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.