A FUNCTIONAL-MODEL OF VISION

This article describes a functional model of vision. Starting front th is model, analytical derivations are given of the Weber-Fechner and fl uctuation laws, the dependence of the differential threshold on the an gular size of a stimulus disk, the frequency-contrast characteristic o f the visual system in the presence of noise, and formulas for calcula ting the threshold contrast of a test grating in the presence of a mas king grating, as well as formulas that make it possible to compare the dependence of the contrast sensitivity of vision on the spatial frequ ency of sinusoidal and square gratings. (C) 1997 The Optical Society o f America.