Rotational-Invariant Pattern Recognition Using Circular Harmonic and Optical Wavelet Transform

Abstract

An improved shift- and rotational-invariant filter using wavelet transform and circular harmonic filtering at the same time is proposed. Computer simulation has shown that this is better than using a phase-only circular harmonic filter in peak sharpness, discriminating ability, SNR and tolerance of position error of the filter. Furthermore, this filter possesses moderate diffraction efficiency.