Optical pattern recognition system method of ferroelectric liquid crystal spatial light modulator
First Claim
1. An optical pattern recognition system which automatically recognizes or measures a specified pattern from two-dimensional images, the optical pattern recognition system comprising:
- image display means for displaying at least one reference image including at least one target and at least one input image to be entered;
first means, 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;
second means having a Fourier transform lens for performing an optical Fourier transform on the coherent image to produce a joint Fourier-transformed image of the reference image and the input image;
an optically addressed type ferroelectric liquid crystal spatial light modulator having no light reflection layer;
third means for converting the joint Fourier-transformed image into an intensity distribution image and displaying the intensity distribution image on the optically addressed type ferroelectric liquid crystal spatial light modulator;
fourth means, including a laser diode having an oscillation wavelength longer than 660 nm, for reading the intensity distribution image displayed on the optically addressed type ferroelectric liquid crystal spatial light modulator by using the coherent light;
fifth means having a Fourier transform lens for Fourier-transforming the intensity distribution image read out to produce a two-dimensional correlation image distribution of the reference image and the input image, the second and the fifth means sharing the same Fourier transform lens; and
a light-electricity conversion element for detecting the correlation peak intensity of the reference image and the input image contained in the correlation image distribution.
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Abstract
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.
39 Citations
12 Claims
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1. An optical pattern recognition system which automatically recognizes or measures a specified pattern from two-dimensional images, the optical pattern recognition system comprising:
- image display means for displaying at least one reference image including at least one target and at least one input image to be entered;
first means, 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;
second means having a Fourier transform lens for performing an optical Fourier transform on the coherent image to produce a joint Fourier-transformed image of the reference image and the input image;
an optically addressed type ferroelectric liquid crystal spatial light modulator having no light reflection layer;
third means for converting the joint Fourier-transformed image into an intensity distribution image and displaying the intensity distribution image on the optically addressed type ferroelectric liquid crystal spatial light modulator;
fourth means, including a laser diode having an oscillation wavelength longer than 660 nm, for reading the intensity distribution image displayed on the optically addressed type ferroelectric liquid crystal spatial light modulator by using the coherent light;
fifth means having a Fourier transform lens for Fourier-transforming the intensity distribution image read out to produce a two-dimensional correlation image distribution of the reference image and the input image, the second and the fifth means sharing the same Fourier transform lens; and
a light-electricity conversion element for detecting the correlation peak intensity of the reference image and the input image contained in the correlation image distribution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- image display means for displaying at least one reference image including at least one target and at least one input image to be entered;
Specification