Optical Pattern Recognition System Based on Parallel Spatial Filtering Using Synthetic Discriminant Function

Abstract

In this paper, we propose an optical pattern recognition system based on spatial filtering using a synthetic discriminant function (SDF). In this system, the input image is multiplexed by a microlens array under incoherent illumination, and then the optical inner product of input images and SDF filters is optically conducted. The image is recognized by thresholding the optical inner product values. The present SDF filter was constructed with pseudogradation transparent filters fabricated by electron-beam lithography. We performed an experiment that involved the recognition of ten Arabic numerals and evaluated the discriminating characteristics of parallel pattern recognition. We confirm that the proposed system can function as a parallel recognition system without the need to scan images.