The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Larry R Squire - One of the best experts on this subject based on the ideXlab platform.
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The visual Paired-Comparison task as a measure of declarative memory
Proceedings of the National Academy of Sciences of the United States of America, 2000Co-Authors: Joseph R. Manns, Craig E.l. Stark, Larry R SquireAbstract:Performance on the visual Paired-Comparison task depends on the integrity of the hippocampal formation in humans, monkeys, and, for an analogous task, in rats. The present study sought additional evidence in healthy volunteers concerning the nature of this task. We found that performance on the visual Paired-Comparison task was predictive of subsequent recognition memory performance whereas perceptual priming was unrelated to subsequent recognition memory performance. The results are consistent with the data from lesions and suggest that performance on the visual Paired-Comparison task measures a form of declarative memory.
Katalin M Gothard - One of the best experts on this subject based on the ideXlab platform.
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how do rhesus monkeys macaca mulatta scan faces in a visual Paired Comparison task
Animal Cognition, 2004Co-Authors: Katalin M Gothard, Cynthia A Erickson, David G AmaralAbstract:When novel and familiar faces are viewed simultaneously, humans and monkeys show a preference for looking at the novel face. The facial features attended to in familiar and novel faces, were determined by analyzing the visual exploration patterns, or scanpaths, of four monkeys performing a visual Paired Comparison task. In this task, the viewer was first familiarized with an image and then it was presented simultaneously with a novel and the familiar image. A looking preference for the novel image indicated that the viewer recognized the familiar image and hence differentiates between the familiar and the novel images. Scanpaths and relative looking preference were compared for four types of images: (1) familiar and novel objects, (2) familiar and novel monkey faces with neutral expressions, (3) familiar and novel inverted monkey faces, and (4) faces from the same monkey with different facial expressions. Looking time was significantly longer for the novel face, whether it was neutral, expressing an emotion, or inverted. Monkeys did not show a preference, or an aversion, for looking at aggressive or affiliative facial expressions. The analysis of scanpaths indicated that the eyes were the most explored facial feature in all faces. When faces expressed emotions such as a fear grimace, then monkeys scanned features of the face, which contributed to the uniqueness of the expression. Inverted facial images were scanned similarly to upright images. Precise measurement of eye movements during the visual Paired Comparison task, allowed a novel and more quantitative assessment of the perceptual processes involved the spontaneous visual exploration of faces and facial expressions. These studies indicate that non-human primates carry out the visual analysis of complex images such as faces in a characteristic and quantifiable manner.
Touradj Ebrahimi - One of the best experts on this subject based on the ideXlab platform.
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How to benchmark objective quality metrics from Paired Comparison data?
2016Co-Authors: Philippe Hanhart, Lukáš Krasula, Patrick Le Callet, Touradj EbrahimiAbstract:The procedures commonly used to evaluate the performance of objective quality metrics rely on ground truth mean opinion scores and associated confidence intervals, which are usually obtained via direct scaling methods. However, indirect scaling methods, such as the Paired Comparison method, can also be used to collect ground truth preference scores. Indirect scaling methods have a higher discriminatory power and are gaining popularity, for example in crowdsourcing evaluations. In this paper, we present how the classification errors, an existing analysis tool, can also be used with subjective preference scores. Additionally, we propose a new analysis tool based on the receiver operating characteristic analysis. This tool can be used to further assess the performance of objective metrics based on ground truth preference scores. We provide a MATLAB script with an implementation of the proposed tools and we show one example of application of the proposed tools.
