendra P; Chaturvedi, Santosh K; Manjunath, Suraj K

2017-01-01

With increasing rates of breast cancer survivors, psychosocial issues surrounding cancer survivorship have been gaining prominence. The following article reports on body image and sexuality-related issues in aftermath of the diagnosis and its treatment in the Indian context. Research design was mixed method, cross-sectional, and exploratory in nature. Quantitative sample consisted of fifty survivors while the qualitative sample size included 15 out of the 50 total breast cancer survivors who were recruited from hospitals, nongovernmental organization, and through word-of-mouth. Data was collected using quantitative measures, and in-depth interviews were done using semi-structured interview schedule that was developed for the study. Qualitative data were analyzed using descriptive phenomenological approach. In body image, emerging themes were about identity (womanhood, motherhood, and attractiveness), impact of surgery, hair loss, clothes, and uncomfortable situations. In sexuality, barriers were faced due to difficulty in disclosure and themes were about adjustments made by spouses, role of age, and sexual difficulties due to treatment. Findings imply need to address the issues of body image and sexuality as it impacts quality of life of survivors.

Digital imagery/telecytology. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.

PubMed

O'Brien, M J; Takahashi, M; Brugal, G; Christen, H; Gahm, T; Goodell, R M; Karakitsos, P; Knesel, E A; Kobler, T; Kyrkou, K A; Labbe, S; Long, E L; Mango, L J; McGoogan, E; Oberholzer, M; Reith, A; Winkler, C

1998-01-01

Optical digital imaging and its related technologies have applications in cytopathology that encompass training and education, image analysis, diagnosis, report documentation and archiving, and telecommunications. Telecytology involves the use of telecommunications to transmit cytology images for the purposes of diagnosis, consultation or education. This working paper provides a mainly informational overview of optical digital imaging and summarizes current technologic resources and applications and some of the ethical and legal implications of the use of these new technologies in cytopathology. Computer hardware standards for optical digital imagery will continue to be driven mainly by commercial interests and nonmedical imperatives, but professional organizations can play a valuable role in developing recommendations or standards for digital image sampling, documentation, archiving, authenticity safeguards and teleconsultation protocols; in addressing patient confidentiality and ethical, legal and informed consent issues; and in providing support for quality assurance and standardization of digital image-based testing. There is some evidence that high levels of accuracy for telepathology diagnosis can be achieved using existing dynamic systems, which may also be applicable to telecytology consultation. Static systems for both telepathology and telecytology, which have the advantage of considerably lower cost, appear to have lower levels of accuracy. Laboratories that maintain digital image databases should adopt practices and protocols that ensure patient confidentiality. Individuals participating in telecommunication of digital images for diagnosis should be properly qualified, meet licensing requirements and use procedures that protect patient confidentiality. Such individuals should be cognizant of the limitations of the technology and employ quality assurance practices that ensure the validity and accuracy of each consultation. Even in an informal teleconsultation setting one should define the extent of participation and be mindful of potential malpractice liability. Digital imagery applications will continue to present new opportunities and challenges. Position papers such as this are directed toward assisting the profession to stay informed and in control of these applications in the laboratory. Telecytology is an area in particular need of studies of good quality to provide data on factors affecting accuracy. New technologic approaches to addressing the issue of selective sampling in static image consultation are needed. The use of artificial intelligence software as an adjunct to enhance the accuracy and reproducibility of cytologic diagnosis of digital images in routine and consultation settings deserves to be pursued. Other telecytology-related issues that require clarification and the adoption of workable guidelines include interstate licensure and protocols to define malpractice liability.

Image quality in thoracic 4D cone-beam CT: A sensitivity analysis of respiratory signal, binning method, reconstruction algorithm, and projection angular spacing

PubMed Central

Shieh, Chun-Chien; Kipritidis, John; O’Brien, Ricky T.; Kuncic, Zdenka; Keall, Paul J.

2014-01-01

Purpose: Respiratory signal, binning method, and reconstruction algorithm are three major controllable factors affecting image quality in thoracic 4D cone-beam CT (4D-CBCT), which is widely used in image guided radiotherapy (IGRT). Previous studies have investigated each of these factors individually, but no integrated sensitivity analysis has been performed. In addition, projection angular spacing is also a key factor in reconstruction, but how it affects image quality is not obvious. An investigation of the impacts of these four factors on image quality can help determine the most effective strategy in improving 4D-CBCT for IGRT. Methods: Fourteen 4D-CBCT patient projection datasets with various respiratory motion features were reconstructed with the following controllable factors: (i) respiratory signal (real-time position management, projection image intensity analysis, or fiducial marker tracking), (ii) binning method (phase, displacement, or equal-projection-density displacement binning), and (iii) reconstruction algorithm [Feldkamp–Davis–Kress (FDK), McKinnon–Bates (MKB), or adaptive-steepest-descent projection-onto-convex-sets (ASD-POCS)]. The image quality was quantified using signal-to-noise ratio (SNR), contrast-to-noise ratio, and edge-response width in order to assess noise/streaking and blur. The SNR values were also analyzed with respect to the maximum, mean, and root-mean-squared-error (RMSE) projection angular spacing to investigate how projection angular spacing affects image quality. Results: The choice of respiratory signals was found to have no significant impact on image quality. Displacement-based binning was found to be less prone to motion artifacts compared to phase binning in more than half of the cases, but was shown to suffer from large interbin image quality variation and large projection angular gaps. Both MKB and ASD-POCS resulted in noticeably improved image quality almost 100% of the time relative to FDK. In addition, SNR values were found to increase with decreasing RMSE values of projection angular gaps with strong correlations (r ≈ −0.7) regardless of the reconstruction algorithm used. Conclusions: Based on the authors’ results, displacement-based binning methods, better reconstruction algorithms, and the acquisition of even projection angular views are the most important factors to consider for improving thoracic 4D-CBCT image quality. In view of the practical issues with displacement-based binning and the fact that projection angular spacing is not currently directly controllable, development of better reconstruction algorithms represents the most effective strategy for improving image quality in thoracic 4D-CBCT for IGRT applications at the current stage. PMID:24694143

Visual Communications And Image Processing

NASA Astrophysics Data System (ADS)

Hsing, T. Russell; Tzou, Kou-Hu

1989-07-01

This special issue on Visual Communications and Image Processing contains 14 papers that cover a wide spectrum in this fast growing area. For the past few decades, researchers and scientists have devoted their efforts to these fields. Through this long-lasting devotion, we witness today the growing popularity of low-bit-rate video as a convenient tool for visual communication. We also see the integration of high-quality video into broadband digital networks. Today, with more sophisticated processing, clearer and sharper pictures are being restored from blurring and noise. Also, thanks to the advances in digital image processing, even a PC-based system can be built to recognize highly complicated Chinese characters at the speed of 300 characters per minute. This special issue can be viewed as a milestone of visual communications and image processing on its journey to eternity. It presents some overviews on advanced topics as well as some new development in specific subjects.

Citizens' role in health services: satisfaction behavior: Kano's model, Part 1.

PubMed

Corbella Jané, Antoni; Maturana Domínguez, Salvador

2003-01-01

When it comes to consumer satisfaction, there is a lack of consensus over the importance of the role of consumers in connection with the quality of services. Widely different points of view exist, ranging from a defense of consumer satisfaction as the ultimate measure of service quality, to its treatment as a commercial issue or as one that merely has to do with image. This first article (part 1 of 2, also in this issue) describes and illustrates Kano's explicative model of how consumer satisfaction behaves and briefly analyzes the main characteristics, advantages, and limitations of the different methods used to assess consumer satisfaction.

Are Disposable and Standard Gonioscopy Lenses Comparable?

PubMed

Lee, Bonny; Szirth, Bernard C; Fechtner, Robert D; Khouri, Albert S

2017-04-01

Gonioscopy is important in the evaluation and treatment of glaucoma. With increased scrutiny of acceptable sterilization processes for health care instruments, disposable gonioscopy lenses have recently been introduced. Single-time use lenses are theorized to decrease infection risk and eliminate the issue of wear and tear seen on standard, reusable lenses. However, patient care would be compromised if the quality of images produced by the disposable lens were inferior to those produced by the reusable lens. The purpose of this study was to compare the quality of images produced by disposable versus standard gonioscopy lenses. A disposable single mirror lens (Sensor Medical Technology) and a standard Volk G-1 gonioscopy lens were used to image 21 volunteers who were prospectively recruited for the study. Images of the inferior and temporal angles of each subject's left eye were acquired using a slit-lamp camera through the disposable and standard gonioscopy lens. In total, 74 images were graded using the Spaeth gonioscopic system and for clarity and quality. Clarity was scored as 1 or 2 and defined as either (1) all structures perceived or (2) all structures not perceived. Quality was scored as 1, 2, or 3, and defined as (1) all angle landmarks clear and well focused, (2) some angle landmarks clear, others blurred, or (3) angle landmarks could not be ascertained. The 74 images were divided into images taken with the disposable single mirror lens and images taken with the standard Volk G-1 gonioscopy lens. The clarity and quality scores for each of these 2 image groups were averaged and P-values were calculated. Average quality of images produced with the standard lens was 1.46±0.56 compared with 1.54±0.61 for those produced with the disposable lens (P=0.55). Average clarity of images produced with the standard lens was 1.47±0.51 compared with 1.49±0.51 (P=0.90) with the disposable lens. We conclude that there is no significant difference in quality of images produced with standard versus disposable gonioscopy lenses. Disposable gonioscopy lenses may be an acceptable alternative to standard reusable lenses, especially in conditions where sterilization is difficult.

Fast and robust wavelet-based dynamic range compression and contrast enhancement model with color restoration

NASA Astrophysics Data System (ADS)

Unaldi, Numan; Asari, Vijayan K.; Rahman, Zia-ur

2009-05-01

Recently we proposed a wavelet-based dynamic range compression algorithm to improve the visual quality of digital images captured from high dynamic range scenes with non-uniform lighting conditions. The fast image enhancement algorithm that provides dynamic range compression, while preserving the local contrast and tonal rendition, is also a good candidate for real time video processing applications. Although the colors of the enhanced images produced by the proposed algorithm are consistent with the colors of the original image, the proposed algorithm fails to produce color constant results for some "pathological" scenes that have very strong spectral characteristics in a single band. The linear color restoration process is the main reason for this drawback. Hence, a different approach is required for the final color restoration process. In this paper the latest version of the proposed algorithm, which deals with this issue is presented. The results obtained by applying the algorithm to numerous natural images show strong robustness and high image quality.

Functional evaluation of telemedicine with super high definition images and B-ISDN.

PubMed

Takeda, H; Matsumura, Y; Okada, T; Kuwata, S; Komori, M; Takahashi, T; Minatom, K; Hashimoto, T; Wada, M; Fujio, Y

1998-01-01

In order to determine whether a super high definition (SHD) image running at a series of 2048 resolution x 2048 line x 60 frame/sec was capable of telemedicine, we established a filing system for medical images and two experiments for transmission of high quality images were performed. All images of various types, produced from one case of ischemic heart disease were digitized and registered into the filing system. Images consisted of plain chest x-ray, electrocardiogram, ultrasound cardiogram, cardiac scintigram, coronary angiogram, left ventriculogram and so on. All images were animated and totaled a number of 243. We prepared a graphic user interface (GUI) for image retrieval based on the medical events and modalities. Twenty one cardiac specialists evaluated quality of the SHD images to be somewhat poor compared to the original pictures but sufficient for making diagnoses, and effective as a tool for teaching and case study purposes. The system capability of simultaneously displaying several animated images was especially deemed effective in grasping comprehension of diagnosis. Efficient input methods and creating capacity of filing all produced images are future issue. Using B-ISDN network, the SHD file was prefetched to the servers at Kyoto University Hospital and BBCC (Bradband ISDN Business chance & Culture Creation) laboratory as an telemedicine experiment. Simultaneous video conference system, the control of image retrieval and pointing function made the teleconference successful in terms of high quality of medical images, quick response time and interactive data exchange.

Segmentation Fusion Techniques with Application to Plenoptic Images: A Survey.

NASA Astrophysics Data System (ADS)

Evin, D.; Hadad, A.; Solano, A.; Drozdowicz, B.

2016-04-01

The segmentation of anatomical and pathological structures plays a key role in the characterization of clinically relevant evidence from digital images. Recently, plenoptic imaging has emerged as a new promise to enrich the diagnostic potential of conventional photography. Since the plenoptic images comprises a set of slightly different versions of the target scene, we propose to make use of those images to improve the segmentation quality in relation to the scenario of a single image segmentation. The problem of finding a segmentation solution from multiple images of a single scene, is called segmentation fusion. This paper reviews the issue of segmentation fusion in order to find solutions that can be applied to plenoptic images, particularly images from the ophthalmological domain.

Ghosting in anaglyphic stereoscopic images

NASA Astrophysics Data System (ADS)

Woods, Andrew J.; Rourke, Tegan

2004-05-01

Anaglyphic 3D images are an easy way of displaying stereoscopic 3D images on a wide range of display types, e.g. CRT, LCD, print, etc. While the anaglyphic 3D image method is cheap and accessible, its use requires a compromise in stereoscopic image quality. A common problem with anaglyphic 3D images is ghosting. Ghosting (or crosstalk) is the leaking of an image to one eye, when it is intended exclusively for the other eye. Ghosting degrades the ability of the observer to fuse the stereoscopic image and hence the quality of the 3D image is reduced. Ghosting is present in various levels with most stereoscopic displays, however it is often particularly evident with anaglyphic 3D images. This paper describes a project whose aim was to characterize the presence of ghosting in anaglyphic 3D images due to spectral issues. The spectral response curves of several different display types and several different brands of anaglyph glasses were measured using a spectroradiometer or spectrophotometer. A mathematical model was then developed to predict the amount of crosstalk in anaglyphic 3D images when different combinations of displays and glasses are used, and therefore predict the best type of anaglyph glasses for use with a particular display type.

Technologist-Directed Repeat Musculoskeletal and Chest Radiographs: How Often Do They Impact Diagnosis?

PubMed

Rosenkrantz, Andrew B; Jacobs, Jill E; Jain, Nidhi; Brusca-Augello, Geraldine; Mechlin, Michael; Parente, Marc; Recht, Michael P

2017-12-01

Radiologic technologists may repeat images within a radiographic examination because of perceived suboptimal image quality, excluding these original images from submission to a PACS. This study assesses the appropriateness of technologists' decisions to repeat musculoskeletal and chest radiographs as well as the utility of repeat radiographs in addressing examinations' clinical indication. We included 95 musculoskeletal and 87 chest radiographic examinations in which the technologist repeated one or more images because of perceived image quality issues, rejecting original images from PACS submission. Rejected images were retrieved from the radiograph unit and uploaded for viewing on a dedicated server. Musculoskeletal and chest radiologists reviewed rejected and repeat images in their timed sequence, in addition to the studies' remaining images. Radiologists answered questions regarding the added value of repeat images. The reviewing radiologist agreed with the reason for rejection for 64.2% of musculoskeletal and 60.9% of chest radiographs. For 77.9% and 93.1% of rejected radiographs, the clinical inquiry could have been satisfied without repeating the image. For 75.8% and 64.4%, the repeated images showed improved image quality. Only 28.4% and 3.4% of repeated images were considered to provide additional information that was helpful in addressing the clinical question. Most repeated radiographs (chest more so than musculoskeletal radiographs) did not add significant clinical information or alter diagnosis, although they did increase radiation exposure. The decision to repeat images should be made after viewing the questionable image in context with all images in a study and might best be made by a radiologist rather than the performing technologist.

Algorithm design for automated transportation photo enforcement camera image and video quality diagnostic check modules

NASA Astrophysics Data System (ADS)

Raghavan, Ajay; Saha, Bhaskar

2013-03-01

Photo enforcement devices for traffic rules such as red lights, toll, stops, and speed limits are increasingly being deployed in cities and counties around the world to ensure smooth traffic flow and public safety. These are typically unattended fielded systems, and so it is important to periodically check them for potential image/video quality problems that might interfere with their intended functionality. There is interest in automating such checks to reduce the operational overhead and human error involved in manually checking large camera device fleets. Examples of problems affecting such camera devices include exposure issues, focus drifts, obstructions, misalignment, download errors, and motion blur. Furthermore, in some cases, in addition to the sub-algorithms for individual problems, one also has to carefully design the overall algorithm and logic to check for and accurately classifying these individual problems. Some of these issues can occur in tandem or have the potential to be confused for each other by automated algorithms. Examples include camera misalignment that can cause some scene elements to go out of focus for wide-area scenes or download errors that can be misinterpreted as an obstruction. Therefore, the sequence in which the sub-algorithms are utilized is also important. This paper presents an overview of these problems along with no-reference and reduced reference image and video quality solutions to detect and classify such faults.

Nonlinear Fusion of Multispectral Citrus Fruit Image Data with Information Contents.

PubMed

Li, Peilin; Lee, Sang-Heon; Hsu, Hung-Yao; Park, Jae-Sam

2017-01-13

The main issue of vison-based automatic harvesting manipulators is the difficulty in the correct fruit identification in the images under natural lighting conditions. Mostly, the solution has been based on a linear combination of color components in the multispectral images. However, the results have not reached a satisfactory level. To overcome this issue, this paper proposes a robust nonlinear fusion method to augment the original color image with the synchronized near infrared image. The two images are fused with Daubechies wavelet transform (DWT) in a multiscale decomposition approach. With DWT, the background noises are reduced and the necessary image features are enhanced by fusing the color contrast of the color components and the homogeneity of the near infrared (NIR) component. The resulting fused color image is classified with a C-means algorithm for reconstruction. The performance of the proposed approach is evaluated with the statistical F measure in comparison to some existing methods using linear combinations of color components. The results show that the fusion of information in different spectral components has the advantage of enhancing the image quality, therefore improving the classification accuracy in citrus fruit identification in natural lighting conditions.

Nonlinear Fusion of Multispectral Citrus Fruit Image Data with Information Contents

PubMed Central

Li, Peilin; Lee, Sang-Heon; Hsu, Hung-Yao; Park, Jae-Sam

2017-01-01

The main issue of vison-based automatic harvesting manipulators is the difficulty in the correct fruit identification in the images under natural lighting conditions. Mostly, the solution has been based on a linear combination of color components in the multispectral images. However, the results have not reached a satisfactory level. To overcome this issue, this paper proposes a robust nonlinear fusion method to augment the original color image with the synchronized near infrared image. The two images are fused with Daubechies wavelet transform (DWT) in a multiscale decomposition approach. With DWT, the background noises are reduced and the necessary image features are enhanced by fusing the color contrast of the color components and the homogeneity of the near infrared (NIR) component. The resulting fused color image is classified with a C-means algorithm for reconstruction. The performance of the proposed approach is evaluated with the statistical F measure in comparison to some existing methods using linear combinations of color components. The results show that the fusion of information in different spectral components has the advantage of enhancing the image quality, therefore improving the classification accuracy in citrus fruit identification in natural lighting conditions. PMID:28098797

Osteoporosis Imaging: State of the Art and Advanced Imaging

PubMed Central

2012-01-01

Osteoporosis is becoming an increasingly important public health issue, and effective treatments to prevent fragility fractures are available. Osteoporosis imaging is of critical importance in identifying individuals at risk for fractures who would require pharmacotherapy to reduce fracture risk and also in monitoring response to treatment. Dual x-ray absorptiometry is currently the state-of-the-art technique to measure bone mineral density and to diagnose osteoporosis according to the World Health Organization guidelines. Motivated by a 2000 National Institutes of Health consensus conference, substantial research efforts have focused on assessing bone quality by using advanced imaging techniques. Among these techniques aimed at better characterizing fracture risk and treatment effects, high-resolution peripheral quantitative computed tomography (CT) currently plays a central role, and a large number of recent studies have used this technique to study trabecular and cortical bone architecture. Other techniques to analyze bone quality include multidetector CT, magnetic resonance imaging, and quantitative ultrasonography. In addition to quantitative imaging techniques measuring bone density and quality, imaging needs to be used to diagnose prevalent osteoporotic fractures, such as spine fractures on chest radiographs and sagittal multidetector CT reconstructions. Radiologists need to be sensitized to the fact that the presence of fragility fractures will alter patient care, and these fractures need to be described in the report. This review article covers state-of-the-art imaging techniques to measure bone mineral density, describes novel techniques to study bone quality, and focuses on how standard imaging techniques should be used to diagnose prevalent osteoporotic fractures. © RSNA, 2012 PMID:22438439

Cross-Border Delivery in Nigeria and Quality Assurance Issues

ERIC Educational Resources Information Center

Idogho, Philipa Omamhe; Eshiotse, Sunday Gabriel

2012-01-01

Access to educational opportunities has witnessed significant facilitation, especially in developing economies where ethnic minorities and other disadvantaged groups abound. The global initiative anchored by COL (commonwealth of learning) in collaboration with institutions and agencies is helping to further reinforce the "global image"…

Automatic assessment of the quality of patient positioning in mammography

NASA Astrophysics Data System (ADS)

Bülow, Thomas; Meetz, Kirsten; Kutra, Dominik; Netsch, Thomas; Wiemker, Rafael; Bergtholdt, Martin; Sabczynski, Jörg; Wieberneit, Nataly; Freund, Manuela; Schulze-Wenck, Ingrid

2013-02-01

Quality assurance has been recognized as crucial for the success of population-based breast cancer screening programs using x-ray mammography. Quality guidelines and criteria have been defined in the US as well as the European Union in order to ensure the quality of breast cancer screening. Taplin et al. report that incorrect positioning of the breast is the major image quality issue in screening mammography. Consequently, guidelines and criteria for correct positioning and for the assessment of the positioning quality in mammograms play an important role in the quality standards. In this paper we present a system for the automatic evaluation of positioning quality in mammography according to the existing standardized criteria. This involves the automatic detection of anatomic landmarks in medio- lateral oblique (MLO) and cranio-caudal (CC) mammograms, namely the pectoral muscle, the mammilla and the infra-mammary fold. Furthermore, the detected landmarks are assessed with respect to their proper presentation in the image. Finally, the geometric relations between the detected landmarks are investigated to assess the positioning quality. This includes the evaluation whether the pectoral muscle is imaged down to the mammilla level, and whether the posterior nipple line diameter of the breast is consistent between the different views (MLO and CC) of the same breast. Results of the computerized assessment are compared to ground truth collected from two expert readers.

Pictorial Review of Digital Radiography Artifacts.

PubMed

Walz-Flannigan, Alisa I; Brossoit, Kimberly J; Magnuson, Dayne J; Schueler, Beth A

2018-01-01

Visual familiarity with the variety of digital radiographic artifacts is needed to identify, resolve, or prevent image artifacts from creating issues with patient imaging. Because the mechanism for image creation is different between flat-panel detectors and computed radiography, the causes and appearances of some artifacts can be unique to these different modalities. Examples are provided of artifacts that were found on clinical images or during quality control testing with flat-panel detectors. The examples are meant to serve as learning tools for future identification and troubleshooting of artifacts and as a reminder for steps that can be taken for prevention. The examples of artifacts provided are classified according to their causal connection in the imaging chain, including an equipment defect as a result of an accident or mishandling, debris or gain calibration flaws, a problematic acquisition technique, signal transmission failures, and image processing issues. Specific artifacts include those that are due to flat-panel detector drops, backscatter, debris in the x-ray field during calibration, detector saturation or underexposure, or collimation detection errors, as well as a variety of artifacts that are processing induced. © RSNA, 2018.

Impact of the Adaptive Statistical Iterative Reconstruction Technique on Radiation Dose and Image Quality in Bone SPECT/CT.

PubMed

Sibille, Louis; Chambert, Benjamin; Alonso, Sandrine; Barrau, Corinne; D'Estanque, Emmanuel; Al Tabaa, Yassine; Collombier, Laurent; Demattei, Christophe; Kotzki, Pierre-Olivier; Boudousq, Vincent

2016-07-01

The purpose of this study was to compare a routine bone SPECT/CT protocol using CT reconstructed with filtered backprojection (FBP) with an optimized protocol using low-dose CT images reconstructed with adaptive statistical iterative reconstruction (ASiR). In this prospective study, enrolled patients underwent bone SPECT/CT, with 1 SPECT acquisition followed by 2 randomized CT acquisitions: FBP CT (FBP; noise index, 25) and ASiR CT (70% ASiR; noise index, 40). The image quality of both attenuation-corrected SPECT and CT images was visually (5-point Likert scale, 2 interpreters) and quantitatively (contrast ratio [CR] and signal-to-noise ratio [SNR]) estimated. The CT dose index volume, dose-length product, and effective dose were compared. Seventy-five patients were enrolled in the study. Quantitative attenuation-corrected SPECT evaluation showed no inferiority for contrast ratio and SNR issued from FBP CT or ASiR CT (respectively, 13.41 ± 7.83 vs. 13.45 ± 7.99 and 2.33 ± 0.83 vs. 2.32 ± 0.84). Qualitative image analysis showed no difference between attenuation-corrected SPECT images issued from FBP CT or ASiR CT for both interpreters (respectively, 3.5 ± 0.6 vs. 3.5 ± 0.6 and 3.6 ± 0.5 vs. 3.6 ± 0.5). Quantitative CT evaluation showed no inferiority for SNR between FBP and ASiR CT images (respectively, 0.93 ± 0.16 and 1.07 ± 0.17). Qualitative image analysis showed no quality difference between FBP and ASiR CT images for both interpreters (respectively, 3.8 ± 0.5 vs. 3.6 ± 0.5 and 4.0 ± 0.1 vs. 4.0 ± 0.2). Mean CT dose index volume, dose-length product, and effective dose for ASiR CT (3.0 ± 2.0 mGy, 148 ± 85 mGy⋅cm, and 2.2 ± 1.3 mSv) were significantly lower than for FBP CT (8.5 ± 3.7 mGy, 365 ± 160 mGy⋅cm, and 5.5 ± 2.4 mSv). The use of 70% ASiR blending in bone SPECT/CT can reduce the CT radiation dose by 60%, with no sacrifice in attenuation-corrected SPECT and CT image quality, compared with the conventional protocol using FBP CT reconstruction technique. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

A qualitative and quantitative analysis of radiation dose and image quality of computed tomography images using adaptive statistical iterative reconstruction.

PubMed

Hussain, Fahad Ahmed; Mail, Noor; Shamy, Abdulrahman M; Suliman, Alghamdi; Saoudi, Abdelhamid

2016-05-08

Image quality is a key issue in radiology, particularly in a clinical setting where it is important to achieve accurate diagnoses while minimizing radiation dose. Some computed tomography (CT) manufacturers have introduced algorithms that claim significant dose reduction. In this study, we assessed CT image quality produced by two reconstruction algorithms provided with GE Healthcare's Discovery 690 Elite positron emission tomography (PET) CT scanner. Image quality was measured for images obtained at various doses with both conventional filtered back-projection (FBP) and adaptive statistical iterative reconstruction (ASIR) algorithms. A stan-dard CT dose index (CTDI) phantom and a pencil ionization chamber were used to measure the CT dose at 120 kVp and an exposure of 260 mAs. Image quality was assessed using two phantoms. CT images of both phantoms were acquired at tube voltage (kV) of 120 with exposures ranging from 25 mAs to 400 mAs. Images were reconstructed using FBP and ASIR ranging from 10% to 100%, then analyzed for noise, low-contrast detectability, contrast-to-noise ratio (CNR), and modulation transfer function (MTF). Noise was 4.6 HU in water phantom images acquired at 260 mAs/FBP 120 kV and 130 mAs/50% ASIR 120 kV. The large objects (fre-quency < 7 lp/cm) retained fairly acceptable image quality at 130 mAs/50% ASIR, compared to 260 mAs/FBP. The application of ASIR for small objects (frequency >7 lp/cm) showed poor visibility compared to FBP at 260 mAs and even worse for images acquired at less than 130 mAs. ASIR blending more than 50% at low dose tends to reduce contrast of small objects (frequency >7 lp/cm). We concluded that dose reduction and ASIR should be applied with close attention if the objects to be detected or diagnosed are small (frequency > 7 lp/cm). Further investigations are required to correlate the small objects (frequency > 7 lp/cm) to patient anatomy and clinical diagnosis.

A TV-constrained decomposition method for spectral CT

NASA Astrophysics Data System (ADS)

Guo, Xiaoyue; Zhang, Li; Xing, Yuxiang

2017-03-01

Spectral CT is attracting more and more attention in medicine, industrial nondestructive testing and security inspection field. Material decomposition is an important issue to a spectral CT to discriminate materials. Because of the spectrum overlap of energy channels, as well as the correlation of basis functions, it is well acknowledged that decomposition step in spectral CT imaging causes noise amplification and artifacts in component coefficient images. In this work, we propose materials decomposition via an optimization method to improve the quality of decomposed coefficient images. On the basis of general optimization problem, total variance minimization is constrained on coefficient images in our overall objective function with adjustable weights. We solve this constrained optimization problem under the framework of ADMM. Validation on both a numerical dental phantom in simulation and a real phantom of pig leg on a practical CT system using dual-energy imaging is executed. Both numerical and physical experiments give visually obvious better reconstructions than a general direct inverse method. SNR and SSIM are adopted to quantitatively evaluate the image quality of decomposed component coefficients. All results demonstrate that the TV-constrained decomposition method performs well in reducing noise without losing spatial resolution so that improving the image quality. The method can be easily incorporated into different types of spectral imaging modalities, as well as for cases with energy channels more than two.

Medical photography: principles for orthopedics.

PubMed

Uzun, Metin; Bülbül, Murat; Toker, Serdar; Beksaç, Burak; Kara, Adnan

2014-04-05

Medical photography is used clinically for patient evaluation, treatment decisions, and scientific documentation. Although standards for medical photography exist in many branches of medicine, we have not encountered such criteria in publications in the area of orthopedics. This study aims to (1) assess the quality of medical images used in an orthopedic publication and (2) to propose standards for medical photography in this area. Clinical photographs were reviewed from all issues of a journal published between the years 2008 and 2012. A quality of clinical images was developed based on the criteria published for the specialties of dermatology and cosmetic surgery. All images were reviewed on the appropriateness of background, patient preparation, and technique. In this study, only 44.9% of clinical images in an orthopedic publication adhered to the proposed conventions. Standards have not been established for medical photography in orthopedics as in other specialty areas. Our results suggest that photographic clinical information in orthopedic publications may be limited by inadequate presentation. We propose that formal conventions for clinical images should be established.

Rapid Measurement and Correction of Phase Errors from B0 Eddy Currents: Impact on Image Quality for Non-Cartesian Imaging

PubMed Central

Brodsky, Ethan K.; Klaers, Jessica L.; Samsonov, Alexey A.; Kijowski, Richard; Block, Walter F.

2014-01-01

Non-Cartesian imaging sequences and navigational methods can be more sensitive to scanner imperfections that have little impact on conventional clinical sequences, an issue which has repeatedly complicated the commercialization of these techniques by frustrating transitions to multi-center evaluations. One such imperfection is phase errors caused by resonant frequency shifts from eddy currents induced in the cryostat by time-varying gradients, a phenomemon known as B0 eddy currents. These phase errors can have a substantial impact on sequences that use ramp sampling, bipolar gradients, and readouts at varying azimuthal angles. We present a method for measuring and correcting phase errors from B0 eddy currents and examine the results on two different scanner models. This technique yields significant improvements in image quality for high-resolution joint imaging on certain scanners. The results suggest that correction of short time B0 eddy currents in manufacturer provided service routines would simplify adoption of non-Cartesian sampling methods. PMID:22488532

Image quality in thoracic 4D cone-beam CT: A sensitivity analysis of respiratory signal, binning method, reconstruction algorithm, and projection angular spacing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shieh, Chun-Chien; Kipritidis, John; O’Brien, Ricky T.

Purpose: Respiratory signal, binning method, and reconstruction algorithm are three major controllable factors affecting image quality in thoracic 4D cone-beam CT (4D-CBCT), which is widely used in image guided radiotherapy (IGRT). Previous studies have investigated each of these factors individually, but no integrated sensitivity analysis has been performed. In addition, projection angular spacing is also a key factor in reconstruction, but how it affects image quality is not obvious. An investigation of the impacts of these four factors on image quality can help determine the most effective strategy in improving 4D-CBCT for IGRT. Methods: Fourteen 4D-CBCT patient projection datasets withmore » various respiratory motion features were reconstructed with the following controllable factors: (i) respiratory signal (real-time position management, projection image intensity analysis, or fiducial marker tracking), (ii) binning method (phase, displacement, or equal-projection-density displacement binning), and (iii) reconstruction algorithm [Feldkamp–Davis–Kress (FDK), McKinnon–Bates (MKB), or adaptive-steepest-descent projection-onto-convex-sets (ASD-POCS)]. The image quality was quantified using signal-to-noise ratio (SNR), contrast-to-noise ratio, and edge-response width in order to assess noise/streaking and blur. The SNR values were also analyzed with respect to the maximum, mean, and root-mean-squared-error (RMSE) projection angular spacing to investigate how projection angular spacing affects image quality. Results: The choice of respiratory signals was found to have no significant impact on image quality. Displacement-based binning was found to be less prone to motion artifacts compared to phase binning in more than half of the cases, but was shown to suffer from large interbin image quality variation and large projection angular gaps. Both MKB and ASD-POCS resulted in noticeably improved image quality almost 100% of the time relative to FDK. In addition, SNR values were found to increase with decreasing RMSE values of projection angular gaps with strong correlations (r ≈ −0.7) regardless of the reconstruction algorithm used. Conclusions: Based on the authors’ results, displacement-based binning methods, better reconstruction algorithms, and the acquisition of even projection angular views are the most important factors to consider for improving thoracic 4D-CBCT image quality. In view of the practical issues with displacement-based binning and the fact that projection angular spacing is not currently directly controllable, development of better reconstruction algorithms represents the most effective strategy for improving image quality in thoracic 4D-CBCT for IGRT applications at the current stage.« less

Implementation of Remote 3-Dimensional Image Guided Radiation Therapy Quality Assurance for Radiation Therapy Oncology Group Clinical Trials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui Yunfeng; Galvin, James M.; Radiation Therapy Oncology Group, American College of Radiology, Philadelphia, Pennsylvania

2013-01-01

Purpose: To report the process and initial experience of remote credentialing of three-dimensional (3D) image guided radiation therapy (IGRT) as part of the quality assurance (QA) of submitted data for Radiation Therapy Oncology Group (RTOG) clinical trials; and to identify major issues resulting from this process and analyze the review results on patient positioning shifts. Methods and Materials: Image guided radiation therapy datasets including in-room positioning CT scans and daily shifts applied were submitted through the Image Guided Therapy QA Center from institutions for the IGRT credentialing process, as required by various RTOG trials. A centralized virtual environment is establishedmore » at the RTOG Core Laboratory, containing analysis tools and database infrastructure for remote review by the Physics Principal Investigators of each protocol. The appropriateness of IGRT technique and volumetric image registration accuracy were evaluated. Registration accuracy was verified by repeat registration with a third-party registration software system. With the accumulated review results, registration differences between those obtained by the Physics Principal Investigators and from the institutions were analyzed for different imaging sites, shift directions, and imaging modalities. Results: The remote review process was successfully carried out for 87 3D cases (out of 137 total cases, including 2-dimensional and 3D) during 2010. Frequent errors in submitted IGRT data and challenges in the review of image registration for some special cases were identified. Workarounds for these issues were developed. The average differences of registration results between reviewers and institutions ranged between 2 mm and 3 mm. Large discrepancies in the superior-inferior direction were found for megavoltage CT cases, owing to low spatial resolution in this direction for most megavoltage CT cases. Conclusion: This first experience indicated that remote review for 3D IGRT as part of QA for RTOG clinical trials is feasible and effective. The magnitude of registration discrepancy between institution and reviewer was presented, and the major issues were investigated to further improve this remote evaluation process.« less

Robust Multi-Frame Adaptive Optics Image Restoration Algorithm Using Maximum Likelihood Estimation with Poisson Statistics.

PubMed

Li, Dongming; Sun, Changming; Yang, Jinhua; Liu, Huan; Peng, Jiaqi; Zhang, Lijuan

2017-04-06

An adaptive optics (AO) system provides real-time compensation for atmospheric turbulence. However, an AO image is usually of poor contrast because of the nature of the imaging process, meaning that the image contains information coming from both out-of-focus and in-focus planes of the object, which also brings about a loss in quality. In this paper, we present a robust multi-frame adaptive optics image restoration algorithm via maximum likelihood estimation. Our proposed algorithm uses a maximum likelihood method with image regularization as the basic principle, and constructs the joint log likelihood function for multi-frame AO images based on a Poisson distribution model. To begin with, a frame selection method based on image variance is applied to the observed multi-frame AO images to select images with better quality to improve the convergence of a blind deconvolution algorithm. Then, by combining the imaging conditions and the AO system properties, a point spread function estimation model is built. Finally, we develop our iterative solutions for AO image restoration addressing the joint deconvolution issue. We conduct a number of experiments to evaluate the performances of our proposed algorithm. Experimental results show that our algorithm produces accurate AO image restoration results and outperforms the current state-of-the-art blind deconvolution methods.

Robust Multi-Frame Adaptive Optics Image Restoration Algorithm Using Maximum Likelihood Estimation with Poisson Statistics

PubMed Central

Li, Dongming; Sun, Changming; Yang, Jinhua; Liu, Huan; Peng, Jiaqi; Zhang, Lijuan

2017-01-01

An adaptive optics (AO) system provides real-time compensation for atmospheric turbulence. However, an AO image is usually of poor contrast because of the nature of the imaging process, meaning that the image contains information coming from both out-of-focus and in-focus planes of the object, which also brings about a loss in quality. In this paper, we present a robust multi-frame adaptive optics image restoration algorithm via maximum likelihood estimation. Our proposed algorithm uses a maximum likelihood method with image regularization as the basic principle, and constructs the joint log likelihood function for multi-frame AO images based on a Poisson distribution model. To begin with, a frame selection method based on image variance is applied to the observed multi-frame AO images to select images with better quality to improve the convergence of a blind deconvolution algorithm. Then, by combining the imaging conditions and the AO system properties, a point spread function estimation model is built. Finally, we develop our iterative solutions for AO image restoration addressing the joint deconvolution issue. We conduct a number of experiments to evaluate the performances of our proposed algorithm. Experimental results show that our algorithm produces accurate AO image restoration results and outperforms the current state-of-the-art blind deconvolution methods. PMID:28383503

Body Image and Sexuality in Women Survivors of Breast Cancer in India: Qualitative Findings

PubMed Central

Barthakur, Michelle S; Sharma, Mahendra P; Chaturvedi, Santosh K; Manjunath, Suraj K

2017-01-01

Objectives: With increasing rates of breast cancer survivors, psychosocial issues surrounding cancer survivorship have been gaining prominence. The following article reports on body image and sexuality-related issues in aftermath of the diagnosis and its treatment in the Indian context. Materials and Methods: Research design was mixed method, cross–sectional, and exploratory in nature. Quantitative sample consisted of fifty survivors while the qualitative sample size included 15 out of the 50 total breast cancer survivors who were recruited from hospitals, nongovernmental organization, and through word-of-mouth. Data was collected using quantitative measures, and in-depth interviews were done using semi-structured interview schedule that was developed for the study. Qualitative data were analyzed using descriptive phenomenological approach. Results: In body image, emerging themes were about identity (womanhood, motherhood, and attractiveness), impact of surgery, hair loss, clothes, and uncomfortable situations. In sexuality, barriers were faced due to difficulty in disclosure and themes were about adjustments made by spouses, role of age, and sexual difficulties due to treatment. Conclusions: Findings imply need to address the issues of body image and sexuality as it impacts quality of life of survivors. PMID:28216857

The Second National Ballistics Imaging Comparison (NBIC-2)

PubMed Central

Vorburger, TV; Yen, J; Song, JF; Thompson, RM; Renegar, TB; Zheng, A; Tong, M; Ols, M

2014-01-01

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, NIST and the ATF initiated a joint project, entitled the National Ballistics Imaging Comparison (NBIC). The NBIC project aims to establish a national traceability and quality system for ballistics identifications in crime laboratories utilizing ATF’s National Integrated Ballistics Information Network (NIBIN). The original NBIC was completed in 2010. In the second NBIC, NIST Standard Reference Material (SRM) 2461 Cartridge Cases were used as reference standards, and 14 experts from 11 U.S. crime laboratories each performed 17 image acquisitions and correlations of the SRM cartridge cases over the course of about half a year. Resulting correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed quality system and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard. PMID:26601051

The Second National Ballistics Imaging Comparison (NBIC-2).

PubMed

Vorburger, T V; Yen, J; Song, J F; Thompson, R M; Renegar, T B; Zheng, A; Tong, M; Ols, M

2014-01-01

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, NIST and the ATF initiated a joint project, entitled the National Ballistics Imaging Comparison (NBIC). The NBIC project aims to establish a national traceability and quality system for ballistics identifications in crime laboratories utilizing ATF's National Integrated Ballistics Information Network (NIBIN). The original NBIC was completed in 2010. In the second NBIC, NIST Standard Reference Material (SRM) 2461 Cartridge Cases were used as reference standards, and 14 experts from 11 U.S. crime laboratories each performed 17 image acquisitions and correlations of the SRM cartridge cases over the course of about half a year. Resulting correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed quality system and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard.

X-ray angiography systems.

PubMed

1993-11-01

Despite the emergence of several alternative angiographic imaging techniques (i.e., magnetic resonance imaging, computed tomography, and ultrasound angiography), x-ray angiography remains the predominant vascular imaging modality, generating over $4 billion in revenue a year in U.S. hospitals. In this issue, we provide a brief overview of the various angiographic imaging techniques, comparing them with x-ray angiography, and discuss the clinical aspects of x-ray vascular imaging, including catheterization and clinical applications. Clinical, cost, usage, and legal issues related to contrast media are discussed in "Contrast Media: Ionic versus Nonionic and Low-osmolality Agents." We also provide a technical overview and selection guidance for a basic x-ray angiography imaging system, including the gantry and table system, x-ray generator, x-ray tube, image intensifier, video camera and display monitors, image-recording devices, and digital acquisition and processing systems. This issue also contains our Evaluation of the GE Advantx L/C cardiac angiography system and the GE Advantx AFM general-purpose angiography system; the AFM can be used for peripheral, pulmonary, and cerebral vascular studied, among others, and can also be configured for cardiac angiography. Many features of the Advantx L/C system, including generator characteristics and ease of use, also apply to the Advantx AFM as configured for cardiac angiography. Our ratings are based on the systems' ability to provide the best possible image quality for diagnosis and therapy while minimizing patient and personnel exposure to radiation, as well as its ability to minimize operator effort and inconvenience. Both units are rated Acceptable. In the Guidance Section, "Radiation Safety and Protection," we discuss the importance of keeping patient and personnel exposures to radiation as low as reasonably possible, especially in procedures such as cardiac catheterization, angiographic imaging for special procedures, and interventional radiology, which produce among the highest radiation exposure of all x-ray imaging techniques. We also provide recommendations for minimizing personnel and patient exposures to radiation. For more information about x-ray angiography systems and similar devices, as well as for additional perspectives on which we based this study, see the following Health Devices Evaluations: "Mobile C-arm Units" (19[8], August 1990) and "Noninvasive Electronic Quality Control Devices for X-ray Generator Testing" (21[6-7], June-July 1992).(ABSTRACT TRUNCATED AT 400 WORDS)

NASA MISR Studies Smoke Plumes from California Sand Fire

NASA Image and Video Library

2016-08-02

39,000 acres (60 square miles, or 160 square kilometers). Thousands of residents were evacuated, and the fire claimed the life of one person. The Multi-angle Imaging SpectroRadiometer (MISR) instrument aboard NASA's Terra satellite passed over the region on July 23 around 11:50 a.m. PDT. At left is an image acquired by MISR's 60-degree forward-viewing camera. The oblique view angle makes the smoke more apparent than it would be in a more conventional vertical view. This cropped image is about 185 miles (300 kilometers) wide. Smoke from the Sand Fire is visible on the right-hand side of the image. Stereoscopic analysis of MISR's multiple camera angles is used to compute the height of the smoke plume from the Sand Fire. In the right-hand image, these heights are superimposed on the underlying image. The color scale shows that the plume extends up to about 4 miles (6 kilometers) above its source in Santa Clarita, but rapidly diminishes in height as winds push it to the southwest. The data compare well with a pilot report issued at Los Angeles International Airport on the evening of July 22, which reported smoke at 15,000-18,000 feet altitude (4.5 to 5.5 kilometers). Air quality warnings were issued for the San Fernando Valley and the western portion of Los Angeles due to this low-hanging smoke. However, data from air quality monitoring instruments seem to indicate that the smoke did not actually reach the ground. These data were captured during Terra orbit 88284. http://photojournal.jpl.nasa.gov/catalog/PIA20724

Direct Patlak Reconstruction From Dynamic PET Data Using the Kernel Method With MRI Information Based on Structural Similarity.

PubMed

Gong, Kuang; Cheng-Liao, Jinxiu; Wang, Guobao; Chen, Kevin T; Catana, Ciprian; Qi, Jinyi

2018-04-01

Positron emission tomography (PET) is a functional imaging modality widely used in oncology, cardiology, and neuroscience. It is highly sensitive, but suffers from relatively poor spatial resolution, as compared with anatomical imaging modalities, such as magnetic resonance imaging (MRI). With the recent development of combined PET/MR systems, we can improve the PET image quality by incorporating MR information into image reconstruction. Previously, kernel learning has been successfully embedded into static and dynamic PET image reconstruction using either PET temporal or MRI information. Here, we combine both PET temporal and MRI information adaptively to improve the quality of direct Patlak reconstruction. We examined different approaches to combine the PET and MRI information in kernel learning to address the issue of potential mismatches between MRI and PET signals. Computer simulations and hybrid real-patient data acquired on a simultaneous PET/MR scanner were used to evaluate the proposed methods. Results show that the method that combines PET temporal information and MRI spatial information adaptively based on the structure similarity index has the best performance in terms of noise reduction and resolution improvement.

STS-107 Debris Characterization Using Re-entry Imaging

NASA Technical Reports Server (NTRS)

Raiche, George A.

2009-01-01

Analysis of amateur video of the early reentry phases of the Columbia accident is discussed. With poor video quality and little theoretical guidance, the analysis team estimated mass and acceleration ranges for the debris shedding events observed in the video. Camera calibration and optical performance issues are also described.

Planning and Implementing Institutional Image and Promoting Academic Programs in Higher Education

ERIC Educational Resources Information Center

Cetin, Rubeena

2003-01-01

Universities face a multitude of issues and challenges in the current era of higher educational endeavors. Universities are being urged to provide high quality education, exist as a well-reputed university, achieve enrollment success, improve competitive positioning, provide contemporary and well-designed academic programs, and maintain financial…

Obese patients and radiography literature: what do we know about a big issue?

PubMed Central

Le, Nhat Tan Thanh; Robinson, John; Lewis, Sarah J

2015-01-01

Obesity is a global health issue with obese patients requiring specialised diagnosis, treatment and care through the health service. The practical and social difficulties associated with medical imaging of obese patients are an increasingly common problem and it is currently unknown how student and qualified radiographers perceive and respond to these challenges. By better understanding challenges presented in providing quality imaging and care of imaging obese patients, education for both qualified and student radiographers can be enhanced. Radiographers are heavily reliant on visual and tactile senses to locate the position of anatomical structures for diagnostic imaging and determine radiation exposure through a delicate consideration of dose, image quality and anatomical attenuation. However, obese patients require modifications to routine radiographic practice in terms of movement/assisted positioning, equipment capabilities to take increased weight or coverage. These patients may also be subject to compromised radiological diagnosis through poor visualisation of structures. In this paper, the professional and educational literature was narratively reviewed to assess gaps in the evidence base related to the skill and care knowledge for obese patients. Literature was sourced relating to discrete radiographic considerations such as the technical factors of imaging obese patients, exposure and the impact of obesity on imaging departments’ service provisions. The recent literature (post-2000 to coincide with the sharp increase in global obesity) on the perceptions of health professionals and student health practitioners has also been explored because there are no specific radiographer studies to report. By understanding the research in similar fields, we may identify what common attitudes qualified and student radiographer's hold and what challenges, technical and care related, can be prepared for. PMID:26229678

Obese patients and radiography literature: what do we know about a big issue?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le, Nhat Tan Thanh; Robinson, John; Lewis, Sarah J, E-mail: sarah.lewis@sydney.edu.au

Obesity is a global health issue with obese patients requiring specialised diagnosis, treatment and care through the health service. The practical and social difficulties associated with medical imaging of obese patients are an increasingly common problem and it is currently unknown how student and qualified radiographers perceive and respond to these challenges. By better understanding challenges presented in providing quality imaging and care of imaging obese patients, education for both qualified and student radiographers can be enhanced. Radiographers are heavily reliant on visual and tactile senses to locate the position of anatomical structures for diagnostic imaging and determine radiation exposuremore » through a delicate consideration of dose, image quality and anatomical attenuation. However, obese patients require modifications to routine radiographic practice in terms of movement/assisted positioning, equipment capabilities to take increased weight or coverage. These patients may also be subject to compromised radiological diagnosis through poor visualisation of structures. In this paper, the professional and educational literature was narratively reviewed to assess gaps in the evidence base related to the skill and care knowledge for obese patients. Literature was sourced relating to discrete radiographic considerations such as the technical factors of imaging obese patients, exposure and the impact of obesity on imaging departments’ service provisions. The recent literature (post-2000 to coincide with the sharp increase in global obesity) on the perceptions of health professionals and student health practitioners has also been explored because there are no specific radiographer studies to report. By understanding the research in similar fields, we may identify what common attitudes qualified and student radiographer's hold and what challenges, technical and care related, can be prepared for.« less

PCB Fault Detection Using Image Processing

NASA Astrophysics Data System (ADS)

Nayak, Jithendra P. R.; Anitha, K.; Parameshachari, B. D., Dr.; Banu, Reshma, Dr.; Rashmi, P.

2017-08-01

The importance of the Printed Circuit Board inspection process has been magnified by requirements of the modern manufacturing environment where delivery of 100% defect free PCBs is the expectation. To meet such expectations, identifying various defects and their types becomes the first step. In this PCB inspection system the inspection algorithm mainly focuses on the defect detection using the natural images. Many practical issues like tilt of the images, bad light conditions, height at which images are taken etc. are to be considered to ensure good quality of the image which can then be used for defect detection. Printed circuit board (PCB) fabrication is a multidisciplinary process, and etching is the most critical part in the PCB manufacturing process. The main objective of Etching process is to remove the exposed unwanted copper other than the required circuit pattern. In order to minimize scrap caused by the wrongly etched PCB panel, inspection has to be done in early stage. However, all of the inspections are done after the etching process where any defective PCB found is no longer useful and is simply thrown away. Since etching process costs 0% of the entire PCB fabrication, it is uneconomical to simply discard the defective PCBs. In this paper a method to identify the defects in natural PCB images and associated practical issues are addressed using Software tools and some of the major types of single layer PCB defects are Pattern Cut, Pin hole, Pattern Short, Nick etc., Therefore the defects should be identified before the etching process so that the PCB would be reprocessed. In the present approach expected to improve the efficiency of the system in detecting the defects even in low quality images

TU-H-CAMPUS-JeP1-04: Deformable Image Registration Performances in Pelvis Patients: Impact of CBCT Image Quality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fusella, M; Loi, G; Fiandra, C

Purpose: To investigate the accuracy and robustness, against image noise and artifacts (typical of CBCT images), of a commercial algorithm for deformable image registration (DIR), to propagate regions of interest (ROIs) in computational phantoms based on real prostate patient images. Methods: The Anaconda DIR algorithm, implemented in RayStation was tested. Two specific Deformation Vector Fields (DVFs) were applied to the reference data set (CTref) using the ImSimQA software, obtaining two deformed CTs. For each dataset twenty-four different level of noise and/or capping artifacts were applied to simulate CBCT images. DIR was performed between CTref and each deformed CTs and CBCTs.more » In order to investigate the relationship between image quality parameters and the DIR results (expressed by a logit transform of the Dice Index) a bilinear regression was defined. Results: More than 550 DIR-mapped ROIs were analyzed. The Statistical analysis states that deformation strenght and artifacts were significant prognostic factors of DIR performances, while noise appeared to have a minor role in DIR process as implemented in RayStation as expected by the image similarity metric built in the registration algorithm. Capping artifacts reveals a determinant role for the accuracy of DIR results. Two optimal values for capping artifacts were found to obtain acceptable DIR results (DICE> 075/ 0.85). Various clinical CBCT acquisition protocol were reported to evaluate the significance of the study. Conclusion: This work illustrates the impact of image quality on DIR performance. Clinical issues like Adaptive Radiation Therapy (ART) and Dose Accumulation need accurate and robust DIR software. The RayStation DIR algorithm resulted robust against noise, but sensitive to image artifacts. This result highlights the need of robustness quality assurance against image noise and artifacts in the commissioning of a DIR commercial system and underlines the importance to adopt optimized protocols for CBCT image acquisitions in ART clinical implementation.« less

Physical security and cyber security issues and human error prevention for 3D printed objects: detecting the use of an incorrect printing material

NASA Astrophysics Data System (ADS)

Straub, Jeremy

2017-06-01

A wide variety of characteristics of 3D printed objects have been linked to impaired structural integrity and use-efficacy. The printing material can also have a significant impact on the quality, utility and safety characteristics of a 3D printed object. Material issues can be created by vendor issues, physical security issues and human error. This paper presents and evaluates a system that can be used to detect incorrect material use in a 3D printer, using visible light imaging. Specifically, it assesses the ability to ascertain the difference between materials of different color and different types of material with similar coloration.

Presence capture cameras - a new challenge to the image quality

NASA Astrophysics Data System (ADS)

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.

Introduction to the GEOBIA 2010 special issue: From pixels to geographic objects in remote sensing image analysis

NASA Astrophysics Data System (ADS)

Addink, Elisabeth A.; Van Coillie, Frieke M. B.; De Jong, Steven M.

2012-04-01

Traditional image analysis methods are mostly pixel-based and use the spectral differences of landscape elements at the Earth surface to classify these elements or to extract element properties from the Earth Observation image. Geographic object-based image analysis (GEOBIA) has received considerable attention over the past 15 years for analyzing and interpreting remote sensing imagery. In contrast to traditional image analysis, GEOBIA works more like the human eye-brain combination does. The latter uses the object's color (spectral information), size, texture, shape and occurrence to other image objects to interpret and analyze what we see. GEOBIA starts by segmenting the image grouping together pixels into objects and next uses a wide range of object properties to classify the objects or to extract object's properties from the image. Significant advances and improvements in image analysis and interpretation are made thanks to GEOBIA. In June 2010 the third conference on GEOBIA took place at the Ghent University after successful previous meetings in Calgary (2008) and Salzburg (2006). This special issue presents a selection of the 2010 conference papers that are worked out as full research papers for JAG. The papers cover GEOBIA applications as well as innovative methods and techniques. The topics range from vegetation mapping, forest parameter estimation, tree crown identification, urban mapping, land cover change, feature selection methods and the effects of image compression on segmentation. From the original 94 conference papers, 26 full research manuscripts were submitted; nine papers were selected and are presented in this special issue. Selection was done on the basis of quality and topic of the studies. The next GEOBIA conference will take place in Rio de Janeiro from 7 to 9 May 2012 where we hope to welcome even more scientists working in the field of GEOBIA.

SEM image quality enhancement technology for bright field mask

NASA Astrophysics Data System (ADS)

Fukuda, Naoki; Chihara, Yuta; Shida, Soichi; Ito, Keisuke

2013-09-01

Bright-field photomasks are used to print small contact holes via ArF immersion multiple patterning lithography. There are some technical difficulties when small floating dots are to be measured by SEM tools because of a false imaging shadow. However, a new scan technology of Multi Vision Metrology SEMTM E3630 presents a solution for this issue. The combination of new scan technology and the other MVM-SEM® functions can provide further extended applications with more accurate measurement results.

The comparative effectiveness of conventional and digital image libraries.

PubMed

McColl, R I; Johnson, A

2001-03-01

Before introducing a hospital-wide image database to improve access, navigation and retrieval speed, a comparative study between a conventional slide library and a matching image database was undertaken to assess its relative benefits. Paired time trials and personal questionnaires revealed faster retrieval rates, higher image quality, and easier viewing for the pilot digital image database. Analysis of confidentiality, copyright and data protection exposed similar issues for both systems, thus concluding that the digital image database is a more effective library system. The authors suggest that in the future, medical images will be stored on large, professionally administered, centrally located file servers, allowing specialist image libraries to be tailored locally for individual users. The further integration of the database with web technology will enable cheap and efficient remote access for a wide range of users.

Image demosaicing: a systematic survey

NASA Astrophysics Data System (ADS)

Li, Xin; Gunturk, Bahadir; Zhang, Lei

2008-01-01

Image demosaicing is a problem of interpolating full-resolution color images from so-called color-filter-array (CFA) samples. Among various CFA patterns, Bayer pattern has been the most popular choice and demosaicing of Bayer pattern has attracted renewed interest in recent years partially due to the increased availability of source codes/executables in response to the principle of "reproducible research". In this article, we provide a systematic survey of over seventy published works in this field since 1999 (complementary to previous reviews 22, 67). Our review attempts to address important issues to demosaicing and identify fundamental differences among competing approaches. Our findings suggest most existing works belong to the class of sequential demosaicing - i.e., luminance channel is interpolated first and then chrominance channels are reconstructed based on recovered luminance information. We report our comparative study results with a collection of eleven competing algorithms whose source codes or executables are provided by the authors. Our comparison is performed on two data sets: Kodak PhotoCD (popular choice) and IMAX high-quality images (more challenging). While most existing demosaicing algorithms achieve good performance on the Kodak data set, their performance on the IMAX one (images with varying-hue and high-saturation edges) degrades significantly. Such observation suggests the importance of properly addressing the issue of mismatch between assumed model and observation data in demosaicing, which calls for further investigation on issues such as model validation, test data selection and performance evaluation.

A qualitative and quantitative analysis of radiation dose and image quality of computed tomography images using adaptive statistical iterative reconstruction

PubMed Central

Mail, Noor; Shamy, Abdulrahman M.; Alghamdi, Suliman; Saoudi, Abdelhamid

2016-01-01

Image quality is a key issue in radiology, particularly in a clinical setting where it is important to achieve accurate diagnoses while minimizing radiation dose. Some computed tomography (CT) manufacturers have introduced algorithms that claim significant dose reduction. In this study, we assessed CT image quality produced by two reconstruction algorithms provided with GE Healthcare's Discovery 690 Elite positron emission tomography (PET) CT scanner. Image quality was measured for images obtained at various doses with both conventional filtered back‐projection (FBP) and adaptive statistical iterative reconstruction (ASIR) algorithms. A standard CT dose index (CTDI) phantom and a pencil ionization chamber were used to measure the CT dose at 120 kVp and an exposure of 260 mAs. Image quality was assessed using two phantoms. CT images of both phantoms were acquired at tube voltage (kV) of 120 with exposures ranging from 25 mAs to 400 mAs. Images were reconstructed using FBP and ASIR ranging from 10% to 100%, then analyzed for noise, low‐contrast detectability, contrast‐to‐noise ratio (CNR), and modulation transfer function (MTF). Noise was 4.6 HU in water phantom images acquired at 260 mAs/FBP 120 kV and 130 mAs/50% ASIR 120 kV. The large objects (frequency<7 lp/cm) retained fairly acceptable image quality at 130 mAs/50% ASIR, compared to 260 mAs/FBP. The application of ASIR for small objects (frequency>7 lp/cm) showed poor visibility compared to FBP at 260 mAs and even worse for images acquired at less than 130 mAs. ASIR blending more than 50% at low dose tends to reduce contrast of small objects (frequency>7 lp/cm). We concluded that dose reduction and ASIR should be applied with close attention if the objects to be detected or diagnosed are small (frequency>7 lp/cm). Further investigations are required to correlate the small objects (frequency>7 lp/cm) to patient anatomy and clinical diagnosis. PACS number(s): 87.57.‐s, 87.57.C, 87.57.cf, 87.57.cj, 87.57.cm, 87.57.cp, 87.57.N, 87.57.nf, 87.57.np, 87.57.nt, 87.57.Q, 87.59.‐e, 87.59.B PMID:27167261

Evaluation of the effect of low tube voltage on radiation dose and image quality

NASA Astrophysics Data System (ADS)

Norhasrina Nik Din, Nik; Zainon, Rafidah; Rahman, A. T. Abdul

2017-05-01

Number of Computed Tomography (CT) examinations performed worldwide is increasing. In 2010, the FDA issued an initiative to reduce unnecessary radiation exposure from CT imaging. The aim of this study is to evaluate the effect of low tube voltage on radiation dose and image quality using CTDI phantom. The CTDI phantom was scanned with dual energy CT at 80 kV and 120 kV with the tube current from 150 mAs to 350 mAs. Pitch was 1.0 while slice thickness was 1 mm and 5 mm. Results show if mAs was increased, the SNR values also will be increased. The 5 mm slice thickness shows higher SNR value compared to 1 mm slice thickness. As the voltage and tube current increased, the amount of dose absorbed is also increased because current is proportional to photon flux.

Portfolio Preparation Tips for Teachers, Part 2

ERIC Educational Resources Information Center

Hunter-Lombardi, Brooke

2009-01-01

In the August/September 2008 issue of "SchoolArts," the author talked about strategies for helping students develop content and good working habits to support making portfolio-quality pieces. In this article, she offers some tips which focus on the importance of critique, presentation, and selection of images to end up with a polished,…

Social Well-Being and Rural Community Development: Issues in Policy and Theory.

ERIC Educational Resources Information Center

Wilkinson, Kenneth P.

Rural development literature yields three images of improved social well-being--economic technical growth, human-interpersonal growth, and environmental-quality protection. While the economic growth dimension of rural development has received much attention, little is known about the structural conditions in the social organization or the kinds of…

Whole surface image reconstruction for machine vision inspection of fruit

NASA Astrophysics Data System (ADS)

Reese, D. Y.; Lefcourt, A. M.; Kim, M. S.; Lo, Y. M.

2007-09-01

Automated imaging systems offer the potential to inspect the quality and safety of fruits and vegetables consumed by the public. Current automated inspection systems allow fruit such as apples to be sorted for quality issues including color and size by looking at a portion of the surface of each fruit. However, to inspect for defects and contamination, the whole surface of each fruit must be imaged. The goal of this project was to develop an effective and economical method for whole surface imaging of apples using mirrors and a single camera. Challenges include mapping the concave stem and calyx regions. To allow the entire surface of an apple to be imaged, apples were suspended or rolled above the mirrors using two parallel music wires. A camera above the apples captured 90 images per sec (640 by 480 pixels). Single or multiple flat or concave mirrors were mounted around the apple in various configurations to maximize surface imaging. Data suggest that the use of two flat mirrors provides inadequate coverage of a fruit but using two parabolic concave mirrors allows the entire surface to be mapped. Parabolic concave mirrors magnify images, which results in greater pixel resolution and reduced distortion. This result suggests that a single camera with two parabolic concave mirrors can be a cost-effective method for whole surface imaging.

