A functional model of vision

This article describes a functional model of vision. Starting front this model, analytical derivations are given of the Weber-Fechner and fluctuation laws, the dependence of the differential threshold on the angular size of a stimulus disk, the frequency-contrast characteristic of the visual system in the presence of noise, and formulas for calculating the threshold contrast of a test grating in the presence of a masking grating, as well as formulas that make it possible to compare the dependence of the contrast sensitivity of vision on the spatial frequency of sinusoidal and square gratings. (C) 1997 The Optical Society of America.