next up previous
Next: The Effect of Up: No Title Previous: Visual stimuli induce

Optimizing information transmission in the compound eye

D. L. Ruderman and S. B. Laughlin

The Physiological Laboratory & The Zoological Laboratory
Cambridge, UK

The design of insects' compound eyes can be seen as a set of tradeoffs. The most basic of these was discussed by Feynman in his Lectures: smaller facets allow for finer sampling of the world but reduce acuity due to diffraction. Good ``ballpark'' estimates of facet size can be made by equating the diffraction limit to resolution with the Nyquist frequency of the sampling lattice. But other factors are involved such as photon shot noise, which fundamentally limits visual processing. In the 1970's, Snyder et al applied information theory to the compound eye, finding that maximizing information capacity gave reasonable estimates of design parameters. In this poster we extend the information-theoretic treatment by introducing the time domain. Basic questions such as ``how fast should a photoreceptor respond as a function of light level and flight speed?'' are addressed, as is the use of moving natural images as a stimulus ensemble. Preliminary results suggest that information theory can provide a useful tool for understanding the tradeoffs and trends in compound eye design, both in the spatial and temporal domains.

Tony Zador
Wed Mar 12 22:07:02 PST 1997