Web-Based Quality Assurance Process Drives Improvements in Obstetric Ultrasound in 5 Low- and Middle-Income Countries

PubMed Central

Swanson, Jonathan O; Plotner, David; Franklin, Holly L; Swanson, David L; Lokomba Bolamba, Victor; Lokangaka, Adrien; Sayury Pineda, Irma; Figueroa, Lester; Garces, Ana; Muyodi, David; Esamai, Fabian; Kanaiza, Nancy; Mirza, Waseem; Naqvi, Farnaz; Saleem, Sarah; Mwenechanya, Musaku; Chiwila, Melody; Hamsumonde, Dorothy; McClure, Elizabeth M; Goldenberg, Robert L; Nathan, Robert O

2016-01-01

ABSTRACT High quality is important in medical imaging, yet in many geographic areas, highly skilled sonographers are in short supply. Advances in Internet capacity along with the development of reliable portable ultrasounds have created an opportunity to provide centralized remote quality assurance (QA) for ultrasound exams performed at rural sites worldwide. We sought to harness these advances by developing a web-based tool to facilitate QA activities for newly trained sonographers who were taking part in a cluster randomized trial investigating the role of limited obstetric ultrasound to improve pregnancy outcomes in 5 low- and middle-income countries. We were challenged by connectivity issues, by country-specific needs for website usability, and by the overall need for a high-throughput system. After systematically addressing these needs, the resulting QA website helped drive ultrasound quality improvement across all 5 countries. It now offers the potential for adoption by future ultrasound- or imaging-based global health initiatives. PMID:28031304

High-Resolution Ultrasound Imaging Using Model-Bases Iterative Reconstruction For Canister Degradation Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatzidakis, Stylianos; Jarrell, Joshua J; Scaglione, John M

The inspection of the dry storage canisters that house spent nuclear fuel is an important issue facing the nuclear industry; currently, there are limited options available to provide for even minimal inspections. An issue of concern is stress corrosion cracking (SCC) in austenitic stainless steel canisters. SCC is difficult to predict and exhibits small crack opening displacements on the order of 15 30 m. Nondestructive examination (NDE) of such microscopic cracks is especially challenging, and it may be possible to miss SCC during inspections. The coarse grain microstructure at the heat affected zone reduces the achievable sensitivity of conventional ultrasoundmore » techniques. At Oak Ridge National Laboratory, a tomographic approach is under development to improve SCC detection using ultrasound guided waves and model-based iterative reconstruction (MBIR). Ultrasound-guided waves propagate parallel to the physical boundaries of the surface and allow for rapid inspection of a large area from a single probe location. MBIR is a novel, effective probabilistic imaging tool that offers higher precision and better image quality than current reconstruction techniques. This paper analyzes the canister environment, stainless steel microstructure, and SCC characteristics. The end goal is to demonstrate the feasibility of an NDE system based on ultrasonic guided waves and MBIR for canister degradation and to produce radar-like images of the canister surface with significantly improved image quality. The proposed methodology can potentially reduce human radiation exposure, result in lower operational costs, and provide a methodology that can be used to verify canister integrity in-situ during extended storage« less

The Quality and Stability of Chandra Telescope Spacial Resolution

NASA Astrophysics Data System (ADS)

Zhao, Ping

2017-08-01

Chandra X-ray Observatory revolutionized the X-ray astronomy as being the first, and so far the only, X-ray telescope achieving sub-arcsecond spacial resolution. Chandra is comprised of three principal elements: the High Resolution Mirror Assembly (HRMA), Pointing Control and Aspect Determination (PCAD) system, and the Science Instrument Module (SIM), which is where the X-ray detectors mounted and is connected to the HRMA by a 10-meter long Optical Bench Assembly. To achieve and retain the unprecedented imaging quality, it is critical that these three principal elements to stay rigid and stable for the entire life time of the Chandra operation. I will review the issues of telescope pointing stability, optical Axis, aimpoint and their impacts to the Chandra operation, and evaluate the integrity and stability of the telescope. I will show images taken from all four detectors since launch to demonstrate the quality and stability of the Chandra spacial resolution.

Rapid portal imaging with a high-efficiency, large field-of-view detector.

PubMed

Mosleh-Shirazi, M A; Evans, P M; Swindell, W; Symonds-Tayler, J R; Webb, S; Partridge, M

1998-12-01

The design, construction, and performance evaluation of an electronic portal imaging device (EPID) are described. The EPID has the same imaging geometry as the current mirror-based systems except for the x-ray detection stage, where a two-dimensional (2D) array of 1 cm thick CsI(Tl) detector elements are utilized. The approximately 18% x-ray quantum efficiency of the scintillation detector and its 30 x 40 cm2 field-of-view at the isocenter are greater than other area-imaging EPIDs. The imaging issues addressed are theoretical and measured signal-to-noise ratio, linearity of the imaging chain, influence of frame-summing on image quality and image calibration. Portal images of test objects and a humanoid phantom are used to measure the performance of the system. An image quality similar to the current devices is achieved but with a lower dose. With approximately 1 cGy dose delivered by a 6 MV beam, a 2 mm diam structure of 1.3% contrast and an 18 mm diam object of 0.125% contrast can be resolved without using image-enhancement methods. A spatial resolution of about 2 mm at the isocenter is demonstrated. The capability of the system to perform fast sequential imaging, synchronized with the radiation pulses, makes it suitable for patient motion studies and verification of intensity-modulated beams as well as its application in cone-beam megavoltage computed tomography.

Quality Control by Artificial Vision

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lam, Edmond Y.; Gleason, Shaun Scott; Niel, Kurt S.

2010-01-01

Computational technology has fundamentally changed many aspects of our lives. One clear evidence is the development of artificial-vision systems, which have effectively automated many manual tasks ranging from quality inspection to quantitative assessment. In many cases, these machine-vision systems are even preferred over manual ones due to their repeatability and high precision. Such advantages come from significant research efforts in advancing sensor technology, illumination, computational hardware, and image-processing algorithms. Similar to the Special Section on Quality Control by Artificial Vision published two years ago in Volume 17, Issue 3 of the Journal of Electronic Imaging, the present one invited papersmore » relevant to fundamental technology improvements to foster quality control by artificial vision, and fine-tuned the technology for specific applications. We aim to balance both theoretical and applied work pertinent to this special section theme. Consequently, we have seven high-quality papers resulting from the stringent peer-reviewing process in place at the Journal of Electronic Imaging. Some of the papers contain extended treatment of the authors work presented at the SPIE Image Processing: Machine Vision Applications conference and the International Conference on Quality Control by Artificial Vision. On the broad application side, Liu et al. propose an unsupervised texture image segmentation scheme. Using a multilayer data condensation spectral clustering algorithm together with wavelet transform, they demonstrate the effectiveness of their approach on both texture and synthetic aperture radar images. A problem related to image segmentation is image extraction. For this, O'Leary et al. investigate the theory of polynomial moments and show how these moments can be compared to classical filters. They also show how to use the discrete polynomial-basis functions for the extraction of 3-D embossed digits, demonstrating superiority over Fourier-basis functions for this task. Image registration is another important task for machine vision. Bingham and Arrowood investigate the implementation and results in applying Fourier phase matching for projection registration, with a particular focus on nondestructive testing using computed tomography. Readers interested in enriching their arsenal of image-processing algorithms for machine-vision tasks should find these papers enriching. Meanwhile, we have four papers dealing with more specific machine-vision tasks. The first one, Yahiaoui et al., is quantitative in nature, using machine vision for real-time passenger counting. Occulsion is a common problem in counting objects and people, and they circumvent this issue with a dense stereovision system, achieving 97 to 99% accuracy in their tests. On the other hand, the second paper by Oswald-Tranta et al. focuses on thermographic crack detection. An infrared camera is used to detect inhomogeneities, which may indicate surface cracks. They describe the various steps in developing fully automated testing equipment aimed at a high throughput. Another paper describing an inspection system is Molleda et al., which handles flatness inspection of rolled products. They employ optical-laser triangulation and 3-D surface reconstruction for this task, showing how these can be achieved in real time. Last but not least, Presles et al. propose a way to monitor the particle-size distribution of batch crystallization processes. This is achieved through a new in situ imaging probe and image-analysis methods. While it is unlikely any reader may be working on these four specific problems at the same time, we are confident that readers will find these papers inspiring and potentially helpful to their own machine-vision system developments.« less

Building large mosaics of confocal edomicroscopic images using visual servoing.

PubMed

Rosa, Benoît; Erden, Mustafa Suphi; Vercauteren, Tom; Herman, Benoît; Szewczyk, Jérôme; Morel, Guillaume

2013-04-01

Probe-based confocal laser endomicroscopy provides real-time microscopic images of tissues contacted by a small probe that can be inserted in vivo through a minimally invasive access. Mosaicking consists in sweeping the probe in contact with a tissue to be imaged while collecting the video stream, and process the images to assemble them in a large mosaic. While most of the literature in this field has focused on image processing, little attention has been paid so far to the way the probe motion can be controlled. This is a crucial issue since the precision of the probe trajectory control drastically influences the quality of the final mosaic. Robotically controlled motion has the potential of providing enough precision to perform mosaicking. In this paper, we emphasize the difficulties of implementing such an approach. First, probe-tissue contacts generate deformations that prevent from properly controlling the image trajectory. Second, in the context of minimally invasive procedures targeted by our research, robotic devices are likely to exhibit limited quality of the distal probe motion control at the microscopic scale. To cope with these problems visual servoing from real-time endomicroscopic images is proposed in this paper. It is implemented on two different devices (a high-accuracy industrial robot and a prototype minimally invasive device). Experiments on different kinds of environments (printed paper and ex vivo tissues) show that the quality of the visually servoed probe motion is sufficient to build mosaics with minimal distortion in spite of disturbances.

The National Ballistics Imaging Comparison (NBIC) project.

PubMed

Song, J; Vorburger, T V; Ballou, S; Thompson, R M; Yen, J; Renegar, T B; Zheng, A; Silver, R M; Ols, M

2012-03-10

In response to the guidelines issued by the American Society of Crime Laboratory Directors/Laboratory Accreditation Board (ASCLD/LAB-International) to establish traceability and quality assurance in U.S. crime laboratories, a NIST/ATF joint project entitled National Ballistics Imaging Comparison (NBIC) was initialized in 2008. The NBIC project aims to establish a National Traceability and Quality System for ballistics identifications in crime laboratories within the National Integrated Ballistics Information Network (NIBIN) of the U.S. NIST Standard Reference Material (SRM) 2460 bullets and 2461 cartridge cases are used as reference standards. 19 ballistics examiners from 13 U.S. crime laboratories participated in this project. They each performed 24 periodic image acquisitions and correlations of the SRM bullets and cartridge cases over the course of a year, but one examiner only participated in Phase 1 tests of SRM cartridge case. The correlation scores were collected by NIST for statistical analyses, from which control charts and control limits were developed for the proposed Quality System and for promoting future assessments and accreditations for firearm evidence in U.S. forensic laboratories in accordance with the ISO 17025 Standard. Published by Elsevier Ireland Ltd.

Intelligent image capture of cartridge cases for firearms examiners

NASA Astrophysics Data System (ADS)

Jones, Brett C.; Guerci, Joseph R.

1997-02-01

The FBI's DRUGFIRETM system is a nationwide computerized networked image database of ballistic forensic evidence. This evidence includes images of cartridge cases and bullets obtained from both crime scenes and controlled test firings of seized weapons. Currently, the system is installed in over 80 forensic labs across the country and has enjoyed a high degree of success. In this paper, we discuss some of the issues and methods associated with providing a front-end semi-automated image capture system that simultaneously satisfies the often conflicting criteria of the many human examiners visual perception versus the criteria associated with optimizing autonomous digital image correlation. Specifically, we detail the proposed processing chain of an intelligent image capture system (IICS), involving a real- time capture 'assistant,' which assesses the quality of the image under test utilizing a custom designed neural network.

Adaptive optics image restoration algorithm based on wavefront reconstruction and adaptive total variation method

NASA Astrophysics Data System (ADS)

Li, Dongming; Zhang, Lijuan; Wang, Ting; Liu, Huan; Yang, Jinhua; Chen, Guifen

2016-11-01

To improve the adaptive optics (AO) image's quality, we study the AO image restoration algorithm based on wavefront reconstruction technology and adaptive total variation (TV) method in this paper. Firstly, the wavefront reconstruction using Zernike polynomial is used for initial estimated for the point spread function (PSF). Then, we develop our proposed iterative solutions for AO images restoration, addressing the joint deconvolution issue. The image restoration experiments are performed to verify the image restoration effect of our proposed algorithm. The experimental results show that, compared with the RL-IBD algorithm and Wiener-IBD algorithm, we can see that GMG measures (for real AO image) from our algorithm are increased by 36.92%, and 27.44% respectively, and the computation time are decreased by 7.2%, and 3.4% respectively, and its estimation accuracy is significantly improved.

SU-D-206-04: Iterative CBCT Scatter Shading Correction Without Prior Information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Y; Wu, P; Mao, T

2016-06-15

Purpose: To estimate and remove the scatter contamination in the acquired projection of cone-beam CT (CBCT), to suppress the shading artifacts and improve the image quality without prior information. Methods: The uncorrected CBCT images containing shading artifacts are reconstructed by applying the standard FDK algorithm on CBCT raw projections. The uncorrected image is then segmented to generate an initial template image. To estimate scatter signal, the differences are calculated by subtracting the simulated projections of the template image from the raw projections. Since scatter signals are dominantly continuous and low-frequency in the projection domain, they are estimated by low-pass filteringmore » the difference signals and subtracted from the raw CBCT projections to achieve the scatter correction. Finally, the corrected CBCT image is reconstructed from the corrected projection data. Since an accurate template image is not readily segmented from the uncorrected CBCT image, the proposed scheme is iterated until the produced template is not altered. Results: The proposed scheme is evaluated on the Catphan©600 phantom data and CBCT images acquired from a pelvis patient. The result shows that shading artifacts have been effectively suppressed by the proposed method. Using multi-detector CT (MDCT) images as reference, quantitative analysis is operated to measure the quality of corrected images. Compared to images without correction, the method proposed reduces the overall CT number error from over 200 HU to be less than 50 HU and can increase the spatial uniformity. Conclusion: An iterative strategy without relying on the prior information is proposed in this work to remove the shading artifacts due to scatter contamination in the projection domain. The method is evaluated in phantom and patient studies and the result shows that the image quality is remarkably improved. The proposed method is efficient and practical to address the poor image quality issue of CBCT images. This work is supported by the Zhejiang Provincial Natural Science Foundation of China (Grant No. LR16F010001), National High-tech R&D Program for Young Scientists by the Ministry of Science and Technology of China (Grant No. 2015AA020917).« less

Quality assessment of internet pharmaceutical products using traditional and non-traditional analytical techniques.

PubMed

Westenberger, Benjamin J; Ellison, Christopher D; Fussner, Andrew S; Jenney, Susan; Kolinski, Richard E; Lipe, Terra G; Lyon, Robbe C; Moore, Terry W; Revelle, Larry K; Smith, Anjanette P; Spencer, John A; Story, Kimberly D; Toler, Duckhee Y; Wokovich, Anna M; Buhse, Lucinda F

2005-12-08

This work investigated the use of non-traditional analytical methods to evaluate the quality of a variety of pharmaceutical products purchased via internet sites from foreign sources and compared the results with those obtained from conventional quality assurance methods. Traditional analytical techniques employing HPLC for potency, content uniformity, chromatographic purity and drug release profiles were used to evaluate the quality of five selected drug products (fluoxetine hydrochloride, levothyroxine sodium, metformin hydrochloride, phenytoin sodium, and warfarin sodium). Non-traditional techniques, such as near infrared spectroscopy (NIR), NIR imaging and thermogravimetric analysis (TGA), were employed to verify the results and investigate their potential as alternative testing methods. Two of 20 samples failed USP monographs for quality attributes. The additional analytical methods found 11 of 20 samples had different formulations when compared to the U.S. product. Seven of the 20 samples arrived in questionable containers, and 19 of 20 had incomplete labeling. Only 1 of the 20 samples had final packaging similar to the U.S. products. The non-traditional techniques complemented the traditional techniques used and highlighted additional quality issues for the products tested. For example, these methods detected suspect manufacturing issues (such as blending), which were not evident from traditional testing alone.

Dental cone-beam CT reconstruction from limited-angle view data based on compressed-sensing (CS) theory for fast, low-dose X-ray imaging

NASA Astrophysics Data System (ADS)

Je, Uikyu; Cho, Hyosung; Lee, Minsik; Oh, Jieun; Park, Yeonok; Hong, Daeki; Park, Cheulkyu; Cho, Heemoon; Choi, Sungil; Koo, Yangseo

2014-06-01

Recently, reducing radiation doses has become an issue of critical importance in the broader radiological community. As a possible technical approach, especially, in dental cone-beam computed tomography (CBCT), reconstruction from limited-angle view data (< 360°) would enable fast scanning with reduced doses to the patient. In this study, we investigated and implemented an efficient reconstruction algorithm based on compressed-sensing (CS) theory for the scan geometry and performed systematic simulation works to investigate the image characteristics. We also performed experimental works by applying the algorithm to a commercially-available dental CBCT system to demonstrate its effectiveness for image reconstruction in incomplete data problems. We successfully reconstructed CBCT images with incomplete projections acquired at selected scan angles of 120, 150, 180, and 200° with a fixed angle step of 1.2° and evaluated the reconstruction quality quantitatively. Both simulation and experimental demonstrations of the CS-based reconstruction from limited-angle view data show that the algorithm can be applied directly to current dental CBCT systems for reducing the imaging doses and further improving the image quality.

The Handbook of Medical Image Perception and Techniques

NASA Astrophysics Data System (ADS)

Samei, Ehsan; Krupinski, Elizabeth

2014-07-01

1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

The Handbook of Medical Image Perception and Techniques

NASA Astrophysics Data System (ADS)

Samei, Ehsan; Krupinski, Elizabeth

2009-12-01

1. Medical image perception Ehsan Samei and Elizabeth Krupinski; Part I. Historical Reflections and Theoretical Foundations: 2. A short history of image perception in medical radiology Harold Kundel and Calvin Nodine; 3. Spatial vision research without noise Arthur Burgess; 4. Signal detection theory, a brief history Arthur Burgess; 5. Signal detection in radiology Arthur Burgess; 6. Lessons from dinners with the giants of modern image science Robert Wagner; Part II. Science of Image Perception: 7. Perceptual factors in reading medical images Elizabeth Krupinski; 8. Cognitive factors in reading medical images David Manning; 9. Satisfaction of search in traditional radiographic imaging Kevin Berbaum, Edmund Franken, Robert Caldwell and Kevin Schartz; 10. The role of expertise in radiologic image interpretation Calvin Nodine and Claudia Mello-Thoms; 11. A primer of image quality and its perceptual relevance Robert Saunders and Ehsan Samei; 12. Beyond the limitations of human vision Maria Petrou; Part III. Perception Metrology: 13. Logistical issues in designing perception experiments Ehsan Samei and Xiang Li; 14. ROC analysis: basic concepts and practical applications Georgia Tourassi; 15. Multi-reader ROC Steve Hillis; 16. Recent developments in FROC methodology Dev Chakraborty; 17. Observer models as a surrogate to perception experiments Craig Abbey and Miguel Eckstein; 18. Implementation of observer models Matthew Kupinski; Part IV. Decision Support and Computer Aided Detection: 19. CAD: an image perception perspective Maryellen Giger and Weijie Chen; 20. Common designs of CAD studies Yulei Jiang; 21. Perceptual effect of CAD in reading chest images Matthew Freedman and Teresa Osicka; 22. Perceptual issues in mammography and CAD Michael Ulissey; 23. How perceptual factors affect the use and accuracy of CAD for interpretation of CT images Ronald Summers; 24. CAD: risks and benefits for radiologists' decisions Eugenio Alberdi, Andrey Povyakalo, Lorenzo Strigini and Peter Ayton; Part V. Optimization and Practical Issues: 25. Optimization of 2D and 3D radiographic systems Jeff Siewerdson; 26. Applications of AFC methodology in optimization of CT imaging systems Kent Ogden and Walter Huda; 27. Perceptual issues in reading mammograms Margarita Zuley; 28. Perceptual optimization of display processing techniques Richard Van Metter; 29. Optimization of display systems Elizabeth Krupinski and Hans Roehrig; 30. Ergonomic radiologist workplaces in the PACS environment Carl Zylack; Part VI. Epilogue: 31. Future prospects of medical image perception Ehsan Samei and Elizabeth Krupinski; Index.

Principles and Applications of Imaging Radar, Manual of Remote Sensing, 3rd Edition, Volume 2

NASA Astrophysics Data System (ADS)

Moran, M. Susan

Aerial photographs and digital images from orbiting optical scanners are a daily source of information for the general public through newspapers, television, magazines, and posters. Such images are just as prevalent in scientific journal literature. In the last 6 months, more than half of the weekly issues of Eos published an image acquired by a remote digital sensor. As a result, most geoscientists are familiar with the characteristics and even the acronyms of the current satellites and their optical sensors, common detector filters, and image presentation. In many cases, this familiarity has bred contempt. This is so because the limitations of optical sensors (imaging in the visible and infrared portions of the electromagnetic spectrum) can be quite formidable. Images of the surface cannot be acquired through clouds, and image quality is impaired with low-light conditions (such as at polar regions), atmospheric scattering and absorption, and variations in sun/sensor/surface geometry.

HIPAA, dermatology images, and the law.

PubMed

Scheinfeld, Noah; Rothstein, Brooke

2013-12-01

From smart phones to iPads, the world has grown increasingly reliant on new technology. In this ever-expanding digital age, medicine is at the forefront of these new technologies. In the field of dermatology and general medicine, digital images have become an important tool used in patient management. Today, one can even find physicians who use their cellular phone cameras to take patient images and transmit them to other physicians. However, as digital imaging technology has become more prevalent so too have concerns about the impact of this technology on the electronic medical record, quality of patient care, and medicolegal issues. This article will discuss the advent of digital imaging technology in dermatology and the legal ramifications digital images have on medical care, abiding by HIPAA, the use of digital images as evidence, and the possible abuses digital images can pose in a health care setting.

Multirotor micro air vehicle autonomous landing system based on image markers recognition

NASA Astrophysics Data System (ADS)

Skoczylas, Marcin; Gadomer, Lukasz; Walendziuk, Wojciech

2017-08-01

In this paper the idea of an autonomic drone landing system which bases on different markers detection, is presented. The issue of safe autonomic drone landing is one of the major aspects connected with drone missions. The idea of the proposed system is to detect the landing place, marked with an image called marker, using one of the image recognition algorithms, and heading during the landing procedure to this place. Choosing the proper marker, which allows the greatest quality of the recognition system, is the main problem faced in this paper. Seven markers are tested and compared. The achieved results are described and discussed.

Improving physics education in radiology.

PubMed

Hendee, William R

2007-08-01

Concern is growing that the physics education of radiologists is flawed and that without knowledge of physics principles and applications, mastery of the technology of medical imaging is impaired. Furthermore, it is proposed that a mastery of imaging technology is necessary to perfect the clinical acumen of radiologists and to preserve the quality, safety, and cost-effectiveness of imaging procedures. These issues were the focus of a multiorganizational educational summit on physics education of radiologists held in January 2006 in Atlanta. Recommendations for improving the physics education and knowledge of radiologists that evolved from this summit are presented here, together with progress made to date on their fulfillment.

Image barcodes

NASA Astrophysics Data System (ADS)

Damera-Venkata, Niranjan; Yen, Jonathan

2003-01-01

A Visually significant two-dimensional barcode (VSB) developed by Shaked et. al. is a method used to design an information carrying two-dimensional barcode, which has the appearance of a given graphical entity such as a company logo. The encoding and decoding of information using the VSB, uses a base image with very few graylevels (typically only two). This typically requires the image histogram to be bi-modal. For continuous-tone images such as digital photographs of individuals, the representation of tone or "shades of gray" is not only important to obtain a pleasing rendition of the face, but in most cases, the VSB renders these images unrecognizable due to its inability to represent true gray-tone variations. This paper extends the concept of a VSB to an image bar code (IBC). We enable the encoding and subsequent decoding of information embedded in the hardcopy version of continuous-tone base-images such as those acquired with a digital camera. The encoding-decoding process is modeled by robust data transmission through a noisy print-scan channel that is explicitly modeled. The IBC supports a high information capacity that differentiates it from common hardcopy watermarks. The reason for the improved image quality over the VSB is a joint encoding/halftoning strategy based on a modified version of block error diffusion. Encoder stability, image quality vs. information capacity tradeoffs and decoding issues with and without explicit knowledge of the base-image are discussed.

Children and Disasters. Issues in Clinical Child Psychology Series.

ERIC Educational Resources Information Center

Saylor, Conway F., Ed.

Few images are as compelling as a child who has become the victim of a manmade or natural disaster. This book is designed to draw together data, theory, and observation that address children's psychological response to disaster. Characterized by its diversity in scope, nature, and quality, some of the material comes in the form of observations…

Marketing. Nourishing News. Volume 3, Issue 7

ERIC Educational Resources Information Center

Idaho State Department of Education, 2009

2009-01-01

The use of marketing can effectively enhance the growth and image of the Child Nutrition Programs. The customer has changed over the years, and today's customer in the Child Nutrition Programs wants the food served to be high-quality at low prices. As a result, many child nutrition managers are looking at what the customer is requesting. This…

Spectral Band Characterization for Hyperspectral Monitoring of Water Quality

NASA Technical Reports Server (NTRS)

Vermillion, Stephanie C.; Raqueno, Rolando; Simmons, Rulon

2001-01-01

A method for selecting the set of spectral characteristics that provides the smallest increase in prediction error is of interest to those using hyperspectral imaging (HSI) to monitor water quality. The spectral characteristics of interest to these applications are spectral bandwidth and location. Three water quality constituents of interest that are detectable via remote sensing are chlorophyll (CHL), total suspended solids (TSS), and colored dissolved organic matter (CDOM). Hyperspectral data provides a rich source of information regarding the content and composition of these materials, but often provides more data than an analyst can manage. This study addresses the spectral characteristics need for water quality monitoring for two reasons. First, determination of the greatest contribution of these spectral characteristics would greatly improve computational ease and efficiency. Second, understanding the spectral capabilities of different spectral resolutions and specific regions is an essential part of future system development and characterization. As new systems are developed and tested, water quality managers will be asked to determine sensor specifications that provide the most accurate and efficient water quality measurements. We address these issues using data from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and a set of models to predict constituent concentrations.

Technical Directions In High Resolution Non-Impact Printers

NASA Astrophysics Data System (ADS)

Dunn, S. Thomas; Dunn, Patrice M.

1987-04-01

There are several factors to consider when addressing the issue of non-impact printer resolution. One will find differences between the imaging resolution and the final output resolution, and most assuradly differences exist between the advertised and actual resolution of many of these systems. Beyond that some of the technical factors that effect the resolution of a system in-clude: . Scan Line Density . Overlap . Spot Size . Energy Profile . Symmetry of Imaging Generally speaking, the user of graphic arts equipment, is best advised to view output to determine the degree of acceptable quality.

Quality Assessment of Collection 6 MODIS Atmospheric Science Products

NASA Astrophysics Data System (ADS)

Manoharan, V. S.; Ridgway, B.; Platnick, S. E.; Devadiga, S.; Mauoka, E.

2015-12-01

Since the launch of the NASA Terra and Aqua satellites in December 1999 and May 2002, respectively, atmosphere and land data acquired by the MODIS (Moderate Resolution Imaging Spectroradiometer) sensor on-board these satellites have been reprocessed five times at the MODAPS (MODIS Adaptive Processing System) located at NASA GSFC. The global land and atmosphere products use science algorithms developed by the NASA MODIS science team investigators. MODAPS completed Collection 6 reprocessing of MODIS Atmosphere science data products in April 2015 and is currently generating the Collection 6 products using the latest version of the science algorithms. This reprocessing has generated one of the longest time series of consistent data records for understanding cloud, aerosol, and other constituents in the earth's atmosphere. It is important to carefully evaluate and assess the quality of this data and remove any artifacts to maintain a useful climate data record. Quality Assessment (QA) is an integral part of the processing chain at MODAPS. This presentation will describe the QA approaches and tools adopted by the MODIS Land/Atmosphere Operational Product Evaluation (LDOPE) team to assess the quality of MODIS operational Atmospheric products produced at MODAPS. Some of the tools include global high resolution images, time series analysis and statistical QA metrics. The new high resolution global browse images with pan and zoom have provided the ability to perform QA of products in real time through synoptic QA on the web. This global browse generation has been useful in identifying production error, data loss, and data quality issues from calibration error, geolocation error and algorithm performance. A time series analysis for various science datasets in the Level-3 monthly product was recently developed for assessing any long term drifts in the data arising from instrument errors or other artifacts. This presentation will describe and discuss some test cases from the recently processed C6 products. We will also describe the various tools and approaches developed to verify and assess the algorithm changes implemented by the science team to address known issues in the products and improve the quality of the products.

The new frontiers of multimodality and multi-isotope imaging

NASA Astrophysics Data System (ADS)

Behnam Azad, Babak; Nimmagadda, Sridhar

2014-06-01

Technological advances in imaging systems and the development of target specific imaging tracers has been rapidly growing over the past two decades. Recent progress in "all-in-one" imaging systems that allow for automated image coregistration has significantly added to the growth of this field. These developments include ultra high resolution PET and SPECT scanners that can be integrated with CT or MR resulting in PET/CT, SPECT/CT, SPECT/PET and PET/MRI scanners for simultaneous high resolution high sensitivity anatomical and functional imaging. These technological developments have also resulted in drastic enhancements in image quality and acquisition time while eliminating cross compatibility issues between modalities. Furthermore, the most cutting edge technology, though mostly preclinical, also allows for simultaneous multimodality multi-isotope image acquisition and image reconstruction based on radioisotope decay characteristics. These scientific advances, in conjunction with the explosion in the development of highly specific multimodality molecular imaging agents, may aid in realizing simultaneous imaging of multiple biological processes and pave the way towards more efficient diagnosis and improved patient care.

Fast and low-dose computed laminography using compressive sensing based technique

NASA Astrophysics Data System (ADS)

Abbas, Sajid; Park, Miran; Cho, Seungryong

2015-03-01

Computed laminography (CL) is well known for inspecting microstructures in the materials, weldments and soldering defects in high density packed components or multilayer printed circuit boards. The overload problem on x-ray tube and gross failure of the radio-sensitive electronics devices during a scan are among important issues in CL which needs to be addressed. The sparse-view CL can be one of the viable option to overcome such issues. In this work a numerical aluminum welding phantom was simulated to collect sparsely sampled projection data at only 40 views using a conventional CL scanning scheme i.e. oblique scan. A compressive-sensing inspired total-variation (TV) minimization algorithm was utilized to reconstruct the images. It is found that the images reconstructed using sparse view data are visually comparable with the images reconstructed using full scan data set i.e. at 360 views on regular interval. We have quantitatively confirmed that tiny structures such as copper and tungsten slags, and copper flakes in the reconstructed images from sparsely sampled data are comparable with the corresponding structure present in the fully sampled data case. A blurring effect can be seen near the edges of few pores at the bottom of the reconstructed images from sparsely sampled data, despite the overall image quality is reasonable for fast and low-dose NDT.

An intermediate significant bit (ISB) watermarking technique using neural networks.

PubMed

Zeki, Akram; Abubakar, Adamu; Chiroma, Haruna

2016-01-01

Prior research studies have shown that the peak signal to noise ratio (PSNR) is the most frequent watermarked image quality metric that is used for determining the levels of strength and weakness of watermarking algorithms. Conversely, normalised cross correlation (NCC) is the most common metric used after attacks were applied to a watermarked image to verify the strength of the algorithm used. Many researchers have used these approaches to evaluate their algorithms. These strategies have been used for a long time, however, which unfortunately limits the value of PSNR and NCC in reflecting the strength and weakness of the watermarking algorithms. This paper considers this issue to determine the threshold values of these two parameters in reflecting the amount of strength and weakness of the watermarking algorithms. We used our novel watermarking technique for embedding four watermarks in intermediate significant bits (ISB) of six image files one-by-one through replacing the image pixels with new pixels and, at the same time, keeping the new pixels very close to the original pixels. This approach gains an improved robustness based on the PSNR and NCC values that were gathered. A neural network model was built that uses the image quality metrics (PSNR and NCC) values obtained from the watermarking of six grey-scale images that use ISB as the desired output and that are trained for each watermarked image's PSNR and NCC. The neural network predicts the watermarked image's PSNR together with NCC after the attacks when a portion of the output of the same or different types of image quality metrics (PSNR and NCC) are obtained. The results indicate that the NCC metric fluctuates before the PSNR values deteriorate.

Prospective PET image quality gain calculation method by optimizing detector parameters.

PubMed

Theodorakis, Lampros; Loudos, George; Prassopoulos, Vasilios; Kappas, Constantine; Tsougos, Ioannis; Georgoulias, Panagiotis

2015-12-01

Lutetium-based scintillators with high-performance electronics introduced time-of-flight (TOF) reconstruction in the clinical setting. Let G' be the total signal to noise ratio gain in a reconstructed image using the TOF kernel compared with conventional reconstruction modes. G' is then the product of G1 gain arising from the reconstruction process itself and (n-1) other gain factors (G2, G3, … Gn) arising from the inherent properties of the detector. We calculated G2 and G3 gains resulting from the optimization of the coincidence and energy window width for prompts and singles, respectively. Both quantitative and image-based validated Monte Carlo models of Lu2SiO5 (LSO) TOF-permitting and Bi4Ge3O12 (BGO) TOF-nonpermitting detectors were used for the calculations. G2 and G3 values were 1.05 and 1.08 for the BGO detector and G3 was 1.07 for the LSO. A value of almost unity for G2 of the LSO detector indicated a nonsignificant optimization by altering the energy window setting. G' was found to be ∼1.4 times higher for the TOF-permitting detector after reconstruction and optimization of the coincidence and energy windows. The method described could potentially predict image noise variations by altering detector acquisition parameters. It could also further contribute toward a long-lasting debate related to cost-efficiency issues of TOF scanners versus the non-TOF ones. Some vendors re-engage nowadays to non-TOF product line designs in an effort to reduce crystal costs. Therefore, exploring the limits of image quality gain by altering the parameters of these detectors remains a topical issue.

An efficient mosaic algorithm considering seasonal variation: application to KOMPSAT-2 satellite images.

PubMed

Choi, Jaewon; Jung, Hyung-Sup; Yun, Sang-Ho

2015-03-09

As the aerospace industry grows, images obtained from Earth observation satellites have been successfully used in various fields. Specifically, the demand for a high-resolution (HR) optical images is gradually increasing, and hence the generation of a high-quality mosaic image is being magnified as an interesting issue. In this paper, we have proposed an efficient mosaic algorithm for HR optical images that are significantly different due to seasonal change. The algorithm includes main steps such as: (1) seamline extraction from gradient magnitude and seam images; (2) histogram matching; and (3) image feathering. Eleven Kompsat-2 images characterized by seasonal variations are used for the performance validation of the proposed method. The results of the performance test show that the proposed method effectively mosaics Kompsat-2 adjacent images including severe seasonal changes. Moreover, the results reveal that the proposed method is applicable to HR optic images such as GeoEye, IKONOS, QuickBird, RapidEye, SPOT, WorldView, etc.

Inverse scattering pre-stack depth imaging and it's comparison to some depth migration methods for imaging rich fault complex structure

NASA Astrophysics Data System (ADS)

Nurhandoko, Bagus Endar B.; Sukmana, Indriani; Mubarok, Syahrul; Deny, Agus; Widowati, Sri; Kurniadi, Rizal

2012-06-01

Migration is important issue for seismic imaging in complex structure. In this decade, depth imaging becomes important tools for producing accurate image in depth imaging instead of time domain imaging. The challenge of depth migration method, however, is in revealing the complex structure of subsurface. There are many methods of depth migration with their advantages and weaknesses. In this paper, we show our propose method of pre-stack depth migration based on time domain inverse scattering wave equation. Hopefully this method can be as solution for imaging complex structure in Indonesia, especially in rich thrusting fault zones. In this research, we develop a recent advance wave equation migration based on time domain inverse scattering wave which use more natural wave propagation using scattering wave. This wave equation pre-stack depth migration use time domain inverse scattering wave equation based on Helmholtz equation. To provide true amplitude recovery, an inverse of divergence procedure and recovering transmission loss are considered of pre-stack migration. Benchmarking the propose inverse scattering pre-stack depth migration with the other migration methods are also presented, i.e.: wave equation pre-stack depth migration, waveequation depth migration, and pre-stack time migration method. This inverse scattering pre-stack depth migration could image successfully the rich fault zone which consist extremely dip and resulting superior quality of seismic image. The image quality of inverse scattering migration is much better than the others migration methods.

On "Japanese Style" Teacher Education Reform: Considering Issues of Quality Development under an "Open System"

ERIC Educational Resources Information Center

Iwata, Yasuyuki

2015-01-01

A complication of teacher education policy in Japan is rooted in a gap between an image of teachers, which is held by society as a whole, and includes various character traits and the reality of Japanese university education. On the other hand, the expansion of an "open system" and lack of nationwide standard are making individual…

Dosimetry for audit and clinical trials: challenges and requirements

NASA Astrophysics Data System (ADS)

Kron, T.; Haworth, A.; Williams, I.

2013-06-01

Many important dosimetry audit networks for radiotherapy have their roots in clinical trial quality assurance (QA). In both scenarios it is essential to test two issues: does the treatment plan conform with the clinical requirements and is the plan a reasonable representation of what is actually delivered to a patient throughout their course of treatment. Part of a sound quality program would be an external audit of these issues with verification of the equivalence of plan and treatment typically referred to as a dosimetry audit. The increasing complexity of radiotherapy planning and delivery makes audits challenging. While verification of absolute dose delivered at a reference point was the standard of external dosimetry audits two decades ago this is often deemed inadequate for verification of treatment approaches such as Intensity Modulated Radiation Therapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT). As such, most dosimetry audit networks have successfully introduced more complex tests of dose delivery using anthropomorphic phantoms that can be imaged, planned and treated as a patient would. The new challenge is to adapt this approach to ever more diversified radiotherapy procedures with image guided/adaptive radiotherapy, motion management and brachytherapy being the focus of current research.

Holographic display system for restoration of sight to the blind

PubMed Central

Goetz, G A; Mandel, Y; Manivanh, R; Palanker, D V; Čižmár, T

2013-01-01

Objective We present a holographic near-the-eye display system enabling optical approaches for sight restoration to the blind, such as photovoltaic retinal prosthesis, optogenetic and other photoactivation techniques. We compare it with conventional LCD or DLP-based displays in terms of image quality, field of view, optical efficiency and safety. Approach We detail the optical configuration of the holographic display system and its characterization using a phase-only spatial light modulator. Main results We describe approaches to controlling the zero diffraction order and speckle related issues in holographic display systems and assess the image quality of such systems. We show that holographic techniques offer significant advantages in terms of peak irradiance and power efficiency, and enable designs that are inherently safer than LCD or DLP-based systems. We demonstrate the performance of our holographic display system in the assessment of cortical response to alternating gratings projected onto the retinas of rats. Significance We address the issues associated with the design of high brightness, near-the-eye display systems and propose solutions to the efficiency and safety challenges with an optical design which could be miniaturized and mounted onto goggles. PMID:24045579

Managing Body Image Difficulties of Adult Cancer Patients: Lessons from Available Research

PubMed Central

Fingeret, Michelle Cororve; Teo, Irene; Epner, Daniel E.

2013-01-01

Background Body image is a critical psychosocial issue for cancer patients as they often undergo significant changes to appearance and functioning. In this review article, our primary purpose was to identify empirically-supported approaches to treat body image difficulties of adult cancer patients that can be incorporated into high-quality comprehensive cancer care. Methods We provided an overview of theoretical models of body image relevant to cancer patients, and presented findings from published literature on body image and cancer from 2003–2013. We integrated these data with information from the patient-doctor communication literature to delineate a practical approach for assessing and treating body image concerns of adult cancer patients. Results Body image difficulties were found across patients with diverse cancer sites, and were most prevalent in the immediate postoperative and treatment period. Age, body mass index, and specific cancer treatments have been identified as potential risk factors for body image disturbance in cancer patients. Current evidence supports the use of time-limited cognitive-behavioral therapy interventions for addressing these difficulties. Other intervention strategies also show promise but require further study. We identified potential indicators of body image difficulties to alert healthcare professionals when to refer patients for psychosocial care, and proposed a framework for approaching conversations about body image that can be used by the oncologic treatment team. Conclusions Body image issues affect a wide array of cancer patients. Providers can use available evidence combined with information from the healthcare communication literature to develop practical strategies for treating body image concerns of cancer patients. PMID:24895287

Managing body image difficulties of adult cancer patients: lessons from available research.

PubMed

Fingeret, Michelle Cororve; Teo, Irene; Epner, Daniel E

2014-03-01

Body image is a critical psychosocial issue for patients with cancer because they often undergo significant changes to appearance and functioning. The primary purpose of this review article was to identify empirically-supported approaches to treat body image difficulties of adult cancer patients that can be incorporated into high-quality comprehensive cancer care. An overview was provided of theoretical models of body image relevant to cancer patients, and findings were presented from published literature on body image and cancer from 2003 to 2013. These data were integrated with information from the patient-doctor communication literature to delineate a practical approach for assessing and treating body image concerns of adult cancer patients. Body image difficulties were found across patients with diverse cancer sites, and were most prevalent in the immediate postoperative and treatment period. Age, body mass index, and specific cancer treatments have been identified as potential risk factors for body image disturbance in cancer patients. Current evidence supports the use of time-limited cognitive-behavioral therapy interventions for addressing these difficulties. Other intervention strategies also show promise but require further study. Potential indicators of body image difficulties were identified to alert health care professionals when to refer patients for psychosocial care, and a framework was proposed for approaching conversations about body image that can be used by the oncologic treatment team. Body image issues affect a wide array of cancer patients. Providers can use available evidence combined with information from the health care communication literature to develop practical strategies for treating body image concerns of patients with cancer. © 2013 American Cancer Society.

Radioactive Quality Evaluation and Cross Validation of Data from the HJ-1A/B Satellites' CCD Sensors

PubMed Central

Zhang, Xin; Zhao, Xiang; Liu, Guodong; Kang, Qian; Wu, Donghai

2013-01-01

Data from multiple sensors are frequently used in Earth science to gain a more complete understanding of spatial information changes. Higher quality and mutual consistency are prerequisites when multiple sensors are jointly used. The HJ-1A/B satellites successfully launched on 6 September 2008. There are four charge-coupled device (CCD) sensors with uniform spatial resolutions and spectral range onboard the HJ-A/B satellites. Whether these data are keeping consistency is a major issue before they are used. This research aims to evaluate the data consistency and radioactive quality from the four CCDs. First, images of urban, desert, lake and ocean are chosen as the objects of evaluation. Second, objective evaluation variables, such as mean, variance and angular second moment, are used to identify image performance. Finally, a cross validation method are used to ensure the correlation of the data from the four HJ-1A/B CCDs and that which is gathered from the moderate resolution imaging spectro-radiometer (MODIS). The results show that the image quality of HJ-1A/B CCDs is stable, and the digital number distribution of CCD data is relatively low. In cross validation with MODIS, the root mean square errors of bands 1, 2 and 3 range from 0.055 to 0.065, and for band 4 it is 0.101. The data from HJ-1A/B CCD have better consistency. PMID:23881127

Radioactive quality evaluation and cross validation of data from the HJ-1A/B satellites' CCD sensors.

PubMed

Zhang, Xin; Zhao, Xiang; Liu, Guodong; Kang, Qian; Wu, Donghai

2013-07-05

Data from multiple sensors are frequently used in Earth science to gain a more complete understanding of spatial information changes. Higher quality and mutual consistency are prerequisites when multiple sensors are jointly used. The HJ-1A/B satellites successfully launched on 6 September 2008. There are four charge-coupled device (CCD) sensors with uniform spatial resolutions and spectral range onboard the HJ-A/B satellites. Whether these data are keeping consistency is a major issue before they are used. This research aims to evaluate the data consistency and radioactive quality from the four CCDs. First, images of urban, desert, lake and ocean are chosen as the objects of evaluation. Second, objective evaluation variables, such as mean, variance and angular second moment, are used to identify image performance. Finally, a cross validation method are used to ensure the correlation of the data from the four HJ-1A/B CCDs and that which is gathered from the moderate resolution imaging spectro-radiometer (MODIS). The results show that the image quality of HJ-1A/B CCDs is stable, and the digital number distribution of CCD data is relatively low. In cross validation with MODIS, the root mean square errors of bands 1, 2 and 3 range from 0.055 to 0.065, and for band 4 it is 0.101. The data from HJ-1A/B CCD have better consistency.

Robust feature estimation by non-rigid hierarchical image registration and its application in disparity measurement

NASA Astrophysics Data System (ADS)

Badshah, Amir; Choudhry, Aadil Jaleel; Ullah, Shan

2017-03-01

Industries are moving towards automation in order to increase productivity and ensure quality. Variety of electronic and electromagnetic systems are being employed to assist human operator in fast and accurate quality inspection of products. Majority of these systems are equipped with cameras and rely on diverse image processing algorithms. Information is lost in 2D image, therefore acquiring accurate 3D data from 2D images is an open issue. FAST, SURF and SIFT are well-known spatial domain techniques for features extraction and henceforth image registration to find correspondence between images. The efficiency of these methods is measured in terms of the number of perfect matches found. A novel fast and robust technique for stereo-image processing is proposed. It is based on non-rigid registration using modified normalized phase correlation. The proposed method registers two images in hierarchical fashion using quad-tree structure. The registration process works through global to local level resulting in robust matches even in presence of blur and noise. The computed matches can further be utilized to determine disparity and depth for industrial product inspection. The same can be used in driver assistance systems. The preliminary tests on Middlebury dataset produced satisfactory results. The execution time for a 413 x 370 stereo-pair is 500ms approximately on a low cost DSP.

A dictionary learning approach for Poisson image deblurring.

PubMed

Ma, Liyan; Moisan, Lionel; Yu, Jian; Zeng, Tieyong

2013-07-01

The restoration of images corrupted by blur and Poisson noise is a key issue in medical and biological image processing. While most existing methods are based on variational models, generally derived from a maximum a posteriori (MAP) formulation, recently sparse representations of images have shown to be efficient approaches for image recovery. Following this idea, we propose in this paper a model containing three terms: a patch-based sparse representation prior over a learned dictionary, the pixel-based total variation regularization term and a data-fidelity term capturing the statistics of Poisson noise. The resulting optimization problem can be solved by an alternating minimization technique combined with variable splitting. Extensive experimental results suggest that in terms of visual quality, peak signal-to-noise ratio value and the method noise, the proposed algorithm outperforms state-of-the-art methods.

A new quality of bone ultrasound research.

PubMed

Gluer, C C

2008-07-01

Quantitative ultrasound (QUS) methods have strong power to predict osteoporotic fractures, but they are also very relevant for the assessment of bone quality. A representative sample of recent studies addressing these topics can be found in this special issue. Further pursuit of these methods will establish micro-QUS imaging methods as tools for measuring specific aspects of bone quality. Once this is achieved, we will be able to link such data to the clinical QUS methods used in vivo to determine which aspects of bone quality cause QUS to be a predictor of fracture risk that is independent of bone mineral density (BMD). Potentially this could lead to the development of a new generation of QUS devices for improved and expanded clinical assessment. Good quality of basic science work will thus lead to good quality of clinical patient examinations on the basis of a more detailed assessment of bone quality.

Iterative CT reconstruction using coordinate descent with ordered subsets of data

NASA Astrophysics Data System (ADS)

Noo, F.; Hahn, K.; Schöndube, H.; Stierstorfer, K.

2016-04-01

Image reconstruction based on iterative minimization of a penalized weighted least-square criteria has become an important topic of research in X-ray computed tomography. This topic is motivated by increasing evidence that such a formalism may enable a significant reduction in dose imparted to the patient while maintaining or improving image quality. One important issue associated with this iterative image reconstruction concept is slow convergence and the associated computational effort. For this reason, there is interest in finding methods that produce approximate versions of the targeted image with a small number of iterations and an acceptable level of discrepancy. We introduce here a novel method to produce such approximations: ordered subsets in combination with iterative coordinate descent. Preliminary results demonstrate that this method can produce, within 10 iterations and using only a constant image as initial condition, satisfactory reconstructions that retain the noise properties of the targeted image.

Athermal design and analysis of glass-plastic hybrid lens

NASA Astrophysics Data System (ADS)

Yang, Jian; Cen, Zhaofeng; Li, Xiaotong

2018-01-01

With the rapid development of security market, the glass-plastic hybrid lens has gradually become a choice for the special requirements like high imaging quality in a wide temperature range and low cost. The reduction of spherical aberration is achieved by using aspherical surface instead of increasing the number of lenses. Obviously, plastic aspherical lens plays a great role in the cost reduction. However, the hybrid lens has a priority issue, which is the large thermal coefficient of expansion of plastic, causing focus shift and seriously affecting the imaging quality, so the hybrid lens is highly sensitive to the change of temperature. To ensure the system operates normally in a wide temperature range, it is necessary to eliminate the influence of temperature on the hybrid lens system. A practical design method named the Athermal Material Map is summarized and verified by an athermal design example according to the design index. It includes the distribution of optical power and selection of glass or plastic. The design result shows that the optical system has excellent imaging quality at a wide temperature range from -20 ° to 70 °. The method of athermal design in this paper has generality which could apply to optical system with plastic aspherical surface.

Nuclear Cardiology: Are We Using the Right Protocols and Tracers the Right Way?

PubMed

Dondi, Maurizio; Pascual, Thomas; Paez, Diana; Einstein, Andrew J

2017-12-01

The field of nuclear cardiology has changed considerably over recent years, with greater attention paid to safety and radiation protection issues. The wider usage of technetium-99m (Tc-99m)-labeled radiopharmaceuticals for single-photon emission computed tomography (SPECT) imaging using gamma cameras has contributed to better quality studies and lower radiation exposure to patients. Increased availability of tracers and scanners for positron emission tomography (PET) will help further improve the quality of studies and quantify myocardial blood flow and myocardial flow reserve, thus enhancing the contribution of non-invasive imaging to the management of coronary artery disease. The introduction of new instrumentation such as solid state cameras and new software will help reduce further radiation exposure to patients undergoing nuclear cardiology studies. Results from recent studies, focused on assessing the relationship between best practices and radiation risk, provide useful insights on simple measures to improve the safety of nuclear cardiology studies without compromising the quality of results.

Measurement issues in the sonographic assessment of tennis elbow.

PubMed

Poltawski, Leon; Jayaram, Vijay; Watson, Tim

2010-05-01

Sonography is increasingly being used for assessment in tennis elbow research and clinical practice, but there are a lack of data regarding its validity, reliability, and responsiveness to change for this application. Studies using the modality were reviewed to establish current levels of evidence for these measurement properties. There is reasonable evidence regarding its validity for identifying tennis elbow tendinopathy, but a lack of data addressing its reliability and responsiveness. Practical issues affecting image quality are discussed, and recommendations for further investigation are suggested, to enhance the credible use of sonography with this debilitating condition.

A variable torque motor compatible with magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Roeck, W. W.; Ha, S.-H.; Farmaka, S.; Nalcioglu, O.

2009-04-01

High magnetic fields used in magnetic resonance imaging (MRI) do not allow the employment of conventional motors due to various incompatibility issues. This paper reports on a new motor that can operate in or near high field magnets used for MRI. The motor was designed to be operational with the MRI equipment and could be used in a rotating imaging gantry inside the magnet designed for dual modality imaging. Furthermore, it could also be used for image guided robotic interventional procedures inside a MRI system if so desired. The prototype motor was developed using magnetic resonance (MR) compatible materials, and its functionality with MR imaging was evaluated experimentally by measuring the performance of the motor and its effect on the MR image quality. Since in our application, namely, single photon emission tomography, the motor has to perform precise stepping of the gantry in small angular steps the most important parameter is the start-up torque. The experimental results showed that the motor has a start-up torque up to 1.37 Nm and rotates at 196 rpm when a constant voltage difference of 12 V is applied at a magnetic field strength of 1 T. The MR image quality was quantified by measuring the signal-to-noise of images acquired under different conditions. The results presented here indicate that the motor is MR compatible and could be used for rotating an imaging gantry or a surgical device inside the magnet.

Diagnosing acute pulmonary embolism with computed tomography: imaging update.

PubMed

Devaraj, Anand; Sayer, Charlie; Sheard, Sarah; Grubnic, Sisa; Nair, Arjun; Vlahos, Ioannis

2015-05-01

Acute pulmonary embolism is recognized as a difficult diagnosis to make. It is potentially fatal if undiagnosed, yet increasing referral rates for imaging and falling diagnostic yields are topics which have attracted much attention. For patients in the emergency department with suspected pulmonary embolism, computed tomography pulmonary angiography (CTPA) is the test of choice for most physicians, and hence radiology has a key role to play in the patient pathway. This review will outline key aspects of the recent literature regarding the following issues: patient selection for imaging, the optimization of CTPA image quality and dose, preferred pathways for pregnant patients and other subgroups, and the role of CTPA beyond diagnosis. The role of newer techniques such as dual-energy CT and single-photon emission-CT will also be discussed.

System Matrix Analysis for Computed Tomography Imaging

PubMed Central

Flores, Liubov; Vidal, Vicent; Verdú, Gumersindo

2015-01-01

In practical applications of computed tomography imaging (CT), it is often the case that the set of projection data is incomplete owing to the physical conditions of the data acquisition process. On the other hand, the high radiation dose imposed on patients is also undesired. These issues demand that high quality CT images can be reconstructed from limited projection data. For this reason, iterative methods of image reconstruction have become a topic of increased research interest. Several algorithms have been proposed for few-view CT. We consider that the accurate solution of the reconstruction problem also depends on the system matrix that simulates the scanning process. In this work, we analyze the application of the Siddon method to generate elements of the matrix and we present results based on real projection data. PMID:26575482

Detection of diabetic foot hyperthermia by using a regionalization method, based on the plantar angiosomes, on infrared images.

PubMed

Liu, Y; Polo, A; Zequera, M; Harba, R; Canals, R; Vilcahuaman, L; Bello, Y

2016-08-01

Prevention of serious diabetic foot complication like ulceration or infection is an important issue. As the development of thermal graphic technologies, foot temperature-guided avoidance therapy has been recommended. Doctors from Hospital National Dos de Mayo are studying on the risk of the diabetic foot passing from Grade 0 to Grade 1 in the Wagner Scale. This risk to develop ulcers is related to the temperature difference of corresponding area between left and right foot. Generally speaking, the diabetic foot with greater mean temperature difference has more potential to develop ulcers; especially, area whose temperature difference of more than 2.2°C is where doctors and patients must pay much attention to potential problems like ulceration or infection. A system in Visual Studio was developed taking the thermal images as input and producing image with absolute mean temperature difference of 7different regions or four plantar angiosomes as output. The program process contained essential medical image processing issues such as segmentation, location and regionalization, in which adapted algorithms were implemented. From a database of 85 patients provided only 60 were used due to the quality of acquisition.

Image Reconstruction is a New Frontier of Machine Learning.

PubMed

Wang, Ge; Ye, Jong Chu; Mueller, Klaus; Fessler, Jeffrey A

2018-06-01

Over past several years, machine learning, or more generally artificial intelligence, has generated overwhelming research interest and attracted unprecedented public attention. As tomographic imaging researchers, we share the excitement from our imaging perspective [item 1) in the Appendix], and organized this special issue dedicated to the theme of "Machine learning for image reconstruction." This special issue is a sister issue of the special issue published in May 2016 of this journal with the theme "Deep learning in medical imaging" [item 2) in the Appendix]. While the previous special issue targeted medical image processing/analysis, this special issue focuses on data-driven tomographic reconstruction. These two special issues are highly complementary, since image reconstruction and image analysis are two of the main pillars for medical imaging. Together we cover the whole workflow of medical imaging: from tomographic raw data/features to reconstructed images and then extracted diagnostic features/readings.

Graphene metamaterial spatial light modulator for infrared single pixel imaging.

PubMed

Fan, Kebin; Suen, Jonathan Y; Padilla, Willie J

2017-10-16

High-resolution and hyperspectral imaging has long been a goal for multi-dimensional data fusion sensing applications - of interest for autonomous vehicles and environmental monitoring. In the long wave infrared regime this quest has been impeded by size, weight, power, and cost issues, especially as focal-plane array detector sizes increase. Here we propose and experimentally demonstrated a new approach based on a metamaterial graphene spatial light modulator (GSLM) for infrared single pixel imaging. A frequency-division multiplexing (FDM) imaging technique is designed and implemented, and relies entirely on the electronic reconfigurability of the GSLM. We compare our approach to the more common raster-scan method and directly show FDM image frame rates can be 64 times faster with no degradation of image quality. Our device and related imaging architecture are not restricted to the infrared regime, and may be scaled to other bands of the electromagnetic spectrum. The study presented here opens a new approach for fast and efficient single pixel imaging utilizing graphene metamaterials with novel acquisition strategies.

Framing Service, Benefit, and Credibility Through Images and Texts: A Content Analysis of Online Promotional Messages of Korean Medical Tourism Industry.

PubMed

Jun, Jungmi

2016-07-01

This study examines how the Korean medical tourism industry frames its service, benefit, and credibility issues through texts and images of online brochures. The results of content analysis suggest that the Korean medical tourism industry attempts to frame their medical/health services as "excellence in surgeries and cancer care" and "advanced health technology and facilities." However, the use of cost-saving appeals was limited, which can be seen as a strategy to avoid consumers' association of lower cost with lower quality services, and to stress safety and credibility.

Wireless live streaming video of laparoscopic surgery: a bandwidth analysis for handheld computers.

PubMed

Gandsas, Alex; McIntire, Katherine; George, Ivan M; Witzke, Wayne; Hoskins, James D; Park, Adrian

2002-01-01

Over the last six years, streaming media has emerged as a powerful tool for delivering multimedia content over networks. Concurrently, wireless technology has evolved, freeing users from desktop boundaries and wired infrastructures. At the University of Kentucky Medical Center, we have integrated these technologies to develop a system that can wirelessly transmit live surgery from the operating room to a handheld computer. This study establishes the feasibility of using our system to view surgeries and describes the effect of bandwidth on image quality. A live laparoscopic ventral hernia repair was transmitted to a single handheld computer using five encoding speeds at a constant frame rate, and the quality of the resulting streaming images was evaluated. No video images were rendered when video data were encoded at 28.8 kilobytes per second (Kbps), the slowest encoding bitrate studied. The highest quality images were rendered at encoding speeds greater than or equal to 150 Kbps. Of note, a 15 second transmission delay was experienced using all four encoding schemes that rendered video images. We believe that the wireless transmission of streaming video to handheld computers has tremendous potential to enhance surgical education. For medical students and residents, the ability to view live surgeries, lectures, courses and seminars on handheld computers means a larger number of learning opportunities. In addition, we envision that wireless enabled devices may be used to telemonitor surgical procedures. However, bandwidth availability and streaming delay are major issues that must be addressed before wireless telementoring becomes a reality.

Overall evaluability of low dose protocol for computed tomography angiography of thoracic aorta using 80 kV and iterative reconstruction algorithm using different concentration contrast media.

PubMed

Annoni, Andrea Daniele; Mancini, Maria E; Andreini, Daniele; Formenti, Alberto; Mushtaq, Saima; Nobili, Enrica; Guglielmo, Marco; Baggiano, Andrea; Conte, Edoardo; Pepi, Mauro

2017-10-01

Multidetector Computed Tomography Angiography (MDCTA) is presently the imaging modality of choice for aortic disease. However, the effective radiation dose and the risk related to the use of contrast agents associated with MDCTA is an issue of concern. Aim of this study was to assess image quality of a low dose ECG-gated MDCTA of thoracic aorta using different concentration contrast media without tailored injection protocol. Two-hundred patients were randomised into four different scan protocols: Group A (Iodixanol 320 and 80 Kvp tube voltage), Group B (Iodixanol 320 and 100 Kvp tube voltage), Group C (Iomeprol 400 and 80 Kvp tube voltage) and Group D (Iomeprol 400 and 100 Kvp tube voltage). Image quality, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and effective dose (ED) were compared among groups. No significant differences in image noise, SNR and CNR between groups with the same tube voltage. Significant differences in SNR and CNR were found among groups with 80 kV versus groups using 100 kV but without differences in terms of image quality. ED was significantly lower in groups with 80 kV. Multidetector Computed Tomography Angiography protocols using 80 kV and low concentration contrast media are feasible without need of tailored injection protocols. © 2017 The Royal Australian and New Zealand College of Radiologists.

An excitation wavelength-scanning spectral imaging system for preclinical imaging

NASA Astrophysics Data System (ADS)

Leavesley, Silas; Jiang, Yanan; Patsekin, Valery; Rajwa, Bartek; Robinson, J. Paul

2008-02-01

Small-animal fluorescence imaging is a rapidly growing field, driven by applications in cancer detection and pharmaceutical therapies. However, the practical use of this imaging technology is limited by image-quality issues related to autofluorescence background from animal tissues, as well as attenuation of the fluorescence signal due to scatter and absorption. To combat these problems, spectral imaging and analysis techniques are being employed to separate the fluorescence signal from background autofluorescence. To date, these technologies have focused on detecting the fluorescence emission spectrum at a fixed excitation wavelength. We present an alternative to this technique, an imaging spectrometer that detects the fluorescence excitation spectrum at a fixed emission wavelength. The advantages of this approach include increased available information for discrimination of fluorescent dyes, decreased optical radiation dose to the animal, and ability to scan a continuous wavelength range instead of discrete wavelength sampling. This excitation-scanning imager utilizes an acousto-optic tunable filter (AOTF), with supporting optics, to scan the excitation spectrum. Advanced image acquisition and analysis software has also been developed for classification and unmixing of the spectral image sets. Filtering has been implemented in a single-pass configuration with a bandwidth (full width at half maximum) of 16nm at 550nm central diffracted wavelength. We have characterized AOTF filtering over a wide range of incident light angles, much wider than has been previously reported in the literature, and we show how changes in incident light angle can be used to attenuate AOTF side lobes and alter bandwidth. A new parameter, in-band to out-of-band ratio, was defined to assess the quality of the filtered excitation light. Additional parameters were measured to allow objective characterization of the AOTF and the imager as a whole. This is necessary for comparing the excitation-scanning imager to other spectral and fluorescence imaging technologies. The effectiveness of the hyperspectral imager was tested by imaging and analysis of mice with injected fluorescent dyes. Finally, a discussion of the optimization of spectral fluorescence imagers is given, relating the effects of filter quality on fluorescence images collected and the analysis outcome.

PACS administrators' and radiologists' perspective on the importance of features for PACS selection.

