Adaptive real-time pattern recognition using a liquid crystal TV based joint transform correlator

Abstract

Since the early works on diffraction of chafJ there has been no mathematical modelization available for a real physical solution. This work presents one and gives a rigorous exploitation of the polarization behavior. One can find here a general model which can take into account all the phenomena appearing in a cloud of dipoles: the polarimetric effects, the mask, and the coupling influences. This development is new and can be generalized for clouds of spheres, discs, cylinders, or other simple shapes [ l , 21. 0 199. T John

Experimental demonstration of a binary single-lens joint transform correlator using chirp-modulated inputs

“…The SLJTC uses this lens encoded in the chirp-modulated joint power spectrum to form the correlation peak. ͑This differs from earlier single-lens systems, 6,7 which use one lens to compute both Fourier transforms.͒ Like the chirpmodulated BJTC, the SLJTC correlation output is a single peak rather than the two peaks in the JTC. The SLJTC autocorrelation peak is more diffuse than the autocorrelation peak in the chirp-encoded BJTC, resulting in better peak-to-noise ratio ͑PNR͒ performance when the correlation peak is near the optical axis.…”

Correlation postprocessing-based method for the detection of defocused images

“…4 Since 1966 several improvements in this architecture have been proposed to obtain real-time detection with liquid-crystal devices. 5,6 During the past few years most authors of papers published in the pattern-recognition field have analyzed different systems to increase discrimination capability. In particular, the binarization of the joint power spectrum ͑JPS͒ has been used widely and has been shown to be a reliable method.…”

Controlled-intensity detection peaks in a binary joint transform correlator

“…This can be obtained optically by registration of I HR (U, V) 12 and then by computation of [HR(u, v)2]-1/2.…”