Abstract

Ternary phase-amplitude filters (TPAFs) are a discrete-valued correlation filters which may be viewed as an extension of binary phase-only filters (BPOFs) by adding a zero-modulation state. Modulation values of −1, 0, and 1 are encoded. The TPAF also has the potential for relatively simple real-time implementation but with much improved performance enabled by the additional modulation state, which allows blocking of some spatial frequencies. This paper reports simulation results demonstrating the design of TPAFs incorporating both in-class distortion invariance and out-of-class discrimination and compares the results with those obtained using other filter formulations.

© 1988 Optical Society of America