Phase-shifting technique applied to circular harmonic-based joint transform correlator

The phase-shifting technique is applied to the circular harmonic expansion- based joint transform correlator, Computer simulation has shown that the li ght efficiency and the discrimination capability are greatly enhanced, and the full rotation invariance is preserved after the phase-shifting techniqu e has been used. A rotation-invariant optical pattern recognition with high discrimination capability and high light efficiency is obtained. The influ ence of the additive noise on the performance of the correlator is also inv estigated. However, the anti-noise capability of this kind of correlator st ill needs improving.