Optical multiple pattern recognition with a correlator using a single binary phase-only filter

摘要

Simulated and experimental results are presented for a mutiplexed, frequency-plane, correlator that is capable of recognizing a plurality of input patterns with a single, binary, phase-only, correlation filter. The correlator incorporates a pixellated, binary phase, random coded, fixed mask in the input plane that gives enhanced performance and, by introducing space-variance, enables the output to be presented in simple coded forms. The correlation filter is designed using a standard optimization technique. As the number of reference patterns stored in the filter is increased, performance is degraded but can be at least partially regained by increasing the number of pixels in the mask and filter. Detailed results are given for a 128×128 pixel, eight-character recognition correlator showing two forms of output coding.