Composite matched filters, and Circular harmonic composite filters in particular, are associated with high sidelobes that degrade the recognition and discrimination performance of the filters. It is proposed to reduce the sidelobes of Circular harmonic composite filters by using coefficients that minimize the energy in the correlation plane, while still taking into account the constraints imposed on the filter by discrimination requirements. Experiments show that the results are much improved when a three-component CHC filter is used.
Henri H. Arsenault,
"Optimum Sidelobe-Reducing Invariant Matched Filters For Pattern Recognition", Proc. SPIE 0963, Optical Computing '88, (8 February 1988); doi: 10.1117/12.947905; https://doi.org/10.1117/12.947905