We introduce a modification of the nonlinear morphological correlation for optical rotation-invariant pattern recognition. The high selectivity of the morphological correlation is conserved compared with standard linear correlation. The operation performs the common morphological correlation by extraction of the information by means of a circular-harmonic component of a reference. In spite of some loss of information good discrimination is obtained, especially for detecting images with a high degree of resemblance. Computer simulations are presented, as well as optical experiments implemented with a joint transform correlator.
© 2000 Optical Society of America
(070.4340) Fourier optics and signal processing : Nonlinear optical signal processing
(070.5010) Fourier optics and signal processing : Pattern recognition
(100.4550) Image processing : Correlators
Pascuala Garcia-Martinez, Carlos Ferreira, Javier Garcia, and Henri H. Arsenault, "Nonlinear Rotation-Invariant Pattern Recognition by Use of the Optical Morphological Correlation," Appl. Opt. 39, 776-781 (2000)