E. Perez et al., DUAL NONLINEAR CORRELATOR BASED ON COMPUTER-CONTROLLED JOINT TRANSFORM PROCESSOR - DIGITAL ANALYSIS AND OPTICAL RESULTS, J. mod. opt., 44(8), 1997, pp. 1535-1552
The hybrid optoelectronic processor, presented in this paper, realizes
the dual nonlinear correlation (DNC) in a set-up based on a two-step
nonlinear joint transform correlator architecture. In the first step t
hree power spectrum distributions (input scene power spectrum, referen
ce target power spectrum, and the joint power spectrum) necessary for
the nonlinear processing are captured with a CCD camera. Nonlinear mod
ification of the joint power spectrum, which does not have to be symme
trical in the input and reference channels, is introduced digitally. I
n the second step, the modified joint power spectrum is Fourier transf
ormed optically. Numerical analysis of this processor shows a crucial
influence of the dynamic range and the limited number of grey levels o
f the CCD camera during image acquisition in the first step, on the ou
tput signal parameters and the discrimination capability of the set-up
. Optical results of recognition obtained for noise-free segmented inp
ut scenes show that the set-up enables the realization of various corr
elation operations as CR-IF, POF, IF, PPC, etc. without any filters an
d that the discrimination capability is easy to control by a proper se
lection of the type of nonlinear processing.