Experimental implementation of a joint transform correlator using synthetic discriminant functions

Abstract

A joint transform correlator (JTC) was implemented in the Optical Science Department at CERT. In order to ensure a rotational invariance, the reference image is replaced by a synthetic discriminant function (SDF) image displayed on an amplitude spatial light modulator (SLM). Numerical simulations are performed and then compared to experiments. We show that the pseudo-inverse SDP (PI-SDF) gives accurate experimental results. The training ability of the PI-SDF allows it to recognize the reference object unambiguously, even if the input view does not explicitly belong to the training set. Then, we propose to replace our amplitude device with a ternary phase and amplitude device, in order to display positive and negative images: this allows us to display any kind of SDF filters, e.g. OT-SDF or MINACE-SDF, which reduce the side lobes, with a good resistance to noise.