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Paired Comparison-based subjective quality assessment of stereoscopic images
Multimedia Tools and Applications, 2013Co-Authors: Lutz Goldmann, Touradj EbrahimiAbstract:As 3D image and video content has gained significant popularity, subjective 3D quality assessment has become an important issue for the creation, processing, and distribution of high quality 3D content. Reliable subjective quality assessment of 3D content is often difficult due to the subjects’ limited 3D experience, the interaction of multiple quality factors, minor quality differences between stimuli, etc. Among subjective evaluation methodologies, Paired Comparison has the advantage of improved simplicity and reliability, which can be useful to tackle the aforementioned difficulties. In this paper, we propose a new method to analyze the results of Paired Comparison-based subjective tests. We assume that ties convey information about the significance of quality score differences between two stimuli. Then, a maximum likelihood estimation is performed to obtain confidence intervals providing intuitive measures of significance of the quality differences. We describe the complete test procedure using the proposed method, from subjective experiment design to outlier detection and score analysis for 3D image quality assessment. Especially, we design the test procedure in a way that quality Comparison across different contents is enabled while the number of pair-wise Comparisons is minimized. Experimental results on a stereoscopic image database with varying camera distances demonstrate the usefulness of the proposed method and enhanced quality discriminability of Paired Comparison in Comparison to the conventional single stimulus methodology.
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a new analysis method for Paired Comparison and its application to 3d quality assessment
ACM Multimedia, 2011Co-Authors: Jongseok Lee, Lutz Goldmann, Touradj EbrahimiAbstract:Among various subjective quality evaluation methodologies, Paired Comparison has the advantage of improved simplicity of the subjects' evaluation task due to simplified rating scales and direct Comparison of two stimuli. Thus, it may lead to more reliable results when individual quality levels are difficult to define, quality differences between stimuli are small or multiple quality factors are involved. This paper proposes a new method to analyze results of Paired Comparison-based subjective tests. By assuming that ties convey information about significant differences between two stimuli being compared, the confidence intervals for the quality scores are estimated using a maximum likelihood criterion, which enables us to intuitively examine the significance of quality score differences. We describe the complete test methodology including the test procedure, outlier detection and score analysis applied to quality assessment of 3D images acquired using varying camera distances. Experimental results demonstrate the usefulness of the proposed analysis method, as well as the enhanced quality discriminability of the Paired Comparison methodology in Comparison to the conventional single stimulus methodology.
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subjective quality evaluation via Paired Comparison application to scalable video coding
IEEE Transactions on Multimedia, 2011Co-Authors: Jongseok Lee, F De Simone, Touradj EbrahimiAbstract:Scalable video coding is a powerful solution for content delivery in many interactive multimedia services due to its adaptability to varying terminal and network constraints. In order to successfully exploit such adaptability, it is necessary to understand users' preference among various scalability options and consequently develop an optimal bit rate adaptation strategy. In this paper, we present a study of subjective quality assessment of scalable video coding, which investigates the influence of the combination of scalability options on perceived quality with the goal of providing guidelines for an adaptive strategy that selects the optimal combination for a given bandwidth constraint. In particular, the study is based on Paired Comparison of stimuli that is suitable for our goal due to its simplicity and easiness. We propose a new method, called Paired Evaluation via Analysis of Reliability (PEAR), which analyzes Paired Comparison results and produces not only quality scores but also intuitive measures of confidence of the scores for significance analysis. Results and analysis of extensive subjective tests for two different scalable video codecs and high definition contents are described, from which general consistent conclusions are drawn. The video and subjective data used in the paper are publicly available to the research community.
Jongseok Lee - One of the best experts on this subject based on the ideXlab platform.
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on designing Paired Comparison experiments for subjective multimedia quality assessment
IEEE Transactions on Multimedia, 2014Co-Authors: Jongseok LeeAbstract:This paper investigates the issue of designing Paired Comparison-based subjective quality assessment experiments for reliable results. In particular, the convergence behavior of the quality scores estimated from Paired Comparison results is considered. Via an extensive computer simulation experiment, the estimation performance in terms of the root mean squared error, the rank order correlation coefficient, and the change of the estimated scores with respect to the number of subjects are mathematically modeled. Furthermore, it is confirmed that the models coincide with the theoretical convergence behavior. Issues such as the effect of human errors and the underlying distribution of the true quality scores are also examined.
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Paired Comparison for subjective multimedia quality assessment theory and practice
International Symposium on Circuits and Systems, 2013Co-Authors: Jongseok LeeAbstract:For subjective multimedia quality assessment, Paired Comparison has been used less frequently than other methodologies such as single stimulus and double stimulus methodologies, mainly due to its increased time complexity. However, it has been shown that Paired Comparison provides improved discriminability between stimuli, which consequently improves reliability of the test results. Analyzing Comparison results involves several challenges in quality score computation, outlier detection, etc. This paper presents theoretical backgrounds on these challenges and use cases where Paired Comparison are successfully applied. In particular, the issue of the increased time complexity is discussed along with recently proposed solutions.
