Abstract

In treating the common case of 2-D lattice sampling of a nominally 1-D grating, the Nyquist limit is commonly defined in terms of the average nearest neighbor spacing. In fact, the redundancy in this stimulus permits the grating to be recovered at frequencies many times the nominal Nyquist limit. To show this, a two-layer visual system is simulated with the following properties: (1) The first layer is a physiologically plausible array of receptors, which undersamples the stimulus. (2) The second layer consists of line detectors, which oversample the output of the first layer. Such a model shows a number of interesting behaviors including (1) the resolution of super-Nyquist gratings and (2) a reversal in apparent orientation at twice the nominal Nyquist frequency.

© 1987 Optical Society of America