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The Alabama A & M University Department of Physics Optics and Information Processing

Computer Simulation of the Properties of Binary Phase Only Filters Used in Optical Correlator Systems

M. P. Schamschula

Master's Thesis, San Diego State University (1987)

Abstract

Theoretical studies of the properties of binary phase only filters (BPOF) are presented. We consider the framework for simulating the characteristics of both classical matched spatial filters (MSF) and BPOFs by computer. The optical counterparts to these filters can be implemented in optical correlator systems. The Fourier transform property of lenses, in conjunction with the discrete Fourier transform (DFT) is used to simulate the operation os spatial light modulators (SLMs). The properties of DFTs as well as the computation of the required DFTs by a two dimensional fast Fourier transform (FFT) is introduced. The effect of binarization on the filter is illustrated and compared to the non-binarized MSF. The changes in amplitude of the correlation peak due to rotational misalignment or change of scale are examined. A form of apodization tailored to BPOFs is suggested to decrease the sensitivity to these changes. Finally we explorethe multiplexing capabilities of the BPOF, that is generating a single filter capable of identyfying multiple objects. Multiplexing may also be used to overcome the high sensitivity to rotational and scale changes.