PubMed

Joshi, Vivek; Narra, Vamsi R; Joshi, Kailash; Lee, Kyootai; Melson, David

2014-08-01

Picture archiving and communication systems (PACS) play a critical role in radiology. This paper presents the criteria important to PACS administrators for selecting a PACS. A set of criteria are identified and organized into an integrative hierarchical framework. Survey responses from 48 administrators are used to identify the relative weights of these criteria through an analytical hierarchy process. The five main dimensions for PACS selection in order of importance are system continuity and functionality, system performance and architecture, user interface for workflow management, user interface for image manipulation, and display quality. Among the subdimensions, the highest weights were assessed for security, backup, and continuity; tools for continuous performance monitoring; support for multispecialty images; and voice recognition/transcription. PACS administrators' preferences were generally in line with that of previously reported results for radiologists. Both groups assigned the highest priority to ensuring business continuity and preventing loss of data through features such as security, backup, downtime prevention, and tools for continuous PACS performance monitoring. PACS administrators' next high priorities were support for multispecialty images, image retrieval speeds from short-term and long-term storage, real-time monitoring, and architectural issues of compatibility and integration with other products. Thus, next to ensuring business continuity, administrators' focus was on issues that impact their ability to deliver services and support. On the other hand, radiologists gave high priorities to voice recognition, transcription, and reporting; structured reporting; and convenience and responsiveness in manipulation of images. Thus, radiologists' focus appears to be on issues that may impact their productivity, effort, and accuracy.

Clustering of Farsi sub-word images for whole-book recognition

NASA Astrophysics Data System (ADS)

Soheili, Mohammad Reza; Kabir, Ehsanollah; Stricker, Didier

2015-01-01

Redundancy of word and sub-word occurrences in large documents can be effectively utilized in an OCR system to improve recognition results. Most OCR systems employ language modeling techniques as a post-processing step; however these techniques do not use important pictorial information that exist in the text image. In case of large-scale recognition of degraded documents, this information is even more valuable. In our previous work, we proposed a subword image clustering method for the applications dealing with large printed documents. In our clustering method, the ideal case is when all equivalent sub-word images lie in one cluster. To overcome the issues of low print quality, the clustering method uses an image matching algorithm for measuring the distance between two sub-word images. The measured distance with a set of simple shape features were used to cluster all sub-word images. In this paper, we analyze the effects of adding more shape features on processing time, purity of clustering, and the final recognition rate. Previously published experiments have shown the efficiency of our method on a book. Here we present extended experimental results and evaluate our method on another book with totally different font face. Also we show that the number of the new created clusters in a page can be used as a criteria for assessing the quality of print and evaluating preprocessing phases.

Optimisation of the digital radiographic imaging of suspected non-accidental injury

NASA Astrophysics Data System (ADS)

Offiah, Amaka

Aim: To optimise the digital (radiographic) imaging of children presenting with suspected non-accidental injury (NAI). Objectives: (i) To evaluate existing radiographic quality criteria, and to develop a more suitable system if these are found to be inapplicable to skeletal surveys obtained in suspected NAI. (ii) To document differences in image quality between conventional film-screen and the recently installed Fuji5000R computed radiography (CR) system at Great Ormond Street Hospital for Children, (iii) To document the extent of variability in the standard of skeletal surveys obtained in the UK for suspected NAI. (iv) To determine those radiographic parameters which yield the highest diagnostic accuracy, while still maintaining acceptable radiation dose to the child, (v) To determine how varying degrees of edge-enhancement affect diagnostic accuracy. (vi) To establish the accuracy of soft compared to hard copy interpretation of images in suspected NAI. Materials and Methods: (i) and (ii) Retrospective analysis of 286 paediatric lateral spine radiographs by two observers based on the Commission of European Communities (CEC) quality criteria, (iii) Review of the skeletal surveys of 50 consecutive infants referred from hospitals throughout the United Kingdom (UK) with suspected NAI. (iv) Phantom studies. Leeds TO. 10 and TO. 16 test objects were used to compare the relationship between film density, exposure parameters and visualisation of object details, (iv) Clinical study. Anteroposterior and lateral post mortem skull radiographs of six consecutive infants were obtained at various exposures. Six observers independently scored the images based on visualisation of five criteria, (v) and (vi) A study of diagnostic accuracy in which six observers independently interpreted 50 radiographs from printed copies (with varying degrees of edge-enhancement) and from a monitor. Results: The CEC criteria are useful for optimisation of imaging parameters and allow the detection of differences in quality of film-screen and digital images. There is much variability in the quality and number of radiographs performed as part of skeletal surveys in the UK for suspected NAI. The Leeds test objects are either not sensitive enough (TO. 10) or perhaps over sensitive (TO. 16) for the purposes of this project. Furthermore, the minimum spatial resolution required for digital imaging in NAI has not been established. Therefore the objective interpretation of phantom studies is difficult. There is scope for reduction of radiation dose to children with no effect on image quality. Diagnostic accuracy (fracture detection) in suspected NAI is generally low, and is not affected by image display modality. Conclusions: The CEC quality criteria are not applicable to the assessment of clinical image quality. A national protocol for skeletal surveys in NAI is required. Dedicated training, close supervision, collaboration and consistent exposure of radiologists to cases of NAI should improve diagnostic accuracy. The potential exists for dose reduction when performing skeletal surveys in children and infants with suspected NAI. Future studies should address this issue.

Technical issues for the eye image database creation at distance

NASA Astrophysics Data System (ADS)

Oropesa Morales, Lester Arturo; Maldonado Cano, Luis Alejandro; Soto Aldaco, Andrea; García Vázquez, Mireya Saraí; Zamudio Fuentes, Luis Miguel; Rodríguez Vázquez, Manuel Antonio; Pérez Rosas, Osvaldo Gerardo; Rodríguez Espejo, Luis; Montoya Obeso, Abraham; Ramírez Acosta, Alejandro Álvaro

2016-09-01

Biometrics refers to identify people through their physical characteristics or behavior such as fingerprints, face, DNA, hand geometries, retina and iris patterns. Typically, the iris pattern is to acquire in short distance to recognize a person, however, in the past few years is a challenge identify a person by its iris pattern at certain distance in non-cooperative environments. This challenge comprises: 1) high quality iris image, 2) light variation, 3) blur reduction, 4) specular reflections reduction, 5) the distance from the acquisition system to the user, and 6) standardize the iris size and the density pixel of iris texture. The solution of the challenge will add robustness and enhance the iris recognition rates. For this reason, we describe the technical issues that must be considered during iris acquisition. Some of these considerations are the camera sensor, lens, the math analysis of depth of field (DOF) and field of view (FOV) for iris recognition. Finally, based on this issues we present experiment that show the result of captures obtained with our camera at distance and captures obtained with cameras in very short distance.

Fast and low-dose computed laminography using compressive sensing based technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbas, Sajid, E-mail: scho@kaist.ac.kr; Park, Miran, E-mail: scho@kaist.ac.kr; Cho, Seungryong, E-mail: scho@kaist.ac.kr

2015-03-31

Computed laminography (CL) is well known for inspecting microstructures in the materials, weldments and soldering defects in high density packed components or multilayer printed circuit boards. The overload problem on x-ray tube and gross failure of the radio-sensitive electronics devices during a scan are among important issues in CL which needs to be addressed. The sparse-view CL can be one of the viable option to overcome such issues. In this work a numerical aluminum welding phantom was simulated to collect sparsely sampled projection data at only 40 views using a conventional CL scanning scheme i.e. oblique scan. A compressive-sensing inspiredmore » total-variation (TV) minimization algorithm was utilized to reconstruct the images. It is found that the images reconstructed using sparse view data are visually comparable with the images reconstructed using full scan data set i.e. at 360 views on regular interval. We have quantitatively confirmed that tiny structures such as copper and tungsten slags, and copper flakes in the reconstructed images from sparsely sampled data are comparable with the corresponding structure present in the fully sampled data case. A blurring effect can be seen near the edges of few pores at the bottom of the reconstructed images from sparsely sampled data, despite the overall image quality is reasonable for fast and low-dose NDT.« less

Blood vessel segmentation algorithms - Review of methods, datasets and evaluation metrics.

PubMed

Moccia, Sara; De Momi, Elena; El Hadji, Sara; Mattos, Leonardo S

2018-05-01

Blood vessel segmentation is a topic of high interest in medical image analysis since the analysis of vessels is crucial for diagnosis, treatment planning and execution, and evaluation of clinical outcomes in different fields, including laryngology, neurosurgery and ophthalmology. Automatic or semi-automatic vessel segmentation can support clinicians in performing these tasks. Different medical imaging techniques are currently used in clinical practice and an appropriate choice of the segmentation algorithm is mandatory to deal with the adopted imaging technique characteristics (e.g. resolution, noise and vessel contrast). This paper aims at reviewing the most recent and innovative blood vessel segmentation algorithms. Among the algorithms and approaches considered, we deeply investigated the most novel blood vessel segmentation including machine learning, deformable model, and tracking-based approaches. This paper analyzes more than 100 articles focused on blood vessel segmentation methods. For each analyzed approach, summary tables are presented reporting imaging technique used, anatomical region and performance measures employed. Benefits and disadvantages of each method are highlighted. Despite the constant progress and efforts addressed in the field, several issues still need to be overcome. A relevant limitation consists in the segmentation of pathological vessels. Unfortunately, not consistent research effort has been addressed to this issue yet. Research is needed since some of the main assumptions made for healthy vessels (such as linearity and circular cross-section) do not hold in pathological tissues, which on the other hand require new vessel model formulations. Moreover, image intensity drops, noise and low contrast still represent an important obstacle for the achievement of a high-quality enhancement. This is particularly true for optical imaging, where the image quality is usually lower in terms of noise and contrast with respect to magnetic resonance and computer tomography angiography. No single segmentation approach is suitable for all the different anatomical region or imaging modalities, thus the primary goal of this review was to provide an up to date source of information about the state of the art of the vessel segmentation algorithms so that the most suitable methods can be chosen according to the specific task. Copyright © 2018 Elsevier B.V. All rights reserved.

Optimal experimental designs for fMRI when the model matrix is uncertain.

PubMed

Kao, Ming-Hung; Zhou, Lin

2017-07-15

This study concerns optimal designs for functional magnetic resonance imaging (fMRI) experiments when the model matrix of the statistical model depends on both the selected stimulus sequence (fMRI design), and the subject's uncertain feedback (e.g. answer) to each mental stimulus (e.g. question) presented to her/him. While practically important, this design issue is challenging. This mainly is because that the information matrix cannot be fully determined at the design stage, making it difficult to evaluate the quality of the selected designs. To tackle this challenging issue, we propose an easy-to-use optimality criterion for evaluating the quality of designs, and an efficient approach for obtaining designs optimizing this criterion. Compared with a previously proposed method, our approach requires a much less computing time to achieve designs with high statistical efficiencies. Copyright © 2017 Elsevier Inc. All rights reserved.

Virtual microscopy and digital cytology: state of the art.

PubMed

Giansanti, Daniele; Grigioni, Mauro; D'Avenio, Giuseppe; Morelli, Sandra; Maccioni, Giovanni; Bondi, Arrigo; Giovagnoli, Maria Rosaria

2010-01-01

The paper approaches a new technological scenario relevant for the introduction of the digital cytology (D-CYT) in the health service. A detailed analysis of the state of the art on the status of the introduction of D-CYT in the hospital and more in general in the dispersed territory has been conducted. The analysis was conducted in a form of review and was arranged into two parts: the first part focused on the technological tools needed to carry out a successful service (client server architectures, e-learning, quality assurance issues); the second part focused on issues oriented to help the introduction and evaluation of the technology (specific training in D-CYT, health technology assessment in-routine application, data format standards and picture archiving computerized systems (PACS) implementation, image quality assessment, strategies of navigation, 3D-virtual-reality potentialities). The work enlightens future scenarios of actions relevant for the introduction of the technology.

Functional magnetic resonance imaging of awake monkeys: some approaches for improving imaging quality

PubMed Central

Chen, Gang; Wang, Feng; Dillenburger, Barbara C.; Friedman, Robert M.; Chen, Li M.; Gore, John C.; Avison, Malcolm J.; Roe, Anna W.

2011-01-01

Functional magnetic resonance imaging (fMRI), at high magnetic field strength can suffer from serious degradation of image quality because of motion and physiological noise, as well as spatial distortions and signal losses due to susceptibility effects. Overcoming such limitations is essential for sensitive detection and reliable interpretation of fMRI data. These issues are particularly problematic in studies of awake animals. As part of our initial efforts to study functional brain activations in awake, behaving monkeys using fMRI at 4.7T, we have developed acquisition and analysis procedures to improve image quality with encouraging results. We evaluated the influence of two main variables on image quality. First, we show how important the level of behavioral training is for obtaining good data stability and high temporal signal-to-noise ratios. In initial sessions, our typical scan session lasted 1.5 hours, partitioned into short (<10 minutes) runs. During reward periods and breaks between runs, the monkey exhibited movements resulting in considerable image misregistrations. After a few months of extensive behavioral training, we were able to increase the length of individual runs and the total length of each session. The monkey learned to wait until the end of a block for fluid reward, resulting in longer periods of continuous acquisition. Each additional 60 training sessions extended the duration of each session by 60 minutes, culminating, after about 140 training sessions, in sessions that last about four hours. As a result, the average translational movement decreased from over 500 μm to less than 80 μm, a displacement close to that observed in anesthetized monkeys scanned in a 7 T horizontal scanner. Another major source of distortion at high fields arises from susceptibility variations. To reduce such artifacts, we used segmented gradient-echo echo-planar imaging (EPI) sequences. Increasing the number of segments significantly decreased susceptibility artifacts and image distortion. Comparisons of images from functional runs using four segments with those using a single-shot EPI sequence revealed a roughly two-fold improvement in functional signal-to-noise-ratio and 50% decrease in distortion. These methods enabled reliable detection of neural activation and permitted blood-oxygenation-level-dependent (BOLD) based mapping of early visual areas in monkeys using a volume coil. In summary, both extensive behavioral training of monkeys and application of segmented gradient-echo EPI sequence improved signal-to-noise and image quality. Understanding the effects these factors have is important for the application of high field imaging methods to the detection of sub-millimeter functional structures in the awake monkey brain. PMID:22055855

A new image representation for compact and secure communication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasad, Lakshman; Skourikhine, A. N.

In many areas of nuclear materials management there is a need for communication, archival, and retrieval of annotated image data between heterogeneous platforms and devices to effectively implement safety, security, and safeguards of nuclear materials. Current image formats such as JPEG are not ideally suited in such scenarios as they are not scalable to different viewing formats, and do not provide a high-level representation of images that facilitate automatic object/change detection or annotation. The new Scalable Vector Graphics (SVG) open standard for representing graphical information, recommended by the World Wide Web Consortium (W3C) is designed to address issues of imagemore » scalability, portability, and annotation. However, until now there has been no viable technology to efficiently field images of high visual quality under this standard. Recently, LANL has developed a vectorized image representation that is compatible with the SVG standard and preserves visual quality. This is based on a new geometric framework for characterizing complex features in real-world imagery that incorporates perceptual principles of processing visual information known from cognitive psychology and vision science, to obtain a polygonal image representation of high fidelity. This representation can take advantage of all textual compression and encryption routines unavailable to other image formats. Moreover, this vectorized image representation can be exploited to facilitate automated object recognition that can reduce time required for data review. The objects/features of interest in these vectorized images can be annotated via animated graphics to facilitate quick and easy display and comprehension of processed image content.« less

International Perspectives on Quality Assurance and New Techniques in Radiation Medicine: Outcomes of an IAEA Conference

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shortt, Ken; Davidsson, Lena; Hendry, Jolyon

2008-05-01

The International Atomic Energy Agency organized an international conference called, 'Quality Assurance and New Techniques in Radiation Medicine' (QANTRM). It dealt with quality assurance (QA) in all aspects of radiation medicine (diagnostic radiology, nuclear medicine, and radiotherapy) at the international level. Participants discussed QA issues pertaining to the implementation of new technologies and the need for education and staff training. The advantage of developing a comprehensive and harmonized approach to QA covering both the technical and the managerial issues was emphasized to ensure the optimization of benefits to patient safety and effectiveness. The necessary coupling between medical radiation imaging andmore » radiotherapy was stressed, particularly for advanced technologies. However, the need for a more systematic approach to the adoption of advanced technologies was underscored by a report on failures in intensity-modulated radiotherapy dosimetry auditing tests in the United States, which could imply inadequate implementation of QA for these new technologies. A plenary session addressed the socioeconomic impact of introducing advanced technologies in resource-limited settings. How shall the dual gaps, one in access to basic medical services and the other in access to high-quality modern technology, be addressed?.« less

International perspectives on quality assurance and new techniques in radiation medicine: outcomes of an IAEA conference.

PubMed

Shortt, Ken; Davidsson, Lena; Hendry, Jolyon; Dondi, Maurizio; Andreo, Pedro

2008-01-01

The International Atomic Energy Agency organized an international conference called, "Quality Assurance and New Techniques in Radiation Medicine" (QANTRM). It dealt with quality assurance (QA) in all aspects of radiation medicine (diagnostic radiology, nuclear medicine, and radiotherapy) at the international level. Participants discussed QA issues pertaining to the implementation of new technologies and the need for education and staff training. The advantage of developing a comprehensive and harmonized approach to QA covering both the technical and the managerial issues was emphasized to ensure the optimization of benefits to patient safety and effectiveness. The necessary coupling between medical radiation imaging and radiotherapy was stressed, particularly for advanced technologies. However, the need for a more systematic approach to the adoption of advanced technologies was underscored by a report on failures in intensity-modulated radiotherapy dosimetry auditing tests in the United States, which could imply inadequate implementation of QA for these new technologies. A plenary session addressed the socioeconomic impact of introducing advanced technologies in resource-limited settings. How shall the dual gaps, one in access to basic medical services and the other in access to high-quality modern technology, be addressed?

Ultrasound imaging based on nonlinear pressure field properties

NASA Astrophysics Data System (ADS)

Bouakaz, Ayache; Frinking, Peter J. A.; de Jong, Nico

2000-07-01

Ultrasound image quality has experienced a significant improvement over the past years with the utilization of harmonic frequencies. This brings the need to understand the physical processes involved in the propagation of finite amplitude sound beams, and the issues for redesigning and optimizing the phased array transducers. New arrays with higher imaging performances are essential for tissue imaging and contrast imaging as well. This study presents measurements and simulations on a 4.6 MHz square transducer. The numerical scheme used solves the KZK equation in the time domain. Comparison of measured and computed data showed good agreement for low and high excitation levels. In a similar way, a numerical simulation was performed on a linear array with five elements. The simulation showed that the second harmonic beam is narrower than the fundamental with less energy in the near field. In addition, the grating lobes are significantly lower. Accordingly, selective harmonic imaging shows less near field artifacts and will lower the clutter, resulting in much cleaner images.

Three-dimensional holoscopic image coding scheme using high-efficiency video coding with kernel-based minimum mean-square-error estimation

NASA Astrophysics Data System (ADS)

Liu, Deyang; An, Ping; Ma, Ran; Yang, Chao; Shen, Liquan; Li, Kai

2016-07-01

Three-dimensional (3-D) holoscopic imaging, also known as integral imaging, light field imaging, or plenoptic imaging, can provide natural and fatigue-free 3-D visualization. However, a large amount of data is required to represent the 3-D holoscopic content. Therefore, efficient coding schemes for this particular type of image are needed. A 3-D holoscopic image coding scheme with kernel-based minimum mean square error (MMSE) estimation is proposed. In the proposed scheme, the coding block is predicted by an MMSE estimator under statistical modeling. In order to obtain the signal statistical behavior, kernel density estimation (KDE) is utilized to estimate the probability density function of the statistical modeling. As bandwidth estimation (BE) is a key issue in the KDE problem, we also propose a BE method based on kernel trick. The experimental results demonstrate that the proposed scheme can achieve a better rate-distortion performance and a better visual rendering quality.

Patient-Centered Imaging: Shared Decision Making for Cardiac Imaging Procedures with Exposure to Ionizing Radiation

PubMed Central

Einstein, Andrew J.; Berman, Daniel S.; Min, James K.; Hendel, Robert C.; Gerber, Thomas C.; Carr, J. Jeffrey; Cerqueira, Manuel D.; Cullom, S. James; DeKemp, Robert; Dickert, Neal; Dorbala, Sharmila; Garcia, Ernest V.; Gibbons, Raymond J.; Halliburton, Sandra S.; Hausleiter, Jörg; Heller, Gary V.; Jerome, Scott; Lesser, John R.; Fazel, Reza; Raff, Gilbert L.; Tilkemeier, Peter; Williams, Kim A.; Shaw, Leslee J.

2014-01-01

Objective To identify key components of a radiation accountability framework fostering patient-centered imaging and shared decision-making in cardiac imaging. Background An NIH-NHLBI/NCI-sponsored symposium was held in November 2012 to address these issues. Methods Symposium participants, working in three tracks, identified key components of a framework to target critical radiation safety issues for the patient, the laboratory, and the larger population of patients with known or suspected cardiovascular disease. Results Use of ionizing radiation during an imaging procedure should be disclosed to all patients by the ordering provider at the time of ordering, and reinforced by the performing provider team. An imaging protocol with effective dose ≤3mSv is considered very low risk, not warranting extensive discussion or written consent. However, a protocol effective dose <20mSv was proposed as a level requiring particular attention in terms of shared decision-making and either formal discussion or written informed consent. Laboratory reporting of radiation dosimetry is a critical component of creating a quality laboratory fostering a patient-centered environment with transparent procedural methodology. Efforts should be directed to avoiding testing involving radiation, in patients with inappropriate indications. Standardized reporting and diagnostic reference levels for computed tomography and nuclear cardiology are important for the goal of public reporting of laboratory radiation dose levels in conjunction with diagnostic performance. Conclusions The development of cardiac imaging technologies revolutionized cardiology practice by allowing routine, noninvasive assessment of myocardial perfusion and anatomy. It is now incumbent upon the imaging community to create an accountability framework to safely drive appropriate imaging utilization. PMID:24530677

Symposium on Machine Processing of Remotely Sensed Data, Purdue University, West Lafayette, Ind., June 29-July 1, 1976, Proceedings

NASA Technical Reports Server (NTRS)

1976-01-01

Papers are presented on the applicability of Landsat data to water management and control needs, IBIS, a geographic information system based on digital image processing and image raster datatype, and the Image Data Access Method (IDAM) for the Earth Resources Interactive Processing System. Attention is also given to the Prototype Classification and Mensuration System (PROCAMS) applied to agricultural data, the use of Landsat for water quality monitoring in North Carolina, and the analysis of geophysical remote sensing data using multivariate pattern recognition. The Illinois crop-acreage estimation experiment, the Pacific Northwest Resources Inventory Demonstration, and the effects of spatial misregistration on multispectral recognition are also considered. Individual items are announced in this issue.

Common-mask guided image reconstruction (c-MGIR) for enhanced 4D cone-beam computed tomography

NASA Astrophysics Data System (ADS)

Park, Justin C.; Zhang, Hao; Chen, Yunmei; Fan, Qiyong; Li, Jonathan G.; Liu, Chihray; Lu, Bo

2015-12-01

Compared to 3D cone beam computed tomography (3D CBCT), the image quality of commercially available four-dimensional (4D) CBCT is severely impaired due to the insufficient amount of projection data available for each phase. Since the traditional Feldkamp-Davis-Kress (FDK)-based algorithm is infeasible for reconstructing high quality 4D CBCT images with limited projections, investigators had developed several compress-sensing (CS) based algorithms to improve image quality. The aim of this study is to develop a novel algorithm which can provide better image quality than the FDK and other CS based algorithms with limited projections. We named this algorithm ‘the common mask guided image reconstruction’ (c-MGIR). In c-MGIR, the unknown CBCT volume is mathematically modeled as a combination of phase-specific motion vectors and phase-independent static vectors. The common-mask matrix, which is the key concept behind the c-MGIR algorithm, separates the common static part across all phase images from the possible moving part in each phase image. The moving part and the static part of the volumes were then alternatively updated by solving two sub-minimization problems iteratively. As the novel mathematical transformation allows the static volume and moving volumes to be updated (during each iteration) with global projections and ‘well’ solved static volume respectively, the algorithm was able to reduce the noise and under-sampling artifact (an issue faced by other algorithms) to the maximum extent. To evaluate the performance of our proposed c-MGIR, we utilized imaging data from both numerical phantoms and a lung cancer patient. The qualities of the images reconstructed with c-MGIR were compared with (1) standard FDK algorithm, (2) conventional total variation (CTV) based algorithm, (3) prior image constrained compressed sensing (PICCS) algorithm, and (4) motion-map constrained image reconstruction (MCIR) algorithm, respectively. To improve the efficiency of the algorithm, the code was implemented with a graphic processing unit for parallel processing purposes. Root mean square error (RMSE) between the ground truth and reconstructed volumes of the numerical phantom were in the descending order of FDK, CTV, PICCS, MCIR, and c-MGIR for all phases. Specifically, the means and the standard deviations of the RMSE of FDK, CTV, PICCS, MCIR and c-MGIR for all phases were 42.64  ±  6.5%, 3.63  ±  0.83%, 1.31%  ±  0.09%, 0.86%  ±  0.11% and 0.52 %  ±  0.02%, respectively. The image quality of the patient case also indicated the superiority of c-MGIR compared to other algorithms. The results indicated that clinically viable 4D CBCT images can be reconstructed while requiring no more projection data than a typical clinical 3D CBCT scan. This makes c-MGIR a potential online reconstruction algorithm for 4D CBCT, which can provide much better image quality than other available algorithms, while requiring less dose and potentially less scanning time.

Common-mask guided image reconstruction (c-MGIR) for enhanced 4D cone-beam computed tomography.

PubMed

Park, Justin C; Zhang, Hao; Chen, Yunmei; Fan, Qiyong; Li, Jonathan G; Liu, Chihray; Lu, Bo

2015-12-07

Compared to 3D cone beam computed tomography (3D CBCT), the image quality of commercially available four-dimensional (4D) CBCT is severely impaired due to the insufficient amount of projection data available for each phase. Since the traditional Feldkamp-Davis-Kress (FDK)-based algorithm is infeasible for reconstructing high quality 4D CBCT images with limited projections, investigators had developed several compress-sensing (CS) based algorithms to improve image quality. The aim of this study is to develop a novel algorithm which can provide better image quality than the FDK and other CS based algorithms with limited projections. We named this algorithm 'the common mask guided image reconstruction' (c-MGIR).In c-MGIR, the unknown CBCT volume is mathematically modeled as a combination of phase-specific motion vectors and phase-independent static vectors. The common-mask matrix, which is the key concept behind the c-MGIR algorithm, separates the common static part across all phase images from the possible moving part in each phase image. The moving part and the static part of the volumes were then alternatively updated by solving two sub-minimization problems iteratively. As the novel mathematical transformation allows the static volume and moving volumes to be updated (during each iteration) with global projections and 'well' solved static volume respectively, the algorithm was able to reduce the noise and under-sampling artifact (an issue faced by other algorithms) to the maximum extent. To evaluate the performance of our proposed c-MGIR, we utilized imaging data from both numerical phantoms and a lung cancer patient. The qualities of the images reconstructed with c-MGIR were compared with (1) standard FDK algorithm, (2) conventional total variation (CTV) based algorithm, (3) prior image constrained compressed sensing (PICCS) algorithm, and (4) motion-map constrained image reconstruction (MCIR) algorithm, respectively. To improve the efficiency of the algorithm, the code was implemented with a graphic processing unit for parallel processing purposes.Root mean square error (RMSE) between the ground truth and reconstructed volumes of the numerical phantom were in the descending order of FDK, CTV, PICCS, MCIR, and c-MGIR for all phases. Specifically, the means and the standard deviations of the RMSE of FDK, CTV, PICCS, MCIR and c-MGIR for all phases were 42.64  ±  6.5%, 3.63  ±  0.83%, 1.31%  ±  0.09%, 0.86%  ±  0.11% and 0.52 %  ±  0.02%, respectively. The image quality of the patient case also indicated the superiority of c-MGIR compared to other algorithms.The results indicated that clinically viable 4D CBCT images can be reconstructed while requiring no more projection data than a typical clinical 3D CBCT scan. This makes c-MGIR a potential online reconstruction algorithm for 4D CBCT, which can provide much better image quality than other available algorithms, while requiring less dose and potentially less scanning time.

Signal uniformity of mammography systems and its impact on test results from contrast detail phantoms

NASA Astrophysics Data System (ADS)

Kaar, M.; Semturs, F.; Hummel, J.; Hoffmann, R.; Figl, M.

2015-03-01

Technical quality assurance (TQA) procedures for mammography systems usually include tests with a contrast-detail phantom. These phantoms contain multiple objects of varying dimensions arranged on a flat body. Exposures of the phantom are then evaluated by an observer, either human or software. One well-known issue of this method is that dose distribution is not uniform across the image area of any mammography system, mainly due to the heel effect. The purpose of this work is to investigate to what extent image quality differs across the detector plane. We analyze a total of 320 homogeneous mammography exposures from 32 radiology institutes. Systems of different models and manufacturers, both computed radiography (CR) and direct radiography (DR) are included. All images were taken from field installations operated within the nationwide Austrian mammography screening program, which includes mandatory continuous TQA. We calculate signal-to-noise ratios (SNR) for 15 regions of interest arranged to cover the area of the phantom. We define the 'signal range' of an image and compare this value categorized by technologies. We found the deviations of SNR greater in anterior-posterior than in lateral direction. SNR ranges are significantly higher for CR systems than for DR systems.

[Marketing orientation in rehabilitation--exemplified by image analysis of a rehabilitation clinic for addictions].

PubMed

Altenhöner, T; Schönhoff, T; Wehmeier, D

2001-06-01

This article presents the findings of an image analysis carried out for a rehabilitation clinic for addictive diseases. The cross-sectional study was designed as an anonymous survey sent to relevant (regional) referral agencies (n = 90), e.g. counselling services for addictive diseases. The study covers the clinic's actual and ideal image, discriminating frequency of referrals, diagnostic categories, region, and type of institution. Results concerning the real profile indicate that on average the dimensions cooperation, communication with regard to personal contact, and reputation of the clinic were more critically judged than the issues information, communication with regard to discharge reports, standards of quality, and consideration of patients' needs. Cooperation, communication with regard to personal contact, and quality standards turned out to be the most important criteria from the referring agencies' perspective (ideal profile). A statistical comparison between those with high and low assignment rates suggested that customers rated the clinic more favourably than non-customers. Thus, it seems that the clinic's image has considerable influence on referral decisions. Particularly interesting is the additional finding that the referring institutions perceive pension insurers' directives to be of secondary relevance.

Methods for the analysis of ordinal response data in medical image quality assessment.

PubMed

Keeble, Claire; Baxter, Paul D; Gislason-Lee, Amber J; Treadgold, Laura A; Davies, Andrew G

2016-07-01

The assessment of image quality in medical imaging often requires observers to rate images for some metric or detectability task. These subjective results are used in optimization, radiation dose reduction or system comparison studies and may be compared to objective measures from a computer vision algorithm performing the same task. One popular scoring approach is to use a Likert scale, then assign consecutive numbers to the categories. The mean of these response values is then taken and used for comparison with the objective or second subjective response. Agreement is often assessed using correlation coefficients. We highlight a number of weaknesses in this common approach, including inappropriate analyses of ordinal data and the inability to properly account for correlations caused by repeated images or observers. We suggest alternative data collection and analysis techniques such as amendments to the scale and multilevel proportional odds models. We detail the suitability of each approach depending upon the data structure and demonstrate each method using a medical imaging example. Whilst others have raised some of these issues, we evaluated the entire study from data collection to analysis, suggested sources for software and further reading, and provided a checklist plus flowchart for use with any ordinal data. We hope that raised awareness of the limitations of the current approaches will encourage greater method consideration and the utilization of a more appropriate analysis. More accurate comparisons between measures in medical imaging will lead to a more robust contribution to the imaging literature and ultimately improved patient care.

A medical application integrating remote 3D visualization tools to access picture archiving and communication system on mobile devices.

PubMed

He, Longjun; Ming, Xing; Liu, Qian

2014-04-01

With computing capability and display size growing, the mobile device has been used as a tool to help clinicians view patient information and medical images anywhere and anytime. However, for direct interactive 3D visualization, which plays an important role in radiological diagnosis, the mobile device cannot provide a satisfactory quality of experience for radiologists. This paper developed a medical system that can get medical images from the picture archiving and communication system on the mobile device over the wireless network. In the proposed application, the mobile device got patient information and medical images through a proxy server connecting to the PACS server. Meanwhile, the proxy server integrated a range of 3D visualization techniques, including maximum intensity projection, multi-planar reconstruction and direct volume rendering, to providing shape, brightness, depth and location information generated from the original sectional images for radiologists. Furthermore, an algorithm that changes remote render parameters automatically to adapt to the network status was employed to improve the quality of experience. Finally, performance issues regarding the remote 3D visualization of the medical images over the wireless network of the proposed application were also discussed. The results demonstrated that this proposed medical application could provide a smooth interactive experience in the WLAN and 3G networks.

Efficient correction of wavefront inhomogeneities in X-ray holographic nanotomography by random sample displacement

NASA Astrophysics Data System (ADS)

Hubert, Maxime; Pacureanu, Alexandra; Guilloud, Cyril; Yang, Yang; da Silva, Julio C.; Laurencin, Jerome; Lefebvre-Joud, Florence; Cloetens, Peter

2018-05-01

In X-ray tomography, ring-shaped artifacts present in the reconstructed slices are an inherent problem degrading the global image quality and hindering the extraction of quantitative information. To overcome this issue, we propose a strategy for suppression of ring artifacts originating from the coherent mixing of the incident wave and the object. We discuss the limits of validity of the empty beam correction in the framework of a simple formalism. We then deduce a correction method based on two-dimensional random sample displacement, with minimal cost in terms of spatial resolution, acquisition, and processing time. The method is demonstrated on bone tissue and on a hydrogen electrode of a ceramic-metallic solid oxide cell. Compared to the standard empty beam correction, we obtain high quality nanotomography images revealing detailed object features. The resulting absence of artifacts allows straightforward segmentation and posterior quantification of the data.

The Stability of Chandra Telescope Pointing and Spacial Resolution

NASA Astrophysics Data System (ADS)

Zhao, Ping

2018-01-01

Chandra X-ray Observatory revolutionized the X-ray astronomy as being the first, and so far the only, X-ray telescope achieving sub-arcsecond spacial resolution. Chandra is comprised of three principal elements: the High Resolution Mirror Assembly (HRMA), Pointing Control and Aspect Determination (PCAD) system, and the Science Instrument Module (SIM), which is where the X-ray detectors mounted and is connected to the HRMA by a 10-meter long Optical Bench Assembly. To achieve and retain the unprecedented imaging quality, it is critical that these three principal elements to stay rigid and stable for the entire life time of the Chandra operation. I will review the issues of telescope pointing stability, optical Axis, aimpoint and their impacts to the Chandra operation, and evaluate the integrity and stability of the telescope. I will show images taken from all four detectors since launch to demonstrate the quality and stability of the Chandra spacial resolution.

Wireless Robotic Communications in Urban Environments: Issues for the Fire Service

DTIC Science & Technology

2008-03-01

affect signal propagation? Do some frequencies perform better than others in specific settings? • Radio Environment: How much impact might...of responders at each scenario, the radio frequency environment for each will be examined. Link budget calculations will be performed to assess...soldiers indicated that the main technical drawbacks were the narrow field of view, poor image quality, and limited radio range. The authors concluded

Multiple Aperture Radiation Therapy (MART) for Breast Cancer

DTIC Science & Technology

2006-11-01

ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Tianfang Li, Ph.D. 5e. TASK NUMBER Email: tfli@reyes.stanford.edu 5f. WORK UNIT...Radiation Therapy, XIVth International Conference on the Use of Computers in Radiation Therapy (ICCR), Soul , Korea, 2004. CONCLUSIONS Compared with...reconstruction artifacts due to in- sufficient angular sampling and dramatically degrades the image quality.24 Crucial issues in developing 4D CBCT are indeed how

Foreword to the theme issue on geospatial computer vision

NASA Astrophysics Data System (ADS)

Wegner, Jan Dirk; Tuia, Devis; Yang, Michael; Mallet, Clement

2018-06-01

Geospatial Computer Vision has become one of the most prevalent emerging fields of investigation in Earth Observation in the last few years. In this theme issue, we aim at showcasing a number of works at the interface between remote sensing, photogrammetry, image processing, computer vision and machine learning. In light of recent sensor developments - both from the ground as from above - an unprecedented (and ever growing) quantity of geospatial data is available for tackling challenging and urgent tasks such as environmental monitoring (deforestation, carbon sequestration, climate change mitigation), disaster management, autonomous driving or the monitoring of conflicts. The new bottleneck for serving these applications is the extraction of relevant information from such large amounts of multimodal data. This includes sources, stemming from multiple sensors, that exhibit distinct physical nature of heterogeneous quality, spatial, spectral and temporal resolutions. They are as diverse as multi-/hyperspectral satellite sensors, color cameras on drones, laser scanning devices, existing open land-cover geodatabases and social media. Such core data processing is mandatory so as to generate semantic land-cover maps, accurate detection and trajectories of objects of interest, as well as by-products of superior added-value: georeferenced data, images with enhanced geometric and radiometric qualities, or Digital Surface and Elevation Models.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naseri, M; Rajabi, H; Wang, J

Purpose: Respiration causes lesion smearing, image blurring and quality degradation, affecting lesion contrast and the ability to define correct lesion size. The spatial resolution of current multi pinhole SPECT (MPHS) scanners is sub-millimeter. Therefore, the effect of motion is more noticeable in comparison to conventional SPECT scanner. Gated imaging aims to reduce motion artifacts. A major issue in gating is the lack of statistics and individual reconstructed frames are noisy. The increased noise in each frame, deteriorates the quantitative accuracy of the MPHS Images. The objective of this work, is to enhance the image quality in 4D-MPHS imaging, by 4Dmore » image reconstruction. Methods: The new algorithm requires deformation vector fields (DVFs) that are calculated by non-rigid Demons registration. The algorithm is based on the motion-incorporated version of ordered subset expectation maximization (OSEM) algorithm. This iterative algorithm is capable to make full use of all projections to reconstruct each individual frame. To evaluate the performance of the proposed algorithm a simulation study was conducted. A fast ray tracing method was used to generate MPHS projections of a 4D digital mouse phantom with a small tumor in liver in eight different respiratory phases. To evaluate the 4D-OSEM algorithm potential, tumor to liver activity ratio was compared with other image reconstruction methods including 3D-MPHS and post reconstruction registered with Demons-derived DVFs. Results: Image quality of 4D-MPHS is greatly improved by the 4D-OSEM algorithm. When all projections are used to reconstruct a 3D-MPHS, motion blurring artifacts are present, leading to overestimation of the tumor size and 24% tumor contrast underestimation. This error reduced to 16% and 10% for post reconstruction registration methods and 4D-OSEM respectively. Conclusion: 4D-OSEM method can be used for motion correction in 4D-MPHS. The statistics and quantification are improved since all projection data are combined together to update the image.« less

Lighting issues in the 1980's. Summary and proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubin, A. I.

1980-01-01

The Lighting Roundtable described in this report was conducted to foster an open discussion of the goals, issues, and responsibilities of the lighting community. It was not a problem-solving session, but rather a time to examine the long-term aspirations and objectives of lighting and the barriers that may stand in the way of achieving them. Eight major issues were addressed by nine panelists and a number of invited auditors. The issues are as follows: (1) The Public Image of the Lighting Community; (2) US Role in the Worldwide Lighting Community; (3) Factors Affecting Human Activities in the Built Environment; (4)more » Effect of Lighting on Environmental Quality; (5) Effects of Barriers; (6) Establishment of Illuminance Levels; (7) Integration of Subsystems; and (8) Professional Development and Lighting Education. Two parts presented are: (1) a summary of the proceedings; and (2) a complete transcript.« less

A review on the current issues and barriers of Industrialised Building System (IBS) adoption in Malaysia’s construction industry

NASA Astrophysics Data System (ADS)

Amin, M. A. Mohd; Abas, N. H.; Shahidan, S.; Rahmat, M. H.; Suhaini, N. A.; Nagapan, S.; Rahim, R. Abdul

2017-11-01

Malaysia considers the construction industry as one of the main contributors to its Gross Domestic Product (GDP). However, there are some unresolved issues arising from the ongoing and widespread adoption of the conventional method of construction such as the resultant fragmentation of the industry itself; delays in production and delivery time of unnecessary wastages and lack of sustainability practice. Malaysian Government has been continuously encouraging the industry to use, partly or if not wholly, the Industrialized Building System (IBS), which is considered to be an important part of sustainable construction initiative. IBS was introduced to Malaysia as the solution to issues related to dependencies of foreign workers, raising demand for affordable accommodations and improving image, quality and productivity of construction industry. However, the IBS adoption in Malaysia remains low. This paper presents the review of the current issues and barriers of IBS adoption in Malaysian construction industry.

Authenticity preservation with histogram-based reversible data hiding and quadtree concepts.

PubMed

Huang, Hsiang-Cheh; Fang, Wai-Chi

2011-01-01

With the widespread use of identification systems, establishing authenticity with sensors has become an important research issue. Among the schemes for making authenticity verification based on information security possible, reversible data hiding has attracted much attention during the past few years. With its characteristics of reversibility, the scheme is required to fulfill the goals from two aspects. On the one hand, at the encoder, the secret information needs to be embedded into the original image by some algorithms, such that the output image will resemble the input one as much as possible. On the other hand, at the decoder, both the secret information and the original image must be correctly extracted and recovered, and they should be identical to their embedding counterparts. Under the requirement of reversibility, for evaluating the performance of the data hiding algorithm, the output image quality, named imperceptibility, and the number of bits for embedding, called capacity, are the two key factors to access the effectiveness of the algorithm. Besides, the size of side information for making decoding possible should also be evaluated. Here we consider using the characteristics of original images for developing our method with better performance. In this paper, we propose an algorithm that has the ability to provide more capacity than conventional algorithms, with similar output image quality after embedding, and comparable side information produced. Simulation results demonstrate the applicability and better performance of our algorithm.

Segmentation of pomegranate MR images using spatial fuzzy c-means (SFCM) algorithm

NASA Astrophysics Data System (ADS)

Moradi, Ghobad; Shamsi, Mousa; Sedaaghi, M. H.; Alsharif, M. R.

2011-10-01

Segmentation is one of the fundamental issues of image processing and machine vision. It plays a prominent role in a variety of image processing applications. In this paper, one of the most important applications of image processing in MRI segmentation of pomegranate is explored. Pomegranate is a fruit with pharmacological properties such as being anti-viral and anti-cancer. Having a high quality product in hand would be critical factor in its marketing. The internal quality of the product is comprehensively important in the sorting process. The determination of qualitative features cannot be manually made. Therefore, the segmentation of the internal structures of the fruit needs to be performed as accurately as possible in presence of noise. Fuzzy c-means (FCM) algorithm is noise-sensitive and pixels with noise are classified inversely. As a solution, in this paper, the spatial FCM algorithm in pomegranate MR images' segmentation is proposed. The algorithm is performed with setting the spatial neighborhood information in FCM and modification of fuzzy membership function for each class. The segmentation algorithm results on the original and the corrupted Pomegranate MR images by Gaussian, Salt Pepper and Speckle noises show that the SFCM algorithm operates much more significantly than FCM algorithm. Also, after diverse steps of qualitative and quantitative analysis, we have concluded that the SFCM algorithm with 5×5 window size is better than the other windows.

Gaia: focus, straylight and basic angle

NASA Astrophysics Data System (ADS)

Mora, A.; Biermann, M.; Bombrun, A.; Boyadjian, J.; Chassat, F.; Corberand, P.; Davidson, M.; Doyle, D.; Escolar, D.; Gielesen, W. L. M.; Guilpain, T.; Hernandez, J.; Kirschner, V.; Klioner, S. A.; Koeck, C.; Laine, B.; Lindegren, L.; Serpell, E.; Tatry, P.; Thoral, P.

2016-07-01

The Gaia all-sky astrometric survey is challenged by several issues affecting the spacecraft stability. Amongst them, we find the focus evolution, straylight and basic angle variations Contrary to pre-launch expectations, the image quality is continuously evolving, during commissioning and the nominal mission. Payload decontaminations and wavefront sensor assisted refocuses have been carried out to recover optimum performance. An ESA-Airbus DS working group analysed the straylight and basic angle issues and worked on a detailed root cause analysis. In parallel, the Gaia scientists have also analysed the data, most notably comparing the BAM signal to global astrometric solutions, with remarkable agreement. In this contribution, a status review of these issues will be provided, with emphasis on the mitigation schemes and the lessons learned for future space missions where extreme stability is a key requirement.

Potential application of machine vision technology to saffron (Crocus sativus L.) quality characterization.

PubMed

Kiani, Sajad; Minaei, Saeid

2016-12-01

Saffron quality characterization is an important issue in the food industry and of interest to the consumers. This paper proposes an expert system based on the application of machine vision technology for characterization of saffron and shows how it can be employed in practical usage. There is a correlation between saffron color and its geographic location of production and some chemical attributes which could be properly used for characterization of saffron quality and freshness. This may be accomplished by employing image processing techniques coupled with multivariate data analysis for quantification of saffron properties. Expert algorithms can be made available for prediction of saffron characteristics such as color as well as for product classification. Copyright © 2016. Published by Elsevier Ltd.

How consumers evaluate health care quality: Part II.

PubMed

Moore, S T; Bopp, K D

1999-01-01

This article is the second in a series which examines the way in which consumers assess information regarding the quality of health care services. In the previous article it was demonstrated that, in the view of health care consumers, three major perceptions held by health care consumers, are: (1) substantial differences in quality exist among health care providers, (2) little information is available that allows for the comparison of health care providers on issues related to quality, and (3) when such information is available it is found to be useful and often serves as the basis for decision regarding the choice of health care providers. We further discussed the short coming of marketing strategies based on complex quality indicators and the difficulties of image advertising in an age of institutional mistrust. The reader is reminded that these findings relate to the subjective assessments of consumers, not to objective facts concerning health care delivery.

Technical flaws in multiple-choice questions in the access exam to medical specialties ("examen MIR") in Spain (2009-2013).

PubMed

Rodríguez-Díez, María Cristina; Alegre, Manuel; Díez, Nieves; Arbea, Leire; Ferrer, Marta

2016-02-03

The main factor that determines the selection of a medical specialty in Spain after obtaining a medical degree is the MIR ("médico interno residente", internal medical resident) exam. This exam consists of 235 multiple-choice questions with five options, some of which include images provided in a separate booklet. The aim of this study was to analyze the technical quality of the multiple-choice questions included in the MIR exam over the last five years. All the questions included in the exams from 2009 to 2013 were analyzed. We studied the proportion of questions including clinical vignettes, the number of items related to an image and the presence of technical flaws in the questions. For the analysis of technical flaws, we adapted the National Board of Medical Examiners (NBME) guidelines. We looked for 18 different issues included in the manual, grouped into two categories: issues related to testwiseness and issues related to irrelevant difficulties. The final number of questions analyzed was 1,143. The percentage of items based on clinical vignettes increased from 50% in 2009 to 56-58% in the following years (2010-2013). The percentage of items based on an image increased progressively from 10% in 2009 to 15% in 2012 and 2013. The percentage of items with at least one technical flaw varied between 68 and 72%. We observed a decrease in the percentage of items with flaws related to testwiseness, from 30% in 2009 to 20% in 2012 and 2013. While most of these issues decreased dramatically or even disappeared (such as the imbalance in the correct option numbers), the presence of non-plausible options remained frequent. With regard to technical flaws related to irrelevant difficulties, no improvement was observed; this is especially true with respect to negative stem questions and "hinged" questions. The formal quality of the MIR exam items has improved over the last five years with regard to testwiseness. A more detailed revision of the items submitted, checking systematically for the presence of technical flaws, could improve the validity and discriminatory power of the exam, without increasing its difficulty.

TU-F-CAMPUS-I-05: Semi-Automated, Open Source MRI Quality Assurance and Quality Control Program for Multi-Unit Institution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yung, J; Stefan, W; Reeve, D

2015-06-15

Purpose: Phantom measurements allow for the performance of magnetic resonance (MR) systems to be evaluated. Association of Physicists in Medicine (AAPM) Report No. 100 Acceptance Testing and Quality Assurance Procedures for MR Imaging Facilities, American College of Radiology (ACR) MR Accreditation Program MR phantom testing, and ACR MRI quality control (QC) program documents help to outline specific tests for establishing system performance baselines as well as system stability over time. Analyzing and processing tests from multiple systems can be time-consuming for medical physicists. Besides determining whether tests are within predetermined limits or criteria, monitoring longitudinal trends can also help preventmore » costly downtime of systems during clinical operation. In this work, a semi-automated QC program was developed to analyze and record measurements in a database that allowed for easy access to historical data. Methods: Image analysis was performed on 27 different MR systems of 1.5T and 3.0T field strengths from GE and Siemens manufacturers. Recommended measurements involved the ACR MRI Accreditation Phantom, spherical homogenous phantoms, and a phantom with an uniform hole pattern. Measurements assessed geometric accuracy and linearity, position accuracy, image uniformity, signal, noise, ghosting, transmit gain, center frequency, and magnetic field drift. The program was designed with open source tools, employing Linux, Apache, MySQL database and Python programming language for the front and backend. Results: Processing time for each image is <2 seconds. Figures are produced to show regions of interests (ROIs) for analysis. Historical data can be reviewed to compare previous year data and to inspect for trends. Conclusion: A MRI quality assurance and QC program is necessary for maintaining high quality, ACR MRI Accredited MR programs. A reviewable database of phantom measurements assists medical physicists with processing and monitoring of large datasets. Longitudinal data can reveal trends that although are within passing criteria indicate underlying system issues.« less

Towards better digital pathology workflows: programming libraries for high-speed sharpness assessment of Whole Slide Images.

PubMed

Ameisen, David; Deroulers, Christophe; Perrier, Valérie; Bouhidel, Fatiha; Battistella, Maxime; Legrès, Luc; Janin, Anne; Bertheau, Philippe; Yunès, Jean-Baptiste

2014-01-01

Since microscopic slides can now be automatically digitized and integrated in the clinical workflow, quality assessment of Whole Slide Images (WSI) has become a crucial issue. We present a no-reference quality assessment method that has been thoroughly tested since 2010 and is under implementation in multiple sites, both public university-hospitals and private entities. It is part of the FlexMIm R&D project which aims to improve the global workflow of digital pathology. For these uses, we have developed two programming libraries, in Java and Python, which can be integrated in various types of WSI acquisition systems, viewers and image analysis tools. Development and testing have been carried out on a MacBook Pro i7 and on a bi-Xeon 2.7GHz server. Libraries implementing the blur assessment method have been developed in Java, Python, PHP5 and MySQL5. For web applications, JavaScript, Ajax, JSON and Sockets were also used, as well as the Google Maps API. Aperio SVS files were converted into the Google Maps format using VIPS and Openslide libraries. We designed the Java library as a Service Provider Interface (SPI), extendable by third parties. Analysis is computed in real-time (3 billion pixels per minute). Tests were made on 5000 single images, 200 NDPI WSI, 100 Aperio SVS WSI converted to the Google Maps format. Applications based on our method and libraries can be used upstream, as calibration and quality control tool for the WSI acquisition systems, or as tools to reacquire tiles while the WSI is being scanned. They can also be used downstream to reacquire the complete slides that are below the quality threshold for surgical pathology analysis. WSI may also be displayed in a smarter way by sending and displaying the regions of highest quality before other regions. Such quality assessment scores could be integrated as WSI's metadata shared in clinical, research or teaching contexts, for a more efficient medical informatics workflow.

Automated optical inspection of liquid crystal display anisotropic conductive film bonding

NASA Astrophysics Data System (ADS)

Ni, Guangming; Du, Xiaohui; Liu, Lin; Zhang, Jing; Liu, Juanxiu; Liu, Yong

2016-10-01

Anisotropic conductive film (ACF) bonding is widely used in the liquid crystal display (LCD) industry. It implements circuit connection between screens and flexible printed circuits or integrated circuits. Conductive microspheres in ACF are key factors that influence LCD quality, because the conductive microspheres' quantity and shape deformation rate affect the interconnection resistance. Although this issue has been studied extensively by prior work, quick and accurate methods to inspect the quality of ACF bonding are still missing in the actual production process. We propose a method to inspect ACF bonding effectively by using automated optical inspection. The method has three steps. The first step is that it acquires images of the detection zones using a differential interference contrast (DIC) imaging system. The second step is that it identifies the conductive microspheres and their shape deformation rate using quantitative analysis of the characteristics of the DIC images. The final step is that it inspects ACF bonding using a back propagation trained neural network. The result shows that the miss rate is lower than 0.1%, and the false inspection rate is lower than 0.05%.

Optimization of Close Range Photogrammetry Network Design Applying Fuzzy Computation

NASA Astrophysics Data System (ADS)

Aminia, A. S.

2017-09-01

Measuring object 3D coordinates with optimum accuracy is one of the most important issues in close range photogrammetry. In this context, network design plays an important role in determination of optimum position of imaging stations. This is, however, not a trivial task due to various geometric and radiometric constraints affecting the quality of the measurement network. As a result, most camera stations in the network are defined on a try and error basis based on the user's experience and generic network concept. In this paper, we propose a post-processing task to investigate the quality of camera positions right after image capturing to achieve the best result. To do this, a new fuzzy reasoning approach is adopted, in which the constraints affecting the network design are all modeled. As a result, the position of all camera locations is defined based on fuzzy rules and inappropriate stations are determined. The experiments carried out show that after determination and elimination of the inappropriate images using the proposed fuzzy reasoning system, the accuracy of measurements is improved and enhanced about 17% for the latter network.

Applications and challenges of digital pathology and whole slide imaging.

PubMed

Higgins, C

2015-07-01

Virtual microscopy is a method for digitizing images of tissue on glass slides and using a computer to view, navigate, change magnification, focus and mark areas of interest. Virtual microscope systems (also called digital pathology or whole slide imaging systems) offer several advantages for biological scientists who use slides as part of their general, pharmaceutical, biotechnology or clinical research. The systems usually are based on one of two methodologies: area scanning or line scanning. Virtual microscope systems enable automatic sample detection, virtual-Z acquisition and creation of focal maps. Virtual slides are layered with multiple resolutions at each location, including the highest resolution needed to allow more detailed review of specific regions of interest. Scans may be acquired at 2, 10, 20, 40, 60 and 100 × or a combination of magnifications to highlight important detail. Digital microscopy starts when a slide collection is put into an automated or manual scanning system. The original slides are archived, then a server allows users to review multilayer digital images of the captured slides either by a closed network or by the internet. One challenge for adopting the technology is the lack of a universally accepted file format for virtual slides. Additional challenges include maintaining focus in an uneven sample, detecting specimens accurately, maximizing color fidelity with optimal brightness and contrast, optimizing resolution and keeping the images artifact-free. There are several manufacturers in the field and each has not only its own approach to these issues, but also its own image analysis software, which provides many options for users to enhance the speed, quality and accuracy of their process through virtual microscopy. Virtual microscope systems are widely used and are trusted to provide high quality solutions for teleconsultation, education, quality control, archiving, veterinary medicine, research and other fields.

Towards a Visual Quality Metric for Digital Video

NASA Technical Reports Server (NTRS)

Watson, Andrew B.

1998-01-01

The advent of widespread distribution of digital video creates a need for automated methods for evaluating visual quality of digital video. This is particularly so since most digital video is compressed using lossy methods, which involve the controlled introduction of potentially visible artifacts. Compounding the problem is the bursty nature of digital video, which requires adaptive bit allocation based on visual quality metrics. In previous work, we have developed visual quality metrics for evaluating, controlling, and optimizing the quality of compressed still images. These metrics incorporate simplified models of human visual sensitivity to spatial and chromatic visual signals. The challenge of video quality metrics is to extend these simplified models to temporal signals as well. In this presentation I will discuss a number of the issues that must be resolved in the design of effective video quality metrics. Among these are spatial, temporal, and chromatic sensitivity and their interactions, visual masking, and implementation complexity. I will also touch on the question of how to evaluate the performance of these metrics.

Automated Assessment of Visual Quality of Digital Video

NASA Technical Reports Server (NTRS)

Watson, Andrew B.; Ellis, Stephen R. (Technical Monitor)

1997-01-01

The advent of widespread distribution of digital video creates a need for automated methods for evaluating visual quality of digital video. This is particularly so since most digital video is compressed using lossy methods, which involve the controlled introduction of potentially visible artifacts. Compounding the problem is the bursty nature of digital video, which requires adaptive bit allocation based on visual quality metrics. In previous work, we have developed visual quality metrics for evaluating, controlling, and optimizing the quality of compressed still images[1-4]. These metrics incorporate simplified models of human visual sensitivity to spatial and chromatic visual signals. The challenge of video quality metrics is to extend these simplified models to temporal signals as well. In this presentation I will discuss a number of the issues that must be resolved in the design of effective video quality metrics. Among these are spatial, temporal, and chromatic sensitivity and their interactions, visual masking, and implementation complexity. I will also touch on the question of how to evaluate the performance of these metrics.

Combined multi-spectrum and orthogonal Laplacianfaces for fast CB-XLCT imaging with single-view data

NASA Astrophysics Data System (ADS)

Zhang, Haibo; Geng, Guohua; Chen, Yanrong; Qu, Xuan; Zhao, Fengjun; Hou, Yuqing; Yi, Huangjian; He, Xiaowei

2017-12-01

Cone-beam X-ray luminescence computed tomography (CB-XLCT) is an attractive hybrid imaging modality, which has the potential of monitoring the metabolic processes of nanophosphors-based drugs in vivo. Single-view data reconstruction as a key issue of CB-XLCT imaging promotes the effective study of dynamic XLCT imaging. However, it suffers from serious ill-posedness in the inverse problem. In this paper, a multi-spectrum strategy is adopted to relieve the ill-posedness of reconstruction. The strategy is based on the third-order simplified spherical harmonic approximation model. Then, an orthogonal Laplacianfaces-based method is proposed to reduce the large computational burden without degrading the imaging quality. Both simulated data and in vivo experimental data were used to evaluate the efficiency and robustness of the proposed method. The results are satisfactory in terms of both location and quantitative recovering with computational efficiency, indicating that the proposed method is practical and promising for single-view CB-XLCT imaging.

Image management and communication in patient care: perspectives on implementation and impact.

PubMed

Greberman, M; Mun, S K

1989-02-01

Image management and communication (IMAC) systems are automated and integrated systems that capture digital medical images and related patient information and transmit them electronically, display them for interpretation, and store them for future retrieval. The IMAC system concept includes images and relevant information from all clinical sources. The First International Conference on Image Management and Communication in Patient Care (IMAC 89) provides a forum for expert presentations, poster sessions, and discussion and debate among all attendees interested in the implementation and impact of IMAC systems. Plenary sessions provide an international perspective and explore the role of image-based information in patient care, approaches to improved IMAC systems, current technical barriers, quality of care issues, evaluation approaches, and scenarios for the future. Invited participants are from North America, Europe, Japan, Australia, and the WHO. Conference organizers are working with numerous professional organizations and representatives of meetings which focus on IMAC-related technology to complement, and not duplicate, the contribution of other groups.

Normative Databases for Imaging Instrumentation.

PubMed

Realini, Tony; Zangwill, Linda M; Flanagan, John G; Garway-Heath, David; Patella, Vincent M; Johnson, Chris A; Artes, Paul H; Gaddie, Ian B; Fingeret, Murray

2015-08-01

To describe the process by which imaging devices undergo reference database development and regulatory clearance. The limitations and potential improvements of reference (normative) data sets for ophthalmic imaging devices will be discussed. A symposium was held in July 2013 in which a series of speakers discussed issues related to the development of reference databases for imaging devices. Automated imaging has become widely accepted and used in glaucoma management. The ability of such instruments to discriminate healthy from glaucomatous optic nerves, and to detect glaucomatous progression over time is limited by the quality of reference databases associated with the available commercial devices. In the absence of standardized rules governing the development of reference databases, each manufacturer's database differs in size, eligibility criteria, and ethnic make-up, among other key features. The process for development of imaging reference databases may be improved by standardizing eligibility requirements and data collection protocols. Such standardization may also improve the degree to which results may be compared between commercial instruments.

Normative Databases for Imaging Instrumentation

PubMed Central

Realini, Tony; Zangwill, Linda; Flanagan, John; Garway-Heath, David; Patella, Vincent Michael; Johnson, Chris; Artes, Paul; Ben Gaddie, I.; Fingeret, Murray

2015-01-01

Purpose To describe the process by which imaging devices undergo reference database development and regulatory clearance. The limitations and potential improvements of reference (normative) data sets for ophthalmic imaging devices will be discussed. Methods A symposium was held in July 2013 in which a series of speakers discussed issues related to the development of reference databases for imaging devices. Results Automated imaging has become widely accepted and used in glaucoma management. The ability of such instruments to discriminate healthy from glaucomatous optic nerves, and to detect glaucomatous progression over time is limited by the quality of reference databases associated with the available commercial devices. In the absence of standardized rules governing the development of reference databases, each manufacturer’s database differs in size, eligibility criteria, and ethnic make-up, among other key features. Conclusions The process for development of imaging reference databases may be improved by standardizing eligibility requirements and data collection protocols. Such standardization may also improve the degree to which results may be compared between commercial instruments. PMID:25265003

A method based on IHS cylindrical transform model for quality assessment of image fusion

NASA Astrophysics Data System (ADS)

Zhu, Xiaokun; Jia, Yonghong

2005-10-01

Image fusion technique has been widely applied to remote sensing image analysis and processing, and methods for quality assessment of image fusion in remote sensing have also become the research issues at home and abroad. Traditional assessment methods combine calculation of quantitative indexes and visual interpretation to compare fused images quantificationally and qualitatively. However, in the existing assessment methods, there are two defects: on one hand, most imdexes lack the theoretic support to compare different fusion methods. On the hand, there is not a uniform preference for most of the quantitative assessment indexes when they are applied to estimate the fusion effects. That is, the spatial resolution and spectral feature could not be analyzed synchronously by these indexes and there is not a general method to unify the spatial and spectral feature assessment. So in this paper, on the basis of the approximate general model of four traditional fusion methods, including Intensity Hue Saturation(IHS) triangle transform fusion, High Pass Filter(HPF) fusion, Principal Component Analysis(PCA) fusion, Wavelet Transform(WT) fusion, a correlation coefficient assessment method based on IHS cylindrical transform is proposed. By experiments, this method can not only get the evaluation results of spatial and spectral features on the basis of uniform preference, but also can acquire the comparison between fusion image sources and fused images, and acquire differences among fusion methods. Compared with the traditional assessment methods, the new methods is more intuitionistic, and in accord with subjective estimation.

Image management research

NASA Technical Reports Server (NTRS)

Watson, Andrew B.

1988-01-01

Two types of research issues are involved in image management systems with space station applications: image processing research and image perception research. The image processing issues are the traditional ones of digitizing, coding, compressing, storing, analyzing, and displaying, but with a new emphasis on the constraints imposed by the human perceiver. Two image coding algorithms have been developed that may increase the efficiency of image management systems (IMS). Image perception research involves a study of the theoretical and practical aspects of visual perception of electronically displayed images. Issues include how rapidly a user can search through a library of images, how to make this search more efficient, and how to present images in terms of resolution and split screens. Other issues include optimal interface to an IMS and how to code images in a way that is optimal for the human perceiver. A test-bed within which such issues can be addressed has been designed.

