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[IEEE 2018 26th European Signal Processing Conference (EUSIPCO) - Roma, Italy (2018.9.3-2018.9.7)] 2018 26th European Signal Processing Conference (EUSIPCO) - Performance Evaluation of N O- Reference Image Quality Metrics for Visible Wavelength Iris Biometric Images
摘要： Image quality assessment plays an important role in iris recognition systems because the system performance is affected by low quality iris images. With the development of electronic color imaging, there are more and more researches about visible wavelength (VW) iris recognition. Compared to the near infrared iris images, using VW iris images acquired under unconstrained imaging conditions is a more challenging task for the iris recognition system. However, the number of quality assessment methods for VW iris images is limited. Therefore, it is interested to investigate whether existing no-reference image quality metrics (IQMs) which are designed for natural images can assess the quality of VW iris images. In this paper, we evaluate the performance of 15 selected no-reference IQMs on VW iris biometrics. The experimental results show that several IQMs can assess iris sample quality according to the system performance.
关键词： image quality assessment,visible wavelength iris,image based attributes,performance evaluation,multi-modality
更新于2025-09-04 15:30:14
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Quantitative measurement of contrast, texture, color, and noise for digital photography of high dynamic range scenes
摘要： Today, most advanced mobile phone cameras integrate multi-image technologies such as high dynamic range (HDR) imaging. The objective of HDR imaging is to overcome some of the limitations imposed by the sensor physics, which limit the performance of small camera sensors used in mobile phones compared to larger sensors used in digital single-lens reflex (DSLR) cameras. In this context, it becomes more and more important to establish new image quality measurement protocols and test scenes that can differentiate the image quality performance of these devices. In this work, we describe image quality measurements for HDR scenes covering local contrast preservation, texture preservation, color consistency, and noise stability. By monitoring these four attributes in both the bright and dark parts of the image, over different dynamic ranges, we benchmarked four leading smartphone cameras using different technologies and contrasted the results with subjective evaluations.
关键词： image quality,texture preservation,color consistency,high dynamic range,noise stability,contrast preservation,HDR
更新于2025-09-04 15:30:14
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Feature comparison and analysis for new challenging research fields of image quality assessment
摘要： Nowadays, objective image quality assessment (IQA) issue becomes increasingly important for both the practical application and scientific research in digital image processing systems. In this paper, we conduct feature comparison and analysis on new challenging research fields including contrast-distorted, screen content, multiply-distorted, tone-mapped, Depth Image Based Rendering (DIBR) and authentically distorted IQA. We describe the performance criteria, design rationale, and benchmark databases for validating IQA metrics in accordance with human perceptions. Then we provide some important conclusions of feature selection in terms of different IQA problems. In this work, our goal is dominantly towards judging the robustness of mainstream features used in the IQA field, which can help current and emerging researchers for better and faster grasping the speciality of each of novel IQA directions reported.
关键词： Image quality assessment (IQA),DIBR distortion,Authentical distortion,Multiple distortion
更新于2025-09-04 15:30:14
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Can a Channelized Hotelling Observer assess image quality in acquired mammographic images of an anthropomorphic breast phantom including image processing?
摘要： Purpose: To study the feasibility of a channelized Hotelling observer (CHO) to predict human observer performance in detecting calcification-like signals in mammography images of an anthropomorphic breast phantom, as part of a quality control (QC) framework. Methods: A prototype anthropomorphic breast phantom with inserted gold discs of 0.25 mm diameter was imaged with two different digital mammography x-ray systems at four different dose levels. Regions of interest (ROIs) were extracted from the acquired processed and unprocessed images, signal-present and signal-absent. The ROIs were evaluated by a CHO using four different formulations of the difference-of-Gaussian (DoG) channel sets. Three human observers scored the ROIs in a two-alternative forced-choice experiment. We compared the human and the CHO performance on the simple task to detect calcification-like discs in ROIs with and without post-processing. The proportion of correct responses of the human reader (PCH) and the CHO (PCCHO) was calculated and the correlation between the two was analyzed using a mixed-effect regression model. To address the signal location uncertainty, the impact of shifting the DoG channel sets in all directions up to two pixels was evaluated. Correlation results including the goodness of fit (r2) of PCH and PCCHO for all different parameters were evaluated. Results: Sub-analysis by system yielded strong correlations between PCH and PCCHO, with r2 between PCH and PCCHO was found to be between 0.926 and 0.958 for the unshifted and between 0.759 and 0.938 for the shifted channel sets, respectively. However, the linear fit suggested a slight system dependence. PCCHO with shifted channel sets increased CHO performance but the correlation with humans was decreased. These correlations were not considerably affected by of the DoG channel set used. Conclusions: There is potential for the CHO to be used in QC for the evaluation of detectability of calcification-like signals. The CHO can predict the PC of humans in images of calcification-like signals of two different systems. However, a global model to be used for all systems requires further investigation.
