Abstract

We have shown that using compression types of nonlinearity at the Fourier plane of joint transform correlators results in higher correlation peak intensity, larger peak-to sidelobe ratio, narrower correlation width, and better discrimination sensitivity.¹ For a Kth law nonlinearity (y = x^k), the compression nonlinearity corresponds to K < 1. In this paper we investigate the performance of the nonlinear joint transform correlator using decompression types of nonlinearity (K > 1) at the Fourier plane. We show that decompression transformations of the joint power spectrum result in correlation signals that are less sensitive to distortion. The decompression nonlinear joint transform correlator is tested using a kth law device for rotation types of distortion. Computer simulations of the nonlinear correlator are provided using an image of a tank and a binary character.

© 1989 Optical Society of America