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: Dynamic visual noise was constrained to produce perceptually continuous unidirectional flow by plotting dots in pairs the members of which were consistently separated in time and in space.
133 citations
TL;DR: It is concluded that optical and neural effects combine in normal viewing to produce saccadic suppression, and minimizing the optically originating effects of contour masking and retinal image smear failed to eliminate the considerable impairment of vision that occurs during a saccades.
133 citations
01 Jan 2000
TL;DR: This method is based on the underlying physics of the degradation and the parameters required for enhancement are estimated from the image itself, and significant improvements in terms of contrast, visible range and color fidelity are evident when compared to existing methods.
Abstract: Degradation of images by the atmosphere often restricts imaging applications to good visibility conditions. For example, when imaging the terrain from a forward-looking airborne camera, the atmospheric degradation causes both a loss in contrast and color information. Enhancement of such images is a difficult task due to the complexity in restoring both the luminance and chrominance while maintaining good color fidelity. One particular problem is the fact that the level of contrast loss depends strongly on the wavelength; shorter wavelengths i.e., blue are more effected. In this paper, a novel method is presented for the enhancement of color images. This method is based on the underlying physics of the degradation and the parameters required for enhancement are estimated from the image itself. The proposed method is tested using synthetic images to explore the limitations and reliability of the method under different visibility conditions. Enhancement is performed on real images taken using an airborne camera at a height of approximately 1000 meters in hazy conditions for which the visibility is approximately 10 kilometers. Significant improvements in terms of contrast, visible range and color fidelity are evident when compared to existing methods.
133 citations
TL;DR: Anatomical and psychophysical data are consistent with the hypothesis that the human retina maximizes the reconstruction of different pictures over the range in luminance required for day and night vision.
133 citations
TL;DR: The performance of individual neurons in monkey striate cortex has been examined in three spatial-resolution tasks by making microelectrode recordings from single cells in anaesthetized, paralyzed animals and calculations indicate that these cells are poorer at localization than many other cells in the cortex.
Abstract: The performance of individual neurons in monkey striate cortex has been examined in three spatial-resolution tasks by making microelectrode recordings from single cells in anaesthetized, paralyzed animals. The statistical reliability of responses from cells was used to estimate threshold levels of performance. For each task (resolution acuity for high-contrast gratings, discrimination of gratings varying in spatial frequency, and localization ability, i.e., discrimination of spatial phase), performance approaching psychophysical thresholds was obtained from single cortical cells. The receptive-field organization underlying localization performance was examined in detail by the use of a linear model that relates localization ability to the sensitivity of the receptive field to luminance contrast. Calculations from this model agree well with direct measurements of localization performance and are comparable with psychophysical measurements of hyperacuity. Though it has been suggested that cells with nonoriented receptive fields in cortical layer ivcβ may be responsible for recovering fine-grain spatial information, our calculations indicate that these cells are poorer at localization than many other cells in the cortex.
133 citations