TRANSLATION SENSITIVITY ADJUSTABLE COMPACT OPTICAL CORRELATOR AND ITSAPPLICATION FOR FINGERPRINT RECOGNITION

A translation sensitivity adjustable compact optical correlator (TSACO C) utilizing a convergent reference wave has been designed and tested. Its properties and performances, including the location of the correl ation peak and the effects of lateral and longitudinal displacements f or both filters and input images, are systematically analyzed based on the nonparaxial approximation for the reference beam. The theoretical analyses have been verified in experiments. By discussing the practic al problems encountered, we have found that the tolerance of the syste m to the input lateral displacement can be conveniently increased by c hanging a geometric factor of the system. This property is very import ant to a TSACOC with a pinhole aperture attached to an ordinary detect or at a fixed place. In addition, the effectiveness of the TSACOC for fingerprint recognition is also presented. (C) 1996 Society of Photo-O ptical Instrumentation Engineers.