Flexoelectric effect in an in-plane switching (IPS) liquid crystal cell for low-power consumption display devices

NASA Astrophysics Data System (ADS)

Kim, Min Su; Bos, Philip J.; Kim, Dong-Woo; Yang, Deng-Ke; Lee, Joong Hee; Lee, Seung Hee

2016-10-01

Technology of displaying static images in portable displays, advertising panels and price tags pursues significant reduction in power consumption and in product cost. Driving at a low-frequency electric field in fringe-field switching (FFS) mode can be one of the efficient ways to save powers of the recent portable devices, but a serious drop of image-quality, so-called image-flickering, has been found in terms of the coupling of elastic deformation to not only quadratic dielectric effect but linear flexoelectric effect. Despite of the urgent requirement of solving the issue, understanding of such a phenomenon is yet vague. Here, we thoroughly analyze and firstly report the flexoelectric effect in in-plane switching (IPS) liquid crystal cell. The effect takes place on the area above electrodes due to splay and bend deformations of nematic liquid crystal along oblique electric fields, so that the obvious spatial shift of the optical transmittance is experimentally observed and is clearly demonstrated based on the relation between direction of flexoelectric polarization and electric field polarity. In addition, we report that the IPS mode has inherent characteristics to solve the image-flickering issue in the low-power consumption display in terms of the physical property of liquid crystal material and the electrode structure.

Flexoelectric effect in an in-plane switching (IPS) liquid crystal cell for low-power consumption display devices.

PubMed

Kim, Min Su; Bos, Philip J; Kim, Dong-Woo; Yang, Deng-Ke; Lee, Joong Hee; Lee, Seung Hee

2016-10-12

Technology of displaying static images in portable displays, advertising panels and price tags pursues significant reduction in power consumption and in product cost. Driving at a low-frequency electric field in fringe-field switching (FFS) mode can be one of the efficient ways to save powers of the recent portable devices, but a serious drop of image-quality, so-called image-flickering, has been found in terms of the coupling of elastic deformation to not only quadratic dielectric effect but linear flexoelectric effect. Despite of the urgent requirement of solving the issue, understanding of such a phenomenon is yet vague. Here, we thoroughly analyze and firstly report the flexoelectric effect in in-plane switching (IPS) liquid crystal cell. The effect takes place on the area above electrodes due to splay and bend deformations of nematic liquid crystal along oblique electric fields, so that the obvious spatial shift of the optical transmittance is experimentally observed and is clearly demonstrated based on the relation between direction of flexoelectric polarization and electric field polarity. In addition, we report that the IPS mode has inherent characteristics to solve the image-flickering issue in the low-power consumption display in terms of the physical property of liquid crystal material and the electrode structure.

A new compact, cost-efficient concept for underwater range-gated imaging: the UTOFIA project

NASA Astrophysics Data System (ADS)

Mariani, Patrizio; Quincoces, Iñaki; Galparsoro, Ibon; Bald, Juan; Gabiña, Gorka; Visser, Andy; Jónasdóttir, Sigrun; Haugholt, Karl Henrik; Thorstensen, Jostein; Risholm, Petter; Thielemann, Jens

2017-04-01

Underwater Time Of Flight Image Acquisition system (UTOFIA) is a recently launched H2020 project (H2020 - 633098) to develop a compact and cost-effective underwater imaging system especially suited for observations in turbid environments. The UTOFIA project targets technology that can overcome the limitations created by scattering, by introducing cost-efficient range-gated imaging for underwater applications. This technology relies on a image acquisition principle that can extends the imaging range of the cameras 2-3 times respect to other cameras. Moreover, the system will simultaneously capture 3D information of the observed objects. Today range-gated imaging is not widely used, as it relies on specialised optical components making systems large and costly. Recent technology developments have made it possible a significant (2-3 times) reduction in size, complexity and cost of underwater imaging systems, whilst addressing the scattering issues at the same time. By acquiring simultaneous 3D data, the system allows to accurately measure the absolute size of marine life and their spatial relationship to their habitat, enhancing the precision of fish stock monitoring and ecology assessment, hence supporting proper management of marine resources. Additionally, the larger observed volume and the improved image quality make the system suitable for cost-effective underwater surveillance operations in e.g. fish farms, underwater infrastructures. The system can be integrated into existing ocean observatories for real time acquisition and can greatly advance present efforts in developing species recognition algorithms, given the additional features provided, the improved image quality and the independent illumination source based on laser. First applications of the most recent prototype of the imaging system will be provided including inspection of underwater infrastructures and observations of marine life under different environmental conditions.

Detection of foreign bodies in foods using continuous wave terahertz imaging.

PubMed

Lee, Young-Ki; Choi, Sung-Wook; Han, Seong-Tae; Woo, Deog Hyun; Chun, Hyang Sook

2012-01-01

Foreign bodies (FBs) in food are health hazards and quality issues for many food manufacturers and enforcement authorities. In this study, continuous wave (CW) terahertz (THz) imaging at 0.2 THz with an output power of 10 mW was compared with X-ray imaging as techniques for inspection of food for FBs. High-density FBs, i.e., aluminum and granite pieces of various sizes, were embedded in a powdered instant noodle product and detected using THz and X-ray imaging. All aluminum and granite pieces (regular hexahedrons with an edge length of 1 to 5 mm) were visualized by both CW THz and X-ray imaging. THz imaging also detected maggots (length = 8 to 22 mm) and crickets (length = 35 and 50 mm), which were embedded in samples as low density FBs. However, not all sizes of maggot pieces embedded in powdered instant noodle were detected with X-ray imaging, although larger crickets (length = 50 mm and thickness = 10 mm) were detected. These results suggest that CW THz imaging has potential for detecting both high-density and low-density FBs embedded in food.

Use of a 1.0 Tesla open scanner for evaluation of pediatric and congenital heart disease: a retrospective cohort study.

PubMed

Lu, Jimmy C; Nielsen, James C; Morowitz, Layne; Musani, Muzammil; Ghadimi Mahani, Maryam; Agarwal, Prachi P; Ibrahim, El-Sayed H; Dorfman, Adam L

2015-05-25

Open cardiovascular magnetic resonance (CMR) scanners offer the potential for imaging patients with claustrophobia or large body size, but at a lower 1.0 Tesla magnetic field. This study aimed to evaluate the efficacy of open CMR for evaluation of pediatric and congenital heart disease. This retrospective, cross-sectional study included all patients ≤18 years old or with congenital heart disease who underwent CMR on an open 1.0 Tesla scanner at two centers from 2012-2014. Indications for CMR and clinical questions were extracted from the medical record. Studies were qualitatively graded for image quality and diagnostic utility. In a subset of 25 patients, signal-to-noise (SNR) and contrast-to-noise (CNR) ratios were compared to size- and diagnosis-matched patients with CMR on a 1.5 Tesla scanner. A total of 65 patients (median 17.3 years old, 60% male) were included. Congenital heart disease was present in 32 (50%), with tetralogy of Fallot and bicuspid aortic valve the most common diagnoses. Open CMR was used due to scheduling/equipment issues in 51 (80%), claustrophobia in 7 (11%), and patient size in 3 (5%); 4 patients with claustrophobia had failed CMR on a different scanner, but completed the study on open CMR without sedation. All patients had good or excellent image quality on black blood, phase contrast, magnetic resonance angiography, and late gadolinium enhancement imaging. There was below average image quality in 3/63 (5%) patients with cine images, and 4/15 (27%) patients with coronary artery imaging. SNR and CNR were decreased in cine and magnetic resonance angiography images compared to 1.5 Tesla. The clinical question was answered adequately in all but 2 patients; 1 patient with a Fontan had artifact from an embolization coil limiting RV volume analysis, and in 1 patient the right coronary artery origin was not well seen. Open 1.0 Tesla scanners can effectively evaluate pediatric and congenital heart disease, including patients with claustrophobia and larger body size. Despite minor artifacts and differences in SNR and CNR, the majority of clinical questions can be answered adequately, with some limitations with coronary artery imaging. Further evaluation is necessary to optimize protocols and image quality.

The development of vector based 2.5D print methods for a painting machine

NASA Astrophysics Data System (ADS)

Parraman, Carinna

2013-02-01

Through recent trends in the application of digitally printed decorative finishes to products, CAD, 3D additive layer manufacturing and research in material perception, [1, 2] there is a growing interest in the accurate rendering of materials and tangible displays. Although current advances in colour management and inkjet printing has meant that users can take for granted high-quality colour and resolution in their printed images, digital methods for transferring a photographic coloured image from screen to paper is constrained by pixel count, file size, colorimetric conversion between colour spaces and the gamut limits of input and output devices. This paper considers new approaches to applying alternative colour palettes by using a vector-based approach through the application of paint mixtures, towards what could be described as a 2.5D printing method. The objective is to not apply an image to a textured surface, but where texture and colour are integral to the mark, that like a brush, delineates the contours in the image. The paper describes the difference between the way inks and paints are mixed and applied. When transcribing the fluid appearance of a brush stroke, there is a difference between a halftone printed mark and a painted mark. The issue of surface quality is significant to subjective qualities when studying the appearance of ink or paint on paper. The paper provides examples of a range of vector marks that are then transcribed into brush stokes by the painting machine.

Evaluation of electrical capacitance tomography sensor based on the coupling of fluid field and electrostatic field

NASA Astrophysics Data System (ADS)

Ye, Jiamin; Wang, Haigang; Yang, Wuqiang

2016-07-01

Electrical capacitance tomography (ECT) is based on capacitance measurements from electrode pairs mounted outside of a pipe or vessel. The structure of ECT sensors is vital to image quality. In this paper, issues with the number of electrodes and the electrode covering ratio for complex liquid-solids flows in a rotating device are investigated based on a new coupling simulation model. The number of electrodes is increased from 4 to 32 while the electrode covering ratio is changed from 0.1 to 0.9. Using the coupling simulation method, real permittivity distributions and the corresponding capacitance data at 0, 0.5, 1, 2, 3, 5, and 8 s with a rotation speed of 96 rotations per minute (rpm) are collected. Linear back projection (LBP) and Landweber iteration algorithms are used for image reconstruction. The quality of reconstructed images is evaluated by correlation coefficient compared with the real permittivity distributions obtained from the coupling simulation. The sensitivity for each sensor is analyzed and compared with the correlation coefficient. The capacitance data with a range of signal-to-noise ratios (SNRs) of 45, 50, 55 and 60 dB are generated to evaluate the effect of data noise on the performance of ECT sensors. Furthermore, the SNRs of experimental data are analyzed for a stationary pipe with permittivity distribution. Based on the coupling simulation, 16-electrode ECT sensors are recommended to achieve good image quality.

Modelling the physics in iterative reconstruction for transmission computed tomography

PubMed Central

Nuyts, Johan; De Man, Bruno; Fessler, Jeffrey A.; Zbijewski, Wojciech; Beekman, Freek J.

2013-01-01

There is an increasing interest in iterative reconstruction (IR) as a key tool to improve quality and increase applicability of X-ray CT imaging. IR has the ability to significantly reduce patient dose, it provides the flexibility to reconstruct images from arbitrary X-ray system geometries and it allows to include detailed models of photon transport and detection physics, to accurately correct for a wide variety of image degrading effects. This paper reviews discretisation issues and modelling of finite spatial resolution, Compton scatter in the scanned object, data noise and the energy spectrum. Widespread implementation of IR with highly accurate model-based correction, however, still requires significant effort. In addition, new hardware will provide new opportunities and challenges to improve CT with new modelling. PMID:23739261

Integration of USB and firewire cameras in machine vision applications

NASA Astrophysics Data System (ADS)

Smith, Timothy E.; Britton, Douglas F.; Daley, Wayne D.; Carey, Richard

1999-08-01

Digital cameras have been around for many years, but a new breed of consumer market cameras is hitting the main stream. By using these devices, system designers and integrators will be well posited to take advantage of technological advances developed to support multimedia and imaging applications on the PC platform. Having these new cameras on the consumer market means lower cost, but it does not necessarily guarantee ease of integration. There are many issues that need to be accounted for like image quality, maintainable frame rates, image size and resolution, supported operating system, and ease of software integration. This paper will describe briefly a couple of the consumer digital standards, and then discuss some of the advantages and pitfalls of integrating both USB and Firewire cameras into computer/machine vision applications.

Body image issues after bilateral prophylactic mastectomy with breast reconstruction in healthy women at risk for hereditary breast cancer.

PubMed

Gopie, Jessica P; Mureau, Marc A M; Seynaeve, Caroline; Ter Kuile, Moniek M; Menke-Pluymers, Marian B E; Timman, Reinier; Tibben, Aad

2013-09-01

The outcome of bilateral prophylactic mastectomy with breast reconstruction (BPM-IBR) in healthy BRCA1/2 mutation carriers can be potentially burdensome for body image and the intimate relationship. Therefore, in the current analysis the impact on body image, sexual and partner relationship satisfaction was prospectively investigated in women opting for BPM-IBR as well as cancer distress and general quality of life. Healthy women undergoing BPM-IBR completed questionnaires preoperatively (T0, n = 48), at 6 months (T1, n = 44) and after finishing breast reconstruction (median 21 months, range 12-35) (T2, n = 36). With multi-level regression analyses the course of outcome variables was investigated and a statistically significant change in body image and/or sexual and partner relationship satisfaction was predicted by baseline covariates. Body image significantly decreased at T1. At T2 sexual relationship satisfaction and body image tended to be lower compared to baseline. The overall partner relationship satisfaction did not significantly change. At T2, 37 % of the women reported that their breasts felt unpleasantly, 29 % was not satisfied with their breast appearance and 21 % felt embarrassed for their naked body. Most body image issues remained unchanged in 30 % of the women. A negative body image was predicted by high preoperative cancer distress. BPM-IBR was associated with adverse impact on body image in a substantial subgroup, but satisfaction with the overall sexual and partner relationship did not significantly change in time. The psychosocial impact of BPM-IBR in unaffected women should not be underestimated. Psychological support should ideally be integrated both before and after BPM-IBR.

MO-D-BRB-02: SBRT Treatment Planning and Delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Y.

2016-06-15

Increased use of SBRT and hypofractionation in radiation oncology practice has posted a number of challenges to medical physicist, ranging from planning, image-guided patient setup and on-treatment monitoring, to quality assurance (QA) and dose delivery. This symposium is designed to provide current knowledge necessary for the safe and efficient implementation of SBRT in various linac platforms, including the emerging digital linacs equipped with high dose rate FFF beams. Issues related to 4D CT, PET and MRI simulations, 3D/4D CBCT guided patient setup, real-time image guidance during SBRT dose delivery using gated/un-gated VMAT/IMRT, and technical advancements in QA of SBRT (inmore » particular, strategies dealing with high dose rate FFF beams) will be addressed. The symposium will help the attendees to gain a comprehensive understanding of the SBRT workflow and facilitate their clinical implementation of the state-of-art imaging and planning techniques. Learning Objectives: Present background knowledge of SBRT, describe essential requirements for safe implementation of SBRT, and discuss issues specific to SBRT treatment planning and QA. Update on the use of multi-dimensional and multi-modality imaging for reliable guidance of SBRT. Discuss treatment planning and QA issues specific to SBRT. Provide a comprehensive overview of emerging digital linacs and summarize the key geometric and dosimetric features of the new generation of linacs for substantially improved SBRT. NIH/NCI; Varian Medical Systems; F. Yin, Duke University has a research agreement with Varian Medical Systems. In addition to research grant, I had a technology license agreement with Varian Medical Systems.« less

Nutritional issues and body weight in long-term survivors of allogeneic blood and marrow transplant (BMT) in NSW Australia.

PubMed

Smith, Jennifer; Poon, Christine; Gilroy, Nicole; Kabir, Masura; Brice, Lisa; Dyer, Gemma; Hogg, Megan; Greenwood, Matthew; Moore, John; Hertzberg, Mark; Brown, Louisa; Tan, Jeff; Huang, Gillian; Kwan, John; Larsen, Stephen; Ward, Christopher; Kerridge, Ian

2017-01-01

The aims of this study were to describe the long-term nutrition, body weight and body image issues facing survivors of Allogeneic Blood and Marrow Transplant (BMT) and their impact on quality of life. It also describes survivors' perception of enteral feeding during BMT. Four hundred and forty-one survivors who had undergone a BMT in NSW, Australia between 2000 and 2012 (n = 441/583) completed the Sydney Post BMT Study Survey (SPBS). Forty-five percent of survivors less than 2-year post-transplant reported a dry mouth, 36 % reported mouth ulcers and 19 % had diarrhoea. This was consistent across all survivor groups, regardless of time since transplant. Patients with one or more gastrointestinal (GI) symptoms had significantly lower quality of life scores. There was a significant difference in quality of life scores when comparing those with no GI symptoms to those with one or more symptoms (P = <0.0001). Quality of life was significantly higher in those who once again enjoyed mealtimes (P < 0.0001). Males were more likely to be satisfied with their body weight compared to females (P = 0.009). The median body mass index (BMI) for all patients reporting body weight satisfaction was significantly lower (BMI 23.5) than those reporting dissatisfaction (BMI 27.5) (P = <0.0001). Survivors who had a normal BMI had significantly higher rates of body weight satisfaction compared to underweight, overweight and obese survivors (P = <0.0001). Those survivors who were overweight or obese were significantly more likely to be diabetic (P = 0.008). This study revealed an important relationship between gastrointestinal symptoms, body weight and body image and survivor's quality of life. It provides further support for the importance of nutrition therapy post-BMT.

Autonomous facial recognition system inspired by human visual system based logarithmical image visualization technique

NASA Astrophysics Data System (ADS)

Wan, Qianwen; Panetta, Karen; Agaian, Sos

2017-05-01

Autonomous facial recognition system is widely used in real-life applications, such as homeland border security, law enforcement identification and authentication, and video-based surveillance analysis. Issues like low image quality, non-uniform illumination as well as variations in poses and facial expressions can impair the performance of recognition systems. To address the non-uniform illumination challenge, we present a novel robust autonomous facial recognition system inspired by the human visual system based, so called, logarithmical image visualization technique. In this paper, the proposed method, for the first time, utilizes the logarithmical image visualization technique coupled with the local binary pattern to perform discriminative feature extraction for facial recognition system. The Yale database, the Yale-B database and the ATT database are used for computer simulation accuracy and efficiency testing. The extensive computer simulation demonstrates the method's efficiency, accuracy, and robustness of illumination invariance for facial recognition.

Integrated satellite data fusion and mining for monitoring lake water quality status of the Albufera de Valencia in Spain.

PubMed

Doña, Carolina; Chang, Ni-Bin; Caselles, Vicente; Sánchez, Juan M; Camacho, Antonio; Delegido, Jesús; Vannah, Benjamin W

2015-03-15

Lake eutrophication is a critical issue in the interplay of water supply, environmental management, and ecosystem conservation. Integrated sensing, monitoring, and modeling for a holistic lake water quality assessment with respect to multiple constituents is in acute need. The aim of this paper is to develop an integrated algorithm for data fusion and mining of satellite remote sensing images to generate daily estimates of some water quality parameters of interest, such as chlorophyll a concentrations and water transparency, to be applied for the assessment of the hypertrophic Albufera de Valencia. The Albufera de Valencia is the largest freshwater lake in Spain, which can often present values of chlorophyll a concentration over 200 mg m(-3) and values of transparency (Secchi Disk, SD) as low as 20 cm. Remote sensing data from Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat Thematic Mapper (TM) and Enhance Thematic Mapper (ETM+) images were fused to carry out an integrative near-real time water quality assessment on a daily basis. Landsat images are useful to study the spatial variability of the water quality parameters, due to its spatial resolution of 30 m, in comparison to the low spatial resolution (250/500 m) of MODIS. While Landsat offers a high spatial resolution, the low temporal resolution of 16 days is a significant drawback to achieve a near real-time monitoring system. This gap may be bridged by using MODIS images that have a high temporal resolution of 1 day, in spite of its low spatial resolution. Synthetic Landsat images were fused for dates with no Landsat overpass over the study area. Finally, with a suite of ground truth data, a few genetic programming (GP) models were derived to estimate the water quality using the fused surface reflectance data as inputs. The GP model for chlorophyll a estimation yielded a R(2) of 0.94, with a Root Mean Square Error (RMSE) = 8 mg m(-3), and the GP model for water transparency estimation using Secchi disk showed a R(2) of 0.89, with an RMSE = 4 cm. With this effort, the spatiotemporal variations of water transparency and chlorophyll a concentrations may be assessed simultaneously on a daily basis throughout the lake for environmental management. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cellscope Aquatic: a Lab Quality, Portable Cellphone-Based Microscope for On-Site Collection of Algae Images

NASA Astrophysics Data System (ADS)

Steinberg, S. J.; Howard, M. D.

2016-02-01

Collecting algae samples from the field presents issues of specimen damage or degradation caused by preservation methods, handling and transport to laboratory facilities for identification. Traditionally, in-field collection of high quality microscopic images has not been possible due to the size, weight and fragility of high quality instruments and training of field staff in species identification. Scientists at the Southern California Coastal Water Research Project (SCCWRP) in collaboration with the Fletcher Lab, University of California Berkeley, Department of Bioengineering, tested and translated Fletcher's original medical CellScope for use in environmental monitoring applications. Field tests conducted by SCCWRP in 2014 led to modifications of the clinical CellScope to one better suited to in-field microscopic imaging for aquatic organisms. SCCWRP subsequently developed a custom cell-phone application to acquire microscopic imagery using the "CellScope Aquatic "in combination with other cell-phone derived field data (e.g. GPS location, date, time and other field observations). Data and imagery collected in-field may be transmitted in real-time to a web-based data system for tele-taxonomy evaluation and assessment by experts in the office. These hardware and software tools was tested in field in a variety of conditions and settings by multiple algae experts during the spring and summer of 2015 to further test and refine the CellScope Aquatic platform. The CellScope Aquatic provides an easy-to-use, affordable, lightweight, professional quality, data collection platform for environmental monitoring. Our ongoing efforts will focus on development of real-time expert systems for data analysis and image processing, to provide onsite feedback to field scientists.

Content-based image retrieval in medical applications for picture archiving and communication systems

NASA Astrophysics Data System (ADS)

Lehmann, Thomas M.; Guld, Mark O.; Thies, Christian; Fischer, Benedikt; Keysers, Daniel; Kohnen, Michael; Schubert, Henning; Wein, Berthold B.

2003-05-01

Picture archiving and communication systems (PACS) aim to efficiently provide the radiologists with all images in a suitable quality for diagnosis. Modern standards for digital imaging and communication in medicine (DICOM) comprise alphanumerical descriptions of study, patient, and technical parameters. Currently, this is the only information used to select relevant images within PACS. Since textual descriptions insufficiently describe the great variety of details in medical images, content-based image retrieval (CBIR) is expected to have a strong impact when integrated into PACS. However, existing CBIR approaches usually are limited to a distinct modality, organ, or diagnostic study. In this state-of-the-art report, we present first results implementing a general approach to content-based image retrieval in medical applications (IRMA) and discuss its integration into PACS environments. Usually, a PACS consists of a DICOM image server and several DICOM-compliant workstations, which are used by radiologists for reading the images and reporting the findings. Basic IRMA components are the relational database, the scheduler, and the web server, which all may be installed on the DICOM image server, and the IRMA daemons running on distributed machines, e.g., the radiologists" workstations. These workstations can also host the web-based front-ends of IRMA applications. Integrating CBIR and PACS, a special focus is put on (a) location and access transparency for data, methods, and experiments, (b) replication transparency for methods in development, (c) concurrency transparency for job processing and feature extraction, (d) system transparency at method implementation time, and (e) job distribution transparency when issuing a query. Transparent integration will have a certain impact on diagnostic quality supporting both evidence-based medicine and case-based reasoning.

Multi-GPU Acceleration of Branchless Distance Driven Projection and Backprojection for Clinical Helical CT.

PubMed

Mitra, Ayan; Politte, David G; Whiting, Bruce R; Williamson, Jeffrey F; O'Sullivan, Joseph A

2017-01-01

Model-based image reconstruction (MBIR) techniques have the potential to generate high quality images from noisy measurements and a small number of projections which can reduce the x-ray dose in patients. These MBIR techniques rely on projection and backprojection to refine an image estimate. One of the widely used projectors for these modern MBIR based technique is called branchless distance driven (DD) projection and backprojection. While this method produces superior quality images, the computational cost of iterative updates keeps it from being ubiquitous in clinical applications. In this paper, we provide several new parallelization ideas for concurrent execution of the DD projectors in multi-GPU systems using CUDA programming tools. We have introduced some novel schemes for dividing the projection data and image voxels over multiple GPUs to avoid runtime overhead and inter-device synchronization issues. We have also reduced the complexity of overlap calculation of the algorithm by eliminating the common projection plane and directly projecting the detector boundaries onto image voxel boundaries. To reduce the time required for calculating the overlap between the detector edges and image voxel boundaries, we have proposed a pre-accumulation technique to accumulate image intensities in perpendicular 2D image slabs (from a 3D image) before projection and after backprojection to ensure our DD kernels run faster in parallel GPU threads. For the implementation of our iterative MBIR technique we use a parallel multi-GPU version of the alternating minimization (AM) algorithm with penalized likelihood update. The time performance using our proposed reconstruction method with Siemens Sensation 16 patient scan data shows an average of 24 times speedup using a single TITAN X GPU and 74 times speedup using 3 TITAN X GPUs in parallel for combined projection and backprojection.

Initial research on the characterization methods of sparkle spots in optical thin films

NASA Astrophysics Data System (ADS)

Jiang, Jinhu; Gu, Wenhua

2018-01-01

In this article, we made a preliminary study on the main influencing factors of sparkle spots, put forward the concept of "sparklingness" to characterize the strength of sparkle spots, and proposed a standard measurement method for the sparklingness. We proposed to use 532 nm green laser pointer as the testing light source, let the light pass through the film and form a sparkle spots image at the receiving CCD or a piece of white paper. A standard image processing method was used to obtain an index number standing for the scattering status of the laser, which is defined as "sparklingness". In the experiment, we also analyzed the power dependence of sparklingness. With proper calibration, the measurement error of the sparklingness can be minimized, and it can be used as a physical quantity to describe the film quality as of the sparkle issue. This work can be a useful reference for further study of the sparkle issue in optical films.

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

PubMed

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 processing can significantly impact image quality when settings are left near default values.

Current issues of personnel and laboratory practices in genetic testing

PubMed Central

Mark, Hon Fong Louie; Kelly, Thaddeus; Watson, Michael S; Hoeltge, Gerald; Miller, Wayne A; Beauregard, Laurent

1995-01-01

As genetic testing is an area with implications extending far beyond that of the primary patient, it is appropriately an area that is under increased scrutiny. To ensure that high quality is maintained in the delivery of genetic services, several agencies have developed standards and guidelines. The present article summarises important recommendations made by the American College of Medical Genetics (ACMG), the College of American Pathologists (CAP), the US Health Care Financing Administration (HCFA), and the US Food and Drug Administration (FDA) as they relate to genetic testing. Some of the standards are based on voluntary compliance, whereas others have the force of regulation. They all address issues of personnel credentials, laboratory operations, and the most critical quality assurance and control measures for diagnostic laboratories from the perspective of various agencies. In most instances, the standards promulgated by these agencies are offered as minimum criteria. The exact impact of these regulations on the practice of medical genetics has yet to be established. Images PMID:8558555

Intensity Modulated Radiotherapy (IMRT) in head and neck cancers - an overview.

PubMed

Nutting, C M

2012-07-01

Radiotherapy (RT) is effective in head and neck cancers. Following RT, dryness and dysphagia are the 2 major sequelae which alter the quality of life (QOL) significantly in these patients. There is randomized evidence that Intensity Modulated Radiotherapy (IMRT) effectively spares the parotid glands. IMRT has been attempted in all head and neck subsites with encouraging results (discussed below). Role of IMRT in swallowing structure (constrictor muscles) sparing is less clear.Further improvement in results may be possible by using functional imaging at the time of RT planning and by image guidance/verification at the time of treatment delivery. The following text discusses these issues in detail. Head and neck cancer, IMRT.

Practical aspects of modern interferometry for optical manufacturing quality control: Part 2

NASA Astrophysics Data System (ADS)

Smythe, Robert

2012-07-01

Modern phase shifting interferometers enable the manufacture of optical systems that drive the global economy. Semiconductor chips, solid-state cameras, cell phone cameras, infrared imaging systems, space based satellite imaging and DVD and Blu-Ray disks are all enabled by phase shifting interferometers. Theoretical treatments of data analysis and instrument design advance the technology but often are not helpful towards the practical use of interferometers. An understanding of the parameters that drive system performance is critical to produce useful results. Any interferometer will produce a data map and results; this paper, in three parts, reviews some of the key issues to minimize error sources in that data and provide a valid measurement.

Practical aspects of modern interferometry for optical manufacturing quality control, Part 3

NASA Astrophysics Data System (ADS)

Smythe, Robert A.

2012-09-01

Modern phase shifting interferometers enable the manufacture of optical systems that drive the global economy. Semiconductor chips, solid-state cameras, cell phone cameras, infrared imaging systems, space-based satellite imaging, and DVD and Blu-Ray disks are all enabled by phase-shifting interferometers. Theoretical treatments of data analysis and instrument design advance the technology but often are not helpful toward the practical use of interferometers. An understanding of the parameters that drive the system performance is critical to produce useful results. Any interferometer will produce a data map and results; this paper, in three parts, reviews some of the key issues to minimize error sources in that data and provide a valid measurement.

Data quality control in eco-environmental monitoring

NASA Astrophysics Data System (ADS)

Lu, Chunyan; Wang, Jing

2007-11-01

With the development of science and technology, a number of environmental issues, such as sustainable development, climate change, environmental pollution, and land degradation become serious. Greater attention has been attached to environmental protection. The government gradually launched some eco--environmental construction projects. In 1999, China begin to carry out the project of Grain-for-Green in the west, to improve the eco-environment, and it make some good effect, but there are some questions that still can not be answered. How about the new grass or forest? Where are they? How can we do in the future? To answer these questions, the government began to monitor the eco-environment, based on remote sensing technology. Geography information can be attained timely, but the issue of uncertainty has become increasingly recognized, and this uncertainty affects the reliability of applications using the data. This article analyzed the process of eco-environment monitoring, the uncertainty of geography information, and discussed the methods of data quality control. The Spot5 span data and multi-spectral data in 2003(2002) were used, combined with land use survey data at the scale of 1:10,000, topography data at the scale of 1:10,000, and the local Grain-for-Green project map. Also the social and economic data were collected. Eco-environmental monitoring is a process which consists of several steps, such as image geometric correction, image matching, information extraction, and so on. Based on visual and automated method, land information turned to grass and forest from cultivated land was obtained by comparing the information form remote sensing data with the land survey data, and local Grain-for-Green project data, combined with field survey. According to the process, the uncertainty in the process was analyzed. Positional uncertainty, attribute uncertainty, and thematic uncertainty was obvious. Positional uncertainty mainly derived from image geometric correction, such as data resource, the number and spatial distribution of the control points are important resource of uncertainty. Attribution uncertainty mainly derived from the process of information extraction. Land classification system, artificial error was the main factor induced uncertainty. Concept defined was not clear, and it reduced thematic uncertainty. According to the resource of uncertainty, data quality control methods were put forward to improve the data quality. At first, it is more important to choose appropriate remote sensing data and other basic data. Secondly, the accuracy of digital orthophoto map should be controlled. Thirdly, it is necessary to check the result data according to relative data quality criterion to guarantee GIS data quality.

Remote Sensing Image Quality Assessment Experiment with Post-Processing

NASA Astrophysics Data System (ADS)

Jiang, W.; Chen, S.; Wang, X.; Huang, Q.; Shi, H.; Man, Y.

2018-04-01

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.

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

NASA Astrophysics Data System (ADS)

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.

Assessment of NPP VIIRS Ocean Color Data Products: Hope and Risk

NASA Technical Reports Server (NTRS)

Turpie, Kevin R.; Meister, Gerhard; Eplee, Gene; Barnes, Robert A.; Franz, Bryan; Patt, Frederick S.; Robinson, Wayne d.; McClain, Charles R.

2010-01-01

For several years, the NASA/Goddard Space Flight Center (GSFC) NPP VIIRS Ocean Science Team (VOST) provided substantial scientific input to the NPP project regarding the use of Visible Infrared Imaging Radiometer Suite (VIIRS) to create science quality ocean color data products. This work has culminated into an assessment of the NPP project and the VIIRS instrument's capability to produce science quality Ocean Color data products. The VOST concluded that many characteristics were similar to earlier instruments, including SeaWiFS or MODIS Aqua. Though instrument performance and calibration risks do exist, it was concluded that programmatic and algorithm issues dominate concerns. Keywords: NPP, VIIRS, Ocean Color, satellite remote sensing, climate data record.

MFP scanner diagnostics using a self-printed target to measure the modulation transfer function

NASA Astrophysics Data System (ADS)

Wang, Weibao; Bauer, Peter; Wagner, Jerry; Allebach, Jan P.

2014-01-01

In the current market, reduction of warranty costs is an important avenue for improving profitability by manufacturers of printer products. Our goal is to develop an autonomous capability for diagnosis of printer and scanner caused defects with mid-range laser multifunction printers (MFPs), so as to reduce warranty costs. If the scanner unit of the MFP is not performing according to specification, this issue needs to be diagnosed. If there is a print quality issue, this can be diagnosed by printing a special test page that is resident in the firmware of the MFP unit, and then scanning it. However, the reliability of this process will be compromised if the scanner unit is defective. Thus, for both scanner and printer image quality issues, it is important to be able to properly evaluate the scanner performance. In this paper, we consider evaluation of the scanner performance by measuring its modulation transfer function (MTF). The MTF is a fundamental tool for assessing the performance of imaging systems. Several ways have been proposed to measure the MTF, all of which require a special target, for example a slanted-edge target. It is unacceptably expensive to ship every MFP with such a standard target, and to expect that the customer can keep track of it. To reduce this cost, in this paper, we develop new approach to this task. It is based on a self-printed slanted-edge target. Then, we propose algorithms to improve the results using a self-printed slanted-edge target. Finally, we present experimental results for MTF measurement using self-printed targets and compare them to the results obtained with standard targets.

Crowdsourcing quality control for Dark Energy Survey images

DOE PAGES

Melchior, P.

2016-07-01

We have developed a crowdsourcing web application for image quality control employed by the Dark Energy Survey. Dubbed the "DES exposure checker", it renders science-grade images directly to a web browser and allows users to mark problematic features from a set of predefined classes. Users can also generate custom labels and thus help identify previously unknown problem classes. User reports are fed back to hardware and software experts to help mitigate and eliminate recognized issues. We report on the implementation of the application and our experience with its over 100 users, the majority of which are professional or prospective astronomersmore » but not data management experts. We discuss aspects of user training and engagement, and demonstrate how problem reports have been pivotal to rapidly correct artifacts which would likely have been too subtle or infrequent to be recognized otherwise. We conclude with a number of important lessons learned, suggest possible improvements, and recommend this collective exploratory approach for future astronomical surveys or other extensive data sets with a sufficiently large user base. We also release open-source code of the web application and host an online demo versionat http://des-exp-checker.pmelchior.net« less

Crowdsourcing quality control for Dark Energy Survey images

NASA Astrophysics Data System (ADS)

Melchior, P.; Sheldon, E.; Drlica-Wagner, A.; Rykoff, E. S.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Brooks, D.; Buckley-Geer, E.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Crocce, M.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Doel, P.; Evrard, A. E.; Finley, D. A.; Flaugher, B.; Frieman, J.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Jarvis, M.; Kuehn, K.; Li, T. S.; Maia, M. A. G.; March, M.; Marshall, J. L.; Nord, B.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Vikram, V.; Walker, A. R.; Wester, W.; Zhang, Y.

2016-07-01

We have developed a crowdsourcing web application for image quality control employed by the Dark Energy Survey. Dubbed the "DES exposure checker", it renders science-grade images directly to a web browser and allows users to mark problematic features from a set of predefined classes. Users can also generate custom labels and thus help identify previously unknown problem classes. User reports are fed back to hardware and software experts to help mitigate and eliminate recognized issues. We report on the implementation of the application and our experience with its over 100 users, the majority of which are professional or prospective astronomers but not data management experts. We discuss aspects of user training and engagement, and demonstrate how problem reports have been pivotal to rapidly correct artifacts which would likely have been too subtle or infrequent to be recognized otherwise. We conclude with a number of important lessons learned, suggest possible improvements, and recommend this collective exploratory approach for future astronomical surveys or other extensive data sets with a sufficiently large user base. We also release open-source code of the web application and host an online demo version at http://des-exp-checker.pmelchior.net.

Crowdsourcing quality control for Dark Energy Survey images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melchior, P.

We have developed a crowdsourcing web application for image quality control employed by the Dark Energy Survey. Dubbed the "DES exposure checker", it renders science-grade images directly to a web browser and allows users to mark problematic features from a set of predefined classes. Users can also generate custom labels and thus help identify previously unknown problem classes. User reports are fed back to hardware and software experts to help mitigate and eliminate recognized issues. We report on the implementation of the application and our experience with its over 100 users, the majority of which are professional or prospective astronomersmore » but not data management experts. We discuss aspects of user training and engagement, and demonstrate how problem reports have been pivotal to rapidly correct artifacts which would likely have been too subtle or infrequent to be recognized otherwise. We conclude with a number of important lessons learned, suggest possible improvements, and recommend this collective exploratory approach for future astronomical surveys or other extensive data sets with a sufficiently large user base. We also release open-source code of the web application and host an online demo versionat http://des-exp-checker.pmelchior.net« less

Investigations of image fusion

NASA Astrophysics Data System (ADS)

Zhang, Zhong

1999-12-01

The objective of image fusion is to combine information from multiple images of the same scene. The result of image fusion is a single image which is more suitable for the purpose of human visual perception or further image processing tasks. In this thesis, a region-based fusion algorithm using the wavelet transform is proposed. The identification of important features in each image, such as edges and regions of interest, are used to guide the fusion process. The idea of multiscale grouping is also introduced and a generic image fusion framework based on multiscale decomposition is studied. The framework includes all of the existing multiscale-decomposition- based fusion approaches we found in the literature which did not assume a statistical model for the source images. Comparisons indicate that our framework includes some new approaches which outperform the existing approaches for the cases we consider. Registration must precede our fusion algorithms. So we proposed a hybrid scheme which uses both feature-based and intensity-based methods. The idea of robust estimation of optical flow from time- varying images is employed with a coarse-to-fine multi- resolution approach and feature-based registration to overcome some of the limitations of the intensity-based schemes. Experiments show that this approach is robust and efficient. Assessing image fusion performance in a real application is a complicated issue. In this dissertation, a mixture probability density function model is used in conjunction with the Expectation- Maximization algorithm to model histograms of edge intensity. Some new techniques are proposed for estimating the quality of a noisy image of a natural scene. Such quality measures can be used to guide the fusion. Finally, we study fusion of images obtained from several copies of a new type of camera developed for video surveillance. Our techniques increase the capability and reliability of the surveillance system and provide an easy way to obtain 3-D information of objects in the space monitored by the system.

Processing Near-Infrared Imagery of the Orion Heatshield During EFT-1 Hypersonic Reentry

NASA Technical Reports Server (NTRS)

Spisz, Thomas S.; Taylor, Jeff C.; Gibson, David M.; Kennerly, Steve; Osei-Wusu, Kwame; Horvath, Thomas J.; Schwartz, Richard J.; Tack, Steven; Bush, Brett C.; Oliver, A. Brandon

2016-01-01

The Scientifically Calibrated In-Flight Imagery (SCIFLI) team captured high-resolution, calibrated, near-infrared imagery of the Orion capsule during atmospheric reentry of the EFT-1 mission. A US Navy NP-3D aircraft equipped with a multi-band optical sensor package, referred to as Cast Glance, acquired imagery of the Orion capsule's heatshield during a period when Orion was slowing from approximately Mach 10 to Mach 7. The line-of-sight distance ranged from approximately 65 to 40 nmi. Global surface temperatures of the capsule's thermal heatshield derived from the near-infrared intensity measurements complemented the in-depth (embedded) thermocouple measurements. Moreover, these derived surface temperatures are essential to the assessment of the thermocouples' reliance on inverse heat transfer methods and material response codes to infer the surface temperature from the in-depth measurements. The paper describes the image processing challenges associated with a manually-tracked, high-angular rate air-to-air observation. Issues included management of significant frame-to-frame motions due to both tracking jerk and jitter as well as distortions due to atmospheric effects. Corrections for changing sky backgrounds (including some cirrus clouds), atmospheric attenuation, and target orientations and ranges also had to be made. The image processing goal is to reduce the detrimental effects due to motion (both sensor and capsule), vibration (jitter), and atmospherics for image quality improvement, without compromising the quantitative integrity of the data, especially local intensity (temperature) variations. The paper will detail the approach of selecting and utilizing only the highest quality images, registering several co-temporal image frames to a single image frame to the extent frame-to-frame distortions would allow, and then co-adding the registered frames to improve image quality and reduce noise. Using preflight calibration data, the registered and averaged infrared intensity images were converted to surface temperatures on the Orion capsule's heatshield. Temperature uncertainties will be discussed relative to uncertainties of surface emissivity and atmospheric transmission loss. Comparison of limited onboard surface thermocouple data to the image derived surface temperature will be presented.

Imagery analysis and the need for standards

NASA Astrophysics Data System (ADS)

Grant, Barbara G.

2014-09-01

While efforts within the optics community focus on the development of high-quality systems and data products, comparatively little attention is paid to their use. Our standards for verification and validation are high; but in some user domains, standards are either lax or do not exist at all. In forensic imagery analysis, for example, standards exist to judge image quality, but do not exist to judge the quality of an analysis. In litigation, a high quality analysis is by default the one performed by the victorious attorney's expert. This paper argues for the need to extend quality standards into the domain of imagery analysis, which is expected to increase in national visibility and significance with the increasing deployment of unmanned aerial vehicle—UAV, or "drone"—sensors in the continental U. S.. It argues that like a good radiometric calibration, made as independent of the calibrated instrument as possible, a good analysis should be subject to standards the most basic of which is the separation of issues of scientific fact from analysis results.

Automatic retinal interest evaluation system (ARIES).

PubMed

Yin, Fengshou; Wong, Damon Wing Kee; Yow, Ai Ping; Lee, Beng Hai; Quan, Ying; Zhang, Zhuo; Gopalakrishnan, Kavitha; Li, Ruoying; Liu, Jiang

2014-01-01

In recent years, there has been increasing interest in the use of automatic computer-based systems for the detection of eye diseases such as glaucoma, age-related macular degeneration and diabetic retinopathy. However, in practice, retinal image quality is a big concern as automatic systems without consideration of degraded image quality will likely generate unreliable results. In this paper, an automatic retinal image quality assessment system (ARIES) is introduced to assess both image quality of the whole image and focal regions of interest. ARIES achieves 99.54% accuracy in distinguishing fundus images from other types of images through a retinal image identification step in a dataset of 35342 images. The system employs high level image quality measures (HIQM) to perform image quality assessment, and achieves areas under curve (AUCs) of 0.958 and 0.987 for whole image and optic disk region respectively in a testing dataset of 370 images. ARIES acts as a form of automatic quality control which ensures good quality images are used for processing, and can also be used to alert operators of poor quality images at the time of acquisition.

Influence of X-ray scatter radiation on image quality in Digital Breast Tomosynthesis (DBT)

NASA Astrophysics Data System (ADS)

Rodrigues, M. J.; Di Maria, S.; Baptista, M.; Belchior, A.; Afonso, J.; Venâncio, J.; Vaz, P.

2017-11-01

Digital breast tomosynthesis (DBT) is a quasi-three-dimensional imaging technique that was developed to solve the principal limitation of mammography, namely the overlapping tissue effect. This issue in standard mammography (SM) leads to two main problems: low sensitivity (difficulty to detect lesions) and low specificity (non-negligible percentage of false positives). Although DBT is now being introduced in clinical practice the features of this technique have not yet been fully and accurately assessed. Consequently, optimization studies in terms of choosing the most suitable parameters which maximize image quality according to the known limits of breast dosimetry are currently performing. In DBT, scatter radiation can lead to a loss of contrast and to an increase of image noise by reducing the signal-to-difference-noise ratio (SDNR) of a lesion. Moreover the use of an anti-scatter grid is a concern due to the low exposure of the photon flux available per projection. For this reason the main aim of this study was to analyze the influence of the scatter radiation on image quality and the dose delivered to the breast. In particular a detailed analysis of the scatter radiation on the optimal energy that maximizes the SDNR was performed for different monochromatic energies and voltages. To reach this objective the PenEasy Monte Carlo (MC) simulation tool imbedded in the general-purpose main program PENELOPE, was used. After a successful validation of the MC model with measurements, 2D projection images of primary, coherent and incoherent photons were obtained. For that, a homogeneous breast phantom (2, 4, 6, 8 cm) with 25%, 50% and 75% glandular compositions was used, including a 5 mm thick tumor. The images were generated for each monochromatic X-ray energies in the range from 16 keV to 32 keV. For each angular projection considered (25 angular projections covering an arc of 50°) the scatter-to-primary ratio (SPR), the mean glandular dose (MGD) and the signal difference to noise ratio (SDNR) were calculated with the aim to assess/determine in which conditions (i.e. energy, angular projection, breast thickness) the scatter radiation affects the image quality. The obtained results on the aforementioned quantities and topics will be reported.

Naturalness and interestingness of test images for visual quality evaluation

NASA Astrophysics Data System (ADS)

Halonen, Raisa; Westman, Stina; Oittinen, Pirkko

2011-01-01

Balanced and representative test images are needed to study perceived visual quality in various application domains. This study investigates naturalness and interestingness as image quality attributes in the context of test images. Taking a top-down approach we aim to find the dimensions which constitute naturalness and interestingness in test images and the relationship between these high-level quality attributes. We compare existing collections of test images (e.g. Sony sRGB images, ISO 12640 images, Kodak images, Nokia images and test images developed within our group) in an experiment combining quality sorting and structured interviews. Based on the data gathered we analyze the viewer-supplied criteria for naturalness and interestingness across image types, quality levels and judges. This study advances our understanding of subjective image quality criteria and enables the validation of current test images, furthering their development.

Evaluation of the visual performance of image processing pipes: information value of subjective image attributes

NASA Astrophysics Data System (ADS)

Nyman, G.; Häkkinen, J.; Koivisto, E.-M.; Leisti, T.; Lindroos, P.; Orenius, O.; Virtanen, T.; Vuori, T.

2010-01-01

Subjective image quality data for 9 image processing pipes and 8 image contents (taken with mobile phone camera, 72 natural scene test images altogether) from 14 test subjects were collected. A triplet comparison setup and a hybrid qualitative/quantitative methodology were applied. MOS data and spontaneous, subjective image quality attributes to each test image were recorded. The use of positive and negative image quality attributes by the experimental subjects suggested a significant difference between the subjective spaces of low and high image quality. The robustness of the attribute data was shown by correlating DMOS data of the test images against their corresponding, average subjective attribute vector length data. The findings demonstrate the information value of spontaneous, subjective image quality attributes in evaluating image quality at variable quality levels. We discuss the implications of these findings for the development of sensitive performance measures and methods in profiling image processing systems and their components, especially at high image quality levels.

Ultrasound breast imaging using frequency domain reverse time migration

NASA Astrophysics Data System (ADS)

Roy, O.; Zuberi, M. A. H.; Pratt, R. G.; Duric, N.

2016-04-01

Conventional ultrasonography reconstruction techniques, such as B-mode, are based on a simple wave propagation model derived from a high frequency approximation. Therefore, to minimize model mismatch, the central frequency of the input pulse is typically chosen between 3 and 15 megahertz. Despite the increase in theoretical resolution, operating at higher frequencies comes at the cost of lower signal-to-noise ratio. This ultimately degrades the image contrast and overall quality at higher imaging depths. To address this issue, we investigate a reflection imaging technique, known as reverse time migration, which uses a more accurate propagation model for reconstruction. We present preliminary simulation results as well as physical phantom image reconstructions obtained using data acquired with a breast imaging ultrasound tomography prototype. The original reconstructions are filtered to remove low-wavenumber artifacts that arise due to the inclusion of the direct arrivals. We demonstrate the advantage of using an accurate sound speed model in the reverse time migration process. We also explain how the increase in computational complexity can be mitigated using a frequency domain approach and a parallel computing platform.

Denoised ordered subset statistically penalized algebraic reconstruction technique (DOS-SPART) in digital breast tomosynthesis

NASA Astrophysics Data System (ADS)

Garrett, John; Li, Yinsheng; Li, Ke; Chen, Guang-Hong

2017-03-01

Digital breast tomosynthesis (DBT) is a three dimensional (3D) breast imaging modality in which projections are acquired over a limited angular span around the compressed breast and reconstructed into image slices parallel to the detector. DBT has been shown to help alleviate the breast tissue overlapping issues of two dimensional (2D) mammography. Since the overlapping tissues may simulate cancer masses or obscure true cancers, this improvement is critically important for improved breast cancer screening and diagnosis. In this work, a model-based image reconstruction method is presented to show that spatial resolution in DBT volumes can be maintained while dose is reduced using the presented method when compared to that of a state-of-the-art commercial reconstruction technique. Spatial resolution was measured in phantom images and subjectively in a clinical dataset. Noise characteristics were explored in a cadaver study. In both the quantitative and subjective results the image sharpness was maintained and overall image quality was maintained at reduced doses when the model-based iterative reconstruction was used to reconstruct the volumes.

Multi-focus image fusion with the all convolutional neural network

NASA Astrophysics Data System (ADS)

Du, Chao-ben; Gao, She-sheng

2018-01-01

A decision map contains complete and clear information about the image to be fused, which is crucial to various image fusion issues, especially multi-focus image fusion. However, in order to get a satisfactory image fusion effect, getting a decision map is very necessary and usually difficult to finish. In this letter, we address this problem with convolutional neural network (CNN), aiming to get a state-of-the-art decision map. The main idea is that the max-pooling of CNN is replaced by a convolution layer, the residuals are propagated backwards by gradient descent, and the training parameters of the individual layers of the CNN are updated layer by layer. Based on this, we propose a new all CNN (ACNN)-based multi-focus image fusion method in spatial domain. We demonstrate that the decision map obtained from the ACNN is reliable and can lead to high-quality fusion results. Experimental results clearly validate that the proposed algorithm can obtain state-of-the-art fusion performance in terms of both qualitative and quantitative evaluations.

Close Range Uav Accurate Recording and Modeling of St-Pierre Neo-Romanesque Church in Strasbourg (france)

NASA Astrophysics Data System (ADS)

Murtiyoso, A.; Grussenmeyer, P.; Freville, T.

2017-02-01

Close-range photogrammetry is an image-based technique which has often been used for the 3D documentation of heritage objects. Recently, advances in the field of image processing and UAVs (Unmanned Aerial Vehicles) have resulted in a renewed interest in this technique. However, commercially ready-to-use UAVs are often equipped with smaller sensors in order to minimize payload and the quality of the documentation is still an issue. In this research, two commercial UAVs (the Sensefly Albris and DJI Phantom 3 Professional) were setup to record the 19th century St-Pierre-le-Jeune church in Strasbourg, France. Several software solutions (commercial and open source) were used to compare both UAVs' images in terms of calibration, accuracy of external orientation, as well as dense matching. Results show some instability in regards to the calibration of Phantom 3, while the Albris had issues regarding its aerotriangulation results. Despite these shortcomings, both UAVs succeeded in producing dense point clouds of up to a few centimeters in accuracy, which is largely sufficient for the purposes of a city 3D GIS (Geographical Information System). The acquisition of close range images using UAVs also provides greater LoD flexibility in processing. These advantages over other methods such as the TLS (Terrestrial Laser Scanning) or terrestrial close range photogrammetry can be exploited in order for these techniques to complement each other.

Helicopter flights with night-vision goggles: Human factors aspects

NASA Technical Reports Server (NTRS)

Brickner, Michael S.

1989-01-01

Night-vision goggles (NVGs) and, in particular, the advanced, helmet-mounted Aviators Night-Vision-Imaging System (ANVIS) allows helicopter pilots to perform low-level flight at night. It consists of light intensifier tubes which amplify low-intensity ambient illumination (star and moon light) and an optical system which together produce a bright image of the scene. However, these NVGs do not turn night into day, and, while they may often provide significant advantages over unaided night flight, they may also result in visual fatigue, high workload, and safety hazards. These problems reflect both system limitations and human-factors issues. A brief description of the technical characteristics of NVGs and of human night-vision capabilities is followed by a description and analysis of specific perceptual problems which occur with the use of NVGs in flight. Some of the issues addressed include: limitations imposed by a restricted field of view; problems related to binocular rivalry; the consequences of inappropriate focusing of the eye; the effects of ambient illumination levels and of various types of terrain on image quality; difficulties in distance and slope estimation; effects of dazzling; and visual fatigue and superimposed symbology. These issues are described and analyzed in terms of their possible consequences on helicopter pilot performance. The additional influence of individual differences among pilots is emphasized. Thermal imaging systems (forward looking infrared (FLIR)) are described briefly and compared to light intensifier systems (NVGs). Many of the phenomena which are described are not readily understood. More research is required to better understand the human-factors problems created by the use of NVGs and other night-vision aids, to enhance system design, and to improve training methods and simulation techniques.

Imaging and applied optics: introduction to the feature issue.

PubMed

Zalevsky, Zeev; Arnison, Matthew R; Javidi, Bahram; Testorf, Markus

2018-03-01

This special issue of Applied Optics contains selected papers from OSA's Imaging Congress with particular emphasis on work from mathematics in imaging, computational optical sensing and imaging, imaging systems and applications, and 3D image acquisition and display.

Limited role of body satisfaction and body image self-consciousness in sexual frequency and satisfaction in pregnant women.

PubMed

Radoš, Sandra Nakić; Vraneš, Hrvojka Soljačić; Šunjić, Marijana

2014-01-01

This cross-sectional study examined the role of maternal body image and body image self-consciousness in sexual satisfaction and intercourse frequency during pregnancy when controlling for satisfaction with partnership. Pregnant women in their third trimester of pregnancy (N = 150) participated in the study. Body image was measured by the Body Areas Satisfaction Scale (BASS) and Body Image Self-Consciousness Scale (BISC), while relationship satisfaction was measured by different subscales of the Perceived Quality of Marital Relationship (PQMR) Scale. Sexual satisfaction was also measured by one of the subscales of the PQMR (Intimate Relationship). The sexual behavior questionnaire comprised questions about frequency of sexual intercourse, desire, and other aspects of sexual functioning as well as the reasons that might prevent women from having intercourse during pregnancy. Findings suggested that satisfaction with body image and body image self-consciousness were related to sexual satisfaction. Nevertheless, other aspects of partnership, such as communication, appeared to be much more important predictors of sexual satisfaction than body image variables. The best predictor of sexual frequency was fear that intercourse might harm the fetus. Implications for education about sexuality issues in pregnancy are discussed.

Halftoning processing on a JPEG-compressed image

NASA Astrophysics Data System (ADS)

Sibade, Cedric; Barizien, Stephane; Akil, Mohamed; Perroton, Laurent

2003-12-01

Digital image processing algorithms are usually designed for the raw format, that is on an uncompressed representation of the image. Therefore prior to transforming or processing a compressed format, decompression is applied; then, the result of the processing application is finally re-compressed for further transfer or storage. The change of data representation is resource-consuming in terms of computation, time and memory usage. In the wide format printing industry, this problem becomes an important issue: e.g. a 1 m2 input color image, scanned at 600 dpi exceeds 1.6 GB in its raw representation. However, some image processing algorithms can be performed in the compressed-domain, by applying an equivalent operation on the compressed format. This paper is presenting an innovative application of the halftoning processing operation by screening, to be applied on JPEG-compressed image. This compressed-domain transform is performed by computing the threshold operation of the screening algorithm in the DCT domain. This algorithm is illustrated by examples for different halftone masks. A pre-sharpening operation, applied on a JPEG-compressed low quality image is also described; it allows to de-noise and to enhance the contours of this image.

Emergent technologies: 25 years

NASA Astrophysics Data System (ADS)

Rising, Hawley K.

2013-03-01

This paper will talk about the technologies that have been emerging over the 25 years since the Human Vision and Electronic Imaging conference began that the conference has been a part of, and that have been a part of the conference, and will look at those technologies that are emerging today, such as social networks, haptic technologies, and still emerging imaging technologies, and what we might look at for the future.Twenty-five years is a long time, and it is not without difficulty that we remember what was emerging in the late 1980s. Yet to be developed: The first commercial digital still camera was not yet on the market, although there were hand held electronic cameras. Personal computers were not displaying standardized images, and image quality was not something that could be talked about in a standardized fashion, if only because image compression algorithms were not standardized yet for several years hence. Even further away were any standards for movie compression standards, there was no personal computer even on the horizon which could display them. What became an emergent technology and filled many sessions later, image comparison and search, was not possible, nor the current emerging technology of social networks- the world wide web was still several years away. Printer technology was still devising dithers and image size manipulations which would consume many years, as would scanning technology, and image quality for both was a major issue for dithers and Fourier noise.From these humble beginnings to the current moves that are changing computing and the meaning of both electronic devices and human interaction with them, we will see a course through the changing technology that holds some features constant for many years, while others come and go.

Strategic planning for radiology: opening an outpatient diagnostic imaging center.

PubMed

Leepson, Evan

2003-01-01

Launching a new diagnostic imaging center involves very specific requirements and roadmaps, including five major areas of change that have a direct impact on planning: Imaging and communication technology Finances and reimbursement Ownership structure of imaging entities Critical workforce shortages Imaging is moving outside radiology First, planning must focus on the strategic level of any organization, whether it is a multi-national corporation or a six-person radiology group. Think of all organizations as a triangle with three horizontal levels: strategic, managerial and operational. The strategic level of decision-making is at the top of the triangle, and here is where planning must take place. For strategic planning to work, there must be focused time and energy spent on this activity, usually away from the reading room and imaging center. There are five planning strategies, which must have the explicit goal of developing and growing the imaging center. The five strategies are: Clinical and quality issues, Governance and administration, Technology, Relationships, Marketing and business development. The best way to plan and implement these strategies is to create work groups of radiologists, technologists, and administrative and support staff. Once the group agrees on the strategy and tactic, it takes responsibility for implementation. Embarking on the launch of a new outpatient diagnostic imaging center is no small undertaking, and anyone who has struggled with such an endeavor can readily attest to the associated challenges and benefits. Success depends on many things, and one of the most important factors relates to the amount of time and the quality of effort spent on strategic planning at the outset. Neglecting or skimping on this phase may lead to unforeseen obstacles that could potentially derail the project.

Variation in the use of advanced imaging at the time of breast cancer diagnosis in a statewide registry.

PubMed

Henry, N Lynn; Braun, Thomas M; Breslin, Tara M; Gorski, David H; Silver, Samuel M; Griggs, Jennifer J

2017-08-01

Although national guidelines do not recommend extent of disease imaging for patients with newly diagnosed early stage breast cancer given that the harm outweighs the benefits, high rates of testing have been documented. The 2012 Choosing Wisely guidelines specifically addressed this issue. We examined the change over time in imaging use across a statewide collaborative, as well as the reasons for performing imaging and the impact on cost of care. Clinicopathologic data and use of advanced imaging tests (positron emission tomography, computed tomography, and bone scan) were abstracted from the medical records of patients treated at 25 participating sites in the Michigan Breast Oncology Quality Initiative (MiBOQI). For patients diagnosed in 2014 and 2015, reasons for testing were abstracted from the medical record. Of the 34,078 patients diagnosed with stage 0-II breast cancer between 2008 and 2015 in MiBOQI, 6853 (20.1%) underwent testing with at least 1 imaging modality in the 90 days after diagnosis. There was considerable variability in rates of testing across the 25 sites for all stages of disease. Between 2008 and 2015, testing decreased over time for patients with stage 0-IIA disease (all P < .001) and remained stable for stage IIB disease (P = .10). This decrease in testing over time resulted in a cost savings, especially for patients with stage I disease. Use of advanced imaging at the time of diagnosis decreased over time in a large statewide collaborative. Additional interventions are warranted to further reduce rates of unnecessary imaging to improve quality of care for patients with breast cancer. Cancer 2017;123:2975-83. © 2017 American Cancer Society. © 2017 American Cancer Society.

78 FR 66929 - Meetings of the Local Government Advisory Committee and the Small Communities Advisory...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-07

... systems waste treatment, water infrastructure, air quality issues and other issues and recommendations... Plan, air quality issues, brownfield clean ups, water quality issues, environmental justice and other...

A comparison of peripheral imaging technologies for bone and muscle quantification: a technical review of image acquisition

PubMed Central

Wong, A.K.O.

2016-01-01

The choice of an appropriate imaging technique to quantify bone, muscle, or muscle adiposity needs to be guided by a thorough understanding of its competitive advantages over other modalities balanced by its limitations. This review details the technical machinery and methods behind peripheral quantitative computed tomography (pQCT), high-resolution (HR)-pQCT, and magnetic resonance imaging (MRI) that drive successful depiction of bone and muscle morphometry, densitometry, and structure. It discusses a number of image acquisition settings, the challenges associated with using one versus another, and compares the risk-benefits across the different modalities. Issues related to all modalities including partial volume artifact, beam hardening, calibration, and motion assessment are also detailed. The review further provides data and images to illustrate differences between methods to better guide the reader in selecting an imaging method strategically. Overall, investigators should be cautious of the impact of imaging parameters on image signal or contrast-to-noise-ratios, and the need to report these settings in future publications. The effect of motion should be assessed on images and a decision made to exclude prior to segmentation. A more standardized approach to imaging bone and muscle on pQCT and MRI could enhance comparability across studies and could improve the quality of meta-analyses. PMID:27973379

A comparison of peripheral imaging technologies for bone and muscle quantification: a technical review of image acquisition.

PubMed

Wong, A K

2016-12-14

The choice of an appropriate imaging technique to quantify bone, muscle, or muscle adiposity needs to be guided by a thorough understanding of its competitive advantages over other modalities balanced by its limitations. This review details the technical machinery and methods behind peripheral quantitative computed tomography (pQCT), high-resolution (HR)-pQCT, and magnetic resonance imaging (MRI) that drive successful depiction of bone and muscle morphometry, densitometry, and structure. It discusses a number of image acquisition settings, the challenges associated with using one versus another, and compares the risk-benefits across the different modalities. Issues related to all modalities including partial volume artifact, beam hardening, calibration, and motion assessment are also detailed. The review further provides data and images to illustrate differences between methods to better guide the reader in selecting an imaging method strategically. Overall, investigators should be cautious of the impact of imaging parameters on image signal or contrast-to-noise-ratios, and the need to report these settings in future publications. The effect of motion should be assessed on images and a decision made to exclude prior to segmentation. A more standardized approach to imaging bone and muscle on pQCT and MRI could enhance comparability across studies and could improve the quality of meta-analyses.

[Quality of life in women with pelvic floor dysfunction].

