Nonlinear distortion-invariant filter performance with false targets, noise, and clutter

We provide insight into the disadvantages of various non-linear distortion-invariant optical correlation filters. From this, guidelines for improved optical correlation filters emerge including: filters for intra-class recognition, filters for clutter rejection and the different types of clutter that arise, hierarchical inference filters, remarks of Fourier vs. image domain synthesis, filter space-bandwidth product (SBWP), techniques to reduce correlation plane energy and filter performance measures and issues.