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RESEARCH PRODUCT

Optical nonlinear correlation based on nonuniform subband decomposition

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description

We present a nonlinear correlation to improve the selectivity for optical pattern recognition. The approach is based on morphological correlation which involves a threshold decomposition concept. Hereby, we propose a subband decomposition in the Fourier domain to perform the threshold decomposition operation. We consider two frequency bands that give rise to two separate channels. We apply the morphological correlation to each channel using a localized threshold decomposition. Then, we define a two-channel morphological correlation. The final detection decision is made as a combination of both correlation outputs. The two-channel morphological correlation yields improved discrimination capability and noise robustness compared with common linear and morphological correlation. Computer simulations are presented as well as optical experiments performed using a joint transform correlator.