FRESNEL TRANSFORM-BASED CORRELATOR

We present a new technique for information processing using Fresnel tr ansform-based correlation. The main emphasis is on the design of a cor relator involving the reference object and its near-field diffraction pattern at an optimized distance. The input-scene image and its diffra ction pattern constitute the input pattern of the new correlator. The new technique shows a significant increase in discrimination ability a nd optical efficiency. Moreover, different encoding methods, such as t he phase-only filter or the matched filter, can be used iri conjunctio n with this method. A theoretical analysis as well as examples are giv en. (C) 1997 Optical Society of America.