Abstract

The joint transform correlator (JTC) is well known to be one of the most convenient devices for correlating two images in the sense that there is no need to fabricate a holographic filter. It has been shown previously that by applying additional non-linearities in the joint spectrum plane, such as binarization or saturation, to the joint spectra it is possible to achieve correlation with phase-only information (i.e., correlation with an inverse filter). This process increases the discrimination ability of the correlator. Previously, the nonlinearities for conventional and enhanced JTC required a camera, a computer, and a spatial light modulator for their implementation. We propose an arrangement of degenerate four wave mixing using two barium titanate crystals. This enables us to replace the previously used electronic processing while simultaneously achieving the two non-linearities, binarization and saturation, for a phase-only JTC.

© 1992 Optical Society of America