Topic
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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TL;DR: The results suggest that specific surface potentials, differing from cognitive possibles, can be derived which are associated with preattentive processing, and are suggested to represent processing of orientation contrast or global processing of texture segregation.
104 citations
TL;DR: It is concluded that the age-related deterioration is primarily caused by changes within the central nervous system rather than the optical media, the transmission quality of which remains unaffected.
Abstract: Contrast sensitivities were measured in human observers of different ages in response to sinusoidal grating patterns generated by laser interferometer and cathode ray tube (c.r.t.). The former method bypasses the effects of the optical media to assess directly the contrast sensitivity of the retina/visual system, while the over-all assessment including optical media is made to the c.r.t. display. The ratio of the two sets of values gives the contrast ratio of the optical media. The latter assessment does not include the effects of wide-angle light scattering which were measured by comparing the responses of eyes with a Perspex lens implant or without any lens at all (i.e. without the major source of scattering) with natural eyes. With increasing age, c.r.t. contrast sensitivities remained steady until the sixth decade when they declined while laser interference fringe contrast sensitivities declined continuously, apart from some abnormally low results for teenage observers. In contrast, the optical contrast did not vary systematically with age nor did its rate of change with spatial frequency vary. The latter was always less than the rate for laser interference fringe contrast sensitivities indicating that the retina/visual system always sets the limit to visual resolution. Wide-angle light scattering was not found to contribute significantly to the changes in ageing nor did reduced retinal illumination, as reproduced by reduced pupil diameter or viewing through a neutral density filter. We therefore conclude that the age-related deterioration is primarily caused by changes within the central nervous system rather than the optical media, the transmission quality of which remains unaffected.
104 citations
TL;DR: The apparent contrast of a small grating patch embedded in the center of an annular grating filled surround was studied as a function of the surround to central patch contrast ratio, the width of the annulus, and the contrast level of the central patch.
103 citations
TL;DR: In this study the sensitivity of these channels for patterns at low mean luminance or high drift rate is measured by the effect of adaptation to sinusoidal gratings on the contrast thresholds for sinusoid gratings.
103 citations
Patent•
11 Sep 1989
TL;DR: In this paper, a system for maintaining the contrast of an LCD at a constant level despite variations in temperature of the liquid crystal medium includes a temperature sensor and digital circuitry for generating a correction voltage that offsets the change in contrast level caused by the operating temperature.
Abstract: A system for maintaining the contrast of an LCD at a constant level despite variations in temperature of the liquid crystal medium includes a temperature sensor and digital circuitry for generating a correction voltage that offsets the change in contrast level caused by the change in operating temperature.
103 citations