关键词： Image quality,mammography,model observers,anthropomorphic breast phantom,human observers
更新于2025-09-04 15:30:14
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Organ doses evaluation for chest computed tomography procedures with TL dosimeters: Comparison with Monte Carlo simulations
摘要： Purpose: To evaluate organ doses in routine and low‐dose chest computed tomography (CT) protocols using an experimental methodology. To compare experimental results with results obtained by the National Cancer Institute dosimetry system for CT (NCICT) organ dose calculator. To address the differences on organ dose measurements using tube current modulation (TCM) and fixed tube current protocols. Methods: An experimental approach to evaluate organ doses in pediatric and adult anthropomorphic phantoms using thermoluminescent dosimeters (TLDs) was employed in this study. Several analyses were performed in order to establish the best way to achieve the main results in this investigation. The protocols used in this study were selected after an analysis of patient data collected from the Institute of Radiology of the School of Medicine of the University of S?o Paulo (InRad). The image quality was evaluated by a radiologist from this institution. Six chest adult protocols and four chest pediatric protocols were evaluated. Lung doses were evaluated for the adult phantom and lung and thyroid doses were evaluated for the pediatric phantom. The irradiations were performed using both a GE and a Philips CT scanner. Finally, organ doses measured with dosimeters were compared with Monte Carlo simulations performed with NCICT. Results: After analyzing the data collected from all CT examinations performed during a period of 3 yr, the authors identified that adult and pediatric chest CT are among the most applied protocol in patients in that clinical institution, demonstrating the relevance on evaluating organ doses due to these examinations. With regards to the scan parameters adopted, the authors identified that using 80 kV instead of 120 kV for a pediatric chest routine CT, with TCM in both situations, can lead up to a 28.7% decrease on the absorbed dose. Moreover, in comparison to the standard adult protocol, which is performed with fixed mAs, TCM, and ultra low‐dose protocols resulted in dose reductions of up to 35.0% and 90.0%, respectively. Finally, the percent differences found between experimental and Monte Carlo simulated organ doses were within a 20% interval. Conclusions: The results obtained in this study measured the impact on the absorbed dose in routine chest CT by changing several scan parameters while the image quality could be potentially preserved.
关键词： Monte Carlo simulations,computed tomography,dosimetry/exposure assessment,organ dose,image quality
更新于2025-09-04 15:30:14
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[Lecture Notes in Computer Science] Algorithms and Architectures for Parallel Processing Volume 11335 (18th International Conference, ICA3PP 2018, Guangzhou, China, November 15-17, 2018, Proceedings, Part II) || SMIM: Superpixel Mutual Information Measurement for Image Quality Assessment
摘要： The image quality assessment (IQA) is a fundamental problem in signal processing that aims to measure the objective quality of an image by designing a mathematical model. Most full-reference (FR) IQA methods use ?xed sliding windows to obtain structure information but ignore the variable spatial con?guration information. In this paper, we propose a novel full-reference IQA method, named “superpixel normalized mutual information (SMIM)” based on the perspective of variable receptive ?eld and information entropy. First, we ?nd that consistence relationship exists between the information ?delity and human visual of individuals. Thus, we reproduce the human visual system (HVS) to semantically divide the image into multiple patches via superpixel segmentation. Then the weights of each image patches are adaptively calculated via its information volume. We veri?ed the e?ectiveness of SMIM by applying it to data from the TID2008 database and data generated using some real application scenarios. Experiments show that SMIM outperforms some state-of-the-art FR IQA algorithms, including visual information ?delity (VIF).
关键词： Superpixel segmentation,Mutual information,Image quality assessment
更新于2025-09-04 15:30:14
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[Communications in Computer and Information Science] Advanced Informatics for Computing Research Volume 955 (Second International Conference, ICAICR 2018, Shimla, India, July 14–15, 2018, Revised Selected Papers, Part I) || A Brief Review of Image Quality Enhancement Techniques Based Multi-modal Biometric Fusion Systems
摘要： An extensive amount of system needs reliable schemes for personal recognition to con?rm the individual identity demanding the services. The aim of these schemes is the authentication of services that can be executed from the genuine user only. Tremendous growth has been seen from last few years in biometric recognition because of the increased requirement of consistent personal identi?cation with the varied government and commercial applications. The biometric recognition is termed as automatic individual recognition on the basis of physiological or behavioural characteristics. This paper provides a brief outline of biometric ?eld and sums up the biometric modalities, biometric framework, and biometric system classi?cation with Image Quality Improvement Techniques. Work done by number of authors in the similar ?eld has been analyzed and de?ned. The review has also shown the observation of different modalities for recognition accuracy with FAR and FRR.
关键词： Biometric modalities,Unimodal and multimodal biometric system,Image Quality Improvement Techniques,Biometric recognition
更新于2025-09-04 15:30:14