Multimatched filtering using a microlens array for an optical-neural pattern recognition system

In the optical-neural recognition system proposed for flexible parallel information processing, a planar microlens array is used to form simultaneously many identical Fourier transforms of an input pattern; from each transform the feature extraction of the input pattern is performed in parallel through optical correlations with memorized standard spatial filters. In this paper, it is experimentally shown that the multimatched filtering system, as the optical feature extracting part of the proposed system, can be composed of a planar array of graded index microlenses of 1.05-mm diameter and 2.6-mm focal length.