PubMed

Segedi, Ljiljana Mladenović; Ilić, Katarina Parezanović; Curcić, Aleksandar; Visnjevac, Nemanja

2011-11-01

Pelvic floor dysfunction is a frequent problem affecting more than 50% of women in peri- and postmenopause. Considering that ageing and menopause befall in the significant factors causing this issue, as well as the expected longevity of women in the world and in our country, pelvic floor dysfunction prevelence is foreseen to be even higher. The aim of the study was to evaluate impact of the symptoms of pelvic dysfunction on quality of life and examine body image satisfaction in adult women with pelvic organ prolapse presenting to tertiary care clinic for surgical treatment. This prospective case-control study included 50 patients who presented to tertiary care gynecology clinic for surgical treatment and 50 controls with normal pelvic floor support and without urinary incontinence who presented tertiary care gynecology clinic for other reasons. Both, patients and controls, completed two quastionnaires recommended for the evaluation of symptoms (Pelvic floor distress inventory - short forms) and quality of life impact (Pelvic floor impact questionnaire - short form) of pelvic organ prolapse, and Body Image Scale. The patients scored significantly worse on the prolapse, urinary, colorectal scales and overall score of Pelvic floor distress inventory--20 than controls subjects (134.91 vs 78.08; p < 0.01). The patients also measured significant decrease in condition-specific quality of life (89.23 vs 3.1; p < 0.01). They were more likely to feel self-conscious (78% vs 42%; p < 0.01), less likely to feel physically attractive (78% vs 22%; p < 0.01), more likely to have difficulty looking at themselves naked (70% vs 42%; p < 0.01), less likely to feel sexually attractive (64% vs 32%; p < 0.01), and less likely to feel feminine (56% vs 16%; p < 0.05), than controls. There were no differencies in their feeling of dissatisfaction with appearance when dressed, avoiding people because of appereance and overall dissatisfaction with their body. There was a positive correlation between decreased quality of life and body image in women with pelvic dysfunction. Women with pelvic floor dysfunction have decreased quality of life and body image.

Towards better digital pathology workflows: programming libraries for high-speed sharpness assessment of Whole Slide Images

PubMed Central

2014-01-01

Background Since microscopic slides can now be automatically digitized and integrated in the clinical workflow, quality assessment of Whole Slide Images (WSI) has become a crucial issue. We present a no-reference quality assessment method that has been thoroughly tested since 2010 and is under implementation in multiple sites, both public university-hospitals and private entities. It is part of the FlexMIm R&D project which aims to improve the global workflow of digital pathology. For these uses, we have developed two programming libraries, in Java and Python, which can be integrated in various types of WSI acquisition systems, viewers and image analysis tools. Methods Development and testing have been carried out on a MacBook Pro i7 and on a bi-Xeon 2.7GHz server. Libraries implementing the blur assessment method have been developed in Java, Python, PHP5 and MySQL5. For web applications, JavaScript, Ajax, JSON and Sockets were also used, as well as the Google Maps API. Aperio SVS files were converted into the Google Maps format using VIPS and Openslide libraries. Results We designed the Java library as a Service Provider Interface (SPI), extendable by third parties. Analysis is computed in real-time (3 billion pixels per minute). Tests were made on 5000 single images, 200 NDPI WSI, 100 Aperio SVS WSI converted to the Google Maps format. Conclusions Applications based on our method and libraries can be used upstream, as calibration and quality control tool for the WSI acquisition systems, or as tools to reacquire tiles while the WSI is being scanned. They can also be used downstream to reacquire the complete slides that are below the quality threshold for surgical pathology analysis. WSI may also be displayed in a smarter way by sending and displaying the regions of highest quality before other regions. Such quality assessment scores could be integrated as WSI's metadata shared in clinical, research or teaching contexts, for a more efficient medical informatics workflow. PMID:25565494

EDITORIAL: Imaging systems and techniques Imaging systems and techniques

NASA Astrophysics Data System (ADS)

Yang, Wuqiang; Giakos, George; Nikita, Konstantina; Pastorino, Matteo; Karras, Dimitrios

2009-10-01

The papers in this special issue focus on providing the state-of-the-art approaches and solutions to some of the most challenging imaging areas, such as the design, development, evaluation and applications of imaging systems, measuring techniques, image processing algorithms and instrumentation, with an ultimate aim of enhancing the measurement accuracy and image quality. This special issue explores the principles, engineering developments and applications of new imaging systems and techniques, and encourages broad discussion of imaging methodologies, shaping the future and identifying emerging trends. The multi-faceted field of imaging requires drastic adaptation to the rapid changes in our society, economy, environment and technological evolution. There is an urgent need to address new problems, which tend to be either static but complex, or dynamic, e.g. rapidly evolving with time, with many unknowns, and to propose innovative solutions. For instance, the battles against cancer and terror, monitoring of space resources and enhanced awareness, management of natural resources and environmental monitoring are some of the areas that need to be addressed. The complexity of the involved imaging scenarios and demanding design parameters, e.g. speed, signal-to-noise ratio (SNR), specificity, contrast, spatial resolution, scatter rejection, complex background and harsh environments, necessitate the development of a multi-functional, scalable and efficient imaging suite of sensors, solutions driven by innovation, and operation on diverse detection and imaging principles. Efficient medical imaging techniques capable of providing physiological information at the molecular level present another important research area. Advanced metabolic and functional imaging techniques, operating on multiple physical principles, and using high-resolution, high-selectivity nano-imaging methods, quantum dots, nanoparticles, biomarkers, nanostructures, nanosensors, micro-array imaging chips and nano-clinics for optical diagnostics and targeted therapy, can play an important role in the diagnosis and treatment of cancer. These techniques can also be used to provide efficient drug delivery for treatment of other diseases, with increased sensitivity and specificity. Similarly, enhanced stand-off detection, classification, identification and surveillance techniques, for comprehensive civilian and military target protection and enhanced space situational awareness can open new frontiers of research and applications in the defence arena and homeland security. For instance, the development of potential imaging sensor architectures, enhanced remote sensing systems, ladars, lidars and radars can provide data capable of ensuring continuous monitoring of various imaging/physical/chemical parameters under different operating conditions, using both active and passive detection principles, reconfigurable and scalable focal plane array architectures, reliable systems for stand-off detection of explosives, and enhanced airport security. The above areas pose challenging problems to the technical community and indicate an ever-growing need for innovative and auspicious solutions. We would like to thank all authors for their valuable contributions, without which this special issue would not have become reality.

Strategic issues in preventing cataract blindness in developing countries.

PubMed Central

Ellwein, L. B.; Kupfer, C.

1995-01-01

Cataract blindness is a public health problem of major proportions in developing countries. Intracapsular cataract extraction with aphakic spectacles has been the standard surgical technique for restoring sight. Because of image magnification in the operated eye, however, the result in unilaterally blind patients is less than satisfactory. Fortunately, with the availability of low-cost intraocular lenses (IOL) and ophthalmologists trained in extracapsular surgery, it is now practical to intervene successfully in the unilateral case. The need for increased attention on the quality of the visual high prevalence of cataract blindness in developing countries and an increasing cataract incidence due to an aging population require substantial increases in surgical volume. The third issue relates to cost. If significant increases in surgical volume and quality of outcomes are to be realized without an increased need for external funding, service delivery must be made more efficient. The expansion of IOL surgery for unilateral blindness is a favourable trend in ensuring financial sustainability of delivery systems; patients can be operated on while still economically productive and able to pay rather than waiting for bilateral blindness and a less favourable economic and social impact. If the quality, volume, and cost issues are to be successfully addressed, operational and structural changes to eye care delivery systems are necessary. These changes can be effected through training, technology introduction, management of facilities, social marketing, organizational partnerships, and evaluation. With improved understanding of the critical factors in successful models their widespread replication will be facilitated. PMID:8846495

Noise Estimation and Quality Assessment of Gaussian Noise Corrupted Images

NASA Astrophysics Data System (ADS)

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seibert, J; Imbergamo, P

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, highmore » 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.« less

Compression and Transmission of RF Signals for Telediagnosis

NASA Astrophysics Data System (ADS)

Seko, Toshihiro; Doi, Motonori; Oshiro, Osamu; Chihara, Kunihiro

2000-05-01

Health care is a critical issue nowadays. Much emphasis is given to quality care for all people. Telediagnosis has attracted public attention. We propose a new method of ultrasound image transmission for telediagnosis. In conventional methods, video image signals are transmitted. In our method, the RF signals which are acquired by an ultrasound probe, are transmitted. The RF signals can be transformed to color Doppler images or high-resolution images by a receiver. Because a stored form is adopted, the proposed system can be realized with existent technology such as hyper text transfer protocol (HTTP) and file transfer protocol (FTP). In this paper, we describe two lossless compression methods which specialize in the transmission of RF signals. One of the methods uses the characteristics of the RF signal. In the other method, the amount of the data is reduced. Measurements were performed in water targeting an iron block and triangular Styrofoam. Additionally, abdominal fat measurement was performed. Our method achieved a compression rate of 13% with 8 bit data.

Earth mapping - aerial or satellite imagery comparative analysis

NASA Astrophysics Data System (ADS)

Fotev, Svetlin; Jordanov, Dimitar; Lukarski, Hristo

Nowadays, solving the tasks for revision of existing map products and creation of new maps requires making a choice of the land cover image source. The issue of the effectiveness and cost of the usage of aerial mapping systems versus the efficiency and cost of very-high resolution satellite imagery is topical [1, 2, 3, 4]. The price of any remotely sensed image depends on the product (panchromatic or multispectral), resolution, processing level, scale, urgency of task and on whether the needed image is available in the archive or has to be requested. The purpose of the present work is: to make a comparative analysis between the two approaches for mapping the Earth having in mind two parameters: quality and cost. To suggest an approach for selection of the map information sources - airplane-based or spacecraft-based imaging systems with very-high spatial resolution. Two cases are considered: area that equals approximately one satellite scene and area that equals approximately the territory of Bulgaria.

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

PubMed

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.

Inspection of fecal contamination on strawberries using fluorescence imaging

NASA Astrophysics Data System (ADS)

Chuang, Yung-Kun; Yang, Chun-Chieh; Kim, Moon S.; Delwiche, Stephen R.; Lo, Y. Martin; Chen, Suming; Chan, Diane E.

2013-05-01

Fecal contamination of produce is a food safety issue associated with pathogens such as Escherichia coli that can easily pollute agricultural products via animal and human fecal matters. Outbreaks of foodborne illnesses associated with consuming raw fruits and vegetables have occurred more frequently in recent years in the United States. Among fruits, strawberry is one high-potential vector of fecal contamination and foodborne illnesses since the fruit is often consumed raw and with minimal processing. In the present study, line-scan LED-induced fluorescence imaging techniques were applied for inspection of fecal material on strawberries, and the spectral characteristics and specific wavebands of strawberries were determined by detection algorithms. The results would improve the safety and quality of produce consumed by the public.

Practical guide for implementing hybrid PET/MR clinical service: lessons learned from our experience

PubMed Central

Parikh, Nainesh; Friedman, Kent P.; Shah, Shetal N.; Chandarana, Hersh

2015-01-01

Positron emission tomography (PET) and magnetic resonance imaging, until recently, have been performed on separate PET and MR systems with varying temporal delay between the two acquisitions. The interpretation of these two separately acquired studies requires cognitive fusion by radiologists/nuclear medicine physicians or dedicated and challenging post-processing. Recent advances in hardware and software with introduction of hybrid PET/MR systems have made it possible to acquire the PET and MR images simultaneously or near simultaneously. This review article serves as a road-map for clinical implementation of hybrid PET/MR systems and briefly discusses hardware systems, the personnel needs, safety and quality issues, and reimbursement topics based on experience at NYU Langone Medical Center and Cleveland Clinic. PMID:25985966

Clinical image quality evaluation for panoramic radiography in Korean dental clinics

PubMed Central

Choi, Bo-Ram; Choi, Da-Hye; Huh, Kyung-Hoe; Yi, Won-Jin; Heo, Min-Suk; Choi, Soon-Chul; Bae, Kwang-Hak

2012-01-01

Purpose The purpose of this study was to investigate the level of clinical image quality of panoramic radiographs and to analyze the parameters that influence the overall image quality. Materials and Methods Korean dental clinics were asked to provide three randomly selected panoramic radiographs. An oral and maxillofacial radiology specialist evaluated those images using our self-developed Clinical Image Quality Evaluation Chart. Three evaluators classified the overall image quality of the panoramic radiographs and evaluated the causes of imaging errors. Results A total of 297 panoramic radiographs were collected from 99 dental hospitals and clinics. The mean of the scores according to the Clinical Image Quality Evaluation Chart was 79.9. In the classification of the overall image quality, 17 images were deemed 'optimal for obtaining diagnostic information,' 153 were 'adequate for diagnosis,' 109 were 'poor but diagnosable,' and nine were 'unrecognizable and too poor for diagnosis'. The results of the analysis of the causes of the errors in all the images are as follows: 139 errors in the positioning, 135 in the processing, 50 from the radiographic unit, and 13 due to anatomic abnormality. Conclusion Panoramic radiographs taken at local dental clinics generally have a normal or higher-level image quality. Principal factors affecting image quality were positioning of the patient and image density, sharpness, and contrast. Therefore, when images are taken, the patient position should be adjusted with great care. Also, standardizing objective criteria of image density, sharpness, and contrast is required to evaluate image quality effectively. PMID:23071969

Sensitive test for sea mine identification based on polarization-aided image processing.

PubMed

Leonard, I; Alfalou, A; Brosseau, C

2013-12-02

Techniques are widely sought to detect and identify sea mines. This issue is characterized by complicated mine shapes and underwater light propagation dependencies. In a preliminary study we use a preprocessing step for denoising underwater images before applying the algorithm for mine detection. Once a mine is detected, the protocol for identifying it is activated. Among many correlation filters, we have focused our attention on the asymmetric segmented phase-only filter for quantifying the recognition rate because it allows us to significantly increase the number of reference images in the fabrication of this filter. Yet they are not entirely satisfactory in terms of recognition rate and the obtained images revealed to be of low quality. In this report, we propose a way to improve upon this preliminary study by using a single wavelength polarimetric camera in order to denoise the images. This permits us to enhance images and improve depth visibility. We present illustrative results using in situ polarization imaging of a target through a milk-water mixture and demonstrate that our challenging objective of increasing the detection rate and decreasing the false alarm rate has been achieved.

Radiologic Assessment of Patellofemoral Pain in the Athlete

PubMed Central

Endo, Yoshimi; Stein, Beth E. Shubin; Potter, Hollis G.

2011-01-01

Context: Although disorders of the patellofemoral joint are common in the athlete, their management can be challenging and require a thorough physical examination and radiologic evaluation, including advanced magnetic resonance imaging techniques. Evidence Acquisition: Relevant articles were searched under OVID and MEDLINE (1968 to 2010) using the keywords patellofemoral joint, patellofemoral pain or patella and radiography, imaging, or magnetic resonance imaging, and the referenced sources were reviewed for additional articles. The quality and validity of the studies were assessed on the basis of careful analysis of the materials and methods before their inclusion in this article. Results: Physical examination and imaging evaluation including standard radiographs are crucial in identifying evidence of malalignment or instability. Magnetic resonance imaging provides valuable information about concomitant soft tissue injuries to the medial stabilizers as well as injuries to the articular cartilage, including chondral shears and osteochondral fractures. Quantitative magnetic resonance imaging assessing the ultrastructure of cartilage has shown high correlation with histology and may be useful for timing surgery. Conclusions: Evaluation of patellofemoral disorders is complex and requires a comprehensive assessment. Recent advancements in imaging have made possible a more precise evaluation of the individual anatomy of the patient, addressing issues of malalignment, instability, and underlying cartilage damage. PMID:23016009

Aerospace Technology Innovation. Volume 10

NASA Technical Reports Server (NTRS)

Turner, Janelle (Editor); Cousins, Liz (Editor); Bennett, Evonne (Editor); Vendette, Joel (Editor); West, Kenyon (Editor)

2002-01-01

Whether finding new applications for existing NASA technologies or developing unique marketing strategies to demonstrate them, NASA's offices are committed to identifying unique partnering opportunities. Through their efforts NASA leverages resources through joint research and development, and gains new insight into the core areas relevant to all NASA field centers. One of the most satisfying aspects of my job comes when I learn of a mission-driven technology that can be spun-off to touch the lives of everyday people. NASA's New Partnerships in Medical Diagnostic Imaging is one such initiative. Not only does it promise to provide greater dividends for the country's investment in aerospace research, but also to enhance the American quality of life. This issue of Innovation highlights the new NASA-sponsored initiative in medical imaging. Early in 2001, NASA announced the launch of the New Partnerships in Medical Diagnostic Imaging initiative to promote the partnership and commercialization of NASA technologies in the medical imaging industry. NASA and the medical imaging industry share a number of crosscutting technologies in areas such as high-performance detectors and image-processing tools. Many of the opportunities for joint development and technology transfer to the medical imaging market also hold the promise for future spin back to NASA.

Foundation and methodologies in computer-aided diagnosis systems for breast cancer detection.

PubMed

Jalalian, Afsaneh; Mashohor, Syamsiah; Mahmud, Rozi; Karasfi, Babak; Saripan, M Iqbal B; Ramli, Abdul Rahman B

2017-01-01

Breast cancer is the most prevalent cancer that affects women all over the world. Early detection and treatment of breast cancer could decline the mortality rate. Some issues such as technical reasons, which related to imaging quality and human error, increase misdiagnosis of breast cancer by radiologists. Computer-aided detection systems (CADs) are developed to overcome these restrictions and have been studied in many imaging modalities for breast cancer detection in recent years. The CAD systems improve radiologists' performance in finding and discriminating between the normal and abnormal tissues. These procedures are performed only as a double reader but the absolute decisions are still made by the radiologist. In this study, the recent CAD systems for breast cancer detection on different modalities such as mammography, ultrasound, MRI, and biopsy histopathological images are introduced. The foundation of CAD systems generally consist of four stages: Pre-processing, Segmentation, Feature extraction, and Classification. The approaches which applied to design different stages of CAD system are summarised. Advantages and disadvantages of different segmentation, feature extraction and classification techniques are listed. In addition, the impact of imbalanced datasets in classification outcomes and appropriate methods to solve these issues are discussed. As well as, performance evaluation metrics for various stages of breast cancer detection CAD systems are reviewed.

Whole-slide imaging: routine pathologic diagnosis.

PubMed

Cornish, Toby C; Swapp, Ryan E; Kaplan, Keith J

2012-05-01

Digital pathology systems offer pathologists an alternate, emerging mechanism to manage and interpret information. They offer increasingly fast and scalable hardware platforms for slide scanning and software that facilitates remote viewing, slide conferencing, archiving, and image analysis. Deployed initially and validated largely within the research and biopharmaceutical industries, WSI is increasingly being implemented for direct patient care. Improvements in image quality, scan times, and imageviewing browsers will hopefully allow pathologists to more seamlessly convert to digital pathology, much like our radiology colleagues have done before us. However, WSI creates both opportunities and challenges. Although niche applications of WSI technology for clinical, educational, and research purposes are clearly successful, it is evident that several areas still require attention and careful consideration before more widespread clinical adoption of WSI takes place. These include regulatory issues, development of standards of practice and validation guidelines, workflow modifications, as well as defining situations where WSI technology will really improve practice in a cost-effective way. Current progress on these and other issues, along with improving technology, will no doubt pave the way for increased adoption over the next decade, allowing the pathology community as a whole to harness the true potential of WSI for patient care. The digital decade will likely redefine how pathology is practiced and the role of the pathologist.

Foundation and methodologies in computer-aided diagnosis systems for breast cancer detection

PubMed Central

Jalalian, Afsaneh; Mashohor, Syamsiah; Mahmud, Rozi; Karasfi, Babak; Saripan, M. Iqbal B.; Ramli, Abdul Rahman B.

2017-01-01

Breast cancer is the most prevalent cancer that affects women all over the world. Early detection and treatment of breast cancer could decline the mortality rate. Some issues such as technical reasons, which related to imaging quality and human error, increase misdiagnosis of breast cancer by radiologists. Computer-aided detection systems (CADs) are developed to overcome these restrictions and have been studied in many imaging modalities for breast cancer detection in recent years. The CAD systems improve radiologists' performance in finding and discriminating between the normal and abnormal tissues. These procedures are performed only as a double reader but the absolute decisions are still made by the radiologist. In this study, the recent CAD systems for breast cancer detection on different modalities such as mammography, ultrasound, MRI, and biopsy histopathological images are introduced. The foundation of CAD systems generally consist of four stages: Pre-processing, Segmentation, Feature extraction, and Classification. The approaches which applied to design different stages of CAD system are summarised. Advantages and disadvantages of different segmentation, feature extraction and classification techniques are listed. In addition, the impact of imbalanced datasets in classification outcomes and appropriate methods to solve these issues are discussed. As well as, performance evaluation metrics for various stages of breast cancer detection CAD systems are reviewed. PMID:28435432

Effect of low refocusing angle in T1-weighted spin echo and fast spin echo MRI on low-contrast detectability: a comparative phantom study at 1.5 and 3 Tesla.

PubMed

Sarkar, Subhendra N; Mangosing, Jason L; Sarkar, Pooja R

2013-01-01

MRI tissue contrast is not well preserved at high field. In this work, we used a phantom with known, intrinsic contrast (3.6%) for model tissue pairs to test the effects of low angle refocusing pulses and magnetization transfer from adjacent slices on intrinsic contrast at 1.5 and 3 Tesla. Only T1-weighted spin echo sequences were tested since for such sequences the contrast loss, tissue heating, and image quality degradation at high fields seem to present significant diagnostic and quality issues. We hypothesized that the sources of contrast loss could be attributed to low refocusing angles that do not fulfill the Hahn spin echo conditions or to magnetization transfer effects from adjacent slices in multislice imaging. At 1.5 T the measured contrast was 3.6% for 180° refocusing pulses and 2% for 120° pulses, while at 3 T, it was 4% for 180° and only 1% for 120° refocusing pulses. There was no significant difference between single slice and multislice imaging suggesting little or no role played by magnetization transfer in the phantom chosen. Hence, one may conclude that low angle refocusing pulses not fulfilling the Hahn spin echo conditions are primarily responsible for significant deterioration of T1-weighted spin echo image contrast in high-field MRI.

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

NASA Astrophysics Data System (ADS)

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.

Achieving quality in cardiovascular imaging: proceedings from the American College of Cardiology-Duke University Medical Center Think Tank on Quality in Cardiovascular Imaging.

PubMed

Douglas, Pamela; Iskandrian, Ami E; Krumholz, Harlan M; Gillam, Linda; Hendel, Robert; Jollis, James; Peterson, Eric; Chen, Jersey; Masoudi, Frederick; Mohler, Emile; McNamara, Robert L; Patel, Manesh R; Spertus, John

2006-11-21

Cardiovascular imaging has enjoyed both rapid technological advances and sustained growth, yet less attention has been focused on quality than in other areas of cardiovascular medicine. To address this deficit, representatives from cardiovascular imaging societies, private payers, government agencies, the medical imaging industry, and experts in quality measurement met, and this report provides an overview of the discussions. A consensus definition of quality in imaging and a convergence of opinion on quality measures across imaging modalities was achieved and are intended to be the start of a process culminating in the development, dissemination, and adoption of quality measures for all cardiovascular imaging modalities.

Shape measurement and vibration analysis of moving speaker cone

NASA Astrophysics Data System (ADS)

Zhang, Qican; Liu, Yuankun; Lehtonen, Petri

2014-06-01

Surface three-dimensional (3-D) shape information is needed for many fast processes such as structural testing of material, standing waves on loudspeaker cone, etc. Usually measurement is done from limited number of points using electrical sensors or laser distance meters. Fourier Transform Profilometry (FTP) enables fast shape measurement of the whole surface. Method is based on angled sinusoidal fringe pattern projection and image capturing. FTP requires only one image of the deformed fringe pattern to restore the 3-D shape of the measured object, which makes real-time or dynamic data processing possible. In our experiment the method was used for loudspeaker cone distortion measurement in dynamic conditions. For sound quality issues it is important that the whole cone moves in same phase and there are no partial waves. Our imaging resolution was 1280x1024 pixels and frame rate was 200 fps. Using our setup we found unwanted spatial waves in our sample cone.

[Whole slide imaging technology: from digitization to online applications].

PubMed

Ameisen, David; Le Naour, Gilles; Daniel, Christel

2012-11-01

As e-health becomes essential to modern care, whole slide images (virtual slides) are now an important clinical, teaching and research tool in pathology. Virtual microscopy consists of digitizing a glass slide by acquiring hundreds of tiles of regions of interest at different zoom levels and assembling them into a structured file. This gigapixel image can then be remotely viewed over a terminal, exactly the way pathologists use a microscope. In this article, we will first describe the key elements of this technology, from the acquisition, using a scanner or a motorized microscope, to the broadcasting of virtual slides through a local or distant viewer over an intranet or Internet connection. As virtual slides are now commonly used in virtual classrooms, clinical data and research databases, we will highlight the main issues regarding its uses in modern pathology. Emphasis will be made on quality assurance policies, standardization and scaling. © 2012 médecine/sciences – Inserm / SRMS.

Automated detection of diabetic retinopathy: barriers to translation into clinical practice.

PubMed

Abramoff, Michael D; Niemeijer, Meindert; Russell, Stephen R

2010-03-01

Automated identification of diabetic retinopathy (DR), the primary cause of blindness and visual loss for those aged 18-65 years, from color images of the retina has enormous potential to increase the quality, cost-effectiveness and accessibility of preventative care for people with diabetes. Through advanced image analysis techniques, retinal images are analyzed for abnormalities that define and correlate with the severity of DR. Translating automated DR detection into clinical practice will require surmounting scientific and nonscientific barriers. Scientific concerns, such as DR detection limits compared with human experts, can be studied and measured. Ethical, legal and political issues can be addressed, but are difficult or impossible to measure. The primary objective of this review is to survey the methods, potential benefits and limitations of automated detection in order to better manage translation into clinical practice, based on extensive experience with the systems we have developed.

77 FR 41403 - Meetings of the Local Government Advisory Committee and the Small Communities Advisory...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-13

... Tuesday, July 31, 2012, 1 p.m.-2 p.m. (EDT). The Committee will discuss air quality issues, water quality.... (EDT). The Committee will discuss air quality issues, water quality issues, environmental justice and...

An investigation of flat panel equipment variables on image quality with a dedicated cardiac phantom

NASA Astrophysics Data System (ADS)

Dragusin, O.; Bosmans, H.; Pappas, C.; Desmet, W.

2008-09-01

Image quality (IQ) evaluation plays a key role in the process of optimization of new x-ray systems. Ideally, this process should be supported by real clinical images, but ethical issues and differences in anatomy and pathology of patients make it impossible. Phantom studies might overcome these issues. This paper presents the IQ evaluation of 30 cineangiographic films acquired with a cardiac flat panel system. The phantom used simulates the anatomy of the heart and allows the circulation of contrast agent boluses through coronary arteries. Variables investigated with influence on IQ and radiation dose are: tube potential, detector dose, added Copper filters, dynamic density optimization (DDO) and viewing angle. The IQ evaluation consisted of scoring 4 simulated calcified lesions located on different coronary artery segments in terms of degree of visualization. Eight cardiologists rated the lesions using a five-point scale ((1) lesion not visible to (5) very good visibility). Radiation doses associated to the angiograms are expressed in terms of incident air kerma (IAK) and effective dose that has been calculated with PCXMX software (STUK, Finland) from the exposure settings assuming a standard sized patient of 70 Kg. Mean IQ scores ranged from 1.68 to 4.88. The highest IQ scores were obtained for the angiograms acquired with tube potential 80 kVp, no added Cu filters, DDO 60%, RAO and LAO views and the highest entrance detector dose that has been used in the present study, namely 0.17 μGy/im. Radiation doses (IAK ~40 mGy and effective dose of 1 mSv) were estimated for angiograms acquired at 15 frames s-1, detector field-of-view 20 cm, and a length of 5 s. The following parameters improved the IQ factor significantly: a change in tube potential from 96 to 80 kVp, detector dose from 0.10 μGy/im to 0.17 μGy/im, the absence of Copper filtration. DDO variable which is a post-processing parameter should be carefully evaluated because it alters the quality of the images independently of radiation exposure settings. The SAM anthropomorphic phantom has the advantage of visualization of stenotic lesions during the injection of a contrast agent and using an anatomical background. In the future, this phantom could potentially bridge the gap between physics tests and the clinical reality in the catheterization laboratory.

Blind image quality assessment without training on human opinion scores

NASA Astrophysics Data System (ADS)

Mittal, Anish; Soundararajan, Rajiv; Muralidhar, Gautam S.; Bovik, Alan C.; Ghosh, Joydeep

2013-03-01

We propose a family of image quality assessment (IQA) models based on natural scene statistics (NSS), that can predict the subjective quality of a distorted image without reference to a corresponding distortionless image, and without any training results on human opinion scores of distorted images. These `completely blind' models compete well with standard non-blind image quality indices in terms of subjective predictive performance when tested on the large publicly available `LIVE' Image Quality database.

Quality control and assurance for validation of DOS/I measurements

NASA Astrophysics Data System (ADS)

Cerussi, Albert; Durkin, Amanda; Kwong, Richard; Quang, Timothy; Hill, Brian; Tromberg, Bruce J.; MacKinnon, Nick; Mantulin, William W.

2010-02-01

Ongoing multi-center clinical trials are crucial for Biophotonics to gain acceptance in medical imaging. In these trials, quality control (QC) and assurance (QA) are key to success and provide "data insurance". Quality control and assurance deal with standardization, validation, and compliance of procedures, materials and instrumentation. Specifically, QC/QA involves systematic assessment of testing materials, instrumentation performance, standard operating procedures, data logging, analysis, and reporting. QC and QA are important for FDA accreditation and acceptance by the clinical community. Our Biophotonics research in the Network for Translational Research in Optical Imaging (NTROI) program for breast cancer characterization focuses on QA/QC issues primarily related to the broadband Diffuse Optical Spectroscopy and Imaging (DOS/I) instrumentation, because this is an emerging technology with limited standardized QC/QA in place. In the multi-center trial environment, we implement QA/QC procedures: 1. Standardize and validate calibration standards and procedures. (DOS/I technology requires both frequency domain and spectral calibration procedures using tissue simulating phantoms and reflectance standards, respectively.) 2. Standardize and validate data acquisition, processing and visualization (optimize instrument software-EZDOS; centralize data processing) 3. Monitor, catalog and maintain instrument performance (document performance; modularize maintenance; integrate new technology) 4. Standardize and coordinate trial data entry (from individual sites) into centralized database 5. Monitor, audit and communicate all research procedures (database, teleconferences, training sessions) between participants ensuring "calibration". This manuscript describes our ongoing efforts, successes and challenges implementing these strategies.

Automatic optical inspection system design for golf ball

NASA Astrophysics Data System (ADS)

Wu, Hsien-Huang; Su, Jyun-Wei; Chen, Chih-Lin

2016-09-01

ith the growing popularity of golf sport all over the world, the quantities of relevant products are increasing year by year. To create innovation and improvement in quality while reducing production cost, automation of manufacturing become a necessary and important issue. This paper reflect the trend of this production automa- tion. It uses the AOI (Automated Optical Inspection) technology to develop a system which can automatically detect defects on the golf ball. The current manual quality-inspection is not only error-prone but also very man- power demanding. Taking into consideration the competition of this industry in the near future, the development of related AOI equipment must be conducted as soon as possible. Due to the strong reflective property of the ball surface, as well as its surface dimples and subtle flaws, it is very difficult to take good quality image for automatic inspection. Based on the surface properties and shape of the ball, lighting has been properly design for image-taking environment and structure. Area-scan cameras have been used to acquire images with good contrast between defects and background to assure the achievement of the goal of automatic defect detection on the golf ball. The result obtained is that more than 973 of the NG balls have be detected, and system maintains less than 103 false alarm rate. The balls which are determined by the system to be NG will be inspected by human eye again. Therefore, the manpower spent in the inspection has been reduced by 903.

Video-based teleradiology for intraosseous lesions. A receiver operating characteristic analysis.

PubMed

Tyndall, D A; Boyd, K S; Matteson, S R; Dove, S B

1995-11-01

Immediate access to off-site expert diagnostic consultants regarding unusual radiographic findings or radiographic quality assurance issues could be a current problem for private dental practitioners. Teleradiology, a system for transmitting radiographic images, offers a potential solution to this problem. Although much research has been done to evaluate feasibility and utilization of teleradiology systems in medical imaging, little research on dental applications has been performed. In this investigation 47 panoramic films with an equal distribution of images with intraosseous jaw lesions and no disease were viewed by a panel of observers with teleradiology and conventional viewing methods. The teleradiology system consisted of an analog video-based system simulating remote radiographic consultation between a general dentist and a dental imaging specialist. Conventional viewing consisted of traditional viewbox methods. Observers were asked to identify the presence or absence of 24 intraosseous lesions and to determine their locations. No statistically significant differences in modalities or observers were identified between methods at the 0.05 level. The results indicate that viewing intraosseous lesions of video-based panoramic images is equal to conventional light box viewing.

Issues in using whole slide imaging for diagnostic pathology: "routine" stains, immunohistochemistry and predictive markers.

PubMed

Taylor, C R

2014-08-01

The traditional microscope, together with the "routine" hematoxylin and eosin (H & E) stain, remains the "gold standard" for diagnosis of cancer and other diseases; remarkably, it and the majority of associated biological stains are more than 150 years old. Immunohistochemistry has added to the repertoire of "stains" available. Because of the need for specific identification and even measurement of "biomarkers," immunohistochemistry has increased the demand for consistency of performance and interpretation of staining results. Rapid advances in the capabilities of digital imaging hardware and software now offer a realistic route to improved reproducibility, accuracy and quantification by utilizing whole slide digital images for diagnosis, education and research. There also are potential efficiencies in work flow and the promise of powerful new analytical methods; however, there also are challenges with respect to validation of the quality and fidelity of digital images, including the standard H & E stain, so that diagnostic performance by pathologists is not compromised when they rely on whole slide images instead of traditional stained tissues on glass slides.

Embedded Implementation of VHR Satellite Image Segmentation

PubMed Central

Li, Chao; Balla-Arabé, Souleymane; Ginhac, Dominique; Yang, Fan

2016-01-01

Processing and analysis of Very High Resolution (VHR) satellite images provide a mass of crucial information, which can be used for urban planning, security issues or environmental monitoring. However, they are computationally expensive and, thus, time consuming, while some of the applications, such as natural disaster monitoring and prevention, require high efficiency performance. Fortunately, parallel computing techniques and embedded systems have made great progress in recent years, and a series of massively parallel image processing devices, such as digital signal processors or Field Programmable Gate Arrays (FPGAs), have been made available to engineers at a very convenient price and demonstrate significant advantages in terms of running-cost, embeddability, power consumption flexibility, etc. In this work, we designed a texture region segmentation method for very high resolution satellite images by using the level set algorithm and the multi-kernel theory in a high-abstraction C environment and realize its register-transfer level implementation with the help of a new proposed high-level synthesis-based design flow. The evaluation experiments demonstrate that the proposed design can produce high quality image segmentation with a significant running-cost advantage. PMID:27240370

Wavelet versus DCT-based spread spectrum watermarking of image databases

NASA Astrophysics Data System (ADS)

Mitrea, Mihai P.; Zaharia, Titus B.; Preteux, Francoise J.; Vlad, Adriana

2004-05-01

This paper addresses the issue of oblivious robust watermarking, within the framework of colour still image database protection. We present an original method which complies with all the requirements nowadays imposed to watermarking applications: robustness (e.g. low-pass filtering, print & scan, StirMark), transparency (both quality and fidelity), low probability of false alarm, obliviousness and multiple bit recovering. The mark is generated from a 64 bit message (be it a logo, a serial number, etc.) by means of a Spread Spectrum technique and is embedded into DWT (Discrete Wavelet Transform) domain, into certain low frequency coefficients, selected according to the hierarchy of their absolute values. The best results were provided by the (9,7) bi-orthogonal transform. The experiments were carried out on 1200 image sequences, each of them of 32 images. Note that these sequences represented several types of images: natural, synthetic, medical, etc. and each time we obtained the same good results. These results are compared with those we already obtained for the DCT domain, the differences being pointed out and discussed.

Local motion-compensated method for high-quality 3D coronary artery reconstruction

PubMed Central

Liu, Bo; Bai, Xiangzhi; Zhou, Fugen

2016-01-01

The 3D reconstruction of coronary artery from X-ray angiograms rotationally acquired on C-arm has great clinical value. While cardiac-gated reconstruction has shown promising results, it suffers from the problem of residual motion. This work proposed a new local motion-compensated reconstruction method to handle this issue. An initial image was firstly reconstructed using a regularized iterative reconstruction method. Then a 3D/2D registration method was proposed to estimate the residual vessel motion. Finally, the residual motion was compensated in the final reconstruction using the extended iterative reconstruction method. Through quantitative evaluation, it was found that high-quality 3D reconstruction could be obtained and the result was comparable to state-of-the-art method. PMID:28018741

Ergonomics in ultrasound equipment: productivity and patient throughput.

PubMed

Atjak, A; Gattinella, J A

1989-01-01

The important issues to consider when purchasing ultrasound equipment are: image quality, speed of interface, controls that are obvious, quick or slow configuring, a narrow or wide triangle of interest, fast or slow function shift capability, the amount of layering, color that is muted or not muted, whether the controls are back lit, easily managed cables and probes, and whether the machine is pleasant to operate and easy to learn. All these factors will provide you with some idea of a system's productivity and assist the buyer in making a purchasing decision. Consider these points as a checklist when shopping for an ultrasound system, especially when the radiology manager is concerned about throughput and the bottom line as well as diagnostic information quality.

DICOM index tracker enterprise: advanced system for enterprise-wide quality assurance and patient safety monitoring

NASA Astrophysics Data System (ADS)

Zhang, Min; Pavlicek, William; Panda, Anshuman; Langer, Steve G.; Morin, Richard; Fetterly, Kenneth A.; Paden, Robert; Hanson, James; Wu, Lin-Wei; Wu, Teresa

2015-03-01

DICOM Index Tracker (DIT) is an integrated platform to harvest rich information available from Digital Imaging and Communications in Medicine (DICOM) to improve quality assurance in radiology practices. It is designed to capture and maintain longitudinal patient-specific exam indices of interests for all diagnostic and procedural uses of imaging modalities. Thus, it effectively serves as a quality assurance and patient safety monitoring tool. The foundation of DIT is an intelligent database system which stores the information accepted and parsed via a DICOM receiver and parser. The database system enables the basic dosimetry analysis. The success of DIT implementation at Mayo Clinic Arizona calls for the DIT deployment at the enterprise level which requires significant improvements. First, for geographically distributed multi-site implementation, the first bottleneck is the communication (network) delay; the second is the scalability of the DICOM parser to handle the large volume of exams from different sites. To address this issue, DICOM receiver and parser are separated and decentralized by site. To facilitate the enterprise wide Quality Assurance (QA), a notable challenge is the great diversities of manufacturers, modalities and software versions, as the solution DIT Enterprise provides the standardization tool for device naming, protocol naming, physician naming across sites. Thirdly, advanced analytic engines are implemented online which support the proactive QA in DIT Enterprise.

JPEG2000 still image coding quality.

PubMed

Chen, Tzong-Jer; Lin, Sheng-Chieh; Lin, You-Chen; Cheng, Ren-Gui; Lin, Li-Hui; Wu, Wei

2013-10-01

This work demonstrates the image qualities between two popular JPEG2000 programs. Two medical image compression algorithms are both coded using JPEG2000, but they are different regarding the interface, convenience, speed of computation, and their characteristic options influenced by the encoder, quantization, tiling, etc. The differences in image quality and compression ratio are also affected by the modality and compression algorithm implementation. Do they provide the same quality? The qualities of compressed medical images from two image compression programs named Apollo and JJ2000 were evaluated extensively using objective metrics. These algorithms were applied to three medical image modalities at various compression ratios ranging from 10:1 to 100:1. Following that, the quality of the reconstructed images was evaluated using five objective metrics. The Spearman rank correlation coefficients were measured under every metric in the two programs. We found that JJ2000 and Apollo exhibited indistinguishable image quality for all images evaluated using the above five metrics (r > 0.98, p < 0.001). It can be concluded that the image quality of the JJ2000 and Apollo algorithms is statistically equivalent for medical image compression.

Potential applications of near infrared auto-fluorescence spectral polarized imaging for assessment of food quality

NASA Astrophysics Data System (ADS)

Zhou, Kenneth J.; Chen, Jun

2016-03-01

The current growing of food industry for low production costs and high efficiency needs for maintenance of high-quality standards and assurance of food safety while avoiding liability issues. Quality and safety of food depend on physical (texture, color, tenderness etc.), chemical (fat content, moisture, protein content, pH, etc.), and biological (total bacterial count etc.) features. There is a need for a rapid (less than a few minutes) and accurate detection system in order to optimize quality and assure safety of food. However, the fluorescence ranges for known fluorophores are limited to ultraviolet emission bands, which are not in the tissue near infrared (NIR) "optical window". Biological tissues excited by far-red or NIR light would exhibit strong emission in spectral range of 650-1,100 nm although no characteristic peaks show the emission from which known fluorophores. The characteristics of the auto-fluorescence emission of different types of tissues were found to be different between different tissue components such as fat, high quality muscle food. In this paper, NIR auto-fluorescence emission from different types of muscle food and fat was measured. The differences of fluorescence intensities of the different types of muscle food and fat emissions were observed. These can be explained by the change of the microscopic structure of physical, chemical, and biological features in meat. The difference of emission intensities of fat and lean meat tissues was applied to monitor food quality and safety using spectral polarized imaging, which can be detect deep depth fat under the muscle food up to several centimeter.

The Relevance of External Quality Assessment for Molecular Testing for ALK Positive Non-Small Cell Lung Cancer: Results from Two Pilot Rounds Show Room for Optimization

PubMed Central

Tembuyser, Lien; Tack, Véronique; Zwaenepoel, Karen; Pauwels, Patrick; Miller, Keith; Bubendorf, Lukas; Kerr, Keith; Schuuring, Ed; Thunnissen, Erik; Dequeker, Elisabeth M. C.

2014-01-01

Background and Purpose Molecular profiling should be performed on all advanced non-small cell lung cancer with non-squamous histology to allow treatment selection. Currently, this should include EGFR mutation testing and testing for ALK rearrangements. ROS1 is another emerging target. ALK rearrangement status is a critical biomarker to predict response to tyrosine kinase inhibitors such as crizotinib. To promote high quality testing in non-small cell lung cancer, the European Society of Pathology has introduced an external quality assessment scheme. This article summarizes the results of the first two pilot rounds organized in 2012–2013. Materials and Methods Tissue microarray slides consisting of cell-lines and resection specimens were distributed with the request for routine ALK testing using IHC or FISH. Participation in ALK FISH testing included the interpretation of four digital FISH images. Results Data from 173 different laboratories was obtained. Results demonstrate decreased error rates in the second round for both ALK FISH and ALK IHC, although the error rates were still high and the need for external quality assessment in laboratories performing ALK testing is evident. Error rates obtained by FISH were lower than by IHC. The lowest error rates were observed for the interpretation of digital FISH images. Conclusion There was a large variety in FISH enumeration practices. Based on the results from this study, recommendations for the methodology, analysis, interpretation and result reporting were issued. External quality assessment is a crucial element to improve the quality of molecular testing. PMID:25386659

The relevance of external quality assessment for molecular testing for ALK positive non-small cell lung cancer: results from two pilot rounds show room for optimization.

PubMed

Tembuyser, Lien; Tack, Véronique; Zwaenepoel, Karen; Pauwels, Patrick; Miller, Keith; Bubendorf, Lukas; Kerr, Keith; Schuuring, Ed; Thunnissen, Erik; Dequeker, Elisabeth M C

2014-01-01

Molecular profiling should be performed on all advanced non-small cell lung cancer with non-squamous histology to allow treatment selection. Currently, this should include EGFR mutation testing and testing for ALK rearrangements. ROS1 is another emerging target. ALK rearrangement status is a critical biomarker to predict response to tyrosine kinase inhibitors such as crizotinib. To promote high quality testing in non-small cell lung cancer, the European Society of Pathology has introduced an external quality assessment scheme. This article summarizes the results of the first two pilot rounds organized in 2012-2013. Tissue microarray slides consisting of cell-lines and resection specimens were distributed with the request for routine ALK testing using IHC or FISH. Participation in ALK FISH testing included the interpretation of four digital FISH images. Data from 173 different laboratories was obtained. Results demonstrate decreased error rates in the second round for both ALK FISH and ALK IHC, although the error rates were still high and the need for external quality assessment in laboratories performing ALK testing is evident. Error rates obtained by FISH were lower than by IHC. The lowest error rates were observed for the interpretation of digital FISH images. There was a large variety in FISH enumeration practices. Based on the results from this study, recommendations for the methodology, analysis, interpretation and result reporting were issued. External quality assessment is a crucial element to improve the quality of molecular testing.

GENDER DIFFERENCES IN QUALITY OF LIFE AMONG LONG-TERM COLORECTAL CANCER SURVIVORS WITH OSTOMIES

PubMed Central

Grant, Marcia; McMullen, Carmit K.; Altschuler, Andrea; Mohler, M. Jane; Hornbrook, Mark C.; Herrinton, Lisa J.; Wendel, Christopher S.; Baldwin, Carol M.; Krouse, Robert S.

2011-01-01

Objective To describe how gender shapes the concerns and adaptations of long-term (> 5 years) colorectal cancer (CRC) survivors with ostomies. Design Qualitative study using content analysis of focus group content. Setting Member of Kaiser Permanente, residing in either Oregon, Southwest Washington State, or Northern California. Sample Four female and four male focus groups selected from quantitative survey participants with health-related quality of life (HRQOL) scores in the highest or lowest quartile. Methods Eight focus groups, discussed challenges of living with an ostomy. Content was recorded, transcribed, and analyzed using directive and summative content analysis. Main Research Variables HRQOL domains of physical, psychological, social and spiritual well being. Findings All groups reported avoiding foods that cause gas or rapid transit, and discussed how limiting the amount of food eaten controlled the output. All groups discussed physical activities, getting support from friends and family, and the importance of being resilient. Both genders identified challenges with sexuality/intimacy. Coping and adjustment difficulties were discussed by women with men only discussing these issues to a small extent. Difficulties with sleep were primarily identified by Low HRQOL women. Problems with body image and depression were discussed only by Low HRQOL women. Conclusions Common issues included diet management, physical activity, social support and sexuality. Women with low HRQOL discussed problems with depression, body image, and sleep. Implications for Nursing Application of these gender-based differences can inform educational interventions for CRC survivors with ostomies. PMID:21875846

Understanding the quality of life (QOL) issues in survivors of cancer: towards the development of an EORTC QOL cancer survivorship questionnaire.

PubMed

van Leeuwen, Marieke; Husson, Olga; Alberti, Paola; Arraras, Juan Ignacio; Chinot, Olivier L; Costantini, Anna; Darlington, Anne-Sophie; Dirven, Linda; Eichler, Martin; Hammerlid, Eva B; Holzner, Bernhard; Johnson, Colin D; Kontogianni, Meropi; Kjær, Trille Kristina; Morag, Ofir; Nolte, Sandra; Nordin, Andrew; Pace, Andrea; Pinto, Monica; Polz, Katja; Ramage, John; Reijneveld, Jaap C; Serpentini, Samantha; Tomaszewski, Krzysztof A; Vassiliou, Vassilios; Verdonck-de Leeuw, Irma M; Vistad, Ingvild; Young, Teresa E; Aaronson, Neil K; van de Poll-Franse, Lonneke V

2018-06-04

The number of cancer survivors is growing steadily and increasingly, clinical trials are being designed to include long-term follow-up to assess not only survival, but also late effects and health-related quality of life (HRQOL). Therefore it is is essential to develop patient-reported outcome measures (PROMs) that capture the full range of issues relevant to disease-free cancer survivors. The objectives of this project are: 1) to develop a European Organisation for Research and Treatment of Cancer (EORTC) questionnaire that captures the full range of physical, mental and social HRQOL issues relevant to disease-free cancer survivors; and 2) to determine at which minimal time since completion of treatment the questionnaire should be used. We reviewed 134 publications on cancer survivorship and interviewed 117 disease-free cancer survivors with 11 different types of cancer across 14 countries in Europe to generate an exhaustive, provisional list of HRQOL issues relevant to cancer survivors. The resulting issue list, the EORTC core questionnaire (QLQ-C30), and site-specific questionnaire modules were completed by a second group of 458 survivors. We identified 116 generic survivorship issues. These issues covered body image, cognitive functioning, health behaviors, negative and positive outlook, health distress, mental health, fatigue, sleep problems, physical functioning, pain, several physical symptoms, social functioning, and sexual problems. Patients rated most of the acute symptoms of cancer and its treatment (e.g. nausea) as no longer relevant approximately one year after completion of treatment. Compared to existing cancer survivorship questionnaires, our findings underscore the relevance of assessing issues related to chronic physical side effects of treatment such as neuropathy and joint pain. We will further develop a core survivorship questionnaire and three site-specific modules for disease-free adult cancer survivors who are at least one year post-treatment.

PIZZARO: Forensic analysis and restoration of image and video data.

PubMed

Kamenicky, Jan; Bartos, Michal; Flusser, Jan; Mahdian, Babak; Kotera, Jan; Novozamsky, Adam; Saic, Stanislav; Sroubek, Filip; Sorel, Michal; Zita, Ales; Zitova, Barbara; Sima, Zdenek; Svarc, Petr; Horinek, Jan

2016-07-01

This paper introduces a set of methods for image and video forensic analysis. They were designed to help to assess image and video credibility and origin and to restore and increase image quality by diminishing unwanted blur, noise, and other possible artifacts. The motivation came from the best practices used in the criminal investigation utilizing images and/or videos. The determination of the image source, the verification of the image content, and image restoration were identified as the most important issues of which automation can facilitate criminalists work. Novel theoretical results complemented with existing approaches (LCD re-capture detection and denoising) were implemented in the PIZZARO software tool, which consists of the image processing functionality as well as of reporting and archiving functions to ensure the repeatability of image analysis procedures and thus fulfills formal aspects of the image/video analysis work. Comparison of new proposed methods with the state of the art approaches is shown. Real use cases are presented, which illustrate the functionality of the developed methods and demonstrate their applicability in different situations. The use cases as well as the method design were solved in tight cooperation of scientists from the Institute of Criminalistics, National Drug Headquarters of the Criminal Police and Investigation Service of the Police of the Czech Republic, and image processing experts from the Czech Academy of Sciences. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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.

Evaluation of image quality of digital photo documentation of female genital injuries following sexual assault.

PubMed

Ernst, E J; Speck, Patricia M; Fitzpatrick, Joyce J

2011-12-01

With the patient's consent, physical injuries sustained in a sexual assault are evaluated and treated by the sexual assault nurse examiner (SANE) and documented on preprinted traumagrams and with photographs. Digital imaging is now available to the SANE for documentation of sexual assault injuries, but studies of the image quality of forensic digital imaging of female genital injuries after sexual assault were not found in the literature. The Photo Documentation Image Quality Scoring System (PDIQSS) was developed to rate the image quality of digital photo documentation of female genital injuries after sexual assault. Three expert observers performed evaluations on 30 separate images at two points in time. An image quality score, the sum of eight integral technical and anatomical attributes on the PDIQSS, was obtained for each image. Individual image quality ratings, defined by rating image quality for each of the data, were also determined. The results demonstrated a high level of image quality and agreement when measured in all dimensions. For the SANE in clinical practice, the results of this study indicate that a high degree of agreement exists between expert observers when using the PDIQSS to rate image quality of individual digital photographs of female genital injuries after sexual assault. © 2011 International Association of Forensic Nurses.

Image aesthetic quality evaluation using convolution neural network embedded learning

NASA Astrophysics Data System (ADS)

Li, Yu-xin; Pu, Yuan-yuan; Xu, Dan; Qian, Wen-hua; Wang, Li-peng

2017-11-01

A way of embedded learning convolution neural network (ELCNN) based on the image content is proposed to evaluate the image aesthetic quality in this paper. Our approach can not only solve the problem of small-scale data but also score the image aesthetic quality. First, we chose Alexnet and VGG_S to compare for confirming which is more suitable for this image aesthetic quality evaluation task. Second, to further boost the image aesthetic quality classification performance, we employ the image content to train aesthetic quality classification models. But the training samples become smaller and only using once fine-tuning cannot make full use of the small-scale data set. Third, to solve the problem in second step, a way of using twice fine-tuning continually based on the aesthetic quality label and content label respective is proposed, the classification probability of the trained CNN models is used to evaluate the image aesthetic quality. The experiments are carried on the small-scale data set of Photo Quality. The experiment results show that the classification accuracy rates of our approach are higher than the existing image aesthetic quality evaluation approaches.

The adolescent and young adult with cancer: state of the art -- psychosocial aspects.

PubMed

Epelman, Claudia L

2013-08-01

Adolescents and young adults with cancer are a distinct subgroup of patients within oncology. From the onset of symptoms until the completion of therapy and beyond, they face physical, psychological, and social challenges that are significantly different from those of adults and children. Survival rates and quality of life outcomes for this population have not improved to the same extent that have for younger and older patients. Improvements in quality of care, overall survival and quality of life for these patients require access to specialized care and participation in clinical trials; assistance with management of disease and treatment effects (especially fertility and body image issues); assessment of psychosocial needs; facilitated transition to off-treatment care; and referral to age-appropriated information and support services. Staff team caring for young patients must be dedicated to working with this age group and should have specialist knowledge and training to support their specific needs.

Issues in Measuring and Improving Health Care Quality

PubMed Central

Friedman, Maria A.

1995-01-01

This issue of the Health Care Financing Review focuses on issues and advances in measuring and improving the quality of care, particularly for Medicare and Medicaid beneficiaries. Discussions of quality-related topics are especially timely, given the growing and widespread interest in improving quality in the organization, financing, and delivery of health care services. This article has several purposes. The first is to provide a brief description of some of the causes underlying the growth of the health care quality movement; the second is to provide a contextual framework for discussion of some of the overarching themes that emerge in this issue. These themes include examining conceptual issues, developing quality measures for specific sites and populations, and creating or adapting data sets for quality-measurement purposes. PMID:10151882

Digital radiography: optimization of image quality and dose using multi-frequency software.

PubMed

Precht, H; Gerke, O; Rosendahl, K; Tingberg, A; Waaler, D

2012-09-01

New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults. To examine whether the use of MFP software reduces the radiation dose without compromising quality at DR of the femur in 5-year-old-equivalent anthropomorphic and technical phantoms. A total of 110 images of an anthropomorphic phantom were imaged on a DR system (Canon DR with CXDI-50 C detector and MLT[S] software) and analyzed by three pediatric radiologists using Visual Grading Analysis. In addition, 3,500 images taken of a technical contrast-detail phantom (CDRAD 2.0) provide an objective image-quality assessment. Optimal image-quality was maintained at a dose reduction of 61% with MLT(S) optimized images. Even for images of diagnostic quality, MLT(S) provided a dose reduction of 88% as compared to the reference image. Software impact on image quality was found significant for dose (mAs), dynamic range dark region and frequency band. By optimizing image processing parameters, a significant dose reduction is possible without significant loss of image quality.

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system.

PubMed

Moore, C S; Wood, T J; Beavis, A W; Saunderson, J R

2013-07-01

The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson's correlation coefficient. Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography.

Process perspective on image quality evaluation

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Digitized hand-wrist radiographs: comparison of subjective and software-derived image quality at various compression ratios.

PubMed

McCord, Layne K; Scarfe, William C; Naylor, Rachel H; Scheetz, James P; Silveira, Anibal; Gillespie, Kevin R

2007-05-01

The objectives of this study were to compare the effect of JPEG 2000 compression of hand-wrist radiographs on observer image quality qualitative assessment and to compare with a software-derived quantitative image quality index. Fifteen hand-wrist radiographs were digitized and saved as TIFF and JPEG 2000 images at 4 levels of compression (20:1, 40:1, 60:1, and 80:1). The images, including rereads, were viewed by 13 orthodontic residents who determined the image quality rating on a scale of 1 to 5. A quantitative analysis was also performed by using a readily available software based on the human visual system (Image Quality Measure Computer Program, version 6.2, Mitre, Bedford, Mass). ANOVA was used to determine the optimal compression level (P < or =.05). When we compared subjective indexes, JPEG compression greater than 60:1 significantly reduced image quality. When we used quantitative indexes, the JPEG 2000 images had lower quality at all compression ratios compared with the original TIFF images. There was excellent correlation (R2 >0.92) between qualitative and quantitative indexes. Image Quality Measure indexes are more sensitive than subjective image quality assessments in quantifying image degradation with compression. There is potential for this software-based quantitative method in determining the optimal compression ratio for any image without the use of subjective raters.

Image quality scaling of electrophotographic prints

NASA Astrophysics Data System (ADS)

Johnson, Garrett M.; Patil, Rohit A.; Montag, Ethan D.; Fairchild, Mark D.

2003-12-01

Two psychophysical experiments were performed scaling overall image quality of black-and-white electrophotographic (EP) images. Six different printers were used to generate the images. There were six different scenes included in the experiment, representing photographs, business graphics, and test-targets. The two experiments were split into a paired-comparison experiment examining overall image quality, and a triad experiment judging overall similarity and dissimilarity of the printed images. The paired-comparison experiment was analyzed using Thurstone's Law, to generate an interval scale of quality, and with dual scaling, to determine the independent dimensions used for categorical scaling. The triad experiment was analyzed using multidimensional scaling to generate a psychological stimulus space. The psychophysical results indicated that the image quality was judged mainly along one dimension and that the relationships among the images can be described with a single dimension in most cases. Regression of various physical measurements of the images to the paired comparison results showed that a small number of physical attributes of the images could be correlated with the psychophysical scale of image quality. However, global image difference metrics did not correlate well with image quality.

Choice of word length in the design of a specialized hardware for lossless wavelet compression of medical images

NASA Astrophysics Data System (ADS)

Urriza, Isidro; Barragan, Luis A.; Artigas, Jose I.; Garcia, Jose I.; Navarro, Denis

1997-11-01

Image compression plays an important role in the archiving and transmission of medical images. Discrete cosine transform (DCT)-based compression methods are not suitable for medical images because of block-like image artifacts that could mask or be mistaken for pathology. Wavelet transforms (WTs) are used to overcome this problem. When implementing WTs in hardware, finite precision arithmetic introduces quantization errors. However, lossless compression is usually required in the medical image field. Thus, the hardware designer must look for the optimum register length that, while ensuring the lossless accuracy criteria, will also lead to a high-speed implementation with small chip area. In addition, wavelet choice is a critical issue that affects image quality as well as system design. We analyze the filters best suited to image compression that appear in the literature. For them, we obtain the maximum quantization errors produced in the calculation of the WT components. Thus, we deduce the minimum word length required for the reconstructed image to be numerically identical to the original image. The theoretical results are compared with experimental results obtained from algorithm simulations on random test images. These results enable us to compare the hardware implementation cost of the different filter banks. Moreover, to reduce the word length, we have analyzed the case of increasing the integer part of the numbers while maintaining constant the word length when the scale increases.

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

PubMed

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.

Assessing product image quality for online shopping

NASA Astrophysics Data System (ADS)

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.

Restoration of Motion-Blurred Image Based on Border Deformation Detection: A Traffic Sign Restoration Model

PubMed Central

Zeng, Yiliang; Lan, Jinhui; Ran, Bin; Wang, Qi; Gao, Jing

2015-01-01

Due to the rapid development of motor vehicle Driver Assistance Systems (DAS), the safety problems associated with automatic driving have become a hot issue in Intelligent Transportation. The traffic sign is one of the most important tools used to reinforce traffic rules. However, traffic sign image degradation based on computer vision is unavoidable during the vehicle movement process. In order to quickly and accurately recognize traffic signs in motion-blurred images in DAS, a new image restoration algorithm based on border deformation detection in the spatial domain is proposed in this paper. The border of a traffic sign is extracted using color information, and then the width of the border is measured in all directions. According to the width measured and the corresponding direction, both the motion direction and scale of the image can be confirmed, and this information can be used to restore the motion-blurred image. Finally, a gray mean grads (GMG) ratio is presented to evaluate the image restoration quality. Compared to the traditional restoration approach which is based on the blind deconvolution method and Lucy-Richardson method, our method can greatly restore motion blurred images and improve the correct recognition rate. Our experiments show that the proposed method is able to restore traffic sign information accurately and efficiently. PMID:25849350

Restoration of motion-blurred image based on border deformation detection: a traffic sign restoration model.

PubMed

Zeng, Yiliang; Lan, Jinhui; Ran, Bin; Wang, Qi; Gao, Jing

2015-01-01

Due to the rapid development of motor vehicle Driver Assistance Systems (DAS), the safety problems associated with automatic driving have become a hot issue in Intelligent Transportation. The traffic sign is one of the most important tools used to reinforce traffic rules. However, traffic sign image degradation based on computer vision is unavoidable during the vehicle movement process. In order to quickly and accurately recognize traffic signs in motion-blurred images in DAS, a new image restoration algorithm based on border deformation detection in the spatial domain is proposed in this paper. The border of a traffic sign is extracted using color information, and then the width of the border is measured in all directions. According to the width measured and the corresponding direction, both the motion direction and scale of the image can be confirmed, and this information can be used to restore the motion-blurred image. Finally, a gray mean grads (GMG) ratio is presented to evaluate the image restoration quality. Compared to the traditional restoration approach which is based on the blind deconvolution method and Lucy-Richardson method, our method can greatly restore motion blurred images and improve the correct recognition rate. Our experiments show that the proposed method is able to restore traffic sign information accurately and efficiently.

Comparative Analysis of Reconstructed Image Quality in a Simulated Chromotomographic Imager

DTIC Science & Technology

2014-03-01

quality . This example uses five basic images a backlit bar chart with random intensity, 100 nm separation. A total of 54 initial target...compared for a variety of scenes. Reconstructed image quality is highly dependent on the initial target hypercube so a total of 54 initial target...COMPARATIVE ANALYSIS OF RECONSTRUCTED IMAGE QUALITY IN A SIMULATED CHROMOTOMOGRAPHIC IMAGER THESIS

Automatic detection of artifacts in converted S3D video

NASA Astrophysics Data System (ADS)

Bokov, Alexander; Vatolin, Dmitriy; Zachesov, Anton; Belous, Alexander; Erofeev, Mikhail

2014-03-01

In this paper we present algorithms for automatically detecting issues specific to converted S3D content. When a depth-image-based rendering approach produces a stereoscopic image, the quality of the result depends on both the depth maps and the warping algorithms. The most common problem with converted S3D video is edge-sharpness mismatch. This artifact may appear owing to depth-map blurriness at semitransparent edges: after warping, the object boundary becomes sharper in one view and blurrier in the other, yielding binocular rivalry. To detect this problem we estimate the disparity map, extract boundaries with noticeable differences, and analyze edge-sharpness correspondence between views. We pay additional attention to cases involving a complex background and large occlusions. Another problem is detection of scenes that lack depth volume: we present algorithms for detecting at scenes and scenes with at foreground objects. To identify these problems we analyze the features of the RGB image as well as uniform areas in the depth map. Testing of our algorithms involved examining 10 Blu-ray 3D releases with converted S3D content, including Clash of the Titans, The Avengers, and The Chronicles of Narnia: The Voyage of the Dawn Treader. The algorithms we present enable improved automatic quality assessment during the production stage.

