An high-speed, high-resolution optical pattern recognition system which automatically recognizes or measures a specified pattern from two-dimensional images comprises an image display device for displaying at least one reference image including at least one target and at least one input image, a device including a laser diode having an oscillation wavelength less than 900 nm for converting the at least one reference image and the at least one input image into a coherent image, a Fourier transform lens for optically Fourier transforming the coherent image to produce a joint Fourier-transformed image, an optically addressed ferroelectric liquid crystal spatial light modulator having no light reflection layer, a device for converting the joint Fourier-transformed image into an intensity distribution image and displaying the intensity distribution image on the optically addressed spatial light modulator, and a device including a laser diode having an oscillation wavelength longer than 660 nm for reading the intensity distribution image displayed on the optically addressed spatial light modulator. The Fourier transform lens also Fourier transforms the intensity distribution image to produce a two-dimensional correlation image distribution of the reference image and the input image and a detector detects the correlation peak intensity of the reference image and the input image contained in the correlation image distribution and outputs a corresponding electrical signal.
Optical pattern recognition system method of ferroelectric liquid crystal spatial light modulator