COMPACT OPTICAL CORRELATOR - PREPROCESSING AND FILTER ENCODING STRATEGIES APPLIED TO IMAGES WITH VARYING ILLUMINATION

We present a portable, versatile optical pattern recognition system th at can process 256x256 pixel images at high speed. The system is fully controlled by Windows-based software and can easily be switched betwe en VanderLugt and joint transform operation. It combines the advantage s of optics and electronics to form an advanced hybrid system where pr e-and postprocessing algorithms can be varied depending on the applica tion. Simulation and experimental results show that edge enhancement c ombined with binarization gives good results when applied to images wh ere the illumination is varying. (C) 1998 Society of Photo-Optical Ins trumentation Engineers.