The optimality of correlation filters is an important issue in applications of pattern recognition. We consider here both binary phase-only filters (BPOFs) and amplitude encoded binary phase-only filters (AE BPOFs) and study the results of optimizing the filters for a real world object (the Space Shuttle). We find that while only small improvements result from optimizing a BPOF, optimization of the AE BPOF is quite important in obtaining a useful correlation function. In the case of an AE BPOF, both signal-to-noise and peak-to-sidelobe measures must be studied. Computer simulation and experimental correlation results are presented.
John D. Downie and Max B. Reid, "Mapping considerations for optimal binary correlation filters," Appl. Opt. 29, 5235-5241 (1990)