Multiple image detection by nonlinear joint-transform correlator

Abstract

It has been shown that the nonlinear joint transform correlator (JTC) produces good correlation performance compared with the linear correlator.1,2 The nonlinear JTC uses nonlinearity at the Fourier plane to non- Iinearly transform the joint power spectrum. In this paper, we provide an investigation of the nonlinear optical processor when multiple objects are present at the input plane. Experiments are used to determine the correlation peak intensity and peak to sidelobe ratio for various types of multiple targets and images present at the input plane. The experiments are performed in the presence of the input scene noise for multiple identical targets and multiple objects. Various types of thresholding the joint power spectrum and its effect on the performance of the system is investigated. The effects of the space- bandwidth product (SBWP) of the input plane such as the input spatial light modulator SBWP on the position requirements of the input signal and the reference signals is investigated. The system performance for different positions of the input targets is examined. The correlation performance of the nonlinear JTC for multiple target detection is compared with the linear JTC. The experiments indicate that compared with the linear JTC, the nonlinear JTC produces reasonably good correlation performance when multiple objects are present at the input plane.