Optical implementation of composite filters as volume holograms in LiNbO3 for pattern recognition

Abstract

The optical correlator originally proposed by Vander Lugt [1] has been extensively investigated as a laboratory novelty but not widely employed in application-specific pattern recognition systems. This result is due in part to the classical matched filter being sensitive to rotation and scale variations of the imagery. Two major avenues of approaching this image distortion limitation are currently being pursued.