The effect of receptor signal-to-noise levels on optimal filtering in a sensory system

Consideration is given to image filtering (temporal and spatial) in a neural system for transmitting images through a limited capacity channel, in the case of a noisy image at the receptors. The authors use an extension of Shannon's (1949) formula for the capacity of a Gaussian channel to determine the optimum filter to be used. For realistic image statistics, they show that the bandwidth of this filter is self-limiting, and it has a high frequency boost that disappears at low signal levels. This behavior is mirrored in biological retinas.<<ETX>>