Cost-effective Optical Correlator for Security Applications

Pattern recognition systems using optical correlation are being developed. The optical correlator is a powerful tool since it simultaneously processes large data arrays. This capability reduces data handling and process control, makes the system less susceptable to obstruction and increases throughput. An optical correlator is also a phase sensitive detector. It can read an optical phase mask and determine if the mask contains a valid code. The phase code is not visible to the eye or ordinary visual sensors such as copiers, scanners or CCD cameras. Optical phase encryption adds another level of security since the patterns are difficult to copy. This proposal describes cost-reduction techniques for the part validation and security verification problem. A major expense in optical pattern recognition systems is the I/O devices such as spatial light modulators, preprocessors, post-processors, and fast-framing CCD arrays. By eliminating electronic processing of large input and output arrays, it is possible to greatly reduce the I/O costs.