Visual Communications and Image Processing

NASA Astrophysics Data System (ADS)

Hsing, T. Russell

1987-07-01

This special issue of Optical Engineering is concerned with visual communications and image processing. The increase in communication of visual information over the past several decades has resulted in many new image processing and visual communication systems being put into service. The growth of this field has been rapid in both commercial and military applications. The objective of this special issue is to intermix advent technology in visual communications and image processing with ideas generated from industry, universities, and users through both invited and contributed papers. The 15 papers of this issue are organized into four different categories: image compression and transmission, image enhancement, image analysis and pattern recognition, and image processing in medical applications.

Spatial resolution requirements for soft-copy reporting in digital radiography

NASA Astrophysics Data System (ADS)

Davies, Andrew G.; Cowen, Arnold R.; Fowler, Richard C.; Bury, Robert F.; Parkin, Geoff J. S.; Lintott, David J.; Martinez, Delia; Safudim, Asif

1996-04-01

The issue of the spatial resolution required in order to present diagnostic quality digital images, especially for softcopy reporting, has received much attention over recent years. The aim of this study was to compare the diagnostic performance reporting from hardcopy and optimized softcopy image presentations. One-hundred-fifteen radiographs of the hand acquired on a photostimulable phosphor computed radiography (CR) system were chosen as the image material. The study group was taken from patients who demonstrated subtle erosions of the bone in the digits. The control group consisted of radiologically normal bands. The images were presented in three modes, the CR system's hardcopy output, and softcopy presentations at full and half spatial resolutions. Four consultant radiologists participated as observers. Results were analyzed using the receiver operating characteristic (ROC) technique, and showed a statistically significant improvement in observer performance for both softcopy formats, when compared to the hardcopy presentation. However, no significant difference in observer performance was found between the two softcopy presentations. We therefore conclude that, with appropriate attention to the processing and presentation of digital image data, softcopy reporting can, for most examinations, provide superior diagnostic performance, even for images viewed at modest (1 k2) resolutions.

Using polynomials to simplify fixed pattern noise and photometric correction of logarithmic CMOS image sensors.

PubMed

Li, Jing; Mahmoodi, Alireza; Joseph, Dileepan

2015-10-16

An important class of complementary metal-oxide-semiconductor (CMOS) image sensors are those where pixel responses are monotonic nonlinear functions of light stimuli. This class includes various logarithmic architectures, which are easily capable of wide dynamic range imaging, at video rates, but which are vulnerable to image quality issues. To minimize fixed pattern noise (FPN) and maximize photometric accuracy, pixel responses must be calibrated and corrected due to mismatch and process variation during fabrication. Unlike literature approaches, which employ circuit-based models of varying complexity, this paper introduces a novel approach based on low-degree polynomials. Although each pixel may have a highly nonlinear response, an approximately-linear FPN calibration is possible by exploiting the monotonic nature of imaging. Moreover, FPN correction requires only arithmetic, and an optimal fixed-point implementation is readily derived, subject to a user-specified number of bits per pixel. Using a monotonic spline, involving cubic polynomials, photometric calibration is also possible without a circuit-based model, and fixed-point photometric correction requires only a look-up table. The approach is experimentally validated with a logarithmic CMOS image sensor and is compared to a leading approach from the literature. The novel approach proves effective and efficient.

Translation-aware semantic segmentation via conditional least-square generative adversarial networks

NASA Astrophysics Data System (ADS)

Zhang, Mi; Hu, Xiangyun; Zhao, Like; Pang, Shiyan; Gong, Jinqi; Luo, Min

2017-10-01

Semantic segmentation has recently made rapid progress in the field of remote sensing and computer vision. However, many leading approaches cannot simultaneously translate label maps to possible source images with a limited number of training images. The core issue is insufficient adversarial information to interpret the inverse process and proper objective loss function to overcome the vanishing gradient problem. We propose the use of conditional least squares generative adversarial networks (CLS-GAN) to delineate visual objects and solve these problems. We trained the CLS-GAN network for semantic segmentation to discriminate dense prediction information either from training images or generative networks. We show that the optimal objective function of CLS-GAN is a special class of f-divergence and yields a generator that lies on the decision boundary of discriminator that reduces possible vanished gradient. We also demonstrate the effectiveness of the proposed architecture at translating images from label maps in the learning process. Experiments on a limited number of high resolution images, including close-range and remote sensing datasets, indicate that the proposed method leads to the improved semantic segmentation accuracy and can simultaneously generate high quality images from label maps.

Multi-scale pixel-based image fusion using multivariate empirical mode decomposition.

PubMed

Rehman, Naveed ur; Ehsan, Shoaib; Abdullah, Syed Muhammad Umer; Akhtar, Muhammad Jehanzaib; Mandic, Danilo P; McDonald-Maier, Klaus D

2015-05-08

A novel scheme to perform the fusion of multiple images using the multivariate empirical mode decomposition (MEMD) algorithm is proposed. Standard multi-scale fusion techniques make a priori assumptions regarding input data, whereas standard univariate empirical mode decomposition (EMD)-based fusion techniques suffer from inherent mode mixing and mode misalignment issues, characterized respectively by either a single intrinsic mode function (IMF) containing multiple scales or the same indexed IMFs corresponding to multiple input images carrying different frequency information. We show that MEMD overcomes these problems by being fully data adaptive and by aligning common frequency scales from multiple channels, thus enabling their comparison at a pixel level and subsequent fusion at multiple data scales. We then demonstrate the potential of the proposed scheme on a large dataset of real-world multi-exposure and multi-focus images and compare the results against those obtained from standard fusion algorithms, including the principal component analysis (PCA), discrete wavelet transform (DWT) and non-subsampled contourlet transform (NCT). A variety of image fusion quality measures are employed for the objective evaluation of the proposed method. We also report the results of a hypothesis testing approach on our large image dataset to identify statistically-significant performance differences.

Multi-Scale Pixel-Based Image Fusion Using Multivariate Empirical Mode Decomposition

PubMed Central

Rehman, Naveed ur; Ehsan, Shoaib; Abdullah, Syed Muhammad Umer; Akhtar, Muhammad Jehanzaib; Mandic, Danilo P.; McDonald-Maier, Klaus D.

2015-01-01

A novel scheme to perform the fusion of multiple images using the multivariate empirical mode decomposition (MEMD) algorithm is proposed. Standard multi-scale fusion techniques make a priori assumptions regarding input data, whereas standard univariate empirical mode decomposition (EMD)-based fusion techniques suffer from inherent mode mixing and mode misalignment issues, characterized respectively by either a single intrinsic mode function (IMF) containing multiple scales or the same indexed IMFs corresponding to multiple input images carrying different frequency information. We show that MEMD overcomes these problems by being fully data adaptive and by aligning common frequency scales from multiple channels, thus enabling their comparison at a pixel level and subsequent fusion at multiple data scales. We then demonstrate the potential of the proposed scheme on a large dataset of real-world multi-exposure and multi-focus images and compare the results against those obtained from standard fusion algorithms, including the principal component analysis (PCA), discrete wavelet transform (DWT) and non-subsampled contourlet transform (NCT). A variety of image fusion quality measures are employed for the objective evaluation of the proposed method. We also report the results of a hypothesis testing approach on our large image dataset to identify statistically-significant performance differences. PMID:26007714

Edge Preserved Speckle Noise Reduction Using Integrated Fuzzy Filters

PubMed Central

Dewal, M. L.; Rohit, Manoj Kumar

2014-01-01

Echocardiographic images are inherent with speckle noise which makes visual reading and analysis quite difficult. The multiplicative speckle noise masks finer details, necessary for diagnosis of abnormalities. A novel speckle reduction technique based on integration of geometric, wiener, and fuzzy filters is proposed and analyzed in this paper. The denoising applications of fuzzy filters are studied and analyzed along with 26 denoising techniques. It is observed that geometric filter retains noise and, to address this issue, wiener filter is embedded into the geometric filter during iteration process. The performance of geometric-wiener filter is further enhanced using fuzzy filters and the proposed despeckling techniques are called integrated fuzzy filters. Fuzzy filters based on moving average and median value are employed in the integrated fuzzy filters. The performances of integrated fuzzy filters are tested on echocardiographic images and synthetic images in terms of image quality metrics. It is observed that the performance parameters are highest in case of integrated fuzzy filters in comparison to fuzzy and geometric-fuzzy filters. The clinical validation reveals that the output images obtained using geometric-wiener, integrated fuzzy, nonlocal means, and details preserving anisotropic diffusion filters are acceptable. The necessary finer details are retained in the denoised echocardiographic images. PMID:27437499

Providing integrity and authenticity in DICOM images: a novel approach.

PubMed

Kobayashi, Luiz Octavio Massato; Furuie, Sergio Shiguemi; Barreto, Paulo Sergio Licciardi Messeder

2009-07-01

The increasing adoption of information systems in healthcare has led to a scenario where patient information security is more and more being regarded as a critical issue. Allowing patient information to be in jeopardy may lead to irreparable damage, physically, morally, and socially to the patient, potentially shaking the credibility of the healthcare institution. Medical images play a crucial role in such context, given their importance in diagnosis, treatment, and research. Therefore, it is vital to take measures in order to prevent tampering and determine their provenance. This demands adoption of security mechanisms to assure information integrity and authenticity. There are a number of works done in this field, based on two major approaches: use of metadata and use of watermarking. However, there still are limitations for both approaches that must be properly addressed. This paper presents a new method using cryptographic means to improve trustworthiness of medical images, providing a stronger link between the image and the information on its integrity and authenticity, without compromising image quality to the end user. Use of Digital Imaging and Communications in Medicine structures is also an advantage for ease of development and deployment.

Retinal Image Quality Assessment for Spaceflight-Induced Vision Impairment Study

NASA Technical Reports Server (NTRS)

Vu, Amanda Cadao; Raghunandan, Sneha; Vyas, Ruchi; Radhakrishnan, Krishnan; Taibbi, Giovanni; Vizzeri, Gianmarco; Grant, Maria; Chalam, Kakarla; Parsons-Wingerter, Patricia

2015-01-01

Long-term exposure to space microgravity poses significant risks for visual impairment. Evidence suggests such vision changes are linked to cephalad fluid shifts, prompting a need to directly quantify microgravity-induced retinal vascular changes. The quality of retinal images used for such vascular remodeling analysis, however, is dependent on imaging methodology. For our exploratory study, we hypothesized that retinal images captured using fluorescein imaging methodologies would be of higher quality in comparison to images captured without fluorescein. A semi-automated image quality assessment was developed using Vessel Generation Analysis (VESGEN) software and MATLAB® image analysis toolboxes. An analysis of ten images found that the fluorescein imaging modality provided a 36% increase in overall image quality (two-tailed p=0.089) in comparison to nonfluorescein imaging techniques.

Can image enhancement allow radiation dose to be reduced whilst maintaining the perceived diagnostic image quality required for coronary angiography?

PubMed Central

Joshi, Anuja; Gislason-Lee, Amber J; Keeble, Claire; Sivananthan, Uduvil M

2017-01-01

Objective: The aim of this research was to quantify the reduction in radiation dose facilitated by image processing alone for percutaneous coronary intervention (PCI) patient angiograms, without reducing the perceived image quality required to confidently make a diagnosis. Methods: Incremental amounts of image noise were added to five PCI angiograms, simulating the angiogram as having been acquired at corresponding lower dose levels (10–89% dose reduction). 16 observers with relevant experience scored the image quality of these angiograms in 3 states—with no image processing and with 2 different modern image processing algorithms applied. These algorithms are used on state-of-the-art and previous generation cardiac interventional X-ray systems. Ordinal regression allowing for random effects and the delta method were used to quantify the dose reduction possible by the processing algorithms, for equivalent image quality scores. Results: Observers rated the quality of the images processed with the state-of-the-art and previous generation image processing with a 24.9% and 15.6% dose reduction, respectively, as equivalent in quality to the unenhanced images. The dose reduction facilitated by the state-of-the-art image processing relative to previous generation processing was 10.3%. Conclusion: Results demonstrate that statistically significant dose reduction can be facilitated with no loss in perceived image quality using modern image enhancement; the most recent processing algorithm was more effective in preserving image quality at lower doses. Advances in knowledge: Image enhancement was shown to maintain perceived image quality in coronary angiography at a reduced level of radiation dose using computer software to produce synthetic images from real angiograms simulating a reduction in dose. PMID:28124572

The influence of body mass index, age, implants, and dental restorations on image quality of cone beam computed tomography.

PubMed

Ritter, Lutz; Mischkowski, Robert A; Neugebauer, Jörg; Dreiseidler, Timo; Scheer, Martin; Keeve, Erwin; Zöller, Joachim E

2009-09-01

The aim was to determine the influence of patient age, gender, body mass index (BMI), amount of dental restorations, and implants on image quality of cone-beam computerized tomography (CBCT). Fifty CBCT scans of a preretail version of Galileos (Sirona, Germany) were investigated retrospectively by 4 observers regarding image quality of 6 anatomic structures, pathologic findings detection, subjective exposure quality, and artifacts. Patient age, BMI, gender, amount of dental restorations, and implants were recorded and statistically tested for correlations to image quality. A negative effect on image quality was found statistically significantly correlated with age and the amount of dental restorations. None of the investigated image features were garbled by any of the investigated influence factors. Age and the amount of dental restorations appear to have a negative impact on CBCT image quality, whereas gender and BMI do not. Image quality of mental foramen, mandibular canal, and nasal floor are affected negatively by age but not by the amount of dental restorations. Further studies are required to elucidate influence factors on CBCT image quality.

Correlation of the clinical and physical image quality in chest radiography for average adults with a computed radiography imaging system

PubMed Central

Wood, T J; Beavis, A W; Saunderson, J R

2013-01-01

Objective: The purpose of this study was to examine the correlation between the quality of visually graded patient (clinical) chest images and a quantitative assessment of chest phantom (physical) images acquired with a computed radiography (CR) imaging system. Methods: The results of a previously published study, in which four experienced image evaluators graded computer-simulated postero-anterior chest images using a visual grading analysis scoring (VGAS) scheme, were used for the clinical image quality measurement. Contrast-to-noise ratio (CNR) and effective dose efficiency (eDE) were used as physical image quality metrics measured in a uniform chest phantom. Although optimal values of these physical metrics for chest radiography were not derived in this work, their correlation with VGAS in images acquired without an antiscatter grid across the diagnostic range of X-ray tube voltages was determined using Pearson’s correlation coefficient. Results: Clinical and physical image quality metrics increased with decreasing tube voltage. Statistically significant correlations between VGAS and CNR (R=0.87, p<0.033) and eDE (R=0.77, p<0.008) were observed. Conclusion: Medical physics experts may use the physical image quality metrics described here in quality assurance programmes and optimisation studies with a degree of confidence that they reflect the clinical image quality in chest CR images acquired without an antiscatter grid. Advances in knowledge: A statistically significant correlation has been found between the clinical and physical image quality in CR chest imaging. The results support the value of using CNR and eDE in the evaluation of quality in clinical thorax radiography. PMID:23568362

Ambient optomechanical alignment and pupil metrology for the flight instruments aboard the James Webb Space Telescope

NASA Astrophysics Data System (ADS)

Coulter, Phillip; Beaton, Alexander; Gum, Jeffery S.; Hadjimichael, Theodore J.; Hayden, Joseph E.; Hummel, Susann; Hylan, Jason E.; Lee, David; Madison, Timothy J.; Maszkiewicz, Michael; Mclean, Kyle F.; McMann, Joseph; Melf, Markus; Miner, Linda; Ohl, Raymond G.; Redman, Kevin; Roedel, Andreas; Schweiger, Paul; Te Plate, Maurice; Wells, Martyn; Wenzel, Greg W.; Williams, Patrick K.; Young, Jerrod

2014-09-01

While efforts within the optics community focus on the development of high-quality systems and data products, comparatively little attention is paid to their use. Our standards for verification and validation are high; but in some user domains, standards are either lax or do not exist at all. In forensic imagery analysis, for example, standards exist to judge image quality, but do not exist to judge the quality of an analysis. In litigation, a high quality analysis is by default the one performed by the victorious attorney's expert. This paper argues for the need to extend quality standards into the domain of imagery analysis, which is expected to increase in national visibility and significance with the increasing deployment of unmanned aerial vehicle—UAV, or "drone"—sensors in the continental U. S.. It argues that like a good radiometric calibration, made as independent of the calibrated instrument as possible, a good analysis should be subject to standards the most basic of which is the separation of issues of scientific fact from analysis results.

Fast Physically Correct Refocusing for Sparse Light Fields Using Block-Based Multi-Rate View Interpolation.

PubMed

Huang, Chao-Tsung; Wang, Yu-Wen; Huang, Li-Ren; Chin, Jui; Chen, Liang-Gee

2017-02-01

Digital refocusing has a tradeoff between complexity and quality when using sparsely sampled light fields for low-storage applications. In this paper, we propose a fast physically correct refocusing algorithm to address this issue in a twofold way. First, view interpolation is adopted to provide photorealistic quality at infocus-defocus hybrid boundaries. Regarding its conventional high complexity, we devised a fast line-scan method specifically for refocusing, and its 1D kernel can be 30× faster than the benchmark View Synthesis Reference Software (VSRS)-1D-Fast. Second, we propose a block-based multi-rate processing flow for accelerating purely infocused or defocused regions, and a further 3- 34× speedup can be achieved for high-resolution images. All candidate blocks of variable sizes can interpolate different numbers of rendered views and perform refocusing in different subsampled layers. To avoid visible aliasing and block artifacts, we determine these parameters and the simulated aperture filter through a localized filter response analysis using defocus blur statistics. The final quadtree block partitions are then optimized in terms of computation time. Extensive experimental results are provided to show superior refocusing quality and fast computation speed. In particular, the run time is comparable with the conventional single-image blurring, which causes serious boundary artifacts.

Quantitative analysis of visible surface defect risk in tablets during film coating using terahertz pulsed imaging.

PubMed

Niwa, Masahiro; Hiraishi, Yasuhiro

2014-01-30

Tablets are the most common form of solid oral dosage produced by pharmaceutical industries. There are several challenges to successful and consistent tablet manufacturing. One well-known quality issue is visible surface defects, which generally occur due to insufficient physical strength, causing breakage or abrasion during processing, packaging, or shipping. Techniques that allow quantitative evaluation of surface strength and the risk of surface defect would greatly aid in quality control. Here terahertz pulsed imaging (TPI) was employed to evaluate the surface properties of core tablets with visible surface defects of varying severity after film coating. Other analytical methods, such as tensile strength measurements, friability testing, and scanning electron microscopy (SEM), were used to validate TPI results. Tensile strength and friability provided no information on visible surface defect risk, whereas the TPI-derived unique parameter terahertz electric field peak strength (TEFPS) provided spatial distribution of surface density/roughness information on core tablets, which helped in estimating tablet abrasion risk prior to film coating and predicting the location of the defects. TPI also revealed the relationship between surface strength and blending condition and is a nondestructive, quantitative approach to aid formulation development and quality control that can reduce visible surface defect risk in tablets. Copyright © 2013 Elsevier B.V. All rights reserved.

Defining Quality in Cardiovascular Imaging: A Scientific Statement From the American Heart Association.

PubMed

Shaw, Leslee J; Blankstein, Ron; Jacobs, Jill E; Leipsic, Jonathon A; Kwong, Raymond Y; Taqueti, Viviany R; Beanlands, Rob S B; Mieres, Jennifer H; Flamm, Scott D; Gerber, Thomas C; Spertus, John; Di Carli, Marcelo F

2017-12-01

The aims of the current statement are to refine the definition of quality in cardiovascular imaging and to propose novel methodological approaches to inform the demonstration of quality in imaging in future clinical trials and registries. We propose defining quality in cardiovascular imaging using an analytical framework put forth by the Institute of Medicine whereby quality was defined as testing being safe, effective, patient-centered, timely, equitable, and efficient. The implications of each of these components of quality health care are as essential for cardiovascular imaging as they are for other areas within health care. Our proposed statement may serve as the foundation for integrating these quality indicators into establishing designations of quality laboratory practices and developing standards for value-based payment reform for imaging services. We also include recommendations for future clinical research to fulfill quality aims within cardiovascular imaging, including clinical hypotheses of improving patient outcomes, the importance of health status as an end point, and deferred testing options. Future research should evolve to define novel methods optimized for the role of cardiovascular imaging for detecting disease and guiding treatment and to demonstrate the role of cardiovascular imaging in facilitating healthcare quality. © 2017 American Heart Association, Inc.

Objective quality assessment for multiexposure multifocus image fusion.

PubMed

Hassen, Rania; Wang, Zhou; Salama, Magdy M A

2015-09-01

There has been a growing interest in image fusion technologies, but how to objectively evaluate the quality of fused images has not been fully understood. Here, we propose a method for objective quality assessment of multiexposure multifocus image fusion based on the evaluation of three key factors of fused image quality: 1) contrast preservation; 2) sharpness; and 3) structure preservation. Subjective experiments are conducted to create an image fusion database, based on which, performance evaluation shows that the proposed fusion quality index correlates well with subjective scores, and gives a significant improvement over the existing fusion quality measures.

Alignment and Integration Techniques for Mirror Segment Pairs on the Constellation X Telescope

NASA Technical Reports Server (NTRS)

Hadjimichael, Theo; Lehan, John; Olsen, Larry; Owens, Scott; Saha, Timo; Wallace, Tom; Zhang, Will

2007-01-01

We present the concepts behind current alignment and integration techniques for testing a Constellation-X primary-secondary mirror segment pair in an x-ray beam line test. We examine the effects of a passive mount on thin glass x-ray mirror segments, and the issues of mount shape and environment on alignment. We also investigate how bonding and transfer to a permanent housing affects the quality of the final image, comparing predicted results to a full x-ray test on a primary secondary pair.

Application of Advanced Nondestructive Evaluation Techniques for Cylindrical Composite Test Samples

NASA Technical Reports Server (NTRS)

Martin, Richard E.; Roth, Donald J.; Salem, Jonathan A.

2013-01-01

Two nondestructive methods were applied to composite cylinder samples pressurized to failure in order to determine manufacturing quality and monitor damage progression under load. A unique computed tomography (CT) image processing methodology developed at NASA Glenn Research was used to assess the condition of the as-received samples while acoustic emission (AE) monitoring was used to identify both the extent and location of damage within the samples up to failure. Results show the effectiveness of both of these methods in identifying potentially critical fabrication issues and their resulting impact on performance.

Perceptual quality prediction on authentically distorted images using a bag of features approach

PubMed Central

Ghadiyaram, Deepti; Bovik, Alan C.

2017-01-01

Current top-performing blind perceptual image quality prediction models are generally trained on legacy databases of human quality opinion scores on synthetically distorted images. Therefore, they learn image features that effectively predict human visual quality judgments of inauthentic and usually isolated (single) distortions. However, real-world images usually contain complex composite mixtures of multiple distortions. We study the perceptually relevant natural scene statistics of such authentically distorted images in different color spaces and transform domains. We propose a “bag of feature maps” approach that avoids assumptions about the type of distortion(s) contained in an image and instead focuses on capturing consistencies—or departures therefrom—of the statistics of real-world images. Using a large database of authentically distorted images, human opinions of them, and bags of features computed on them, we train a regressor to conduct image quality prediction. We demonstrate the competence of the features toward improving automatic perceptual quality prediction by testing a learned algorithm using them on a benchmark legacy database as well as on a newly introduced distortion-realistic resource called the LIVE In the Wild Image Quality Challenge Database. We extensively evaluate the perceptual quality prediction model and algorithm and show that it is able to achieve good-quality prediction power that is better than other leading models. PMID:28129417

Development of a stationary chest tomosynthesis system using carbon nanotube x-ray source array

NASA Astrophysics Data System (ADS)

Shan, Jing

X-ray imaging system has shown its usefulness for providing quick and easy access of imaging in both clinic settings and emergency situations. It greatly improves the workflow in hospitals. However, the conventional radiography systems, lacks 3D information in the images. The tissue overlapping issue in the 2D projection image result in low sensitivity and specificity. Both computed tomography and digital tomosynthesis, the two conventional 3D imaging modalities, requires a complex gantry to mechanically translate the x-ray source to various positions. Over the past decade, our research group has developed a carbon nanotube (CNT) based x-ray source technology. The CNT x-ray sources allows compacting multiple x-ray sources into a single x-ray tube. Each individual x-ray source in the source array can be electronically switched. This technology allows development of stationary tomographic imaging modalities without any complex mechanical gantries. The goal of this work is to develop a stationary digital chest tomosynthesis (s-DCT) system, and implement it for a clinical trial. The feasibility of s-DCT was investigated. It is found that the CNT source array can provide sufficient x-ray output for chest imaging. Phantom images have shown comparable image qualities as conventional DCT. The s-DBT system was then used to study the effects of source array configurations and tomosynthesis image quality, and the feasibility of a physiological gated s-DCT. Using physical measures for spatial resolution, the 2D source configuration was shown to have improved depth resolution and comparable in-plane resolution. The prospective gated tomosynthesis images have shown substantially reduction of image blur associated with lung motions. The system was also used to investigate the feasibility of using s-DCT as a diagnosis and monitoring tools for cystic fibrosis patients. A new scatter reduction methods for s-DCT was also studied. Finally, a s-DCT system was constructed by retrofitting the source array to a Carestream digital radiography system. The system passed the electrical and radiation safety tests, and was installed in Marsico Hall. The patient trial started in March of 2015, and the first patient was successfully imaged.

Automated cell analysis tool for a genome-wide RNAi screen with support vector machine based supervised learning

NASA Astrophysics Data System (ADS)

Remmele, Steffen; Ritzerfeld, Julia; Nickel, Walter; Hesser, Jürgen

2011-03-01

RNAi-based high-throughput microscopy screens have become an important tool in biological sciences in order to decrypt mostly unknown biological functions of human genes. However, manual analysis is impossible for such screens since the amount of image data sets can often be in the hundred thousands. Reliable automated tools are thus required to analyse the fluorescence microscopy image data sets usually containing two or more reaction channels. The herein presented image analysis tool is designed to analyse an RNAi screen investigating the intracellular trafficking and targeting of acylated Src kinases. In this specific screen, a data set consists of three reaction channels and the investigated cells can appear in different phenotypes. The main issue of the image processing task is an automatic cell segmentation which has to be robust and accurate for all different phenotypes and a successive phenotype classification. The cell segmentation is done in two steps by segmenting the cell nuclei first and then using a classifier-enhanced region growing on basis of the cell nuclei to segment the cells. The classification of the cells is realized by a support vector machine which has to be trained manually using supervised learning. Furthermore, the tool is brightness invariant allowing different staining quality and it provides a quality control that copes with typical defects during preparation and acquisition. A first version of the tool has already been successfully applied for an RNAi-screen containing three hundred thousand image data sets and the SVM extended version is designed for additional screens.

The positive impact of simultaneous implementation of the BD FocalPoint GS Imaging System and lean principles on the operation of gynecologic cytology.

PubMed

Wong, Rebecca; Levi, Angelique W; Harigopal, Malini; Schofield, Kevin; Chhieng, David C

2012-02-01

Our cytology laboratory, like many others, is under pressure to improve quality and provide test results faster while decreasing costs. We sought to address these issues by introducing new technology and lean principles. To determine the combined impact of the FocalPoint Guided Screener (GS) Imaging System (BD Diagnostics-TriPath, Burlington, North Carolina) and lean manufacturing principles on the turnaround time (TAT) and productivity of the gynecologic cytology operation. We established a baseline measure of the TAT for Papanicolaou tests. We then compared that to the performance after implementing the FocalPoint GS Imaging System and lean principles. The latter included value-stream mapping, workflow modification, and a first in-first out policy. The mean (SD) TAT for Papanicolaou tests before and after the implementation of FocalPoint GS Imaging System and lean principles was 4.38 (1.28) days and 3.20 (1.32) days, respectively. This represented a 27% improvement in the average TAT, which was statistically significant (P < .001). In addition, the productivity of staff improved 17%, as evidenced by the increase in slides screened from 8.85/h to 10.38/h. The false-negative fraction decreased from 1.4% to 0.9%, representing a 36% improvement. In our laboratory, the implementation of FocalPoint GS Imaging System in conjunction with lean principles resulted in a significant decrease in the average TAT for Papanicolaou tests and a substantial increase in the productivity of cytotechnologists while maintaining the diagnostic quality of gynecologic cytology.

The Diagnosis of Periprosthetic Infection

PubMed Central

del Arco, Alfonso; Bertrand, María Luisa

2013-01-01

Periprosthetic infection (PJI) is the most serious joint replacement complication, occurring in 0.8-1.9% of knee arthroplasties and 0.3-1.7% of hip arthroplasties. A definition of PJI was proposed in the November 2011 issue of the journal Clinical Orthopedics and Related Research. The presence of a fistula or of local inflammatory signs is indicative of PJI, but in many cases local pain is the only symptom. In the absence of underlying inflammatory conditions, C-reactive protein measurement is the most useful preoperative blood test for detecting infection associated with a prosthetic joint. The most useful preoperative diagnostic test is the aspiration of synovial joint fluid to obtain a total and differential cell count and culture. Intraoperative frozen sections of periprosthetic tissues produce excellent accuracy in predicting a diagnosis of PJI but only moderate accuracy in ruling out the diagnosis. In this process, obtaining a quality sample is the first step, and determines the quality of microbiological results. Specimens for culture should be obtained prior to the initiation of antibiotic treatment. Sonication of a removed implant may increase the culture yield. Plain radiography has low sensitivity and low specificity for detecting infection associated with a prosthetic joint. Computed tomography and magnetic resonance imaging may be useful in the evaluation of complex cases, but metal inserts interfere with these tests, and abnormalities may be non-specific. Labelled-leucocyte imaging (e.g., leucocytes labelled with indium-111) combined with bone marrow imaging with the use of technetium-99m–labelled sulphur colloid is considered the imaging test of choice when imaging is necessary. PMID:23898349

When the oocyte becomes an embryo. The social life of an ambiguous scientific image in Italian newspapers (1996-2007).

PubMed

Beltrame, Lorenzo; Giovanetti, Silvia

2009-01-01

This paper analyses the social life of a scientific image frequently used in media coverage of human genetic and biotechnology issues. The expression "social life of an image" refers to the set of functions performed in the public sphere and the relations interweaved with narratives and discourses. This paper starts from the assumption that the sense of an image is reflexive to its local contexts of use. Therefore, the social meaning of an image relies on the web of discursive links which constitute its social life. The paper explores the functions performed by a photograph of a fertilized oocyte in Italian media coverage of human genetic issues. We conclude asserting that such an image: (a) acts as a visual link between several controversial issues; (b) it has become the icon of a general master-frame of human genetics issues and (c) it takes a not neutral part in the debates over these issues.

Real-Time Interactive Facilities Associated With A 3-D Medical Workstation

NASA Astrophysics Data System (ADS)

Goldwasser, S. M.; Reynolds, R. A.; Talton, D.; Walsh, E.

1986-06-01

Biomedical workstations of the future will incorporate three-dimensional interactive capabilities which provide real-time response to most common operator requests. Such systems will find application in many areas of medicine including clinical diagnosis, surgical and radiation therapy planning, biomedical research based on functional imaging, and medical education. This paper considers the requirements of these future systems in terms of image quality, performance, and the interactive environment, and examines the relationship of workstation capabilities to specific medical applications. We describe a prototype physician's workstation that we have designed and built to meet many of these requirements (using conventional graphics technology in conjunction with a custom real-time 3-D processor), and give an account of the remaining issues and challenges that future designers of such systems will have to address.

Guidance for Efficient Small Animal Imaging Quality Control.

PubMed

Osborne, Dustin R; Kuntner, Claudia; Berr, Stuart; Stout, David

2017-08-01

Routine quality control is a critical aspect of properly maintaining high-performance small animal imaging instrumentation. A robust quality control program helps produce more reliable data both for academic purposes and as proof of system performance for contract imaging work. For preclinical imaging laboratories, the combination of costs and available resources often limits their ability to produce efficient and effective quality control programs. This work presents a series of simplified quality control procedures that are accessible to a wide range of preclinical imaging laboratories. Our intent is to provide minimum guidelines for routine quality control that can assist preclinical imaging specialists in setting up an appropriate quality control program for their facility.

Task-based measures of image quality and their relation to radiation dose and patient risk

PubMed Central

Barrett, Harrison H.; Myers, Kyle J.; Hoeschen, Christoph; Kupinski, Matthew A.; Little, Mark P.

2015-01-01

The theory of task-based assessment of image quality is reviewed in the context of imaging with ionizing radiation, and objective figures of merit (FOMs) for image quality are summarized. The variation of the FOMs with the task, the observer and especially with the mean number of photons recorded in the image is discussed. Then various standard methods for specifying radiation dose are reviewed and related to the mean number of photons in the image and hence to image quality. Current knowledge of the relation between local radiation dose and the risk of various adverse effects is summarized, and some graphical depictions of the tradeoffs between image quality and risk are introduced. Then various dose-reduction strategies are discussed in terms of their effect on task-based measures of image quality. PMID:25564960

No-reference multiscale blur detection tool for content based image retrieval

NASA Astrophysics Data System (ADS)

Ezekiel, Soundararajan; Stocker, Russell; Harrity, Kyle; Alford, Mark; Ferris, David; Blasch, Erik; Gorniak, Mark

2014-06-01

In recent years, digital cameras have been widely used for image capturing. These devices are equipped in cell phones, laptops, tablets, webcams, etc. Image quality is an important component of digital image analysis. To assess image quality for these mobile products, a standard image is required as a reference image. In this case, Root Mean Square Error and Peak Signal to Noise Ratio can be used to measure the quality of the images. However, these methods are not possible if there is no reference image. In our approach, a discrete-wavelet transformation is applied to the blurred image, which decomposes into the approximate image and three detail sub-images, namely horizontal, vertical, and diagonal images. We then focus on noise-measuring the detail images and blur-measuring the approximate image to assess the image quality. We then compute noise mean and noise ratio from the detail images, and blur mean and blur ratio from the approximate image. The Multi-scale Blur Detection (MBD) metric provides both an assessment of the noise and blur content. These values are weighted based on a linear regression against full-reference y values. From these statistics, we can compare to normal useful image statistics for image quality without needing a reference image. We then test the validity of our obtained weights by R2 analysis as well as using them to estimate image quality of an image with a known quality measure. The result shows that our method provides acceptable results for images containing low to mid noise levels and blur content.

Determinants of image quality of rotational angiography for on-line assessment of frame geometry after transcatheter aortic valve implantation.

PubMed

Rodríguez-Olivares, Ramón; El Faquir, Nahid; Rahhab, Zouhair; Maugenest, Anne-Marie; Van Mieghem, Nicolas M; Schultz, Carl; Lauritsch, Guenter; de Jaegere, Peter P T

2016-07-01

To study the determinants of image quality of rotational angiography using dedicated research prototype software for motion compensation without rapid ventricular pacing after the implantation of four commercially available catheter-based valves. Prospective observational study including 179 consecutive patients who underwent transcatheter aortic valve implantation (TAVI) with either the Medtronic CoreValve (MCS), Edward-SAPIEN Valve (ESV), Boston Sadra Lotus (BSL) or Saint-Jude Portico Valve (SJP) in whom rotational angiography (R-angio) with motion compensation 3D image reconstruction was performed. Image quality was evaluated from grade 1 (excellent image quality) to grade 5 (strongly degraded). Distinction was made between good (grades 1, 2) and poor image quality (grades 3-5). Clinical (gender, body mass index, Agatston score, heart rate and rhythm, artifacts), procedural (valve type) and technical variables (isocentricity) were related with the image quality assessment. Image quality was good in 128 (72 %) and poor in 51 (28 %) patients. By univariable analysis only valve type (BSL) and the presence of an artefact negatively affected image quality. By multivariate analysis (in which BMI was forced into the model) BSL valve (Odds 3.5, 95 % CI [1.3-9.6], p = 0.02), presence of an artifact (Odds 2.5, 95 % CI [1.2-5.4], p = 0.02) and BMI (Odds 1.1, 95 % CI [1.0-1.2], p = 0.04) were independent predictors of poor image quality. Rotational angiography with motion compensation 3D image reconstruction using a dedicated research prototype software offers good image quality for the evaluation of frame geometry after TAVI in the majority of patients. Valve type, presence of artifacts and higher BMI negatively affect image quality.

Digital processing of radiographic images from PACS to publishing.

PubMed

Christian, M E; Davidson, H C; Wiggins, R H; Berges, G; Cannon, G; Jackson, G; Chapman, B; Harnsberger, H R

2001-03-01

Several studies have addressed the implications of filmless radiologic imaging on telemedicine, diagnostic ability, and electronic teaching files. However, many publishers still require authors to submit hard-copy images for publication of articles and textbooks. This study compares the quality digital images directly exported from picture archive and communications systems (PACS) to images digitized from radiographic film. The authors evaluated the quality of publication-grade glossy photographs produced from digital radiographic images using 3 different methods: (1) film images digitized using a desktop scanner and then printed, (2) digital images obtained directly from PACS then printed, and (3) digital images obtained from PACS and processed to improve sharpness prior to printing. Twenty images were printed using each of the 3 different methods and rated for quality by 7 radiologists. The results were analyzed for statistically significant differences among the image sets. Subjective evaluations of the filmless images found them to be of equal or better quality than the digitized images. Direct electronic transfer of PACS images reduces the number of steps involved in creating publication-quality images as well as providing the means to produce high-quality radiographic images in a digital environment.

Human visual system consistent quality assessment for remote sensing image fusion

NASA Astrophysics Data System (ADS)

Liu, Jun; Huang, Junyi; Liu, Shuguang; Li, Huali; Zhou, Qiming; Liu, Junchen

2015-07-01

Quality assessment for image fusion is essential for remote sensing application. Generally used indices require a high spatial resolution multispectral (MS) image for reference, which is not always readily available. Meanwhile, the fusion quality assessments using these indices may not be consistent with the Human Visual System (HVS). As an attempt to overcome this requirement and inconsistency, this paper proposes an HVS-consistent image fusion quality assessment index at the highest resolution without a reference MS image using Gaussian Scale Space (GSS) technology that could simulate the HVS. The spatial details and spectral information of original and fused images are first separated in GSS, and the qualities are evaluated using the proposed spatial and spectral quality index respectively. The overall quality is determined without a reference MS image by a combination of the proposed two indices. Experimental results on various remote sensing images indicate that the proposed index is more consistent with HVS evaluation compared with other widely used indices that may or may not require reference images.

Low-cost oblique illumination: an image quality assessment.

PubMed

Ruiz-Santaquiteria, Jesus; Espinosa-Aranda, Jose Luis; Deniz, Oscar; Sanchez, Carlos; Borrego-Ramos, Maria; Blanco, Saul; Cristobal, Gabriel; Bueno, Gloria

2018-01-01

We study the effectiveness of several low-cost oblique illumination filters to improve overall image quality, in comparison with standard bright field imaging. For this purpose, a dataset composed of 3360 diatom images belonging to 21 taxa was acquired. Subjective and objective image quality assessments were done. The subjective evaluation was performed by a group of diatom experts by psychophysical test where resolution, focus, and contrast were assessed. Moreover, some objective nonreference image quality metrics were applied to the same image dataset to complete the study, together with the calculation of several texture features to analyze the effect of these filters in terms of textural properties. Both image quality evaluation methods, subjective and objective, showed better results for images acquired using these illumination filters in comparison with the no filtered image. These promising results confirm that this kind of illumination filters can be a practical way to improve the image quality, thanks to the simple and low cost of the design and manufacturing process. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

Novel Method to Detect and Characterize 18F-FDG Infiltration at the Injection Site: A Single-Institution Experience.

PubMed

Muzaffar, Razi; Frye, Sarah A; McMunn, Anna; Ryan, Kelley; Lattanze, Ron; Osman, Medhat M

2017-12-01

A novel quality control and quality assurance device provides time-activity curves that can identify and characterize PET/CT radiotracer infiltration at the injection site during the uptake phase. The purpose of this study was to compare rates of infiltration detected by the device with rates detected by physicians. We also assessed the value of using the device to improve injection results in our center. Methods: 109 subjects consented to the study. All had passive device sensors applied to their skin near the injection site and mirrored on the contralateral arm during the entire uptake period. Nuclear medicine physicians reviewed standard images for the presence of dose infiltration. Sensor-generated time-activity curves were independently examined and then compared with the physician reports. Injection data captured by the software were analyzed, and the results were provided to the technologists. Improvement measures were implemented, and rates were remeasured. Results: Physician review of the initial 40 head-to-toe field-of-view images identified 15 cases (38%) of dose infiltration (9 minor, 5 moderate, and 1 significant). Sensor time-activity curves on these 40 cases independently identified 22 cases (55%) of dose infiltration (16 minor, 5 moderate, and 1 significant). After the time-activity curve results and the contributing factor analysis were shared with technologists, injection techniques were modified and an additional 69 cases were studied. Of these, physician review identified 17 cases (25%) of infiltration (13 minor, 3 moderate, and 1 significant), a 34% decline. Sensor time-activity curves identified 4 cases (6%) of infiltration (2 minor and 2 moderate), an 89% decline. Conclusion: The device provides valuable quality control information for each subject. Time-activity curves can further characterize visible infiltration. Even when the injection site was out of the field of view, the time-activity curves could still detect and characterize infiltration. Our initial experience showed that the quality assurance information obtained from the device helped reduce the rate and severity of infiltration. The device revealed site-specific contributing factors that helped nuclear medicine physicians and technologists customize their quality improvement efforts to these site-specific issues. Reducing infiltration can improve image quality and SUV quantification, as well as the ability to minimize variability in a site's PET/CT results. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Crowdtruth validation: a new paradigm for validating algorithms that rely on image correspondences.

PubMed

Maier-Hein, Lena; Kondermann, Daniel; Roß, Tobias; Mersmann, Sven; Heim, Eric; Bodenstedt, Sebastian; Kenngott, Hannes Götz; Sanchez, Alexandro; Wagner, Martin; Preukschas, Anas; Wekerle, Anna-Laura; Helfert, Stefanie; März, Keno; Mehrabi, Arianeb; Speidel, Stefanie; Stock, Christian

2015-08-01

Feature tracking and 3D surface reconstruction are key enabling techniques to computer-assisted minimally invasive surgery. One of the major bottlenecks related to training and validation of new algorithms is the lack of large amounts of annotated images that fully capture the wide range of anatomical/scene variance in clinical practice. To address this issue, we propose a novel approach to obtaining large numbers of high-quality reference image annotations at low cost in an extremely short period of time. The concept is based on outsourcing the correspondence search to a crowd of anonymous users from an online community (crowdsourcing) and comprises four stages: (1) feature detection, (2) correspondence search via crowdsourcing, (3) merging multiple annotations per feature by fitting Gaussian finite mixture models, (4) outlier removal using the result of the clustering as input for a second annotation task. On average, 10,000 annotations were obtained within 24 h at a cost of $100. The annotation of the crowd after clustering and before outlier removal was of expert quality with a median distance of about 1 pixel to a publically available reference annotation. The threshold for the outlier removal task directly determines the maximum annotation error, but also the number of points removed. Our concept is a novel and effective method for fast, low-cost and highly accurate correspondence generation that could be adapted to various other applications related to large-scale data annotation in medical image computing and computer-assisted interventions.

WE-A-12A-01: Medical Physics 1.0 to 2.0, Session 2: Radiography, Mammography and Fluoroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gingold, E; Karellas, A; Strauss, K

Medical Physics 2.0 is a bold vision for an existential transition of clinical imaging physics in face of the new realities of value-based and evidencebased medicine, comparative effectiveness, and meaningful use. It speaks to how clinical imaging physics can expand beyond traditional insular models of inspection and acceptance testing, oriented toward compliance, towards team-based models of operational engagement, prospective definition and assurance of effective use, and retrospective evaluation of clinical performance. Organized into four sessions of the AAPM, this particular session focuses on three specific modalities as outlined below. Radiography 2.0: The development of electronic capture in recent years hasmore » changed the landscape and spurred reinvestment by healthcare providers. The radiography presentation will explore how the diagnostic medical physicist must adapt to these changes to support radiographic imaging, and how she/he can add value in radiography practice over the next 5-10 years. Topics of discussion include new metrology of evaluation, new models of clinical engagement, and effective integration of new technologies. Mammography 2.0: Mammography has been an interesting testing ground on the effectiveness of close involvement of medical physicists with equipment in the past twenty years. The outcomes have clearly shown major improvements in image quality and significant reduction in the average glandular dose. However, the medical physicist's role in mammography has been largely focused to annual surveys and with limited input on operational issues with image artifacts, optimal mammographic acquisition mode and problems with image quality. This mammography presentation will address why and how medical physicists must be prepared to address the new models of practice that include new metrics of performance and the integration of new technologies (DBT, syncretized mammograms, contrast mammography, breast CT) into clinical practice. Fluoroscopy 2.0: Physics support of fluoroscopy should be operationally as opposed to compliance focused. Testing protocols must address new hardware, acquisition methods, and image processing. Future available tools are discussed. Proper configuration of acquisition parameters (focal spot size, voltage and added filter, tube current, pulse width, pulse rate, scatter removal) as a function of patient size from the neonate to bariatric patient is key to providing diagnostic image quality at properly managed radiation doses. Learning Objectives: Appreciate the limitations of the currently available tools and techniques in clinical medical physics in radiography, mammography, and fluoroscopy, and ways to improve upon current deficiencies. Appreciate the changing environment of imaging practice and the need for the medical physicist to be an expert consultant and educator in a capacity that extends beyond the annual survey of equipment. Understand the status of the rapidly changing environment in breast imaging from planar imaging to tomosynthesis and possibly to breast CT. Identify appropriate configuration of acquisition parameters as a function of patient size to manage radiation dose and ensure diagnostic image quality.« less

Quantifying the quality of medical x-ray images: An evaluation based on normal anatomy for lumbar spine and chest radiography

NASA Astrophysics Data System (ADS)

Tingberg, Anders Martin

Optimisation in diagnostic radiology requires accurate methods for determination of patient absorbed dose and clinical image quality. Simple methods for evaluation of clinical image quality are at present scarce and this project aims at developing such methods. Two methods are used and further developed; fulfillment of image criteria (IC) and visual grading analysis (VGA). Clinical image quality descriptors are defined based on these two methods: image criteria score (ICS) and visual grading analysis score (VGAS), respectively. For both methods the basis is the Image Criteria of the ``European Guidelines on Quality Criteria for Diagnostic Radiographic Images''. Both methods have proved to be useful for evaluation of clinical image quality. The two methods complement each other: IC is an absolute method, which means that the quality of images of different patients and produced with different radiographic techniques can be compared with each other. The separating power of IC is, however, weaker than that of VGA. VGA is the best method for comparing images produced with different radiographic techniques and has strong separating power, but the results are relative, since the quality of an image is compared to the quality of a reference image. The usefulness of the two methods has been verified by comparing the results from both of them with results from a generally accepted method for evaluation of clinical image quality, receiver operating characteristics (ROC). The results of the comparison between the two methods based on visibility of anatomical structures and the method based on detection of pathological structures (free-response forced error) indicate that the former two methods can be used for evaluation of clinical image quality as efficiently as the method based on ROC. More studies are, however, needed for us to be able to draw a general conclusion, including studies of other organs, using other radiographic techniques, etc. The results of the experimental evaluation of clinical image quality are compared with physical quantities calculated with a theoretical model based on a voxel phantom, and correlations are found. The results demonstrate that the computer model can be a useful toot in planning further experimental studies.

Red and far-red fluorescent dyes for the characterization of head and neck cancer at the cellular level.

PubMed

Abbaci, Muriel; Casiraghi, Odile; Temam, Stephane; Ferchiou, Malek; Bosq, Jacques; Dartigues, Peggy; De Leeuw, Frederic; Breuskin, Ingrid; Laplace-Builhé, Corinne

2015-11-01

Primary upper aerodigestive tract malignancy remains a cancer having a poor prognosis, despite current progress in treatment, due to a generally late diagnosis. We conducted a preliminary assessment of five dyes approved for human use for the imaging of head and neck tissues at the cellular level, which could be considered for clinical examination. We investigated fluorescence endomicroscopic images on fresh samples obtained from head and neck surgeries after staining with hypericin, methylene blue, toluidine blue, patent blue or indocyanine green to provide a preliminary consideration as to whether these images contain enough information for identification of non-pathologic and pathologic tissues. The distribution pattern of dye has been examined using probe-based confocal laser endomicroscopy (pCLE) in ex vivo specimens and compared with corresponding histology. In most samples, the image quality provided by pCLE with both dyes allowed pathologists to recognize histological characteristics to identify the tissues. The combination of pCLE imaging with these dyes provides interpretable images close to conventional histology; a promising clinical tool to assist physicians in examination of upper aerodigestive tract, as long as depth imaging issues can be overcome. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Deepwater seismic acquisition technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caldwell, J.

1996-09-01

Although truly new technology is not required for successful acquisition of seismic data in deep Gulf of Mexico waters, it is helpful to review some basic aspects of these seismic surveys. Additionally, such surveys are likely to see early use of some emerging new technology which can improve data quality. Because such items as depth imaging, borehole seismic, 4-D and marine 3-component recording were mentioned in the May 1996 issue of World Oil, they are not discussed again here. However, these technologies will also play some role in the deepwater seismic activities. What is covered in this paper are somemore » new considerations for: (1) longer data records needed in deeper water, (2) some pros and cons of very long steamer use, and (3) two new commercial systems for quantifying data quality.« less

Research on assessment and improvement method of remote sensing image reconstruction

NASA Astrophysics Data System (ADS)

Sun, Li; Hua, Nian; Yu, Yanbo; Zhao, Zhanping

2018-01-01

Remote sensing image quality assessment and improvement is an important part of image processing. Generally, the use of compressive sampling theory in remote sensing imaging system can compress images while sampling which can improve efficiency. A method of two-dimensional principal component analysis (2DPCA) is proposed to reconstruct the remote sensing image to improve the quality of the compressed image in this paper, which contain the useful information of image and can restrain the noise. Then, remote sensing image quality influence factors are analyzed, and the evaluation parameters for quantitative evaluation are introduced. On this basis, the quality of the reconstructed images is evaluated and the different factors influence on the reconstruction is analyzed, providing meaningful referential data for enhancing the quality of remote sensing images. The experiment results show that evaluation results fit human visual feature, and the method proposed have good application value in the field of remote sensing image processing.

Does clinical pretest probability influence image quality and diagnostic accuracy in dual-source coronary CT angiography?

PubMed

Thomas, Christoph; Brodoefel, Harald; Tsiflikas, Ilias; Bruckner, Friederike; Reimann, Anja; Ketelsen, Dominik; Drosch, Tanja; Claussen, Claus D; Kopp, Andreas; Heuschmid, Martin; Burgstahler, Christof

2010-02-01

To prospectively evaluate the influence of the clinical pretest probability assessed by the Morise score onto image quality and diagnostic accuracy in coronary dual-source computed tomography angiography (DSCTA). In 61 patients, DSCTA and invasive coronary angiography were performed. Subjective image quality and accuracy for stenosis detection (>50%) of DSCTA with invasive coronary angiography as gold standard were evaluated. The influence of pretest probability onto image quality and accuracy was assessed by logistic regression and chi-square testing. Correlations of image quality and accuracy with the Morise score were determined using linear regression. Thirty-eight patients were categorized into the high, 21 into the intermediate, and 2 into the low probability group. Accuracies for the detection of significant stenoses were 0.94, 0.97, and 1.00, respectively. Logistic regressions and chi-square tests showed statistically significant correlations between Morise score and image quality (P < .0001 and P < .001) and accuracy (P = .0049 and P = .027). Linear regression revealed a cutoff Morise score for a good image quality of 16 and a cutoff for a barely diagnostic image quality beyond the upper Morise scale. Pretest probability is a weak predictor of image quality and diagnostic accuracy in coronary DSCTA. A sufficient image quality for diagnostic images can be reached with all pretest probabilities. Therefore, coronary DSCTA might be suitable also for patients with a high pretest probability. Copyright 2010 AUR. Published by Elsevier Inc. All rights reserved.

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

PubMed

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.

No-reference quality assessment based on visual perception

NASA Astrophysics Data System (ADS)

Li, Junshan; Yang, Yawei; Hu, Shuangyan; Zhang, Jiao

2014-11-01

The visual quality assessment of images/videos is an ongoing hot research topic, which has become more and more important for numerous image and video processing applications with the rapid development of digital imaging and communication technologies. The goal of image quality assessment (IQA) algorithms is to automatically assess the quality of images/videos in agreement with human quality judgments. Up to now, two kinds of models have been used for IQA, namely full-reference (FR) and no-reference (NR) models. For FR models, IQA algorithms interpret image quality as fidelity or similarity with a perfect image in some perceptual space. However, the reference image is not available in many practical applications, and a NR IQA approach is desired. Considering natural vision as optimized by the millions of years of evolutionary pressure, many methods attempt to achieve consistency in quality prediction by modeling salient physiological and psychological features of the human visual system (HVS). To reach this goal, researchers try to simulate HVS with image sparsity coding and supervised machine learning, which are two main features of HVS. A typical HVS captures the scenes by sparsity coding, and uses experienced knowledge to apperceive objects. In this paper, we propose a novel IQA approach based on visual perception. Firstly, a standard model of HVS is studied and analyzed, and the sparse representation of image is accomplished with the model; and then, the mapping correlation between sparse codes and subjective quality scores is trained with the regression technique of least squaresupport vector machine (LS-SVM), which gains the regressor that can predict the image quality; the visual metric of image is predicted with the trained regressor at last. We validate the performance of proposed approach on Laboratory for Image and Video Engineering (LIVE) database, the specific contents of the type of distortions present in the database are: 227 images of JPEG2000, 233 images of JPEG, 174 images of White Noise, 174 images of Gaussian Blur, 174 images of Fast Fading. The database includes subjective differential mean opinion score (DMOS) for each image. The experimental results show that the proposed approach not only can assess many kinds of distorted images quality, but also exhibits a superior accuracy and monotonicity.

Impact of acquisition and interpretation on total inter-observer variability in echocardiography: results from the quality assurance program of the STAAB cohort study.

PubMed

Morbach, Caroline; Gelbrich, Götz; Breunig, Margret; Tiffe, Theresa; Wagner, Martin; Heuschmann, Peter U; Störk, Stefan

2018-02-14

Variability related to image acquisition and interpretation is an important issue of echocardiography in clinical trials. Nevertheless, there is no broadly accepted standard method for quality assessment of echocardiography in clinical research reports. We present analyses based on the echocardiography quality-assurance program of the ongoing STAAB cohort study (characteristics and course of heart failure stages A-B and determinants of progression). In 43 healthy individuals (mean age 50 ± 14 years; 18 females), duplicate echocardiography scans were acquired and mutually interpreted by one of three trained sonographers and an EACVI certified physician, respectively. Acquisition (AcV), interpretation (InV), and inter-observer variability (IOV; i.e., variability between the acquisition-interpretation sequences of two different observers), were determined for selected M-mode, B-mode, and Doppler parameters. We calculated Bland-Altman upper 95% limits of absolute differences, implying that 95% of measurement differences were smaller/equal to the given value: e.g. LV end-diastolic volume (mL): 25.0, 25.0, 27.9; septal e' velocity (cm/s): 3.03, 1.25, 3.58. Further, 90, 85, and 80% upper limits of absolute differences were determined for the respective parameters. Both, acquisition and interpretation, independently and sizably contributed to IOV. As such, separate assessment of AcV and InV is likely to aid in echocardiography training and quality-assurance. Our results further suggest to routinely determine IOV in clinical trials as a comprehensive measure of imaging quality. The derived 95, 90, 85, and 80% upper limits of absolute differences are suggested as reproducibility targets of future studies, thus contributing to the international efforts of standardization in quality-assurance.

Abdominal applications of 3.0-T MR imaging: comparative review versus a 1.5-T system.

PubMed

Choi, Jin-Young; Kim, Myeong-Jin; Chung, Yong Eun; Kim, Ji Youn; Jones, Alun C; de Becker, Jan; van Cauteren, Marc

2008-01-01

With the development of dedicated receiver coils and increased gradient performance, 3.0-T magnetic resonance (MR) systems are gaining wider acceptance in clinical practice. The expected twofold increase in signal-to-noise ratio (SNR) compared with that of 1.5-T MR systems may help improve spatial resolution or increase temporal resolution when used with parallel acquisition techniques. Several issues must be considered when applying 3.0-T MR in the abdomen, including the alteration of the radiofrequency field and relaxation time, increase in energy deposition and susceptibility effects, and problems associated with motion artifacts. For the evaluation of liver lesions, higher SNR and greater resolution achieved with the 3.0-T system could translate into better detection of malignant lesions on T2-weighted images obtained with adjusted imaging parameters. For the evaluation of pancreatic and biliary diseases, high-resolution T2-weighted imaging using single-shot turbo spin-echo sequences is useful; improvement in SNR was noticeable on two-dimensional MR cholangiopancreatographic images. For the preoperative imaging of rectal cancer, a single-shot sequence is useful for dramatically decreasing imaging time while maintaining image quality. Substantial modification of examination protocols, with optimized imaging parameters and sequence designs along with ongoing development of hardware, could contribute to an increased role of the 3.0-T system for abdominal MR examinations.

Evaluation of image registration in PET/CT of the liver and recommendations for optimized imaging.

PubMed

Vogel, Wouter V; van Dalen, Jorn A; Wiering, Bas; Huisman, Henkjan; Corstens, Frans H M; Ruers, Theo J M; Oyen, Wim J G

2007-06-01

Multimodality PET/CT of the liver can be performed with an integrated (hybrid) PET/CT scanner or with software fusion of dedicated PET and CT. Accurate anatomic correlation and good image quality of both modalities are important prerequisites, regardless of the applied method. Registration accuracy is influenced by breathing motion differences on PET and CT, which may also have impact on (attenuation correction-related) artifacts, especially in the upper abdomen. The impact of these issues was evaluated for both hybrid PET/CT and software fusion, focused on imaging of the liver. Thirty patients underwent hybrid PET/CT, 20 with CT during expiration breath-hold (EB) and 10 with CT during free breathing (FB). Ten additional patients underwent software fusion of dedicated PET and dedicated expiration breath-hold CT (SF). The image registration accuracy was evaluated at the location of liver borders on CT and uncorrected PET images and at the location of liver lesions. Attenuation-correction artifacts were evaluated by comparison of liver borders on uncorrected and attenuation-corrected PET images. CT images were evaluated for the presence of breathing artifacts. In EB, 40% of patients had an absolute registration error of the diaphragm in the craniocaudal direction of >1 cm (range, -16 to 44 mm), and 45% of lesions were mispositioned >1 cm. In 50% of cases, attenuation-correction artifacts caused a deformation of the liver dome on PET of >1 cm. Poor compliance to breath-hold instructions caused CT artifacts in 55% of cases. In FB, 30% had registration errors of >1 cm (range, -4 to 16 mm) and PET artifacts were less extensive, but all CT images had breathing artifacts. As SF allows independent alignment of PET and CT, no registration errors or artifacts of >1 cm of the diaphragm occurred. Hybrid PET/CT of the liver may have significant registration errors and artifacts related to breathing motion. The extent of these issues depends on the selected breathing protocol and the speed of the CT scanner. No protocol or scanner can guarantee perfect image fusion. On the basis of these findings, recommendations were formulated with regard to scanner requirements, breathing protocols, and reporting.

Interacting with target tracking algorithms in a gaze-enhanced motion video analysis system

NASA Astrophysics Data System (ADS)

Hild, Jutta; Krüger, Wolfgang; Heinze, Norbert; Peinsipp-Byma, Elisabeth; Beyerer, Jürgen

2016-05-01

Motion video analysis is a challenging task, particularly if real-time analysis is required. It is therefore an important issue how to provide suitable assistance for the human operator. Given that the use of customized video analysis systems is more and more established, one supporting measure is to provide system functions which perform subtasks of the analysis. Recent progress in the development of automated image exploitation algorithms allow, e.g., real-time moving target tracking. Another supporting measure is to provide a user interface which strives to reduce the perceptual, cognitive and motor load of the human operator for example by incorporating the operator's visual focus of attention. A gaze-enhanced user interface is able to help here. This work extends prior work on automated target recognition, segmentation, and tracking algorithms as well as about the benefits of a gaze-enhanced user interface for interaction with moving targets. We also propose a prototypical system design aiming to combine both the qualities of the human observer's perception and the automated algorithms in order to improve the overall performance of a real-time video analysis system. In this contribution, we address two novel issues analyzing gaze-based interaction with target tracking algorithms. The first issue extends the gaze-based triggering of a target tracking process, e.g., investigating how to best relaunch in the case of track loss. The second issue addresses the initialization of tracking algorithms without motion segmentation where the operator has to provide the system with the object's image region in order to start the tracking algorithm.

Backward Registration Based Aspect Ratio Similarity (ARS) for Image Retargeting Quality Assessment.

PubMed

Zhang, Yabin; Fang, Yuming; Lin, Weisi; Zhang, Xinfeng; Li, Leida

2016-06-28

During the past few years, there have been various kinds of content-aware image retargeting operators proposed for image resizing. However, the lack of effective objective retargeting quality assessment metrics limits the further development of image retargeting techniques. Different from traditional Image Quality Assessment (IQA) metrics, the quality degradation during image retargeting is caused by artificial retargeting modifications, and the difficulty for Image Retargeting Quality Assessment (IRQA) lies in the alternation of the image resolution and content, which makes it impossible to directly evaluate the quality degradation like traditional IQA. In this paper, we interpret the image retargeting in a unified framework of resampling grid generation and forward resampling. We show that the geometric change estimation is an efficient way to clarify the relationship between the images. We formulate the geometric change estimation as a Backward Registration problem with Markov Random Field (MRF) and provide an effective solution. The geometric change aims to provide the evidence about how the original image is resized into the target image. Under the guidance of the geometric change, we develop a novel Aspect Ratio Similarity metric (ARS) to evaluate the visual quality of retargeted images by exploiting the local block changes with a visual importance pooling strategy. Experimental results on the publicly available MIT RetargetMe and CUHK datasets demonstrate that the proposed ARS can predict more accurate visual quality of retargeted images compared with state-of-the-art IRQA metrics.

Adaptive gamma correction-based expert system for nonuniform illumination face enhancement

NASA Astrophysics Data System (ADS)

Abdelhamid, Iratni; Mustapha, Aouache; Adel, Oulefki

2018-03-01

The image quality of a face recognition system suffers under severe lighting conditions. Thus, this study aims to develop an approach for nonuniform illumination adjustment based on an adaptive gamma correction (AdaptGC) filter that can solve the aforementioned issue. An approach for adaptive gain factor prediction was developed via neural network model-based cross-validation (NN-CV). To achieve this objective, a gamma correction function and its effects on the face image quality with different gain values were examined first. Second, an orientation histogram (OH) algorithm was assessed as a face's feature descriptor. Subsequently, a density histogram module was developed for face label generation. During the NN-CV construction, the model was assessed to recognize the OH descriptor and predict the face label. The performance of the NN-CV model was evaluated by examining the statistical measures of root mean square error and coefficient of efficiency. Third, to evaluate the AdaptGC enhancement approach, an image quality metric was adopted using enhancement by entropy, contrast per pixel, second-derivative-like measure of enhancement, and sharpness, then supported by visual inspection. The experiment results were examined using five face's databases, namely, extended Yale-B, Carnegie Mellon University-Pose, Illumination, and Expression, Mobio, FERET, and Oulu-CASIA-NIR-VIS. The final results prove that AdaptGC filter implementation compared with state-of-the-art methods is the best choice in terms of contrast and nonuniform illumination adjustment. In summary, the benefits attained prove that AdaptGC is driven by a profitable enhancement rate, which provides satisfying features for high rate face recognition systems.

