ABSTRACT

This study was supported in part by National Eye Institute Grant EY01241-02 to the second author.

Much oi the scholarly and experimental rcsearw'l that contributed to this paper was done while the first author was on leave of absence from the University of Houston, between July 1973 and August 1974, at the Bell Laboratories, Murray Hiil, New Jersey. He L'lanks Bela Julesz of the Bell Laborac tories for sponsoring and encouraging his research efforts. We also thank Naomi Wcisstein for helpful criticisms and suggestions.