Abstract

This study explores the relation between the activity of 'sensors' in different visual codes and the statistics of natural scenes. The codes that will be described have properties similar to those of the mammalian visual cortex. They represent images with a Gabor-like transform in which sensors have parameters of position, orientation, frequency, and phase. It has been shown that the amplitude spectra of natural scenes falls as a function of frequency by a factor of roughly 1/f. Using 25 images, results will be described which show that codes with constant spatial frequency bandwidths (in octaves) and constant orientation bandwidths (in degrees) can produce equal activity across the entire array of sensors. The variance of activity across the above parameters was determined, and will be discussed in relation to efficient coding of the environment. Codes of this type often make use of quadrature pairs with even and odd symmetry although the physiological evidence for these particular symmetries is weak. We will demonstrate that although quadrature pairs may be useful, no particular symmetry (e.g., phase relations) adds to the efficiency of the code.

© 1990 Optical Society of America