engleski

Optimization in mapping of correlation filters in a liquid crystal display based frequency plane correlator

An optimization procedure for the optical implementation of correlation filters (CFs) in an optical-hybrid frequency plane correlator is presented. Our approach is based on mapping of the given calculated CF values to the values constrained by the available spatial light modulator (SLM) device to achieve the maximum intensity of the output correlation peak. The optimization is provided for the implementation of the CFs using a Sanyo liquid crystal display (SLCD). The commercially available SLCDs are characterized by the phase modulation curves that are (1) nonlinear, (2) of a smaller total phase change interval than desired (0,2PI) interval, and (3) significantly disturbed by the coupled amplitude variations. For such a case, the optimization achieved by varying a phase shift parameter is explained theoretically, demonstrated numerically, and confirmed experimentally.

liquid crystal display; spatial light modulators; phase-only filters; optical pattern recognition

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