TECHNIQUE FOR REDUCING THE REDUNDANT AND SELF-CORRELATION TERMS IN JOINT TRANSFORM CORRELATORS

We describe a joint transform correlator in which the reference signal and the input scene are placed in different input planes along the optical axis. We show that this system focuses the off-axis cross-correlation functions and the on-axis autocorrelation functions in different output planes. In a conventional joint transform correlator these terms are produced in the same output plane. The effect of placing the input scene and the reference signal in different input planes is analyzed mathematically. Computer simulations and experimental results are presented to illustrate the performance of this correlator. We show that for the nonlinear joint transform correlator the higher-order correlation terms are produced in different output planes.