Image quality assessment using deep convolutional networks

NASA Astrophysics Data System (ADS)

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.

Impact of B-Scan Averaging on Spectralis Optical Coherence Tomography Image Quality before and after Cataract Surgery

PubMed Central

Podkowinski, Dominika; Sharian Varnousfaderani, Ehsan; Simader, Christian; Bogunovic, Hrvoje; Philip, Ana-Maria; Gerendas, Bianca S.

2017-01-01

Background and Objective To determine optimal image averaging settings for Spectralis optical coherence tomography (OCT) in patients with and without cataract. Study Design/Material and Methods In a prospective study, the eyes were imaged before and after cataract surgery using seven different image averaging settings. Image quality was quantitatively evaluated using signal-to-noise ratio, distinction between retinal layer image intensity distributions, and retinal layer segmentation performance. Measures were compared pre- and postoperatively across different degrees of averaging. Results 13 eyes of 13 patients were included and 1092 layer boundaries analyzed. Preoperatively, increasing image averaging led to a logarithmic growth in all image quality measures up to 96 frames. Postoperatively, increasing averaging beyond 16 images resulted in a plateau without further benefits to image quality. Averaging 16 frames postoperatively provided comparable image quality to 96 frames preoperatively. Conclusion In patients with clear media, averaging 16 images provided optimal signal quality. A further increase in averaging was only beneficial in the eyes with senile cataract. However, prolonged acquisition time and possible loss of details have to be taken into account. PMID:28630764

Use of focus measure operators for characterization of flood illumination adaptive optics ophthalmoscopy image quality

PubMed Central

Alonso-Caneiro, David; Sampson, Danuta M.; Chew, Avenell L.; Collins, Michael J.; Chen, Fred K.

2018-01-01

Adaptive optics flood illumination ophthalmoscopy (AO-FIO) allows imaging of the cone photoreceptor in the living human retina. However, clinical interpretation of the AO-FIO image remains challenging due to suboptimal quality arising from residual uncorrected wavefront aberrations and rapid eye motion. An objective method of assessing image quality is necessary to determine whether an AO-FIO image is suitable for grading and diagnostic purpose. In this work, we explore the use of focus measure operators as a surrogate measure of AO-FIO image quality. A set of operators are tested on data sets acquired at different focal depths and different retinal locations from healthy volunteers. Our results demonstrate differences in focus measure operator performance in quantifying AO-FIO image quality. Further, we discuss the potential application of the selected focus operators in (i) selection of the best quality AO-FIO image from a series of images collected at the same retinal location and (ii) assessment of longitudinal changes in the diseased retina. Focus function could be incorporated into real-time AO-FIO image processing and provide an initial automated quality assessment during image acquisition or reading center grading. PMID:29552404

Gradient Magnitude Similarity Deviation: A Highly Efficient Perceptual Image Quality Index.

PubMed

Xue, Wufeng; Zhang, Lei; Mou, Xuanqin; Bovik, Alan C

2014-02-01

It is an important task to faithfully evaluate the perceptual quality of output images in many applications, such as image compression, image restoration, and multimedia streaming. A good image quality assessment (IQA) model should not only deliver high quality prediction accuracy, but also be computationally efficient. The efficiency of IQA metrics is becoming particularly important due to the increasing proliferation of high-volume visual data in high-speed networks. We present a new effective and efficient IQA model, called gradient magnitude similarity deviation (GMSD). The image gradients are sensitive to image distortions, while different local structures in a distorted image suffer different degrees of degradations. This motivates us to explore the use of global variation of gradient based local quality map for overall image quality prediction. We find that the pixel-wise gradient magnitude similarity (GMS) between the reference and distorted images combined with a novel pooling strategy-the standard deviation of the GMS map-can predict accurately perceptual image quality. The resulting GMSD algorithm is much faster than most state-of-the-art IQA methods, and delivers highly competitive prediction accuracy. MATLAB source code of GMSD can be downloaded at http://www4.comp.polyu.edu.hk/~cslzhang/IQA/GMSD/GMSD.htm.

Use of focus measure operators for characterization of flood illumination adaptive optics ophthalmoscopy image quality.

PubMed

Alonso-Caneiro, David; Sampson, Danuta M; Chew, Avenell L; Collins, Michael J; Chen, Fred K

2018-02-01

Adaptive optics flood illumination ophthalmoscopy (AO-FIO) allows imaging of the cone photoreceptor in the living human retina. However, clinical interpretation of the AO-FIO image remains challenging due to suboptimal quality arising from residual uncorrected wavefront aberrations and rapid eye motion. An objective method of assessing image quality is necessary to determine whether an AO-FIO image is suitable for grading and diagnostic purpose. In this work, we explore the use of focus measure operators as a surrogate measure of AO-FIO image quality. A set of operators are tested on data sets acquired at different focal depths and different retinal locations from healthy volunteers. Our results demonstrate differences in focus measure operator performance in quantifying AO-FIO image quality. Further, we discuss the potential application of the selected focus operators in (i) selection of the best quality AO-FIO image from a series of images collected at the same retinal location and (ii) assessment of longitudinal changes in the diseased retina. Focus function could be incorporated into real-time AO-FIO image processing and provide an initial automated quality assessment during image acquisition or reading center grading.

Comprehensive model for predicting perceptual image quality of smart mobile devices.

PubMed

Gong, Rui; Xu, Haisong; Luo, M R; Li, Haifeng

2015-01-01

An image quality model for smart mobile devices was proposed based on visual assessments of several image quality attributes. A series of psychophysical experiments were carried out on two kinds of smart mobile devices, i.e., smart phones and tablet computers, in which naturalness, colorfulness, brightness, contrast, sharpness, clearness, and overall image quality were visually evaluated under three lighting environments via categorical judgment method for various application types of test images. On the basis of Pearson correlation coefficients and factor analysis, the overall image quality could first be predicted by its two constituent attributes with multiple linear regression functions for different types of images, respectively, and then the mathematical expressions were built to link the constituent image quality attributes with the physical parameters of smart mobile devices and image appearance factors. The procedure and algorithms were applicable to various smart mobile devices, different lighting conditions, and multiple types of images, and performance was verified by the visual data.

Indigenous obesity in the news: a media analysis of news representation of obesity in Australia's Indigenous population.

PubMed

Islam, Salwa; Fitzgerald, Lisa

2016-01-01

High rates of obesity are a significant issue amongst Indigenous populations in many countries around the world. Media framing of issues can play a critical role in shaping public opinion and government policy. A broad range of media analyses have been conducted on various aspects of obesity, however media representation of Indigenous obesity remains unexplored. In this study we investigate how obesity in Australia's Indigenous population is represented in newsprint media coverage. Media articles published between 2007 and 2014 were analysed for the distribution and extent of coverage over time and across Indigenous and mainstream media sources using quantitative content analysis. Representation of the causes and solutions of Indigenous obesity and framing in text and image content was examined using qualitative framing analysis. Media coverage of Indigenous obesity was very limited with no clear trends in reporting over time or across sources. The single Indigenous media source was the second largest contributor to the media discourse of this issue. Structural causes/origins were most often cited and individual solutions were comparatively overrepresented. A range of frames were employed across the media sources. All images reinforced textual framing except for one article where the image depicted individual factors whereas the text referred to structural determinants. This study provides a starting point for an important area of research that needs further investigation. The findings highlight the importance of alternative news media outlets, such as The Koori Mail, and that these should be developed to enhance the quality and diversity of media coverage. Media organisations can actively contribute to improving Indigenous health through raising awareness, evidence-based balanced reporting, and development of closer ties with Indigenous health workers.

Development of X-ray CCD camera based X-ray micro-CT system

NASA Astrophysics Data System (ADS)

Sarkar, Partha S.; Ray, N. K.; Pal, Manoj K.; Baribaddala, Ravi; Agrawal, Ashish; Kashyap, Y.; Sinha, A.; Gadkari, S. C.

2017-02-01

Availability of microfocus X-ray sources and high resolution X-ray area detectors has made it possible for high resolution microtomography studies to be performed outside the purview of synchrotron. In this paper, we present the work towards the use of an external shutter on a high resolution microtomography system using X-ray CCD camera as a detector. During micro computed tomography experiments, the X-ray source is continuously ON and owing to the readout mechanism of the CCD detector electronics, the detector registers photons reaching it during the read-out period too. This introduces a shadow like pattern in the image known as smear whose direction is defined by the vertical shift register. To resolve this issue, the developed system has been incorporated with a synchronized shutter just in front of the X-ray source. This is positioned in the X-ray beam path during the image readout period and out of the beam path during the image acquisition period. This technique has resulted in improved data quality and hence the same is reflected in the reconstructed images.

Video indexing based on image and sound

NASA Astrophysics Data System (ADS)

Faudemay, Pascal; Montacie, Claude; Caraty, Marie-Jose

1997-10-01

Video indexing is a major challenge for both scientific and economic reasons. Information extraction can sometimes be easier from sound channel than from image channel. We first present a multi-channel and multi-modal query interface, to query sound, image and script through 'pull' and 'push' queries. We then summarize the segmentation phase, which needs information from the image channel. Detection of critical segments is proposed. It should speed-up both automatic and manual indexing. We then present an overview of the information extraction phase. Information can be extracted from the sound channel, through speaker recognition, vocal dictation with unconstrained vocabularies, and script alignment with speech. We present experiment results for these various techniques. Speaker recognition methods were tested on the TIMIT and NTIMIT database. Vocal dictation as experimented on newspaper sentences spoken by several speakers. Script alignment was tested on part of a carton movie, 'Ivanhoe'. For good quality sound segments, error rates are low enough for use in indexing applications. Major issues are the processing of sound segments with noise or music, and performance improvement through the use of appropriate, low-cost architectures or networks of workstations.

DSCOVR/EPIC Images and Science: A New Way to View the Entire Sunlit Earth From A Sun-Earth Lagrange-1 Orbit

NASA Astrophysics Data System (ADS)

Herman, J. R.; Marshak, A.; Szabo, A.

2015-12-01

The DSCOVR mission was launched into a Sun-Earth Lagrange-1 orbit 1.5 million kilometers from earth in February 2015 onboard a SpaceX Falcon-9 rocket. The solar wind and earth science instruments were tested during the 4.5 month journey to L-1. The first data were obtained during the June-July commissioning phase, which included the first moderate resolution (10 km) color images of the entire sunlit earth, color images of the Moon, and scientific data from 10 narrow band filters (317.5, 325, 340, 388, 443, 551, 680, 687.75, 764, and 779.5 nm). Three of these filters were used to construct the color images (443, 551, 680 nm) based on the average eye response histogram of the sunlit earth. This talk will discuss some of the issues involved in deriving science quality data for global ozone, the aerosol index (dust, smoke, and volcanic ash), cloud amounts and reflectivity, and cloud height (measured from the O2 A- and B-bands). As with most new satellites, the science data are preliminary.

Partial Deconvolution with Inaccurate Blur Kernel.

PubMed

Ren, Dongwei; Zuo, Wangmeng; Zhang, David; Xu, Jun; Zhang, Lei

2017-10-17

Most non-blind deconvolution methods are developed under the error-free kernel assumption, and are not robust to inaccurate blur kernel. Unfortunately, despite the great progress in blind deconvolution, estimation error remains inevitable during blur kernel estimation. Consequently, severe artifacts such as ringing effects and distortions are likely to be introduced in the non-blind deconvolution stage. In this paper, we tackle this issue by suggesting: (i) a partial map in the Fourier domain for modeling kernel estimation error, and (ii) a partial deconvolution model for robust deblurring with inaccurate blur kernel. The partial map is constructed by detecting the reliable Fourier entries of estimated blur kernel. And partial deconvolution is applied to wavelet-based and learning-based models to suppress the adverse effect of kernel estimation error. Furthermore, an E-M algorithm is developed for estimating the partial map and recovering the latent sharp image alternatively. Experimental results show that our partial deconvolution model is effective in relieving artifacts caused by inaccurate blur kernel, and can achieve favorable deblurring quality on synthetic and real blurry images.Most non-blind deconvolution methods are developed under the error-free kernel assumption, and are not robust to inaccurate blur kernel. Unfortunately, despite the great progress in blind deconvolution, estimation error remains inevitable during blur kernel estimation. Consequently, severe artifacts such as ringing effects and distortions are likely to be introduced in the non-blind deconvolution stage. In this paper, we tackle this issue by suggesting: (i) a partial map in the Fourier domain for modeling kernel estimation error, and (ii) a partial deconvolution model for robust deblurring with inaccurate blur kernel. The partial map is constructed by detecting the reliable Fourier entries of estimated blur kernel. And partial deconvolution is applied to wavelet-based and learning-based models to suppress the adverse effect of kernel estimation error. Furthermore, an E-M algorithm is developed for estimating the partial map and recovering the latent sharp image alternatively. Experimental results show that our partial deconvolution model is effective in relieving artifacts caused by inaccurate blur kernel, and can achieve favorable deblurring quality on synthetic and real blurry images.

Study on Classification Accuracy Inspection of Land Cover Data Aided by Automatic Image Change Detection Technology

NASA Astrophysics Data System (ADS)

Xie, W.-J.; Zhang, L.; Chen, H.-P.; Zhou, J.; Mao, W.-J.

2018-04-01

The purpose of carrying out national geographic conditions monitoring is to obtain information of surface changes caused by human social and economic activities, so that the geographic information can be used to offer better services for the government, enterprise and public. Land cover data contains detailed geographic conditions information, thus has been listed as one of the important achievements in the national geographic conditions monitoring project. At present, the main issue of the production of the land cover data is about how to improve the classification accuracy. For the land cover data quality inspection and acceptance, classification accuracy is also an important check point. So far, the classification accuracy inspection is mainly based on human-computer interaction or manual inspection in the project, which are time consuming and laborious. By harnessing the automatic high-resolution remote sensing image change detection technology based on the ERDAS IMAGINE platform, this paper carried out the classification accuracy inspection test of land cover data in the project, and presented a corresponding technical route, which includes data pre-processing, change detection, result output and information extraction. The result of the quality inspection test shows the effectiveness of the technical route, which can meet the inspection needs for the two typical errors, that is, missing and incorrect update error, and effectively reduces the work intensity of human-computer interaction inspection for quality inspectors, and also provides a technical reference for the data production and quality control of the land cover data.

Image Quality Performance Measurement of the microPET Focus 120

NASA Astrophysics Data System (ADS)

Ballado, Fernando Trejo; López, Nayelli Ortega; Flores, Rafael Ojeda; Ávila-Rodríguez, Miguel A.

2010-12-01

The aim of this work is to evaluate the characteristics involved in the image reconstruction of the microPET Focus 120. For this evaluation were used two different phantoms; a miniature hot-rod Derenzo phantom and a National Electrical Manufacturers Association (NEMA) NU4-2008 image quality (IQ) phantom. The best image quality was obtained when using OSEM3D as the reconstruction method reaching a spatial resolution of 1.5 mm with the Derenzo phantom filled with 18F. Image quality test results indicate a superior image quality for the Focus 120 when compared to previous microPET models.

WINDS (KIZUNA)-based Collaborative e-Learning Project in Thailand, Malaysia and Japan

NASA Astrophysics Data System (ADS)

Hisanaga, Makoto; Takahashi, Shin; Kameyama, Keisuke; Fukui, Yukio; Kitawaki, Nobuhiko

The expanding digital divide deprives students in developing countries with opportunities for education. Advanced countries have the ability to enhance those opportunities. For this study, the authors set up and tested a remote lecture system using a commercial communication satellite beginning in 2002. This project attempted to solve issues in remote lecture systems using conventional satellite systems, and to build up a real-time collaborative lecture delivery system using a new satellite, called the Wideband InterNetworking engineering test and Demonstration Satellite (WINDS). This work proposes a remote education system using satellites, enabling the issues raised in the pilot experiments to be solved. Principal outcomes in this project include improvements of the quality of image and sound, and the communication delay. The authors also demonstrate the usefulness of WINDS in the education field.

Image quality assessment metric for frame accumulated image

NASA Astrophysics Data System (ADS)

Yu, Jianping; Li, Gang; Wang, Shaohui; Lin, Ling

2018-01-01

The medical image quality determines the accuracy of diagnosis, and the gray-scale resolution is an important parameter to measure image quality. But current objective metrics are not very suitable for assessing medical images obtained by frame accumulation technology. Little attention was paid to the gray-scale resolution, basically based on spatial resolution and limited to the 256 level gray scale of the existing display device. Thus, this paper proposes a metric, "mean signal-to-noise ratio" (MSNR) based on signal-to-noise in order to be more reasonable to evaluate frame accumulated medical image quality. We demonstrate its potential application through a series of images under a constant illumination signal. Here, the mean image of enough images was regarded as the reference image. Several groups of images by different frame accumulation and their MSNR were calculated. The results of the experiment show that, compared with other quality assessment methods, the metric is simpler, more effective, and more suitable for assessing frame accumulated images that surpass the gray scale and precision of the original image.

Predicting Causes of Data Quality Issues in a Clinical Data Research Network.

PubMed

Khare, Ritu; Ruth, Byron J; Miller, Matthew; Tucker, Joshua; Utidjian, Levon H; Razzaghi, Hanieh; Patibandla, Nandan; Burrows, Evanette K; Bailey, L Charles

2018-01-01

Clinical data research networks (CDRNs) invest substantially in identifying and investigating data quality problems. While identification is largely automated, the investigation and resolution are carried out manually at individual institutions. In the PEDSnet CDRN, we found that only approximately 35% of the identified data quality issues are resolvable as they are caused by errors in the extract-transform-load (ETL) code. Nonetheless, with no prior knowledge of issue causes, partner institutions end up spending significant time investigating issues that represent either inherent data characteristics or false alarms. This work investigates whether the causes (ETL, Characteristic, or False alarm) can be predicted before spending time investigating issues. We trained a classifier on the metadata from 10,281 real-world data quality issues, and achieved a cause prediction F1-measure of up to 90%. While initially tested on PEDSnet, the proposed methodology is applicable to other CDRNs facing similar bottlenecks in handling data quality results.

Synthesized view comparison method for no-reference 3D image quality assessment

NASA Astrophysics Data System (ADS)

Luo, Fangzhou; Lin, Chaoyi; Gu, Xiaodong; Ma, Xiaojun

2018-04-01

We develop a no-reference image quality assessment metric to evaluate the quality of synthesized view rendered from the Multi-view Video plus Depth (MVD) format. Our metric is named Synthesized View Comparison (SVC), which is designed for real-time quality monitoring at the receiver side in a 3D-TV system. The metric utilizes the virtual views in the middle which are warped from left and right views by Depth-image-based rendering algorithm (DIBR), and compares the difference between the virtual views rendered from different cameras by Structural SIMilarity (SSIM), a popular 2D full-reference image quality assessment metric. The experimental results indicate that our no-reference quality assessment metric for the synthesized images has competitive prediction performance compared with some classic full-reference image quality assessment metrics.

Deep supervised dictionary learning for no-reference image quality assessment

NASA Astrophysics Data System (ADS)

Huang, Yuge; Liu, Xuesong; Tian, Xiang; Zhou, Fan; Chen, Yaowu; Jiang, Rongxin

2018-03-01

We propose a deep convolutional neural network (CNN) for general no-reference image quality assessment (NR-IQA), i.e., accurate prediction of image quality without a reference image. The proposed model consists of three components such as a local feature extractor that is a fully CNN, an encoding module with an inherent dictionary that aggregates local features to output a fixed-length global quality-aware image representation, and a regression module that maps the representation to an image quality score. Our model can be trained in an end-to-end manner, and all of the parameters, including the weights of the convolutional layers, the dictionary, and the regression weights, are simultaneously learned from the loss function. In addition, the model can predict quality scores for input images of arbitrary sizes in a single step. We tested our method on commonly used image quality databases and showed that its performance is comparable with that of state-of-the-art general-purpose NR-IQA algorithms.

In Pursuit of Image: How We Think about Photographs We Seek

ERIC Educational Resources Information Center

Oyarce, Sara

2012-01-01

The user perspective of image search remains poorly understood. The purpose of this study is to identify and investigate the key issues relevant to a user's interaction with images and the user's approach to image search. A deeper understanding of these issues will serve to inform the design of image retrieval systems and in turn better…

An Underwater Color Image Quality Evaluation Metric.

PubMed

Yang, Miao; Sowmya, Arcot

2015-12-01

Quality evaluation of underwater images is a key goal of underwater video image retrieval and intelligent processing. To date, no metric has been proposed for underwater color image quality evaluation (UCIQE). The special absorption and scattering characteristics of the water medium do not allow direct application of natural color image quality metrics especially to different underwater environments. In this paper, subjective testing for underwater image quality has been organized. The statistical distribution of the underwater image pixels in the CIELab color space related to subjective evaluation indicates the sharpness and colorful factors correlate well with subjective image quality perception. Based on these, a new UCIQE metric, which is a linear combination of chroma, saturation, and contrast, is proposed to quantify the non-uniform color cast, blurring, and low-contrast that characterize underwater engineering and monitoring images. Experiments are conducted to illustrate the performance of the proposed UCIQE metric and its capability to measure the underwater image enhancement results. They show that the proposed metric has comparable performance to the leading natural color image quality metrics and the underwater grayscale image quality metrics available in the literature, and can predict with higher accuracy the relative amount of degradation with similar image content in underwater environments. Importantly, UCIQE is a simple and fast solution for real-time underwater video processing. The effectiveness of the presented measure is also demonstrated by subjective evaluation. The results show better correlation between the UCIQE and the subjective mean opinion score.

Learning to rank for blind image quality assessment.

PubMed

Gao, Fei; Tao, Dacheng; Gao, Xinbo; Li, Xuelong

2015-10-01

Blind image quality assessment (BIQA) aims to predict perceptual image quality scores without access to reference images. State-of-the-art BIQA methods typically require subjects to score a large number of images to train a robust model. However, subjective quality scores are imprecise, biased, and inconsistent, and it is challenging to obtain a large-scale database, or to extend existing databases, because of the inconvenience of collecting images, training the subjects, conducting subjective experiments, and realigning human quality evaluations. To combat these limitations, this paper explores and exploits preference image pairs (PIPs) such as the quality of image Ia is better than that of image Ib for training a robust BIQA model. The preference label, representing the relative quality of two images, is generally precise and consistent, and is not sensitive to image content, distortion type, or subject identity; such PIPs can be generated at a very low cost. The proposed BIQA method is one of learning to rank. We first formulate the problem of learning the mapping from the image features to the preference label as one of classification. In particular, we investigate the utilization of a multiple kernel learning algorithm based on group lasso to provide a solution. A simple but effective strategy to estimate perceptual image quality scores is then presented. Experiments show that the proposed BIQA method is highly effective and achieves a performance comparable with that of state-of-the-art BIQA algorithms. Moreover, the proposed method can be easily extended to new distortion categories.

Standardizing Quality Assessment of Fused Remotely Sensed Images

NASA Astrophysics Data System (ADS)

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.

Bayesian framework inspired no-reference region-of-interest quality measure for brain MRI images

PubMed Central

Osadebey, Michael; Pedersen, Marius; Arnold, Douglas; Wendel-Mitoraj, Katrina

2017-01-01

Abstract. We describe a postacquisition, attribute-based quality assessment method for brain magnetic resonance imaging (MRI) images. It is based on the application of Bayes theory to the relationship between entropy and image quality attributes. The entropy feature image of a slice is segmented into low- and high-entropy regions. For each entropy region, there are three separate observations of contrast, standard deviation, and sharpness quality attributes. A quality index for a quality attribute is the posterior probability of an entropy region given any corresponding region in a feature image where quality attribute is observed. Prior belief in each entropy region is determined from normalized total clique potential (TCP) energy of the slice. For TCP below the predefined threshold, the prior probability for a region is determined by deviation of its percentage composition in the slice from a standard normal distribution built from 250 MRI volume data provided by Alzheimer’s Disease Neuroimaging Initiative. For TCP above the threshold, the prior is computed using a mathematical model that describes the TCP–noise level relationship in brain MRI images. Our proposed method assesses the image quality of each entropy region and the global image. Experimental results demonstrate good correlation with subjective opinions of radiologists for different types and levels of quality distortions. PMID:28630885

Difference Image Analysis of Defocused Observations With CSTAR

NASA Astrophysics Data System (ADS)

Oelkers, Ryan J.; Macri, Lucas M.; Wang, Lifan; Ashley, Michael C. B.; Cui, Xiangqun; Feng, Long-Long; Gong, Xuefei; Lawrence, Jon S.; Qiang, Liu; Luong-Van, Daniel; Pennypacker, Carl R.; Yang, Huigen; Yuan, Xiangyan; York, Donald G.; Zhou, Xu; Zhu, Zhenxi

2015-02-01

The Chinese Small Telescope ARray carried out high-cadence time-series observations of 27 square degrees centered on the South Celestial Pole during the Antarctic winter seasons of 2008-2010. Aperture photometry of the 2008 and 2010 i-band images resulted in the discovery of over 200 variable stars. Yearly servicing left the array defocused for the 2009 winter season, during which the system also suffered from intermittent frosting and power failures. Despite these technical issues, nearly 800,000 useful images were obtained using g, r, and clear filters. We developed a combination of difference imaging and aperture photometry to compensate for the highly crowded, blended, and defocused frames. We present details of this approach, which may be useful for the analysis of time-series data from other small-aperture telescopes regardless of their image quality. Using this approach, we were able to recover 68 previously known variables and detected variability in 37 additional objects. We also have determined the observing statistics for Dome A during the 2009 winter season; we find the extinction due to clouds to be less than 0.1 and 0.4 mag for 40% and 63% of the dark time, respectively.

Compressed Sensing Techniques Applied to Ultrasonic Imaging of Cargo Containers.

PubMed

López, Yuri Álvarez; Lorenzo, José Ángel Martínez

2017-01-15

One of the key issues in the fight against the smuggling of goods has been the development of scanners for cargo inspection. X-ray-based radiographic system scanners are the most developed sensing modality. However, they are costly and use bulky sources that emit hazardous, ionizing radiation. Aiming to improve the probability of threat detection, an ultrasonic-based technique, capable of detecting the footprint of metallic containers or compartments concealed within the metallic structure of the inspected cargo, has been proposed. The system consists of an array of acoustic transceivers that is attached to the metallic structure-under-inspection, creating a guided acoustic Lamb wave. Reflections due to discontinuities are detected in the images, provided by an imaging algorithm. Taking into consideration that the majority of those images are sparse, this contribution analyzes the application of Compressed Sensing (CS) techniques in order to reduce the amount of measurements needed, thus achieving faster scanning, without compromising the detection capabilities of the system. A parametric study of the image quality, as a function of the samples needed in spatial and frequency domains, is presented, as well as the dependence on the sampling pattern. For this purpose, realistic cargo inspection scenarios have been simulated.

State of the art and trends for digital pathology.

PubMed

García Rojo, Marcial

2012-01-01

Anatomic pathology is a medical specialty where both information management systems and digital images systems paly a most important role. Digital pathology is a new concept that considers all uses of this information, including diagnosis, biomedical research and education. Virtual microscopy or whole slide imaging, resulting in digital slides, is an outreaching technology in anatomic pathology. Limiting factors in the expansion of virtual microscopy are formidable storage dimension, scanning speed, quality of image and cultural change. Anatomic pathology data and images should be an important part of the patient electronic health records as well as of clinical data warehouse, epidemiological or biomedical research databases, and platforms dedicated to translational medicine. Integrating anatomic pathology to the "healthcare enterprise" can only be achieved using existing and emerging medical informatics standards like Digital Imaging and Communications in Medicine (DICOM®¹), Health Level Seven (HL7®), and Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT®), following the recommendations of Integrating the Healthcare Enterprise (IHE®). The consequences of the full digitalization of pathology departments are hard to foresee, but short term issues have arisen that imply interesting challenges for health care standards bodies.

Compressed Sensing Techniques Applied to Ultrasonic Imaging of Cargo Containers

PubMed Central

Álvarez López, Yuri; Martínez Lorenzo, José Ángel

2017-01-01

One of the key issues in the fight against the smuggling of goods has been the development of scanners for cargo inspection. X-ray-based radiographic system scanners are the most developed sensing modality. However, they are costly and use bulky sources that emit hazardous, ionizing radiation. Aiming to improve the probability of threat detection, an ultrasonic-based technique, capable of detecting the footprint of metallic containers or compartments concealed within the metallic structure of the inspected cargo, has been proposed. The system consists of an array of acoustic transceivers that is attached to the metallic structure-under-inspection, creating a guided acoustic Lamb wave. Reflections due to discontinuities are detected in the images, provided by an imaging algorithm. Taking into consideration that the majority of those images are sparse, this contribution analyzes the application of Compressed Sensing (CS) techniques in order to reduce the amount of measurements needed, thus achieving faster scanning, without compromising the detection capabilities of the system. A parametric study of the image quality, as a function of the samples needed in spatial and frequency domains, is presented, as well as the dependence on the sampling pattern. For this purpose, realistic cargo inspection scenarios have been simulated. PMID:28098841

Comparison of turbulence mitigation algorithms

NASA Astrophysics Data System (ADS)

Kozacik, Stephen T.; Paolini, Aaron; Sherman, Ariel; Bonnett, James; Kelmelis, Eric

2017-07-01

When capturing imagery over long distances, atmospheric turbulence often degrades the data, especially when observation paths are close to the ground or in hot environments. These issues manifest as time-varying scintillation and warping effects that decrease the effective resolution of the sensor and reduce actionable intelligence. In recent years, several image processing approaches to turbulence mitigation have shown promise. Each of these algorithms has different computational requirements, usability demands, and degrees of independence from camera sensors. They also produce different degrees of enhancement when applied to turbulent imagery. Additionally, some of these algorithms are applicable to real-time operational scenarios while others may only be suitable for postprocessing workflows. EM Photonics has been developing image-processing-based turbulence mitigation technology since 2005. We will compare techniques from the literature with our commercially available, real-time, GPU-accelerated turbulence mitigation software. These comparisons will be made using real (not synthetic), experimentally obtained data for a variety of conditions, including varying optical hardware, imaging range, subjects, and turbulence conditions. Comparison metrics will include image quality, video latency, computational complexity, and potential for real-time operation. Additionally, we will present a technique for quantitatively comparing turbulence mitigation algorithms using real images of radial resolution targets.

A whole-heart motion-correction algorithm: Effects on CT image quality and diagnostic accuracy of mechanical valve prosthesis abnormalities.

PubMed

Suh, Young Joo; Kim, Young Jin; Kim, Jin Young; Chang, Suyon; Im, Dong Jin; Hong, Yoo Jin; Choi, Byoung Wook

2017-11-01

We aimed to determine the effect of a whole-heart motion-correction algorithm (new-generation snapshot freeze, NG SSF) on the image quality of cardiac computed tomography (CT) images in patients with mechanical valve prostheses compared to standard images without motion correction and to compare the diagnostic accuracy of NG SSF and standard CT image sets for the detection of prosthetic valve abnormalities. A total of 20 patients with 32 mechanical valves who underwent wide-coverage detector cardiac CT with single-heartbeat acquisition were included. The CT image quality for subvalvular (below the prosthesis) and valvular regions (valve leaflets) of mechanical valves was assessed by two observers on a four-point scale (1 = poor, 2 = fair, 3 = good, and 4 = excellent). Paired t-tests or Wilcoxon signed rank tests were used to compare image quality scores and the number of diagnostic phases (image quality score≥3) between the standard image sets and NG SSF image sets. Diagnostic performance for detection of prosthetic valve abnormalities was compared between two image sets with the final diagnosis set by re-operation or clinical findings as the standard reference. NG SSF image sets had better image quality scores than standard image sets for both valvular and subvalvular regions (P < 0.05 for both). The number of phases that were of diagnostic image quality per patient was significantly greater in the NG SSF image set than standard image set for both valvular and subvalvular regions (P < 0.0001). Diagnostic performance of NG SSF image sets for the detection of prosthetic abnormalities (20 pannus and two paravalvular leaks) was greater than that of standard image sets (P < 0.05). Application of NG SSF can improve CT image quality and diagnostic accuracy in patients with mechanical valves compared to standard images. Copyright © 2017 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

Digital mammography--DQE versus optimized image quality in clinical environment: an on site study

NASA Astrophysics Data System (ADS)

Oberhofer, Nadia; Fracchetti, Alessandro; Springeth, Margareth; Moroder, Ehrenfried

2010-04-01

The intrinsic quality of the detection system of 7 different digital mammography units (5 direct radiography DR; 2 computed radiography CR), expressed by DQE, has been compared with their image quality/dose performances in clinical use. DQE measurements followed IEC 62220-1-2 using a tungsten test object for MTF determination. For image quality assessment two different methods have been applied: 1) measurement of contrast to noise ratio (CNR) according to the European guidelines and 2) contrast-detail (CD) evaluation. The latter was carried out with the phantom CDMAM ver. 3.4 and the commercial software CDMAM Analyser ver. 1.1 (both Artinis) for automated image analysis. The overall image quality index IQFinv proposed by the software has been validated. Correspondence between the two methods has been shown figuring out a linear correlation between CNR and IQFinv. All systems were optimized with respect to image quality and average glandular dose (AGD) within the constraints of automatic exposure control (AEC). For each equipment, a good image quality level was defined by means of CD analysis, and the corresponding CNR value considered as target value. The goal was to achieve for different PMMA-phantom thicknesses constant image quality, that means the CNR target value, at minimum dose. All DR systems exhibited higher DQE and significantly better image quality compared to CR systems. Generally switching, where available, to a target/filter combination with an x-ray spectrum of higher mean energy permitted dose savings at equal image quality. However, several systems did not allow to modify the AEC in order to apply optimal radiographic technique in clinical use. The best ratio image quality/dose was achieved by a unit with a-Se detector and W anode only recently available on the market.

Image quality classification for DR screening using deep learning.

PubMed

FengLi Yu; Jing Sun; Annan Li; Jun Cheng; Cheng Wan; Jiang Liu

2017-07-01

The quality of input images significantly affects the outcome of automated diabetic retinopathy (DR) screening systems. Unlike the previous methods that only consider simple low-level features such as hand-crafted geometric and structural features, in this paper we propose a novel method for retinal image quality classification (IQC) that performs computational algorithms imitating the working of the human visual system. The proposed algorithm combines unsupervised features from saliency map and supervised features coming from convolutional neural networks (CNN), which are fed to an SVM to automatically detect high quality vs poor quality retinal fundus images. We demonstrate the superior performance of our proposed algorithm on a large retinal fundus image dataset and the method could achieve higher accuracy than other methods. Although retinal images are used in this study, the methodology is applicable to the image quality assessment and enhancement of other types of medical images.

Relationships among muscle dysmorphia characteristics, body image quality of life, and coping in males.

PubMed

Tod, D; Edwards, C

2015-09-01

The purpose of this study was to examine relationships among bodybuilding dependence, muscle satisfaction, body image-related quality of life and body image-related coping strategies, and test the hypothesis that muscle dysmorphia characteristics may predict quality of life via coping strategies. Participants (294 males, Mage=20.5 years, SD=3.1) participated in a cross-sectional survey. Participants completed questionnaires assessing muscle satisfaction, bodybuilding dependence, body image-related quality of life and body image-related coping. Quality of life was correlated positively with muscle satisfaction and bodybuilding dependence but negatively with body image coping (P<0.05). Body image coping was correlated positively with bodybuilding dependence and negatively with muscle satisfaction (P<0.05). Mediation analysis found that bodybuilding dependence and muscle satisfaction predicted quality of life both directly and indirectly via body image coping strategies (as evidenced by the bias corrected and accelerated bootstrapped confidence intervals). These results provide preliminary evidence regarding the ways that muscularity concerns might influence body image-related quality of life. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Antiscatter grid use in pediatric digital tomosynthesis imaging†

PubMed Central

King, Jenna M.; Reed, Martin

2011-01-01

The objective of this study was to assess the effect of antiscatter grid use on tomosynthesis image quality. We performed an observer study that rated the image quality of digital tomosynthesis scout radiographs and slice images of a Leeds TO.20 contrast‐detail test object embedded in acrylic with and without a grid. We considered 10, 15, 20 and 25 cm of acrylic to represent the wide range of patient thicknesses encountered in pediatric imaging. We also acquired and rated images without a grid at an increased patient dose. The readers counted the total number of visible details in each image as a measure of relative image quality. We observed that the antiscatter grid improves tomosynthesis image quality compared to the grid‐out case, which received image quality scores similar to grid‐in radiography. Our results suggest that, in order to achieve the best image quality in exchange for the increase in patient dose, it may often be appropriate to include an antiscatter grid for pediatric tomosynthesis imaging, particularly if the patient thickness is greater than 10 cm. PACS number: 87.57.‐s PMID:22089021

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

PubMed

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.

Advanced microlens and color filter process technology for the high-efficiency CMOS and CCD image sensors

NASA Astrophysics Data System (ADS)

Fan, Yang-Tung; Peng, Chiou-Shian; Chu, Cheng-Yu

2000-12-01

New markets are emerging for digital electronic image device, especially in visual communications, PC camera, mobile/cell phone, security system, toys, vehicle image system and computer peripherals for document capture. To enable one-chip image system that image sensor is with a full digital interface, can make image capture devices in our daily lives. Adding a color filter to such image sensor in a pattern of mosaics pixel or wide stripes can make image more real and colorful. We can say 'color filter makes the life more colorful color filter is? Color filter means can filter image light source except the color with specific wavelength and transmittance that is same as color filter itself. Color filter process is coating and patterning green, red and blue (or cyan, magenta and yellow) mosaic resists onto matched pixel in image sensing array pixels. According to the signal caught from each pixel, we can figure out the environment image picture. Widely use of digital electronic camera and multimedia applications today makes the feature of color filter becoming bright. Although it has challenge but it is very worthy to develop the process of color filter. We provide the best service on shorter cycle time, excellent color quality, high and stable yield. The key issues of advanced color process have to be solved and implemented are planarization and micro-lens technology. Lost of key points of color filter process technology have to consider will also be described in this paper.

Cone-beam volume CT mammographic imaging: feasibility study

NASA Astrophysics Data System (ADS)

Chen, Biao; Ning, Ruola

2001-06-01

X-ray projection mammography, using a film/screen combination or digital techniques, has proven to be the most effective imaging modality for early detection of breast cancer currently available. However, the inherent superimposition of structures makes small carcinoma (a few millimeters in size) difficult to detect in the occultation case or in dense breasts, resulting in a high false positive biopsy rate. The cone-beam x-ray projection based volume imaging using flat panel detectors (FPDs) makes it possible to obtain three-dimensional breast images. This may benefit diagnosis of the structure and pattern of the lesion while eliminating hard compression of the breast. This paper presents a novel cone-beam volume CT mammographic imaging protocol based on the above techniques. Through computer simulation, the key issues of the system and imaging techniques, including the x-ray imaging geometry and corresponding reconstruction algorithms, x-ray characteristics of breast tissues, x-ray setting techniques, the absorbed dose estimation and the quantitative effect of x-ray scattering on image quality, are addressed. The preliminary simulation results support the proposed cone-beam volume CT mammographic imaging modality in respect to feasibility and practicability for mammography. The absorbed dose level is comparable to that of current two-view mammography and would not be a prominent problem for this imaging protocol. Compared to traditional mammography, the proposed imaging protocol with isotropic spatial resolution will potentially provide significantly better low contrast detectability of breast tumors and more accurate location of breast lesions.

Next-generation digital camera integration and software development issues

NASA Astrophysics Data System (ADS)

Venkataraman, Shyam; Peters, Ken; Hecht, Richard

1998-04-01

This paper investigates the complexities associated with the development of next generation digital cameras due to requirements in connectivity and interoperability. Each successive generation of digital camera improves drastically in cost, performance, resolution, image quality and interoperability features. This is being accomplished by advancements in a number of areas: research, silicon, standards, etc. As the capabilities of these cameras increase, so do the requirements for both hardware and software. Today, there are two single chip camera solutions in the market including the Motorola MPC 823 and LSI DCAM- 101. Real time constraints for a digital camera may be defined by the maximum time allowable between capture of images. Constraints in the design of an embedded digital camera include processor architecture, memory, processing speed and the real-time operating systems. This paper will present the LSI DCAM-101, a single-chip digital camera solution. It will present an overview of the architecture and the challenges in hardware and software for supporting streaming video in such a complex device. Issues presented include the development of the data flow software architecture, testing and integration on this complex silicon device. The strategy for optimizing performance on the architecture will also be presented.

10 CFR 32.25 - Conditions of licenses issued under § 32.22: Quality control, labeling, and reports of transfer.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false Conditions of licenses issued under § 32.22: Quality... Concentrations and Items § 32.25 Conditions of licenses issued under § 32.22: Quality control, labeling, and... in the manufacture of the product to assure that each production lot meets the quality control...

10 CFR 32.25 - Conditions of licenses issued under § 32.22: Quality control, labeling, and reports of transfer.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 1 2011-01-01 2011-01-01 false Conditions of licenses issued under § 32.22: Quality... Concentrations and Items § 32.25 Conditions of licenses issued under § 32.22: Quality control, labeling, and... in the manufacture of the product to assure that each production lot meets the quality control...

Practical Framework for an Electron Beam Induced Current Technique Based on a Numerical Optimization Approach

NASA Astrophysics Data System (ADS)

Yamaguchi, Hideshi; Soeda, Takeshi

2015-03-01

A practical framework for an electron beam induced current (EBIC) technique has been established for conductive materials based on a numerical optimization approach. Although the conventional EBIC technique is useful for evaluating the distributions of dopants or crystal defects in semiconductor transistors, issues related to the reproducibility and quantitative capability of measurements using this technique persist. For instance, it is difficult to acquire high-quality EBIC images throughout continuous tests due to variation in operator skill or test environment. Recently, due to the evaluation of EBIC equipment performance and the numerical optimization of equipment items, the constant acquisition of high contrast images has become possible, improving the reproducibility as well as yield regardless of operator skill or test environment. The technique proposed herein is even more sensitive and quantitative than scanning probe microscopy, an imaging technique that can possibly damage the sample. The new technique is expected to benefit the electrical evaluation of fragile or soft materials along with LSI materials.

Deep Learning and Image Processing for Automated Crack Detection and Defect Measurement in Underground Structures

NASA Astrophysics Data System (ADS)

Panella, F.; Boehm, J.; Loo, Y.; Kaushik, A.; Gonzalez, D.

2018-05-01

This work presents the combination of Deep-Learning (DL) and image processing to produce an automated cracks recognition and defect measurement tool for civil structures. The authors focus on tunnel civil structures and survey and have developed an end to end tool for asset management of underground structures. In order to maintain the serviceability of tunnels, regular inspection is needed to assess their structural status. The traditional method of carrying out the survey is the visual inspection: simple, but slow and relatively expensive and the quality of the output depends on the ability and experience of the engineer as well as on the total workload (stress and tiredness may influence the ability to observe and record information). As a result of these issues, in the last decade there is the desire to automate the monitoring using new methods of inspection. The present paper has the goal of combining DL with traditional image processing to create a tool able to detect, locate and measure the structural defect.

Survey of the prevalence and methodology of quality assurance for B-mode ultrasound image quality among veterinary sonographers.

PubMed

Hoscheit, Larry P; Heng, Hock Gan; Lim, Chee Kin; Weng, Hsin-Yi

2018-05-01

Image quality in B-mode ultrasound is important as it reflects the diagnostic accuracy and diagnostic information provided during clinical scanning. Quality assurance programs for B-mode ultrasound systems/components are comprised of initial quality acceptance testing and subsequent regularly scheduled quality control testing. The importance of quality assurance programs for B-mode ultrasound image quality using ultrasound phantoms is well documented in the human medical and medical physics literature. The purpose of this prospective, cross-sectional, survey study was to determine the prevalence and methodology of quality acceptance testing and quality control testing of image quality for ultrasound system/components among veterinary sonographers. An online electronic survey was sent to 1497 members of veterinary imaging organizations: the American College of Veterinary Radiology, the Veterinary Ultrasound Society, and the European Association of Veterinary Diagnostic Imaging, and a total of 167 responses were received. The results showed that the percentages of veterinary sonographers performing quality acceptance testing and quality control testing are 42% (64/151; 95% confidence interval 34-52%) and 26% (40/156: 95% confidence interval 19-33%) respectively. Of the respondents who claimed to have quality acceptance testing or quality control testing of image quality in place for their ultrasound system/components, 0% have performed quality acceptance testing or quality control testing correctly (quality acceptance testing 95% confidence interval: 0-6%, quality control testing 95% confidence interval: 0-11%). Further education and guidelines are recommended for veterinary sonographers in the area of quality acceptance testing and quality control testing for B-mode ultrasound equipment/components. © 2018 American College of Veterinary Radiology.

Document Image Processing: Going beyond the Black-and-White Barrier. Progress, Issues and Options with Greyscale and Colour Image Processing.

ERIC Educational Resources Information Center

Hendley, Tom

1995-01-01

Discussion of digital document image processing focuses on issues and options associated with greyscale and color image processing. Topics include speed; size of original document; scanning resolution; markets for different categories of scanners, including photographic libraries, publishing, and office applications; hybrid systems; data…

Image quality evaluation of eight complementary metal-oxide semiconductor intraoral digital X-ray sensors.

PubMed

Teich, Sorin; Al-Rawi, Wisam; Heima, Masahiro; Faddoul, Fady F; Goldzweig, Gil; Gutmacher, Zvi; Aizenbud, Dror

2016-10-01

To evaluate the image quality generated by eight commercially available intraoral sensors. Eighteen clinicians ranked the quality of a bitewing acquired from one subject using eight different intraoral sensors. Analytical methods used to evaluate clinical image quality included the Visual Grading Characteristics method, which helps to quantify subjective opinions to make them suitable for analysis. The Dexis sensor was ranked significantly better than Sirona and Carestream-Kodak sensors; and the image captured using the Carestream-Kodak sensor was ranked significantly worse than those captured using Dexis, Schick and Cyber Medical Imaging sensors. The Image Works sensor image was rated the lowest by all clinicians. Other comparisons resulted in non-significant results. None of the sensors was considered to generate images of significantly better quality than the other sensors tested. Further research should be directed towards determining the clinical significance of the differences in image quality reported in this study. © 2016 FDI World Dental Federation.

Newspaper Coverage of the 1992 Presidential Campaign: A Content Analysis of Character/Competence/Image Issues versus Platform/Political Issues.

ERIC Educational Resources Information Center

Sims, Judy R.; Giordano, Joseph

A research study assessed the amount of front page newspaper coverage allotted to "character/competence/image" issues versus "platform/political" issues in the 1992 presidential campaign. Using textual analysis, methodology of content analysis, researchers coded the front page of the following 5 newspapers between August 1 and…

Image Ads and Issue Ads in U.S. Presidential Advertising: Using Videostyle To Explore Stylistic Differences in Televised Political Ads From 1952 to 2000.

ERIC Educational Resources Information Center

Johnston, Anne; Kaid, Lynda Lee

2002-01-01

Explores the differences in techniques, strategies, narratives, and symbols used in 1,213 television issue ads and image ads from 13 U.S. presidential campaigns. Concludes that although the majority of both types of ads were positive, negative appeals dominated a higher percentage of issue ads as compared with image ads. (SG)

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Optimizing Cone Beam Computed Tomography (CBCT) System for Image Guided Radiation Therapy

NASA Astrophysics Data System (ADS)

Park, Chun Joo

Cone Beam Computed Tomography (CBCT) system is the most widely used imaging device in image guided radiation therapy (IGRT), where set of 3D volumetric image of patient can be reconstructed to identify and correct position setup errors prior to the radiation treatment. This CBCT system can significantly improve precision of on-line setup errors of patient position and tumor target localization prior to the treatment. However, there are still a number of issues that needs to be investigated with CBCT system such as 1) progressively increasing defective pixels in imaging detectors by its frequent usage, 2) hazardous radiation exposure to patients during the CBCT imaging, 3) degradation of image quality due to patients' respiratory motion when CBCT is acquired and 4) unknown knowledge of certain anatomical features such as liver, due to lack of soft-tissue contrast which makes tumor motion verification challenging. In this dissertation, we explore on optimizing the use of cone beam computed tomography (CBCT) system under such circumstances. We begin by introducing general concept of IGRT. We then present the development of automated defective pixel detection algorithm for X-ray imagers that is used for CBCT imaging using wavelet analysis. We next investigate on developing fast and efficient low-dose volumetric reconstruction techniques which includes 1) fast digital tomosynthesis reconstruction using general-purpose graphics processing unit (GPGPU) programming and 2) fast low-dose CBCT image reconstruction based on the Gradient-Projection-Barzilai-Borwein formulation (GP-BB). We further developed two efficient approaches that could reduce the degradation of CBCT images from respiratory motion. First, we propose reconstructing four dimensional (4D) CBCT and DTS using respiratory signal extracted from fiducial markers implanted in liver. Second, novel motion-map constrained image reconstruction (MCIR) is proposed that allows reconstruction of high quality and high phase resolution 4DCBCT images with no more than the imaging dose used in a standard Free Breathing 3DCBCT (FB-3DCBCT) scan. Finally, we demonstrate a method to analyze motion characteristics of liver that are particularly important for image guided stereotactic body radiation therapy (IG-SBRT). It is anticipated that all the approaches proposed in this study, which are both technically and clinically feasible, will allow much improvement in IGRT process.

Image Quality Improvement in Adaptive Optics Scanning Laser Ophthalmoscopy Assisted Capillary Visualization Using B-spline-based Elastic Image Registration

PubMed Central

Uji, Akihito; Ooto, Sotaro; Hangai, Masanori; Arichika, Shigeta; Yoshimura, Nagahisa

2013-01-01

Purpose To investigate the effect of B-spline-based elastic image registration on adaptive optics scanning laser ophthalmoscopy (AO-SLO)-assisted capillary visualization. Methods AO-SLO videos were acquired from parafoveal areas in the eyes of healthy subjects and patients with various diseases. After nonlinear image registration, the image quality of capillary images constructed from AO-SLO videos using motion contrast enhancement was compared before and after B-spline-based elastic (nonlinear) image registration performed using ImageJ. For objective comparison of image quality, contrast-to-noise ratios (CNRS) for vessel images were calculated. For subjective comparison, experienced ophthalmologists ranked images on a 5-point scale. Results All AO-SLO videos were successfully stabilized by elastic image registration. CNR was significantly higher in capillary images stabilized by elastic image registration than in those stabilized without registration. The average ratio of CNR in images with elastic image registration to CNR in images without elastic image registration was 2.10 ± 1.73, with no significant difference in the ratio between patients and healthy subjects. Improvement of image quality was also supported by expert comparison. Conclusions Use of B-spline-based elastic image registration in AO-SLO-assisted capillary visualization was effective for enhancing image quality both objectively and subjectively. PMID:24265796

Agricultural Land Use mapping by multi-sensor approach for hydrological water quality monitoring

NASA Astrophysics Data System (ADS)

Brodsky, Lukas; Kodesova, Radka; Kodes, Vit

2010-05-01

The main objective of this study is to demonstrate potential of operational use of the high and medium resolution remote sensing data for hydrological water quality monitoring by mapping agriculture intensity and crop structures. In particular use of remote sensing mapping for optimization of pesticide monitoring. The agricultural mapping task is tackled by means of medium spatial and high temporal resolution ESA Envisat MERIS FR images together with single high spatial resolution IRS AWiFS image covering the whole area of interest (the Czech Republic). High resolution data (e.g. SPOT, ALOS, Landsat) are often used for agricultural land use classification, but usually only at regional or local level due to data availability and financial constraints. AWiFS data (nominal spatial resolution 56 m) due to the wide satellite swath seems to be more suitable for use at national level. Nevertheless, one of the critical issues for such a classification is to have sufficient image acquisitions over the whole vegetation period to describe crop development in appropriate way. ESA MERIS middle-resolution data were used in several studies for crop classification. The high temporal and also spectral resolution of MERIS data has indisputable advantage for crop classification. However, spatial resolution of 300 m results in mixture signal in a single pixel. AWiFS-MERIS data synergy brings new perspectives in agricultural Land Use mapping. Also, the developed methodology procedure is fully compatible with future use of ESA (GMES) Sentinel satellite images. The applied methodology of hybrid multi-sensor approach consists of these main stages: a/ parcel segmentation and spectral pre-classification of high resolution image (AWiFS); b/ ingestion of middle resolution (MERIS) vegetation spectro-temporal features; c/ vegetation signatures unmixing; and d/ semantic object-oriented classification of vegetation classes into final classification scheme. These crop groups were selected to be classified: winter crops, spring crops, oilseed rape, legumes, summer and other crops. This study highlights operational potentials of high temporal full resolution MERIS images in agricultural land use monitoring. Practical application of this methodology is foreseen, among others, in the water quality monitoring. Effective pesticide monitoring relies also on spatial distribution of applied pesticides, which can be derived from crop - plant protection product relationship. Knowledge of areas with predominant occurrence of specific crop based on remote sensing data described above can be used for a forecast of probable plant protection product application, thus cost-effective pesticide monitoring. The remote sensing data used on a continuous basis can be used in other long-term water management issues and provide valuable data for decision makers. Acknowledgement: Authors acknowledge the financial support of the Ministry of Education, Youth and Sports of the Czech Republic (grants No. 2B06095 and No. MSM 6046070901). The study was also supported by ESA CAT-1 (ref. 4358) and SOSI projects (Spatial Observation Services and Infrastructure; ref. GSTP-RTDA-EOPG-SW-08-0004).

Patient issues in health research and quality of care: an inventory and data synthesis.

PubMed

Teunissen, Truus; Visse, Merel; de Boer, Pim; Abma, Tineke A

2013-12-01

The purpose of this review is to generate an inventory of issues that matter from a patient perspective in health research and quality of care. From these issues, criteria will be elicited to support patient(s) (groups) in their role as advisor or advocate when appraising health research, health policy and quality of health care. Literature shows that patients are beginning to develop their own voice and agenda's with issues in order to be prepared for the collaboration with professionals. Yet, patient issues have not been investigated systematically. This review addresses what patients find important and help to derive patient criteria for appraising research and quality of care. METHODS/SEARCH STRATEGY: Information was gathered from Western countries with similar economic, societal and health-care situations. We searched (from January 2000 to March 2010) for primary sources, secondary sources and tertiary sources; non-scientific publications were also included. The international inventory of issues that were defined by patients is covering a large array of domains. In total, 35 issue clusters further referred to as criteria were found ranging from dignity to cost effectiveness and family involvement. Issues from a patient perspective reveal patient values and appear to be adding to professional issues. Patient issues cover a broad domain, including fundamental values, quality of life, quality of care and personal development. Quite a few issues do not find its reflection in the scientific literature in spite of their clear and obvious appearance from tertiary sources. This may indicate a gap between the scientific research community and patient networks. © 2011 John Wiley & Sons Ltd.

Patient issues in health research and quality of care: an inventory and data synthesis

PubMed Central

Teunissen, Truus; Visse, Merel; de Boer, Pim; Abma, Tineke A.

2011-01-01

Abstract Aim  The purpose of this review is to generate an inventory of issues that matter from a patient perspective in health research and quality of care. From these issues, criteria will be elicited to support patient(s) (groups) in their role as advisor or advocate when appraising health research, health policy and quality of health care. Background  Literature shows that patients are beginning to develop their own voice and agenda’s with issues in order to be prepared for the collaboration with professionals. Yet, patient issues have not been investigated systematically. This review addresses what patients find important and help to derive patient criteria for appraising research and quality of care. Methods/search strategy  Information was gathered from Western countries with similar economic, societal and health‐care situations. We searched (from January 2000 to March 2010) for primary sources, secondary sources and tertiary sources; non‐scientific publications were also included. Results  The international inventory of issues that were defined by patients is covering a large array of domains. In total, 35 issue clusters further referred to as criteria were found ranging from dignity to cost effectiveness and family involvement. Issues from a patient perspective reveal patient values and appear to be adding to professional issues. Conclusions  Patient issues cover a broad domain, including fundamental values, quality of life, quality of care and personal development. Quite a few issues do not find its reflection in the scientific literature in spite of their clear and obvious appearance from tertiary sources. This may indicate a gap between the scientific research community and patient networks. PMID:21771226

Radiation Protection in Pediatric Radiology: Results of a Survey Among Dutch Hospitals.

PubMed

Bijwaard, Harmen; Valk, Doreth; de Waard-Schalkx, Ischa

2016-10-01

A survey about radiation protection in pediatric radiology was conducted among 22 general and seven children's hospitals in the Netherlands. Questions concerned, for example, child protocols used for CT, fluoroscopy and x-ray imaging, number of images and scans made, radiation doses and measures taken to reduce these, special tools used for children, and quality assurance issues. The answers received from 27 hospitals indicate that radiation protection practices differ considerably between general and children's hospitals but also between the respective general and children's hospitals. It is recommended that hospitals consult each other to come up with more uniform best practices. Few hospitals were able to supply doses that can be compared to the national Diagnostic Reference Levels (DRLs). The ones that could be compared exceeded the DRLs in one in five cases, which is more than was expected beforehand.

Information retrieval based on single-pixel optical imaging with quick-response code

NASA Astrophysics Data System (ADS)

Xiao, Yin; Chen, Wen

2018-04-01

Quick-response (QR) code technique is combined with ghost imaging (GI) to recover original information with high quality. An image is first transformed into a QR code. Then the QR code is treated as an input image in the input plane of a ghost imaging setup. After measurements, traditional correlation algorithm of ghost imaging is utilized to reconstruct an image (QR code form) with low quality. With this low-quality image as an initial guess, a Gerchberg-Saxton-like algorithm is used to improve its contrast, which is actually a post processing. Taking advantage of high error correction capability of QR code, original information can be recovered with high quality. Compared to the previous method, our method can obtain a high-quality image with comparatively fewer measurements, which means that the time-consuming postprocessing procedure can be avoided to some extent. In addition, for conventional ghost imaging, the larger the image size is, the more measurements are needed. However, for our method, images with different sizes can be converted into QR code with the same small size by using a QR generator. Hence, for the larger-size images, the time required to recover original information with high quality will be dramatically reduced. Our method makes it easy to recover a color image in a ghost imaging setup, because it is not necessary to divide the color image into three channels and respectively recover them.

Feature maps driven no-reference image quality prediction of authentically distorted images

NASA Astrophysics Data System (ADS)

Ghadiyaram, Deepti; Bovik, Alan C.

2015-03-01

Current blind image quality prediction models rely on benchmark databases comprised of singly and synthetically distorted images, thereby learning image features that are only adequate to predict human perceived visual quality on such inauthentic distortions. However, real world images often contain complex mixtures of multiple distortions. Rather than a) discounting the effect of these mixtures of distortions on an image's perceptual quality and considering only the dominant distortion or b) using features that are only proven to be efficient for singly distorted images, we deeply study the natural scene statistics of authentically distorted images, in different color spaces and transform domains. We propose a feature-maps-driven statistical approach which avoids any latent assumptions about the type of distortion(s) contained in an image, and focuses instead on modeling the remarkable consistencies in the scene statistics of real world images in the absence of distortions. We design a deep belief network that takes model-based statistical image features derived from a very large database of authentically distorted images as input and discovers good feature representations by generalizing over different distortion types, mixtures, and severities, which are later used to learn a regressor for quality prediction. We demonstrate the remarkable competence of our features for improving automatic perceptual quality prediction on a benchmark database and on the newly designed LIVE Authentic Image Quality Challenge Database and show that our approach of combining robust statistical features and the deep belief network dramatically outperforms the state-of-the-art.

High-field open versus short-bore magnetic resonance imaging of the spine: a randomized controlled comparison of image quality.

PubMed

Enders, Judith; Rief, Matthias; Zimmermann, Elke; Asbach, Patrick; Diederichs, Gerd; Wetz, Christoph; Siebert, Eberhard; Wagner, Moritz; Hamm, Bernd; Dewey, Marc

2013-01-01

The purpose of the present study was to compare the image quality of spinal magnetic resonance (MR) imaging performed on a high-field horizontal open versus a short-bore MR scanner in a randomized controlled study setup. Altogether, 93 (80% women, mean age 53) consecutive patients underwent spine imaging after random assignement to a 1-T horizontal open MR scanner with a vertical magnetic field or a 1.5-T short-bore MR scanner. This patient subset was part of a larger cohort. Image quality was assessed by determining qualitative parameters, signal-to-noise (SNR) and contrast-to-noise ratios (CNR), and quantitative contour sharpness. The image quality parameters were higher for short-bore MR imaging. Regarding all sequences, the relative differences were 39% for the mean overall qualitative image quality, 53% for the mean SNR values, and 34-37% for the quantitative contour sharpness (P<0.0001). The CNR values were also higher for images obtained with the short-bore MR scanner. No sequence was of very poor (nondiagnostic) image quality. Scanning times were significantly longer for examinations performed on the open MR scanner (mean: 32±22 min versus 20±9 min; P<0.0001). In this randomized controlled comparison of spinal MR imaging with an open versus a short-bore scanner, short-bore MR imaging revealed considerably higher image quality with shorter scanning times. ClinicalTrials.gov NCT00715806.

High-Field Open versus Short-Bore Magnetic Resonance Imaging of the Spine: A Randomized Controlled Comparison of Image Quality

PubMed Central

Zimmermann, Elke; Asbach, Patrick; Diederichs, Gerd; Wetz, Christoph; Siebert, Eberhard; Wagner, Moritz; Hamm, Bernd; Dewey, Marc

2013-01-01

Background The purpose of the present study was to compare the image quality of spinal magnetic resonance (MR) imaging performed on a high-field horizontal open versus a short-bore MR scanner in a randomized controlled study setup. Methods Altogether, 93 (80% women, mean age 53) consecutive patients underwent spine imaging after random assignement to a 1-T horizontal open MR scanner with a vertical magnetic field or a 1.5-T short-bore MR scanner. This patient subset was part of a larger cohort. Image quality was assessed by determining qualitative parameters, signal-to-noise (SNR) and contrast-to-noise ratios (CNR), and quantitative contour sharpness. Results The image quality parameters were higher for short-bore MR imaging. Regarding all sequences, the relative differences were 39% for the mean overall qualitative image quality, 53% for the mean SNR values, and 34–37% for the quantitative contour sharpness (P<0.0001). The CNR values were also higher for images obtained with the short-bore MR scanner. No sequence was of very poor (nondiagnostic) image quality. Scanning times were significantly longer for examinations performed on the open MR scanner (mean: 32±22 min versus 20±9 min; P<0.0001). Conclusions In this randomized controlled comparison of spinal MR imaging with an open versus a short-bore scanner, short-bore MR imaging revealed considerably higher image quality with shorter scanning times. Trial Registration ClinicalTrials.gov NCT00715806 PMID:24391767

Multiscale image processing and antiscatter grids in digital radiography.

