Abstract

In this paper we describe and experimentally demonstrate optical image correlators that are implemented using optical memory disks. Optical correlation for pattern recognition [1] has long been considered a promising application for optical processing. One of the reasons such correlators have not been used in practical applications yet has been the lack of suitable spatial light modulators to be used as real time input devices. Recently, this limitation has to a large extent been removed through the development of a variety of 2-D SLM’s [2] and concepts that allow the utilization of mature 1-D (acoustooptic) SLM’s [3]. Attention has therefore shifted to the design of appropriate filters to perform reliable recognition [4]. In most practical applications a single filter is not suffiicient to produce reliable recognition, and the use of spatial [5] and temporal [3] multiplexing to search through a library of filters emerges as the most straightforward solution to the problem. The optical disk correlator architectures we describe in this paper provide an extremely efficient method for performing this task since they combine in a single device the huge memory required for storage of the library of reference images, the spatial light modulator needed to represent the reference in the optical correlator, and the scanning mechanism to temporally search through the library.

© 1989 Optical Society of America