background: adverse effect of sun rays mainly uv ray on the human eye documented and protection of eyes is necessary using different methods such as, sun glasses. sunglasses are designed in different colors. the aim of this study was evaluation of the effect of different colors of sunglasses on the visual acuity, contrast sensitivity, stereopsis and color vision. methods: 81 normal subjects wer...

JLhere are four recognized types of cell involved in color vision. Receptors absorb light over a restricted region of the visible spectrum, the wavelength of greatest sensitivity being different for different receptors, but the type of response (hyperpolarization) being the same for all wavelengths in all vertebrate receptors. Beyond the receptors, one finds opponent color cells which give one ...

This article presents a computational model of the process through which the human visual system transforms reflectance spectra into perceptions of color. Using physical reflectance spectra data and standard human cone sensitivity functions we describe the transformations necessary for predicting the location of colors in the Munsell color space. These transformations include quantitative estim...

Staining for the mitochondrial enzyme cytochrome oxidase reveals an array of dense regions (blobs) in the primate primary visual cortex. They are most obvious in the upper layers, 2 and 3, but can also be seen in layers 4B, 5, and 6, in register with the blobs in layers 2 and 3. We compared cells inside and outside blobs in macaque and squirrel monkeys, looking at their physiological responses ...

Model calculations are used to find an optimal color vision system for the coding of natural objects. The criteria to assess the quality of color vision are (a) discriminability between all colors of a given set; (b) discriminability between nearest neighbors (only the most similar colors of a set); and (c) detectability (color difference between target and background). The colored objects inve...

This paper presents a novel and automatic artificial-intelligence (AI) method for grape-bunch detection from RGB images. It mainly consists of cascade support vector machine (SVM)-based classifiers that rely on visual contrast-based features that, in turn, are defined according to grape bunch color perception. Due some principles opponent theory proper contrast measures, precise estimate bunche...

A psychophysical experiment was performed to measure the visibility of chromatic noise. Through Principle Component Analysis (PCA) on the results of this experiment, an orthogonal color space with the luminance channel independent of chromatic channels was constructed. By transforming noise images into this space, the visibility of chromatic noise can be predicted. Comparison with other opponen...

INTRODUCTION .......................................................................................................... 42 Trichromacy and the Trichromatic Theory .............................................................. 42 Psychol~hysical l~$timates of the Cone Sensitivities .................................................... 44 The Two-Color Procedure and the ~" Mechanisms ................

A biologically-based neural network simulation is used to analyze the contributions to color perception of each of several processing steps in the visual system from the retina to cortical area V4. We consider the effects on color constancy and color induction of adaptation, spectral opponency, non-linearities including saturation and rectification, and spectrally-specific long-range inhibition...

We explored the neural basis for spatial color contrast (red looks redder surrounded by green) and temporal color contrast (red looks redder if preceded by green) in primary visual cortex (V1) of the alert macaque. Using pairs of stimuli, we found a subset of neurons that gave stronger responses to sequences of red and green spots and stronger responses to adjacent red and green spots. These ce...