Rotation-invariant phase-shifting joint transform correlator by use of circular harmonic expansion

The performance merits of the phase-shifting joint transform correlator (PS JTC) are evaluated based on the criteria of light efficiency and discrimina tion capability. The PSJTC is shown to possess much higher light efficiency (three orders of magnitude) and much better discrimination capability (thr ee times with the selected images) than does the conventional joint transfo rm correlator (JTC). The PSJTC is combined with the circular harmonic expan sion to achieve a full rotation-invariant correlation with high light effic iency and high discrimination capability. Computer simulation results and 3 -D computer plots are presented. (C) 2000 Society of Photo-Optical Instrume ntation Engineers. [S0091-3286(00)01508-7].