PubMed

Lo, Winnie Y; Hornof, William J; Zwingenberger, Allison L; Robertson, Ian D

2009-01-01

Scatter radiation is a source of noise and results in decreased signal-to-noise ratio and thus decreased image quality in digital radiography. We determined subjectively whether a digitally processed image made without a grid would be of similar quality to an image made with a grid but without image processing. Additionally the effects of exposure dose and of a using a grid with digital radiography on overall image quality were studied. Thoracic and abdominal radiographs of five dogs of various sizes were made. Four acquisition techniques were included (1) with a grid, standard exposure dose, digital image processing; (2) without a grid, standard exposure dose, digital image processing; (3) without a grid, half the exposure dose, digital image processing; and (4) with a grid, standard exposure dose, no digital image processing (to mimic a film-screen radiograph). Full-size radiographs as well as magnified images of specific anatomic regions were generated. Nine reviewers rated the overall image quality subjectively using a five-point scale. All digitally processed radiographs had higher overall scores than nondigitally processed radiographs regardless of patient size, exposure dose, or use of a grid. The images made at half the exposure dose had a slightly lower quality than those made at full dose, but this was only statistically significant in magnified images. Using a grid with digital image processing led to a slight but statistically significant increase in overall quality when compared with digitally processed images made without a grid but whether this increase in quality is clinically significant is unknown.

Quality and safety aspects in histopathology laboratory

PubMed Central

Adyanthaya, Soniya; Jose, Maji

2013-01-01

Histopathology is an art of analyzing and interpreting the shapes, sizes and architectural patterns of cells and tissues within a given specific clinical background and a science by which the image is placed in the context of knowledge of pathobiology, to arrive at an accurate diagnosis. To function effectively and safely, all the procedures and activities of histopathology laboratory should be evaluated and monitored accurately. In histopathology laboratory, the concept of quality control is applicable to pre-analytical, analytical and post-analytical activities. Ensuring safety of working personnel as well as environment is also highly important. Safety issues that may come up in a histopathology lab are primarily those related to potentially hazardous chemicals, biohazardous materials, accidents linked to the equipment and instrumentation employed and general risks from electrical and fire hazards. This article discusses quality management system which can ensure quality performance in histopathology laboratory. The hazards in pathology laboratories and practical safety measures aimed at controlling the dangers are also discussed with the objective of promoting safety consciousness and the practice of laboratory safety. PMID:24574660

[Satisfaction with life, dental experience and self-perception of oral health among the elderly].

PubMed

Rigo, Lilian; Basso, Kenny; Pauli, Jandir; Cericato, Graziela Oro; Paranhos, Luiz Renato; Garbin, Raissa Rigo

2015-12-01

The scope of this article is to analyze the relationship between satisfaction with quality of life, self-perception of oral health and experience with dental surgeons. The study is cross-sectional epidemiological in structure with a sample of 326 elderly individuals over 60 years of age living in a city in the north of the State of Rio Grande do Sul, Brazil. The instrument for data collection was a self-administered questionnaire with queries relating to self-perception in oral health (OHIP - Oral Health Impact Profile), Quality of Life Satisfaction scale and sociodemographic issues. The findings showed that the elderly with higher levels of quality of life satisfaction manifested an enhanced perception of their own oral health as well as a better perceived image of dental surgeons and less anxiety about their experiences with the dentist. It was proven that both the self-perception that the elderly have about oral health as well as their experience with dentists is associated with the quality of life satisfaction of the elderly. The results have important implications for decision-makers and formulators of public policy.

Computer-aided diagnosis based on enhancement of degraded fundus photographs.

PubMed

Jin, Kai; Zhou, Mei; Wang, Shaoze; Lou, Lixia; Xu, Yufeng; Ye, Juan; Qian, Dahong

2018-05-01

Retinal imaging is an important and effective tool for detecting retinal diseases. However, degraded images caused by the aberrations of the eye can disguise lesions, so that a diseased eye can be mistakenly diagnosed as normal. In this work, we propose a new image enhancement method to improve the quality of degraded images. A new method is used to enhance degraded-quality fundus images. In this method, the image is converted from the input RGB colour space to LAB colour space and then each normalized component is enhanced using contrast-limited adaptive histogram equalization. Human visual system (HVS)-based fundus image quality assessment, combined with diagnosis by experts, is used to evaluate the enhancement. The study included 191 degraded-quality fundus photographs of 143 subjects with optic media opacity. Objective quality assessment of image enhancement (range: 0-1) indicated that our method improved colour retinal image quality from an average of 0.0773 (variance 0.0801) to an average of 0.3973 (variance 0.0756). Following enhancement, area under curves (AUC) were 0.996 for the glaucoma classifier, 0.989 for the diabetic retinopathy (DR) classifier, 0.975 for the age-related macular degeneration (AMD) classifier and 0.979 for the other retinal diseases classifier. The relatively simple method for enhancing degraded-quality fundus images achieves superior image enhancement, as demonstrated in a qualitative HVS-based image quality assessment. This retinal image enhancement may, therefore, be employed to assist ophthalmologists in more efficient screening of retinal diseases and the development of computer-aided diagnosis. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Optimization of a 3.6-THz quantum cascade laser for real-time imaging with a microbolometer focal plane array

NASA Astrophysics Data System (ADS)

Behnken, Barry N.; Karunasiri, Gamani; Chamberlin, Danielle; Robrish, Peter; Faist, Jérôme

2008-02-01

Real-time imaging in the terahertz (THz) spectral range was achieved using a 3.6-THz quantum cascade laser (QCL) and an uncooled, 160×120 pixel microbolometer camera fitted with a picarin lens. Noise equivalent temperature difference of the camera in the 1-5 THz frequency range was calculated to be at least 3 K, confirming the need for external THz illumination when imaging in this frequency regime. After evaluating the effects of various operating parameters on laser performance, the QCL found to perform optimally at 1.9 A in pulsed mode with a 300 kHz repetition rate and 10-20% duty cycle; average output power was approximately 1 mW. Under this scheme, a series of metallic objects were imaged while wrapped in various obscurants. Single-frame and extended video recordings demonstrate strong contrast between metallic materials and those of plastic, cloth, and paper - supporting the viability of this imaging technology in security screening applications. Thermal effects arising from Joule heating of the laser were found to be the dominant issue affecting output power and image quality; these effects were mitigated by limiting laser pulse widths to 670 ns and operating the system under closed-cycle refrigeration at a temperature of 10 K.

Adaptively Tuned Iterative Low Dose CT Image Denoising

PubMed Central

Hashemi, SayedMasoud; Paul, Narinder S.; Beheshti, Soosan; Cobbold, Richard S. C.

2015-01-01

Improving image quality is a critical objective in low dose computed tomography (CT) imaging and is the primary focus of CT image denoising. State-of-the-art CT denoising algorithms are mainly based on iterative minimization of an objective function, in which the performance is controlled by regularization parameters. To achieve the best results, these should be chosen carefully. However, the parameter selection is typically performed in an ad hoc manner, which can cause the algorithms to converge slowly or become trapped in a local minimum. To overcome these issues a noise confidence region evaluation (NCRE) method is used, which evaluates the denoising residuals iteratively and compares their statistics with those produced by additive noise. It then updates the parameters at the end of each iteration to achieve a better match to the noise statistics. By combining NCRE with the fundamentals of block matching and 3D filtering (BM3D) approach, a new iterative CT image denoising method is proposed. It is shown that this new denoising method improves the BM3D performance in terms of both the mean square error and a structural similarity index. Moreover, simulations and patient results show that this method preserves the clinically important details of low dose CT images together with a substantial noise reduction. PMID:26089972

Using Polynomials to Simplify Fixed Pattern Noise and Photometric Correction of Logarithmic CMOS Image Sensors

PubMed Central

Li, Jing; Mahmoodi, Alireza; Joseph, Dileepan

2015-01-01

An important class of complementary metal-oxide-semiconductor (CMOS) image sensors are those where pixel responses are monotonic nonlinear functions of light stimuli. This class includes various logarithmic architectures, which are easily capable of wide dynamic range imaging, at video rates, but which are vulnerable to image quality issues. To minimize fixed pattern noise (FPN) and maximize photometric accuracy, pixel responses must be calibrated and corrected due to mismatch and process variation during fabrication. Unlike literature approaches, which employ circuit-based models of varying complexity, this paper introduces a novel approach based on low-degree polynomials. Although each pixel may have a highly nonlinear response, an approximately-linear FPN calibration is possible by exploiting the monotonic nature of imaging. Moreover, FPN correction requires only arithmetic, and an optimal fixed-point implementation is readily derived, subject to a user-specified number of bits per pixel. Using a monotonic spline, involving cubic polynomials, photometric calibration is also possible without a circuit-based model, and fixed-point photometric correction requires only a look-up table. The approach is experimentally validated with a logarithmic CMOS image sensor and is compared to a leading approach from the literature. The novel approach proves effective and efficient. PMID:26501287

Automatic spectral imaging protocol selection and iterative reconstruction in abdominal CT with reduced contrast agent dose: initial experience.

PubMed

Lv, Peijie; Liu, Jie; Chai, Yaru; Yan, Xiaopeng; Gao, Jianbo; Dong, Junqiang

2017-01-01

To evaluate the feasibility, image quality, and radiation dose of automatic spectral imaging protocol selection (ASIS) and adaptive statistical iterative reconstruction (ASIR) with reduced contrast agent dose in abdominal multiphase CT. One hundred and sixty patients were randomly divided into two scan protocols (n = 80 each; protocol A, 120 kVp/450 mgI/kg, filtered back projection algorithm (FBP); protocol B, spectral CT imaging with ASIS and 40 to 70 keV monochromatic images generated per 300 mgI/kg, ASIR algorithm. Quantitative parameters (image noise and contrast-to-noise ratios [CNRs]) and qualitative visual parameters (image noise, small structures, organ enhancement, and overall image quality) were compared. Monochromatic images at 50 keV and 60 keV provided similar or lower image noise, but higher contrast and overall image quality as compared with 120-kVp images. Despite the higher image noise, 40-keV images showed similar overall image quality compared to 120-kVp images. Radiation dose did not differ between the two protocols, while contrast agent dose in protocol B was reduced by 33 %. Application of ASIR and ASIS to monochromatic imaging from 40 to 60 keV allowed contrast agent dose reduction with adequate image quality and without increasing radiation dose compared to 120 kVp with FBP. • Automatic spectral imaging protocol selection provides appropriate scan protocols. • Abdominal CT is feasible using spectral imaging and 300 mgI/kg contrast agent. • 50-keV monochromatic images with 50 % ASIR provide optimal image quality.

Image Quality Ranking Method for Microscopy

PubMed Central

Koho, Sami; Fazeli, Elnaz; Eriksson, John E.; Hänninen, Pekka E.

2016-01-01

Automated analysis of microscope images is necessitated by the increased need for high-resolution follow up of events in time. Manually finding the right images to be analyzed, or eliminated from data analysis are common day-to-day problems in microscopy research today, and the constantly growing size of image datasets does not help the matter. We propose a simple method and a software tool for sorting images within a dataset, according to their relative quality. We demonstrate the applicability of our method in finding good quality images in a STED microscope sample preparation optimization image dataset. The results are validated by comparisons to subjective opinion scores, as well as five state-of-the-art blind image quality assessment methods. We also show how our method can be applied to eliminate useless out-of-focus images in a High-Content-Screening experiment. We further evaluate the ability of our image quality ranking method to detect out-of-focus images, by extensive simulations, and by comparing its performance against previously published, well-established microscopy autofocus metrics. PMID:27364703

Social image quality

NASA Astrophysics Data System (ADS)

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.

Assessing image quality of low-cost laparoscopic box trainers: options for residents training at home.

PubMed

Kiely, Daniel J; Stephanson, Kirk; Ross, Sue

2011-10-01

Low-cost laparoscopic box trainers built using home computers and webcams may provide residents with a useful tool for practice at home. This study set out to evaluate the image quality of low-cost laparoscopic box trainers compared with a commercially available model. Five low-cost laparoscopic box trainers including the components listed were compared in random order to one commercially available box trainer: A (high-definition USB 2.0 webcam, PC laptop), B (Firewire webcam, Mac laptop), C (high-definition USB 2.0 webcam, Mac laptop), D (standard USB webcam, PC desktop), E (Firewire webcam, PC desktop), and F (the TRLCD03 3-DMEd Standard Minimally Invasive Training System). Participants observed still image quality and performed a peg transfer task using each box trainer. Participants rated still image quality, image quality with motion, and whether the box trainer had sufficient image quality to be useful for training. Sixteen residents in obstetrics and gynecology took part in the study. The box trainers showing no statistically significant difference from the commercially available model were A, B, C, D, and E for still image quality; A for image quality with motion; and A and B for usefulness of the simulator based on image quality. The cost of the box trainers A-E is approximately $100 to $160 each, not including a computer or laparoscopic instruments. Laparoscopic box trainers built from a high-definition USB 2.0 webcam with a PC (box trainer A) or from a Firewire webcam with a Mac (box trainer B) provide image quality comparable with a commercial standard.

Hybrid ECG-gated versus non-gated 512-slice CT angiography of the aorta and coronary artery: image quality and effect of a motion correction algorithm.

PubMed

Lee, Ji Won; Kim, Chang Won; Lee, Geewon; Lee, Han Cheol; Kim, Sang-Pil; Choi, Bum Sung; Jeong, Yeon Joo

2018-02-01

Background Using the hybrid electrocardiogram (ECG)-gated computed tomography (CT) technique, assessment of entire aorta, coronary arteries, and aortic valve can be possible using single-bolus contrast administration within a single acquisition. Purpose To compare the image quality of hybrid ECG-gated and non-gated CT angiography of the aorta and evaluate the effect of a motion correction algorithm (MCA) on coronary artery image quality in a hybrid ECG-gated aorta CT group. Material and Methods In total, 104 patients (76 men; mean age = 65.8 years) prospectively randomized into two groups (Group 1 = hybrid ECG-gated CT; Group 2 = non-gated CT) underwent wide-detector array aorta CT. Image quality, assessed using a four-point scale, was compared between the groups. Coronary artery image quality was compared between the conventional reconstruction and motion correction reconstruction subgroups in Group 1. Results Group 1 showed significant advantages over Group 2 in aortic wall, cardiac chamber, aortic valve, coronary ostia, and main coronary arteries image quality (all P < 0.001). All Group 1 patients had diagnostic image quality of the aortic wall and left ostium. The MCA significantly improved the image quality of the three main coronary arteries ( P < 0.05). Moreover, per-vessel interpretability improved from 92.3% to 97.1% with the MCA ( P = 0.013). Conclusion Hybrid ECG-gated CT significantly improved the heart and aortic wall image quality and the MCA can further improve the image quality and interpretability of coronary arteries.

First CaSSIS Colour Images of Mars

NASA Astrophysics Data System (ADS)

Alfred, M.; Pommerol, A.; Thomas, N.; Cremonese, G.

2017-12-01

The Colour and Stereo Surface Imaging System (CaSSIS) on board ESA's Exomars Trace Gas Orbiter has acquired its first images of the surface of Mars on the 22nd and 26th of November, 2016. This commissioning campaign on the initial capture orbit was highly successful, allowing us to test the instrument, establish its performance and collect detailed images from the surface. Many of them have been publicly released within days following acquisition. These images and other commissioning data have demonstrated that the capabilities of the instrument are fully in-line with expectation. Although a colour image of Phobos produced from observations acquired on the 26th of November was rapidly released, the calibration and production of colour images from the surface of Mars proved to be more challenging. Having fixed technical issues, acquired and processed necessary in-flight calibration data, we have recently recalibrated the whole dataset, improving significantly the quality of the data and allowing us, for the first time, to produce high-quality colour images from the surface of Mars with CaSSIS data. The absolute calibration of the instrument is currently verified using stellar observations but the values of reflectivity obtained in each of the four colour channels for the surfaces of Mars and Phobos already show good consistency with other orbital data. The timing of CaSSIS acquisitions is very accurate and results in good colour matching, as already verified on-ground during the calibration campaign. The first few images acquired on the 22nd of November, shortly after TGO crossed the morning terminator, show unique views of the dusty terrains of the Tharsis region with solar incidence angle ranging between 60° and 80°. Comparison with images of the same areas acquired at later local times by other orbiters shows intriguing differences, related in particular to the brightness and colour of the floor of dust-filled craters that look bluer in the morning than in the afternoon. These observations and possible explanations of these changes in terms of diurnal volatile cycles will be presented and discussed, providing a glimpse into the future scientific activities permitted by CaSSIS once the nominal science phase begins in 2018.

2D XD-GRASP provides better image quality than conventional 2D cardiac cine MRI for patients who cannot suspend respiration

PubMed Central

Piekarski, Eve; Chitiboi, Teodora; Ramb, Rebecca; Latson, Larry A; Bhatla, Puneet; Feng, Li; Axel, Leon

2017-01-01

Object Residual respiratory motion degrades image quality in conventional cardiac cine MRI (CCMR). We evaluated whether a free-breathing (FB) radial imaging CCMR sequence with compressed sensing reconstruction (eXtra-Dimension (e.g. cardiac and respiratory phases) Golden-angle RAdial Sparse Parallel, or XD-GRASP) could provide better image quality than a conventional Cartesian breath-held (BH) sequence, in an unselected population of patients undergoing clinical CCMR. Material and Methods 101 patients who underwent BH and FB imaging in a mid-ventricular short-axis plane at a matching location were included. Visual and quantitative image analysis was performed by two blinded experienced readers, using a 5-point qualitative scale to score overall image quality and visual signal-to-noise ratio (SNR) grade, with measures of noise and sharpness. End-diastole (ED) and end-systole (ES) left-ventricular areas were also measured and compared for both BH and FB images. Results Image quality was generally better with the BH cines (overall quality grade BH vs FB: 4 vs 2.9, p<0.001; noise 0.06 vs 0.08 p< 0.001; SNR grade: 4.1 vs 3, p<0.001), except for sharpness (p=0.48). There were no significant differences between BH and FB images regarding ED or ES areas (p=0.35 and 0.12). 18 of the 101 patients had impaired BH image quality (grades 1 or 2). In this subgroup, image quality of the FB images was better (p=0.0032), as was the SNR grade (p=0.003), but there were no significant differences regarding noise and sharpness (p=0.45, p=0.47). Conclusion Although FB XD-GRASP CCMR was visually inferior to conventional BH cardiac cine in general, it provided improved image quality in the subgroup of patients presenting respiratory motion-induced artifacts on breath-held images. PMID:29067539

Two-dimensional XD-GRASP provides better image quality than conventional 2D cardiac cine MRI for patients who cannot suspend respiration.

PubMed

Piekarski, Eve; Chitiboi, Teodora; Ramb, Rebecca; Latson, Larry A; Bhatla, Puneet; Feng, Li; Axel, Leon

2018-02-01

Residual respiratory motion degrades image quality in conventional cardiac cine MRI (CCMRI). We evaluated whether a free-breathing (FB) radial imaging CCMRI sequence with compressed sensing reconstruction [extradimensional (e.g. cardiac and respiratory phases) golden-angle radial sparse parallel, or XD-GRASP] could provide better image quality than a conventional Cartesian breath-held (BH) sequence in an unselected population of patients undergoing clinical CCMRI. One hundred one patients who underwent BH and FB imaging in a midventricular short-axis plane at a matching location were included. Visual and quantitative image analysis was performed by two blinded experienced readers, using a five-point qualitative scale to score overall image quality and visual signal-to-noise ratio (SNR) grade, with measures of noise and sharpness. End-diastolic and end-systolic left ventricular areas were also measured and compared for both BH and FB images. Image quality was generally better with the BH cines (overall quality grade for BH vs FB images 4 vs 2.9, p < 0.001; noise 0.06 vs 0.08 p < 0.001; SNR grade 4.1 vs 3, p < 0.001), except for sharpness (p = 0.48). There were no significant differences between BH and FB images regarding end-diastolic or end-systolic areas (p = 0.35 and p = 0.12). Eighteen of the 101 patients had poor BH image quality (grade 1 or 2). In this subgroup, the quality of the FB images was better (p = 0.0032), as was the SNR grade (p = 0.003), but there were no significant differences regarding noise and sharpness (p = 0.45 and p = 0.47). Although FB XD-GRASP CCMRI was visually inferior to conventional BH CCMRI in general, it provided improved image quality in the subgroup of patients with respiratory-motion-induced artifacts on BH images.

Development and prospective evaluation of an automated software system for quality control of quantitative 99mTc-MAG3 renal studies.

PubMed

Folks, Russell D; Garcia, Ernest V; Taylor, Andrew T

2007-03-01

Quantitative nuclear renography has numerous potential sources of error. We previously reported the initial development of a computer software module for comprehensively addressing the issue of quality control (QC) in the analysis of radionuclide renal images. The objective of this study was to prospectively test the QC software. The QC software works in conjunction with standard quantitative renal image analysis using a renal quantification program. The software saves a text file that summarizes QC findings as possible errors in user-entered values, calculated values that may be unreliable because of the patient's clinical condition, and problems relating to acquisition or processing. To test the QC software, a technologist not involved in software development processed 83 consecutive nontransplant clinical studies. The QC findings of the software were then tabulated. QC events were defined as technical (study descriptors that were out of range or were entered and then changed, unusually sized or positioned regions of interest, or missing frames in the dynamic image set) or clinical (calculated functional values judged to be erroneous or unreliable). Technical QC events were identified in 36 (43%) of 83 studies. Clinical QC events were identified in 37 (45%) of 83 studies. Specific QC events included starting the camera after the bolus had reached the kidney, dose infiltration, oversubtraction of background activity, and missing frames in the dynamic image set. QC software has been developed to automatically verify user input, monitor calculation of renal functional parameters, summarize QC findings, and flag potentially unreliable values for the nuclear medicine physician. Incorporation of automated QC features into commercial or local renal software can reduce errors and improve technologist performance and should improve the efficiency and accuracy of image interpretation.

New patient-controlled abdominal compression method in radiography: radiation dose and image quality.

PubMed

Piippo-Huotari, Oili; Norrman, Eva; Anderzén-Carlsson, Agneta; Geijer, Håkan

2018-05-01

The radiation dose for patients can be reduced with many methods and one way is to use abdominal compression. In this study, the radiation dose and image quality for a new patient-controlled compression device were compared with conventional compression and compression in the prone position . To compare radiation dose and image quality of patient-controlled compression compared with conventional and prone compression in general radiography. An experimental design with quantitative approach. After obtaining the approval of the ethics committee, a consecutive sample of 48 patients was examined with the standard clinical urography protocol. The radiation doses were measured as dose-area product and analyzed with a paired t-test. The image quality was evaluated by visual grading analysis. Four radiologists evaluated each image individually by scoring nine criteria modified from the European quality criteria for diagnostic radiographic images. There was no significant difference in radiation dose or image quality between conventional and patient-controlled compression. Prone position resulted in both higher dose and inferior image quality. Patient-controlled compression gave similar dose levels as conventional compression and lower than prone compression. Image quality was similar with both patient-controlled and conventional compression and was judged to be better than in the prone position.

dipIQ: Blind Image Quality Assessment by Learning-to-Rank Discriminable Image Pairs.

PubMed

Ma, Kede; Liu, Wentao; Liu, Tongliang; Wang, Zhou; Tao, Dacheng

2017-05-26

Objective assessment of image quality is fundamentally important in many image processing tasks. In this work, we focus on learning blind image quality assessment (BIQA) models which predict the quality of a digital image with no access to its original pristine-quality counterpart as reference. One of the biggest challenges in learning BIQA models is the conflict between the gigantic image space (which is in the dimension of the number of image pixels) and the extremely limited reliable ground truth data for training. Such data are typically collected via subjective testing, which is cumbersome, slow, and expensive. Here we first show that a vast amount of reliable training data in the form of quality-discriminable image pairs (DIP) can be obtained automatically at low cost by exploiting largescale databases with diverse image content. We then learn an opinion-unaware BIQA (OU-BIQA, meaning that no subjective opinions are used for training) model using RankNet, a pairwise learning-to-rank (L2R) algorithm, from millions of DIPs, each associated with a perceptual uncertainty level, leading to a DIP inferred quality (dipIQ) index. Extensive experiments on four benchmark IQA databases demonstrate that dipIQ outperforms state-of-the-art OU-BIQA models. The robustness of dipIQ is also significantly improved as confirmed by the group MAximum Differentiation (gMAD) competition method. Furthermore, we extend the proposed framework by learning models with ListNet (a listwise L2R algorithm) on quality-discriminable image lists (DIL). The resulting DIL Inferred Quality (dilIQ) index achieves an additional performance gain.

Assessment of Restoration Methods of X-Ray Images with Emphasis on Medical Photogrammetric Usage

NASA Astrophysics Data System (ADS)

Hosseinian, S.; Arefi, H.

2016-06-01

Nowadays, various medical X-ray imaging methods such as digital radiography, computed tomography and fluoroscopy are used as important tools in diagnostic and operative processes especially in the computer and robotic assisted surgeries. The procedures of extracting information from these images require appropriate deblurring and denoising processes on the pre- and intra-operative images in order to obtain more accurate information. This issue becomes more considerable when the X-ray images are planned to be employed in the photogrammetric processes for 3D reconstruction from multi-view X-ray images since, accurate data should be extracted from images for 3D modelling and the quality of X-ray images affects directly on the results of the algorithms. For restoration of X-ray images, it is essential to consider the nature and characteristics of these kinds of images. X-ray images exhibit severe quantum noise due to limited X-ray photons involved. The assumptions of Gaussian modelling are not appropriate for photon-limited images such as X-ray images, because of the nature of signal-dependant quantum noise. These images are generally modelled by Poisson distribution which is the most common model for low-intensity imaging. In this paper, existing methods are evaluated. For this purpose, after demonstrating the properties of medical X-ray images, the more efficient and recommended methods for restoration of X-ray images would be described and assessed. After explaining these approaches, they are implemented on samples from different kinds of X-ray images. By considering the results, it is concluded that using PURE-LET, provides more effective and efficient denoising than other examined methods in this research.

Parameter-based estimation of CT dose index and image quality using an in-house android™-based software

NASA Astrophysics Data System (ADS)

Mubarok, S.; Lubis, L. E.; Pawiro, S. A.

2016-03-01

Compromise between radiation dose and image quality is essential in the use of CT imaging. CT dose index (CTDI) is currently the primary dosimetric formalisms in CT scan, while the low and high contrast resolutions are aspects indicating the image quality. This study was aimed to estimate CTDIvol and image quality measures through a range of exposure parameters variation. CTDI measurements were performed using PMMA (polymethyl methacrylate) phantom of 16 cm diameter, while the image quality test was conducted by using catphan ® 600. CTDI measurements were carried out according to IAEA TRS 457 protocol using axial scan mode, under varied parameters of tube voltage, collimation or slice thickness, and tube current. Image quality test was conducted accordingly under the same exposure parameters with CTDI measurements. An Android™ based software was also result of this study. The software was designed to estimate the value of CTDIvol with maximum difference compared to actual CTDIvol measurement of 8.97%. Image quality can also be estimated through CNR parameter with maximum difference to actual CNR measurement of 21.65%.

An evaluation of the use of oral contrast media in abdominopelvic CT.

PubMed

Buttigieg, Erica Lauren; Grima, Karen Borg; Cortis, Kelvin; Soler, Sandro Galea; Zarb, Francis

2014-11-01

To evaluate the diagnostic efficacy of different oral contrast media (OCM) for abdominopelvic CT examinations performed for follow-up general oncological indications. The objectives were to establish anatomical image quality criteria for abdominopelvic CT; use these criteria to evaluate and compare image quality using positive OCM, neutral OCM and no OCM; and evaluate possible benefits for the medical imaging department. Forty-six adult patients attending a follow-up abdominopelvic CT for general oncological indications and who had a previous abdominopelvic CT with positive OCM (n = 46) were recruited and prospectively placed into either the water (n = 25) or no OCM (n = 21) group. Three radiologists performed absolute visual grading analysis (VGA) to assess image quality by grading the fulfilment of 24 anatomical image quality criteria. Visual grading characteristics (VGC) analysis of the data showed comparable image quality with regards to reproduction of abdominal structures, bowel discrimination, presence of artefacts, and visualization of the amount of intra-abdominal fat for the three OCM protocols. All three OCM protocols provided similar image quality for follow-up abdominopelvic CT for general oncological indications. • Positive oral contrast media are routinely used for abdominopelvic multidetector computed tomography • Experimental study comparing image quality using three different oral contrast materials • Three different oral contrast materials result in comparable CT image quality • Benefits for patients and medical imaging department.

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

PubMed

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.

MO-C-18A-01: Advances in Model-Based 3D Image Reconstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, G; Pan, X; Stayman, J

2014-06-15

Recent years have seen the emergence of CT image reconstruction techniques that exploit physical models of the imaging system, photon statistics, and even the patient to achieve improved 3D image quality and/or reduction of radiation dose. With numerous advantages in comparison to conventional 3D filtered backprojection, such techniques bring a variety of challenges as well, including: a demanding computational load associated with sophisticated forward models and iterative optimization methods; nonlinearity and nonstationarity in image quality characteristics; a complex dependency on multiple free parameters; and the need to understand how best to incorporate prior information (including patient-specific prior images) within themore » reconstruction process. The advantages, however, are even greater – for example: improved image quality; reduced dose; robustness to noise and artifacts; task-specific reconstruction protocols; suitability to novel CT imaging platforms and noncircular orbits; and incorporation of known characteristics of the imager and patient that are conventionally discarded. This symposium features experts in 3D image reconstruction, image quality assessment, and the translation of such methods to emerging clinical applications. Dr. Chen will address novel methods for the incorporation of prior information in 3D and 4D CT reconstruction techniques. Dr. Pan will show recent advances in optimization-based reconstruction that enable potential reduction of dose and sampling requirements. Dr. Stayman will describe a “task-based imaging” approach that leverages models of the imaging system and patient in combination with a specification of the imaging task to optimize both the acquisition and reconstruction process. Dr. Samei will describe the development of methods for image quality assessment in such nonlinear reconstruction techniques and the use of these methods to characterize and optimize image quality and dose in a spectrum of clinical applications. Learning Objectives: Learn the general methodologies associated with model-based 3D image reconstruction. Learn the potential advantages in image quality and dose associated with model-based image reconstruction. Learn the challenges associated with computational load and image quality assessment for such reconstruction methods. Learn how imaging task can be incorporated as a means to drive optimal image acquisition and reconstruction techniques. Learn how model-based reconstruction methods can incorporate prior information to improve image quality, ease sampling requirements, and reduce dose.« less

Readout-Segmented Echo-Planar Imaging in Diffusion-Weighted MR Imaging in Breast Cancer: Comparison with Single-Shot Echo-Planar Imaging in Image Quality

PubMed Central

Kim, Yun Ju; Kang, Bong Joo; Park, Chang Suk; Kim, Hyeon Sook; Son, Yo Han; Porter, David Andrew; Song, Byung Joo

2014-01-01

Objective The purpose of this study was to compare the image quality of standard single-shot echo-planar imaging (ss-EPI) and that of readout-segmented EPI (rs-EPI) in patients with breast cancer. Materials and Methods Seventy-one patients with 74 breast cancers underwent both ss-EPI and rs-EPI. For qualitative comparison of image quality, three readers independently assessed the two sets of diffusion-weighted (DW) images. To evaluate geometric distortion, a comparison was made between lesion lengths derived from contrast enhanced MR (CE-MR) images and those obtained from the corresponding DW images. For assessment of image parameters, signal-to-noise ratio (SNR), lesion contrast, and contrast-to-noise ratio (CNR) were calculated. Results The rs-EPI was superior to ss-EPI in most criteria regarding the qualitative image quality. Anatomical structure distinction, delineation of the lesion, ghosting artifact, and overall image quality were significantly better in rs-EPI. Regarding the geometric distortion, lesion length on ss-EPI was significantly different from that of CE-MR, whereas there were no significant differences between CE-MR and rs-EPI. The rs-EPI was superior to ss-EPI in SNR and CNR. Conclusion Readout-segmented EPI is superior to ss-EPI in the aspect of image quality in DW MR imaging of the breast. PMID:25053898

Effect of metal artifact reduction software on image quality of C-arm cone-beam computed tomography during intracranial aneurysm treatment.

PubMed

Enomoto, Yukiko; Yamauchi, Keita; Asano, Takahiko; Otani, Katharina; Iwama, Toru

2018-01-01

Background and purpose C-arm cone-beam computed tomography (CBCT) has the drawback that image quality is degraded by artifacts caused by implanted metal objects. We evaluated whether metal artifact reduction (MAR) prototype software can improve the subjective image quality of CBCT images of patients with intracranial aneurysms treated with coils or clips. Materials and methods Forty-four patients with intracranial aneurysms implanted with coils (40 patients) or clips (four patients) underwent one CBCT scan from which uncorrected and MAR-corrected CBCT image datasets were reconstructed. Three blinded readers evaluated the image quality of the image sets using a four-point scale (1: Excellent, 2: Good, 3: Poor, 4: Bad). The median scores of the three readers of uncorrected and MAR-corrected images were compared with the paired Wilcoxon signed-rank and inter-reader agreement of change scores was assessed by weighted kappa statistics. The readers also recorded new clinical findings, such as intracranial hemorrhage, air, or surrounding anatomical structures on MAR-corrected images. Results The image quality of MAR-corrected CBCT images was significantly improved compared with the uncorrected CBCT image ( p < 0.001). Additional clinical findings were seen on CBCT images of 70.4% of patients after MAR correction. Conclusion MAR software improved image quality of CBCT images degraded by metal artifacts.

Coupled dictionary learning for joint MR image restoration and segmentation

NASA Astrophysics Data System (ADS)

Yang, Xuesong; Fan, Yong

2018-03-01

To achieve better segmentation of MR images, image restoration is typically used as a preprocessing step, especially for low-quality MR images. Recent studies have demonstrated that dictionary learning methods could achieve promising performance for both image restoration and image segmentation. These methods typically learn paired dictionaries of image patches from different sources and use a common sparse representation to characterize paired image patches, such as low-quality image patches and their corresponding high quality counterparts for the image restoration, and image patches and their corresponding segmentation labels for the image segmentation. Since learning these dictionaries jointly in a unified framework may improve the image restoration and segmentation simultaneously, we propose a coupled dictionary learning method to concurrently learn dictionaries for joint image restoration and image segmentation based on sparse representations in a multi-atlas image segmentation framework. Particularly, three dictionaries, including a dictionary of low quality image patches, a dictionary of high quality image patches, and a dictionary of segmentation label patches, are learned in a unified framework so that the learned dictionaries of image restoration and segmentation can benefit each other. Our method has been evaluated for segmenting the hippocampus in MR T1 images collected with scanners of different magnetic field strengths. The experimental results have demonstrated that our method achieved better image restoration and segmentation performance than state of the art dictionary learning and sparse representation based image restoration and image segmentation methods.

Data processing and analysis for 2D imaging GEM detector system

NASA Astrophysics Data System (ADS)

Czarski, T.; Chernyshova, M.; Pozniak, K. T.; Kasprowicz, G.; Byszuk, A.; Juszczyk, B.; Kolasinski, P.; Linczuk, M.; Wojenski, A.; Zabolotny, W.; Zienkiewicz, P.

2014-11-01

The Triple Gas Electron Multiplier (T-GEM) is presented as soft X-ray (SXR) energy and position sensitive detector for high-resolution X-ray diagnostics of magnetic confinement fusion plasmas [1]. Multi-channel measurement system and essential data processing for X-ray energy and position recognition is consider. Several modes of data acquisition are introduced depending on processing division for hardware and software components. Typical measuring issues aredeliberated for enhancement of data quality. Fundamental output characteristics are presented for one and two dimensional detector structure. Representative results for reference X-ray source and tokamak plasma are demonstrated.

Color quality management in advanced flat panel display engines

NASA Astrophysics Data System (ADS)

Lebowsky, Fritz; Neugebauer, Charles F.; Marnatti, David M.

2003-01-01

During recent years color reproduction systems for consumer needs have experienced various difficulties. In particular, flat panels and printers could not reach a satisfactory color match. The RGB image stored on an Internet server of a retailer did not show the desired colors on a consumer display device or printer device. STMicroelectronics addresses this important color reproduction issue inside their advanced display engines using novel algorithms targeted for low cost consumer flat panels. Using a new and genuine RGB color space transformation, which combines a gamma correction Look-Up-Table, tetrahedrization, and linear interpolation, we satisfy market demands.

Automated image quality assessment for chest CT scans.

PubMed

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.

Smartphone-based assessment of blood alteration severity

NASA Astrophysics Data System (ADS)

Li, Xianglin; Xue, Jiaxin; Li, Wei; Li, Ting

2018-02-01

Blood quality and safety management is a critical issue for cold chain transportation of blood or blood-based biological reagent. The conventional methods of blood alteration severity assessment mainly rely on kit test or blood-gas analysis required opening the blood package to get samples, which cause possible blood pollution and are complicate, timeconsuming, and expensive. Here we proposed to develop a portable, real-time, safety, easy-operated and low cost method aimed at assessing blood alteration severity. Color images of the blood in transparent blood bags were collected with a smartphone and the alteration severity of the blood was assessed by the smartphone app offered analysis of RGB color values of the blood. The algorithm is based on a large number sample of RGB values of blood at different alteration degree. The blood quality results evaluated by the smartphone are in accordance with the actual data. This study indicates the potential of smart phone in real time, convenient, and reliable blood quality assessment.

Lightweight UAV with on-board photogrammetry and single-frequency GPS positioning for metrology applications

NASA Astrophysics Data System (ADS)

Daakir, M.; Pierrot-Deseilligny, M.; Bosser, P.; Pichard, F.; Thom, C.; Rabot, Y.; Martin, O.

2017-05-01

This article presents a coupled system consisting of a single-frequency GPS receiver and a light photogrammetric quality camera embedded in an Unmanned Aerial Vehicle (UAV). The aim is to produce high quality data that can be used in metrology applications. The issue of Integrated Sensor Orientation (ISO) of camera poses using only GPS measurements is presented and discussed. The accuracy reached by our system based on sensors developed at the French Mapping Agency (IGN) Opto-Electronics, Instrumentation and Metrology Laboratory (LOEMI) is qualified. These sensors are specially designed for close-range aerial image acquisition with a UAV. Lever-arm calibration and time synchronization are explained and performed to reach maximum accuracy. All processing steps are detailed from data acquisition to quality control of final products. We show that an accuracy of a few centimeters can be reached with this system which uses low-cost UAV and GPS module coupled with the IGN-LOEMI home-made camera.

Water Quality Assessment using Satellite Remote Sensing

NASA Astrophysics Data System (ADS)

Haque, Saad Ul

2016-07-01

The two main global issues related to water are its declining quality and quantity. Population growth, industrialization, increase in agriculture land and urbanization are the main causes upon which the inland water bodies are confronted with the increasing water demand. The quality of surface water has also been degraded in many countries over the past few decades due to the inputs of nutrients and sediments especially in the lakes and reservoirs. Since water is essential for not only meeting the human needs but also to maintain natural ecosystem health and integrity, there are efforts worldwide to assess and restore quality of surface waters. Remote sensing techniques provide a tool for continuous water quality information in order to identify and minimize sources of pollutants that are harmful for human and aquatic life. The proposed methodology is focused on assessing quality of water at selected lakes in Pakistan (Sindh); namely, HUBDAM, KEENJHAR LAKE, HALEEJI and HADEERO. These lakes are drinking water sources for several major cities of Pakistan including Karachi. Satellite imagery of Landsat 7 (ETM+) is used to identify the variation in water quality of these lakes in terms of their optical properties. All bands of Landsat 7 (ETM+) image are analyzed to select only those that may be correlated with some water quality parameters (e.g. suspended solids, chlorophyll a). The Optimum Index Factor (OIF) developed by Chavez et al. (1982) is used for selection of the optimum combination of bands. The OIF is calculated by dividing the sum of standard deviations of any three bands with the sum of their respective correlation coefficients (absolute values). It is assumed that the band with the higher standard deviation contains the higher amount of 'information' than other bands. Therefore, OIF values are ranked and three bands with the highest OIF are selected for the visual interpretation. A color composite image is created using these three bands. The water quality of these lakes are assessed by comparing their reflectance values with the spectral signatures of distilled water. The layout water quality maps of these lakes are prepared in terms of these deviations. The results of the study can be utilized for preliminary water quality monitoring of the selected lakes.

MO-C-BRCD-03: The Role of Informatics in Medical Physics and Vice Versa.

PubMed

Andriole, K

2012-06-01

Like Medical Physics, Imaging Informatics encompasses concepts touching every aspect of the imaging chain from image creation, acquisition, management and archival, to image processing, analysis, display and interpretation. The two disciplines are in fact quite complementary, with similar goals to improve the quality of care provided to patients using an evidence-based approach, to assure safety in the clinical and research environments, to facilitate efficiency in the workplace, and to accelerate knowledge discovery. Use-cases describing several areas of informatics activity will be given to illustrate current limitations that would benefit from medical physicist participation, and conversely areas in which informaticists may contribute to the solution. Topics to be discussed include radiation dose monitoring, process management and quality control, display technologies, business analytics techniques, and quantitative imaging. Quantitative imaging is increasingly becoming an essential part of biomedicalresearch as well as being incorporated into clinical diagnostic activities. Referring clinicians are asking for more objective information to be gleaned from the imaging tests that they order so that they may make the best clinical management decisions for their patients. Medical Physicists may be called upon to identify existing issues as well as develop, validate and implement new approaches and technologies to help move the field further toward quantitative imaging methods for the future. Biomedical imaging informatics tools and techniques such as standards, integration, data mining, cloud computing and new systems architectures, ontologies and lexicons, data visualization and navigation tools, and business analytics applications can be used to overcome some of the existing limitations. 1. Describe what is meant by Medical Imaging Informatics and understand why the medical physicist should care. 2. Identify existing limitations in information technologies with respect to Medical Physics, and conversely see how Informatics may assist the medical physicist in filling some of the current gaps in their activities. 3. Understand general informatics concepts and areas of investigation including imaging and workflow standards, systems integration, computing architectures, ontologies, data mining and business analytics, data visualization and human-computer interface tools, and the importance of quantitative imaging for the future of Medical Physics and Imaging Informatics. 4. Become familiar with on-going efforts to address current challenges facing future research into and clinical implementation of quantitative imaging applications. © 2012 American Association of Physicists in Medicine.

Network design and quality checks in automatic orientation of close-range photogrammetric blocks.

PubMed

Dall'Asta, Elisa; Thoeni, Klaus; Santise, Marina; Forlani, Gianfranco; Giacomini, Anna; Roncella, Riccardo

2015-04-03

Due to the recent improvements of automatic measurement procedures in photogrammetry, multi-view 3D reconstruction technologies are becoming a favourite survey tool. Rapidly widening structure-from-motion (SfM) software packages offer significantly easier image processing workflows than traditional photogrammetry packages. However, while most orientation and surface reconstruction strategies will almost always succeed in any given task, estimating the quality of the result is, to some extent, still an open issue. An assessment of the precision and reliability of block orientation is necessary and should be included in every processing pipeline. Such a need was clearly felt from the results of close-range photogrammetric surveys of in situ full-scale and laboratory-scale experiments. In order to study the impact of the block control and the camera network design on the block orientation accuracy, a series of Monte Carlo simulations was performed. Two image block configurations were investigated: a single pseudo-normal strip and a circular highly-convergent block. The influence of surveying and data processing choices, such as the number and accuracy of the ground control points, autofocus and camera calibration was investigated. The research highlights the most significant aspects and processes to be taken into account for adequate in situ and laboratory surveys, when modern SfM software packages are used, and evaluates their effect on the quality of the results of the surface reconstruction.

Quality assessment for color reproduction using a blind metric

NASA Astrophysics Data System (ADS)

Bringier, B.; Quintard, L.; Larabi, M.-C.

2007-01-01

This paper deals with image quality assessment. This field plays nowadays an important role in various image processing applications. Number of objective image quality metrics, that correlate or not, with the subjective quality have been developed during the last decade. Two categories of metrics can be distinguished, the first with full-reference and the second with no-reference. Full-reference metric tries to evaluate the distortion introduced to an image with regards to the reference. No-reference approach attempts to model the judgment of image quality in a blind way. Unfortunately, the universal image quality model is not on the horizon and empirical models established on psychophysical experimentation are generally used. In this paper, we focus only on the second category to evaluate the quality of color reproduction where a blind metric, based on human visual system modeling is introduced. The objective results are validated by single-media and cross-media subjective tests.

Sparse-view proton computed tomography using modulated proton beams.

PubMed

Lee, Jiseoc; Kim, Changhwan; Min, Byungjun; Kwak, Jungwon; Park, Seyjoon; Lee, Se Byeong; Park, Sungyong; Cho, Seungryong

2015-02-01

Proton imaging that uses a modulated proton beam and an intensity detector allows a relatively fast image acquisition compared to the imaging approach based on a trajectory tracking detector. In addition, it requires a relatively simple implementation in a conventional proton therapy equipment. The model of geometric straight ray assumed in conventional computed tomography (CT) image reconstruction is however challenged by multiple-Coulomb scattering and energy straggling in the proton imaging. Radiation dose to the patient is another important issue that has to be taken care of for practical applications. In this work, the authors have investigated iterative image reconstructions after a deconvolution of the sparsely view-sampled data to address these issues in proton CT. Proton projection images were acquired using the modulated proton beams and the EBT2 film as an intensity detector. Four electron-density cylinders representing normal soft tissues and bone were used as imaged object and scanned at 40 views that are equally separated over 360°. Digitized film images were converted to water-equivalent thickness by use of an empirically derived conversion curve. For improving the image quality, a deconvolution-based image deblurring with an empirically acquired point spread function was employed. They have implemented iterative image reconstruction algorithms such as adaptive steepest descent-projection onto convex sets (ASD-POCS), superiorization method-projection onto convex sets (SM-POCS), superiorization method-expectation maximization (SM-EM), and expectation maximization-total variation minimization (EM-TV). Performance of the four image reconstruction algorithms was analyzed and compared quantitatively via contrast-to-noise ratio (CNR) and root-mean-square-error (RMSE). Objects of higher electron density have been reconstructed more accurately than those of lower density objects. The bone, for example, has been reconstructed within 1% error. EM-based algorithms produced an increased image noise and RMSE as the iteration reaches about 20, while the POCS-based algorithms showed a monotonic convergence with iterations. The ASD-POCS algorithm outperformed the others in terms of CNR, RMSE, and the accuracy of the reconstructed relative stopping power in the region of lung and soft tissues. The four iterative algorithms, i.e., ASD-POCS, SM-POCS, SM-EM, and EM-TV, have been developed and applied for proton CT image reconstruction. Although it still seems that the images need to be improved for practical applications to the treatment planning, proton CT imaging by use of the modulated beams in sparse-view sampling has demonstrated its feasibility.

Recognizable or Not: Towards Image Semantic Quality Assessment for Compression

NASA Astrophysics Data System (ADS)

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.

Automatic quality assessment of planetary images

NASA Astrophysics Data System (ADS)

Sidiropoulos, P.; Muller, J.-P.

2015-10-01

A significant fraction of planetary images are corrupted beyond the point that much scientific meaning can be extracted. For example, transmission errors result in missing data which is unrecoverable. The available planetary image datasets include many such "bad data", which both occupy valuable scientific storage resources and create false impressions about planetary image availability for specific planetary objects or target areas. In this work, we demonstrate a pipeline that we have developed to automatically assess the quality of planetary images. Additionally, this method discriminates between different types of image degradation, such as low-quality originating from camera flaws or low-quality triggered by atmospheric conditions, etc. Examples of quality assessment results for Viking Orbiter imagery will be also presented.

Quality assessment of color images based on the measure of just noticeable color difference

NASA Astrophysics Data System (ADS)

Chou, Chun-Hsien; Hsu, Yun-Hsiang

2014-01-01

Accurate assessment on the quality of color images is an important step to many image processing systems that convey visual information of the reproduced images. An accurate objective image quality assessment (IQA) method is expected to give the assessment result highly agreeing with the subjective assessment. To assess the quality of color images, many approaches simply apply the metric for assessing the quality of gray scale images to each of three color channels of the color image, neglecting the correlation among three color channels. In this paper, a metric for assessing color images' quality is proposed, in which the model of variable just-noticeable color difference (VJNCD) is employed to estimate the visibility thresholds of distortion inherent in each color pixel. With the estimated visibility thresholds of distortion, the proposed metric measures the average perceptible distortion in terms of the quantized distortion according to the perceptual error map similar to that defined by National Bureau of Standards (NBS) for converting the color difference enumerated by CIEDE2000 to the objective score of perceptual quality assessment. The perceptual error map in this case is designed for each pixel according to the visibility threshold estimated by the VJNCD model. The performance of the proposed metric is verified by assessing the test images in the LIVE database, and is compared with those of many well-know IQA metrics. Experimental results indicate that the proposed metric is an effective IQA method that can accurately predict the image quality of color images in terms of the correlation between objective scores and subjective evaluation.

Image quality assessment of automatic three-segment MR attenuation correction vs. CT attenuation correction.

PubMed

Partovi, Sasan; Kohan, Andres; Gaeta, Chiara; Rubbert, Christian; Vercher-Conejero, Jose L; Jones, Robert S; O'Donnell, James K; Wojtylak, Patrick; Faulhaber, Peter

2013-01-01

The purpose of this study is to systematically evaluate the usefulness of Positron emission tomography/Magnetic resonance imaging (PET/MRI) images in a clinical setting by assessing the image quality of Positron emission tomography (PET) images using a three-segment MR attenuation correction (MRAC) versus the standard CT attenuation correction (CTAC). We prospectively studied 48 patients who had their clinically scheduled FDG-PET/CT followed by an FDG-PET/MRI. Three nuclear radiologists evaluated the image quality of CTAC vs. MRAC using a Likert scale (five-point scale). A two-sided, paired t-test was performed for comparison purposes. The image quality was further assessed by categorizing it as acceptable (equal to 4 and 5 on the five-point Likert scale) or unacceptable (equal to 1, 2, and 3 on the five-point Likert scale) quality using the McNemar test. When assessing the image quality using the Likert scale, one reader observed a significant difference between CTAC and MRAC (p=0.0015), whereas the other readers did not observe a difference (p=0.8924 and p=0.1880, respectively). When performing the grouping analysis, no significant difference was found between CTAC vs. MRAC for any of the readers (p=0.6137 for reader 1, p=1 for reader 2, and p=0.8137 for reader 3). All three readers more often reported artifacts on the MRAC images than on the CTAC images. There was no clinically significant difference in quality between PET images generated on a PET/MRI system and those from a Positron emission tomography/Computed tomography (PET/CT) system. PET images using the automatic three-segmented MR attenuation method provided diagnostic image quality. However, future research regarding the image quality obtained using different MR attenuation based methods is warranted before PET/MRI can be used clinically.

SU-F-J-211: Scatter Correction for Clinical Cone-Beam CT System Using An Optimized Stationary Beam Blocker with a Single Scan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, X; Zhang, Z; Xie, Y

Purpose: X-ray scatter photons result in significant image quality degradation of cone-beam CT (CBCT). Measurement based algorithms using beam blocker directly acquire the scatter samples and achieve significant improvement on the quality of CBCT image. Within existing algorithms, single-scan and stationary beam blocker proposed previously is promising due to its simplicity and practicability. Although demonstrated effectively on tabletop system, the blocker fails to estimate the scatter distribution on clinical CBCT system mainly due to the gantry wobble. In addition, the uniform distributed blocker strips in our previous design results in primary data loss in the CBCT system and leads tomore » the image artifacts due to data insufficiency. Methods: We investigate the motion behavior of the beam blocker in each projection and design an optimized non-uniform blocker strip distribution which accounts for the data insufficiency issue. An accurate scatter estimation is then achieved from the wobble modeling. Blocker wobble curve is estimated using threshold-based segmentation algorithms in each projection. In the blocker design optimization, the quality of final image is quantified using the number of the primary data loss voxels and the mesh adaptive direct search algorithm is applied to minimize the objective function. Scatter-corrected CT images are obtained using the optimized blocker. Results: The proposed method is evaluated using Catphan@504 phantom and a head patient. On the Catphan©504, our approach reduces the average CT number error from 115 Hounsfield unit (HU) to 11 HU in the selected regions of interest, and improves the image contrast by a factor of 1.45 in the high-contrast regions. On the head patient, the CT number error is reduced from 97 HU to 6 HU in the soft tissue region and image spatial non-uniformity is decreased from 27% to 5% after correction. Conclusion: The proposed optimized blocker design is practical and attractive for CBCT guided radiation therapy. This work is supported by grants from Guangdong Innovative Research Team Program of China (Grant No. 2011S013), National 863 Programs of China (Grant Nos. 2012AA02A604 and 2015AA043203), the National High-tech R&D Program for Young Scientists by the Ministry of Science and Technology of China (Grant No. 2015AA020917)« less

Applications of emerging imaging techniques for meat quality and safety detection and evaluation: A review.

PubMed

Xiong, Zhenjie; Sun, Da-Wen; Pu, Hongbin; Gao, Wenhong; Dai, Qiong

2017-03-04

With improvement in people's living standards, many people nowadays pay more attention to quality and safety of meat. However, traditional methods for meat quality and safety detection and evaluation, such as manual inspection, mechanical methods, and chemical methods, are tedious, time-consuming, and destructive, which cannot meet the requirements of modern meat industry. Therefore, seeking out rapid, non-destructive, and accurate inspection techniques is important for the meat industry. In recent years, a number of novel and noninvasive imaging techniques, such as optical imaging, ultrasound imaging, tomographic imaging, thermal imaging, and odor imaging, have emerged and shown great potential in quality and safety assessment. In this paper, a detailed overview of advanced applications of these emerging imaging techniques for quality and safety assessment of different types of meat (pork, beef, lamb, chicken, and fish) is presented. In addition, advantages and disadvantages of each imaging technique are also summarized. Finally, future trends for these emerging imaging techniques are discussed, including integration of multiple imaging techniques, cost reduction, and developing powerful image-processing algorithms.

PICASSO: an end-to-end image simulation tool for space and airborne imaging systems

NASA Astrophysics Data System (ADS)

Cota, Steve A.; Bell, Jabin T.; Boucher, Richard H.; Dutton, Tracy E.; Florio, Chris J.; Franz, Geoffrey A.; Grycewicz, Thomas J.; Kalman, Linda S.; Keller, Robert A.; Lomheim, Terrence S.; Paulson, Diane B.; Willkinson, Timothy S.

2008-08-01

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. Image chain analysis - the prediction of image quality from fundamental design parameters - is an important part of this design process. At The Aerospace Corporation we have been using a variety of image chain analysis tools for many years, the Parameterized Image Chain Analysis & Simulation SOftware (PICASSO) among them. In this paper we describe our PICASSO tool, showing how, starting with a high quality input image and hypothetical design descriptions representative of the current state of the art in commercial imaging satellites, PICASSO can generate standard metrics of image quality in support of the decision processes of designers and program managers alike.

PICASSO: an end-to-end image simulation tool for space and airborne imaging systems

NASA Astrophysics Data System (ADS)

Cota, Stephen A.; Bell, Jabin T.; Boucher, Richard H.; Dutton, Tracy E.; Florio, Christopher J.; Franz, Geoffrey A.; Grycewicz, Thomas J.; Kalman, Linda S.; Keller, Robert A.; Lomheim, Terrence S.; Paulson, Diane B.; Wilkinson, Timothy S.

2010-06-01

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. Image chain analysis - the prediction of image quality from fundamental design parameters - is an important part of this design process. At The Aerospace Corporation we have been using a variety of image chain analysis tools for many years, the Parameterized Image Chain Analysis & Simulation SOftware (PICASSO) among them. In this paper we describe our PICASSO tool, showing how, starting with a high quality input image and hypothetical design descriptions representative of the current state of the art in commercial imaging satellites, PICASSO can generate standard metrics of image quality in support of the decision processes of designers and program managers alike.

Spatially-controlled illumination with rescan confocal microscopy enhances image quality, resolution and reduces photodamage

NASA Astrophysics Data System (ADS)

Krishnaswami, Venkataraman; De Luca, Giulia M. R.; Breedijk, Ronald M. P.; Van Noorden, Cornelis J. F.; Manders, Erik M. M.; Hoebe, Ron A.

2017-02-01

Fluorescence microscopy is an important tool in biomedical imaging. An inherent trade-off lies between image quality and photodamage. Recently, we have introduced rescan confocal microscopy (RCM) that improves the lateral resolution of a confocal microscope down to 170 nm. Previously, we have demonstrated that with controlled-light exposure microscopy, spatial control of illumination reduces photodamage without compromising image quality. Here, we show that the combination of these two techniques leads to high resolution imaging with reduced photodamage without compromising image quality. Implementation of spatially-controlled illumination was carried out in RCM using a line scanning-based approach. Illumination is spatially-controlled for every line during imaging with the help of a prediction algorithm that estimates the spatial profile of the fluorescent specimen. The estimation is based on the information available from previously acquired line images. As a proof-of-principle, we show images of N1E-115 neuroblastoma cells, obtained by this new setup with reduced illumination dose, improved resolution and without compromising image quality.

MR imaging of the prostate at 3 Tesla: comparison of an external phased-array coil to imaging with an endorectal coil at 1.5 Tesla.

PubMed

Sosna, Jacob; Pedrosa, Ivan; Dewolf, William C; Mahallati, Houman; Lenkinski, Robert E; Rofsky, Neil M

2004-08-01

To qualitatively compare the image quality of torso phased-array 3-Tesla (3T) imaging of the prostate with that of endorectal 1.5-Tesla imaging. Twenty cases of torso phased-array prostate imaging performed at 3-Tesla with FSE T2 weighted images were evaluated by two readers independently for visualization of the posterior border (PB), seminal vesicles (SV), neurovascular bundles (NVB), and image quality rating (IQR). Studies were performed at large fields of view(FOV) (25 cm) (14 cases) (3TL) and smaller FOV (14 cm) (19 cases) (3TS). A comparison was made to 20 consecutive cases of 1.5-T endorectal evaluation performed during the same time period.Results. 3TL produced a significantly better image quality compared with the small FOV for PB (P = .0001), SV (P =.0001), and IQR (P = .0001). There was a marginally significant difference within the NVB category (P = .0535). 3TL produced an image of similar quality to image quality at 1.5 T for PB (P = .3893), SV (P = .8680), NB (P = .2684), and IQR (P = .8599). Prostate image quality at 3T with a torso phased-array coil can be comparable with that of endorectal 1.5-T imaging. These findings suggest that additional options are now available for magnetic resonance imaging of the prostate gland.

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

PubMed

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.

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.

PubMed

Yuan, Tao; Zheng, Xinqi; Hu, Xuan; Zhou, Wei; Wang, Wei

2014-01-01

Objective and effective image quality assessment (IQA) is directly related to the application of optical remote sensing images (ORSI). In this study, a new IQA method of standardizing the target object recognition rate (ORR) is presented to reflect quality. First, several quality degradation treatments with high-resolution ORSIs are implemented to model the ORSIs obtained in different imaging conditions; then, a machine learning algorithm is adopted for recognition experiments on a chosen target object to obtain ORRs; finally, a comparison with commonly used IQA indicators was performed to reveal their applicability and limitations. The results showed that the ORR of the original ORSI was calculated to be up to 81.95%, whereas the ORR ratios of the quality-degraded images to the original images were 65.52%, 64.58%, 71.21%, and 73.11%. The results show that these data can more accurately reflect the advantages and disadvantages of different images in object identification and information extraction when compared with conventional digital image assessment indexes. By recognizing the difference in image quality from the application effect perspective, using a machine learning algorithm to extract regional gray scale features of typical objects in the image for analysis, and quantitatively assessing quality of ORSI according to the difference, this method provides a new approach for objective ORSI assessment.

Impact of image quality on OCT angiography based quantitative measurements.

PubMed

Al-Sheikh, Mayss; Ghasemi Falavarjani, Khalil; Akil, Handan; Sadda, SriniVas R

2017-01-01

To study the impact of image quality on quantitative measurements and the frequency of segmentation error with optical coherence tomography angiography (OCTA). Seventeen eyes of 10 healthy individuals were included in this study. OCTA was performed using a swept-source device (Triton, Topcon). Each subject underwent three scanning sessions 1-2 min apart; the first two scans were obtained under standard conditions and for the third session, the image quality index was reduced using application of a topical ointment. En face OCTA images of the retinal vasculature were generated using the default segmentation for the superficial and deep retinal layer (SRL, DRL). Intraclass correlation coefficient (ICC) was used as a measure for repeatability. The frequency of segmentation error, motion artifact, banding artifact and projection artifact was also compared among the three sessions. The frequency of segmentation error, and motion artifact was statistically similar between high and low image quality sessions (P = 0.707, and P = 1 respectively). However, the frequency of projection and banding artifact was higher with a lower image quality. The vessel density in the SRL was highly repeatable in the high image quality sessions (ICC = 0.8), however, the repeatability was low, comparing the high and low image quality measurements (ICC = 0.3). In the DRL, the repeatability of the vessel density measurements was fair in the high quality sessions (ICC = 0.6 and ICC = 0.5, with and without automatic artifact removal, respectively) and poor comparing high and low image quality sessions (ICC = 0.3 and ICC = 0.06, with and without automatic artifact removal, respectively). The frequency of artifacts is higher and the repeatability of the measurements is lower with lower image quality. The impact of image quality index should be always considered in OCTA based quantitative measurements.

Quality in Postgraduate Education.

ERIC Educational Resources Information Center

Zuber-Skerritt, Ortrun, Ed.; Ryan, Yoni, Ed.

This collection of papers discusses issues of quality, institutional research culture, and processes which encourage, achieve, sustain, and assure high quality teaching and research in universities, primarily from a British and Australian perspective. Part 1 is titled "Issues of Quality and Institutional Research Culture" and contains…

Quantitative analysis of image quality for acceptance and commissioning of an MRI simulator with a semiautomatic method.

PubMed

Chen, Xinyuan; Dai, Jianrong

2018-05-01

Magnetic Resonance Imaging (MRI) simulation differs from diagnostic MRI in purpose, technical requirements, and implementation. We propose a semiautomatic method for image acceptance and commissioning for the scanner, the radiofrequency (RF) coils, and pulse sequences for an MRI simulator. The ACR MRI accreditation large phantom was used for image quality analysis with seven parameters. Standard ACR sequences with a split head coil were adopted to examine the scanner's basic performance. The performance of simulation RF coils were measured and compared using the standard sequence with different clinical diagnostic coils. We used simulation sequences with simulation coils to test the quality of image and advanced performance of the scanner. Codes and procedures were developed for semiautomatic image quality analysis. When using standard ACR sequences with a split head coil, image quality passed all ACR recommended criteria. The image intensity uniformity with a simulation RF coil decreased about 34% compared with the eight-channel diagnostic head coil, while the other six image quality parameters were acceptable. Those two image quality parameters could be improved to more than 85% by built-in intensity calibration methods. In the simulation sequences test, the contrast resolution was sensitive to the FOV and matrix settings. The geometric distortion of simulation sequences such as T1-weighted and T2-weighted images was well-controlled in the isocenter and 10 cm off-center within a range of ±1% (2 mm). We developed a semiautomatic image quality analysis method for quantitative evaluation of images and commissioning of an MRI simulator. The baseline performances of simulation RF coils and pulse sequences have been established for routine QA. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.