Space integrating joint transform correlator using a moving grating

Abstract

A new one-step joint transform correlator (JTC) is presented, in which the joint transform of the images to be correlated is filtered by a moving Ronchi ruling. An alternative JTC architecture without moving parts using two Ronchi rulings is also suggested. A lens produces the spatial integral of the product of the joint transform image and the transmission factor of the Ronchi ruling, and a single element detector is used to capture the integral. The amplitude of the light modulation on the detector gives the cross-correlation function of the input images at coordinates (0,0) without major processing. Therefore, in principle this technique significantly reduces the time required to evaluate the cross-correlation function, compared to that for usual JTCs. Experimental validation of the proposed one-step architecture is presented.