NONLINEAR FILTERING IN OBJECT AND FOURIER SPACE IN A JOINT TRANSFORM OPTICAL CORRELATOR - COMPARISON AND EXPERIMENTAL REALIZATION

The use of different kinds of nonlinear filtering in a joint transform correlator are studied and compared. The study is divided into two pa rts, one corresponding to object space and the second to the Fourier d omain of the joint power spectrum. In the first part, phase and invers e filters are computed; their inverse Fourier transforms are also comp uted, thereby becoming the reference in the object space. In the Fouri er space, the binarization of the power spectrum is realized and compa red with a new procedure for removing the spatial envelope. Ail cases are simulated and experimentally implemented by a compact joint transf orm correlator.