Optimal Incoherent Filtering for Distortion-Invariant Image Recognition^*

Abstract

An optimal incoherent filter is proposed for distortion-invariant correlation. The optical transfer function (OTF) of the correlator is specified as a realizable phase-only term which is optimized by the simulated annealing algorithm. The phase-only OTF is used in image recognition to produce a sharp peak response and can be generated by dual-filter synthesis. Image recognition is achieved by subtracting two spatially incoherent correlation outputs produced from a positive and negative filters with an input image. Computer simulations show that the proposed correlator can yield a sharp correlation peak with excellent distortion tolerance.