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Contrast (vision)

About: Contrast (vision) is a research topic. Over the lifetime, 10379 publications have been published within this topic receiving 221480 citations.


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Journal ArticleDOI
04 Jan 1996-Nature
TL;DR: It is reported here that observers reliably distinguish the direction of motion of a colour pattern presented for only 17 milliseconds, provided that the contrast is several times the threshold value (the contrast needed to detect the presence of the pattern).
Abstract: The human visual system is much better at analysing the motion of luminance (black and white) patterns than it is at analysing the motion of colour patterns, especially if the pattern is presented very briefly or moves rapidly. We report here that observers reliably distinguish the direction of motion of a colour pattern presented for only 17 milliseconds, provided that the contrast is several times the threshold value (the contrast needed to detect the presence of the pattern). A control experiment, in which a static luminance 'mask' is added to the moving colour pattern, proves that discrimination of the direction of motion of these brief stimuli is colour-specific. The mask drastically impairs discrimination of the direction of motion of a luminance pattern, but it has little effect on a colour pattern. We conclude that the human visual system contains colour-specific motion-detection mechanisms that are capable of analysing very brief signals.

103 citations

Journal ArticleDOI
TL;DR: The proposed reversible data hiding method with contrast enhancement can achieve more contrast enhancement effects and better visual quality for medical images and the visibility of ROI can be improved.

103 citations

Journal ArticleDOI
TL;DR: Central PCO affects psychophysical test results with differing degrees of sensitivity, and forward light-scatter is the most sensitive, followed by contrast sensitivity and visual acuity.
Abstract: PURPOSE. To investigate how posterior capsule opacification (PCO) affects visual function in pseudophakic eyes. METHODS. One hundred and six eyes that had undergone uncomplicated phacoemulsification were recruited sequentially. Patients with surgical complications or other ocular disease were excluded. PCO was assessed by a digital retroillumination camera using a software program based on the analysis of texture in the image, and the percentage area within the central 3-mm zone of the posterior capsule was calculated. Visual function assessment included Early Treatment Diabetic Retinopathy Study (ETDRS) high- and low-contrast visual acuity, contrast sensitivity with the Pelli-Robson and CSV-1000 grating charts, and forward light-scatter by the direct-compensation method (van den Berg). RESULTS. The percentage PCO required for decline in high-contrast ETDRS was 78%; for low-contrast acuity and Pelli-Robson, 46%; for CSV-1000 contrast sensitivity, 38% to 51%; and for forward light-scatter, less than 1% PCO. CONCLUSIONS. Central PCO affects psychophysical test results with differing degrees of sensitivity. Forward light-scatter is the most sensitive, followed by contrast sensitivity and visual acuity.

103 citations

Journal ArticleDOI
TL;DR: Improved visual quality metrics need further investigation and will likely involve preferential weighing of light passing through the central area of the pupil and/or incorporating neural factors into image quality computation.
Abstract: Purpose Root mean square (RMS) wavefront error may not be the best metric for predicting a patient's visual function; other metrics should be considered. We describe the most important metrics of optical quality, which are being investigated to predict vision quality and visual performance. Methods Optical quality can be described in two different ways. Pupil plane metrics describe variability of the wavefront error at the pupillary plane (eg, RMS wavefront error). Image plane metrics describe the retinal image and do so for either a point source of light (eg, point-spread function [PSF]) or sinusoidal gratings (optical transfer function [OTF]). Visual quality metrics, however, must also consider neural processing and subjective perception. Results Since vision is more sensitive to rays coming from the center of the pupil, "pupil fraction" appears to be a better predictor of visual acuity (r2 = 0.50) than RMS error (r2 = 0.13). However, image plane metrics, such as the visual Strehl ratio (r2 = 0.62) and the volume between the optical transfer function and neural contrast sensitivity function (r2 = 0.80) appear to be even better. Conclusion Visual perception is highly subjective and involves many aspects of image quality. A single metric to describe all aspects of image quality may be unrealistic. Nevertheless, improved visual quality metrics need further investigation and will likely involve preferential weighing of light passing through the central area of the pupil and/or incorporating neural factors into image quality computation.

103 citations

Journal ArticleDOI
TL;DR: Two experiments investigating face learning with “ambient images”—relatively unconstrained photos taken from internet searches show that exposure to a large range of within-person variability leads to enhanced learning of new identities.
Abstract: Research on face learning has tended to use sets of images that vary systematically on dimensions such as pose and illumination. In contrast, we have proposed that exposure to naturally varying ima...

102 citations


Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20231,864
20223,760
2021413
2020329
2019354