Optical correlators with (-k)th-law nonlinearity: optimal and suboptimal solutions.
A computer simulation of nonlinear correlators with (-k)th-law nonlinearity has been implemented. The nonlinearity is applied to the input-image power spectrum, with either a matched filter or a phase-only filter representing the reference object. Optimal correlators (with an exactly known power spectrum of the background-image component) and suboptimal correlators have been studied in order to establish potential limits and achievable figures for the correlator's discrimination capability in a target location in a cluttered background. For the suboptimal correlators, different values of the nonlinearity index k have been investigated for two methods of the image's power-spectrum estimation and for different degrees on the limitation of the nonlinearity's dynamic range. The results show that the nonlinear correlators promise significant improvement in the correlator's discrimination capability and provide important information for evaluating the practical aspects of the correlator's design.
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Yaroslavsky