Distortion invariant color image recognition by the joint transform correlator with a real-valued reference function

A technique for distortion invariant color pattern recognition is proposed. We arrange the RGB channels of both the reference and the target image in a particular way. Moreover, a joint transform power-spectrum (JTPS) subtraction method is applied to remove the zero-order part. The reference images will be synthesized with real valued templates, which are more suitable for optical implementation. Computer simulation results are presented in which the correlation peak is quite sharp at the output plane.