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a new analysis method for Paired Comparison and its application to 3d quality assessment
ACM Multimedia, 2011Co-Authors: Jongseok Lee, Lutz Goldmann, Touradj EbrahimiAbstract:Among various subjective quality evaluation methodologies, Paired Comparison has the advantage of improved simplicity of the subjects' evaluation task due to simplified rating scales and direct Comparison of two stimuli. Thus, it may lead to more reliable results when individual quality levels are difficult to define, quality differences between stimuli are small or multiple quality factors are involved. This paper proposes a new method to analyze results of Paired Comparison-based subjective tests. By assuming that ties convey information about significant differences between two stimuli being compared, the confidence intervals for the quality scores are estimated using a maximum likelihood criterion, which enables us to intuitively examine the significance of quality score differences. We describe the complete test methodology including the test procedure, outlier detection and score analysis applied to quality assessment of 3D images acquired using varying camera distances. Experimental results demonstrate the usefulness of the proposed analysis method, as well as the enhanced quality discriminability of the Paired Comparison methodology in Comparison to the conventional single stimulus methodology.
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subjective quality evaluation via Paired Comparison application to scalable video coding
IEEE Transactions on Multimedia, 2011Co-Authors: Jongseok Lee, F De Simone, Touradj EbrahimiAbstract:Scalable video coding is a powerful solution for content delivery in many interactive multimedia services due to its adaptability to varying terminal and network constraints. In order to successfully exploit such adaptability, it is necessary to understand users' preference among various scalability options and consequently develop an optimal bit rate adaptation strategy. In this paper, we present a study of subjective quality assessment of scalable video coding, which investigates the influence of the combination of scalability options on perceived quality with the goal of providing guidelines for an adaptive strategy that selects the optimal combination for a given bandwidth constraint. In particular, the study is based on Paired Comparison of stimuli that is suitable for our goal due to its simplicity and easiness. We propose a new method, called Paired Evaluation via Analysis of Reliability (PEAR), which analyzes Paired Comparison results and produces not only quality scores but also intuitive measures of confidence of the scores for significance analysis. Results and analysis of extensive subjective tests for two different scalable video codecs and high definition contents are described, from which general consistent conclusions are drawn. The video and subjective data used in the paper are publicly available to the research community.
Kimberly S Grant - One of the best experts on this subject based on the ideXlab platform.
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measuring infant memory utility of the visual Paired Comparison test paradigm for studies in developmental neurotoxicology
Neurotoxicology and Teratology, 2012Co-Authors: Thomas M Burbacher, Kimberly S GrantAbstract:The assessment of brain function and behavior in young infants is central to understanding the effects of chemical exposure on central nervous system development. One approach to infant cognitive assessment, based on the direct observation of infant eye movements, is known as the Visual Paired-Comparison task. The Visual Paired-Comparison test methodology uses selective visual attention as a vehicle to study emerging recognition memory skills. The utility of this procedure to study visual recognition memory has been well established in both human and nonhuman primate infants. The primary outcome measure produced by this assessment technique is known as the Novelty Preference Score, reflecting the amount of time the infant spends actively looking at novel rather than familiar test stimuli. Visual recognition memory testing has demonstrated a strong sensitivity to conditions that may place infants at risk for poor developmental outcome (e.g. preterm birth, Down syndrome) and in humans; performance is significantly related to later measures of I.Q. and language competency. This assessment methodology has been successfully applied to the study of neurobehavioral effects after fetal neurotoxicant exposure. Field and laboratory studies have used tests of visual recognition memory to better understand the effects of compounds such as lead, methylmercury and polychlorinated biphenyls on emergent cognitive processing. The Visual Paired-Comparison paradigm and its capacity to measure recognition memory in preverbal infants provides a valid and theoretically meaningful approach to neurobehavioral assessment for studies in developmental toxicology and teratology.
