Optical pattern recognition apparatus
First Claim
1. An optical pattern recognition apparatus for applying optical correlation processing using coherent light to a two-dimensional image so as to automatically recognize and measure a particular pattern, comprising:
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
means for Fourier transforming the joint coherent image to produce a joint Fourier transform image of each said reference image and each said input image;
means including a spatial light modulator of the light addressed type for converting the joint Fourier transform image into an intensity distribution image and recording the same on the spatial light modulator;
means for reading the image recorded in the spatial light modulator of the light addressed type by using coherent light;
means for Fourier transforming the read image into a correlation image;
means for converting the correlation image into correlation signals;
means for processing the correlation, signals to determine a correlation coefficient between each said reference image and each said input image; and
means including another spatial light modulator adjacent to a plane of each said reference image for changing the intensity of the coherent light passing through the plane of each said reference image before the joint coherent image is Fourier transformed again by the means for Fourier transforming the joint coherent image, the intensity of the coherent light being changed according to the determined correlation coefficient between each said reference image and each said input image to thereby effect correction of the correlation coefficient through feedback.
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Abstract
In a joint transform correlator utilizing a spatial optic modulator, depending on the light intensity of each correlation peak obtained from optical correlation processing between at least one reference image and at least one input image, the light intensity passing through each reference image corresponding to each correlation peak is substantially adjusted so as to constitute a feedback system. By such construction, when processing a relatively large number of input or reference images, the correlator can avoid failure of recognition due to the reduction of light intensity of the correlation peaks and can avoid erroneous recognition to enable fast pattern recognition.
42 Citations
27 Claims
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1. An optical pattern recognition apparatus for applying optical correlation processing using coherent light to a two-dimensional image so as to automatically recognize and measure a particular pattern, comprising:
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
means for Fourier transforming the joint coherent image to produce a joint Fourier transform image of each said reference image and each said input image;
means including a spatial light modulator of the light addressed type for converting the joint Fourier transform image into an intensity distribution image and recording the same on the spatial light modulator;
means for reading the image recorded in the spatial light modulator of the light addressed type by using coherent light;
means for Fourier transforming the read image into a correlation image;
means for converting the correlation image into correlation signals;
means for processing the correlation, signals to determine a correlation coefficient between each said reference image and each said input image; and
means including another spatial light modulator adjacent to a plane of each said reference image for changing the intensity of the coherent light passing through the plane of each said reference image before the joint coherent image is Fourier transformed again by the means for Fourier transforming the joint coherent image, the intensity of the coherent light being changed according to the determined correlation coefficient between each said reference image and each said input image to thereby effect correction of the correlation coefficient through feedback.
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
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2. An optical pattern recognition apparatus for applying optical correlation processing using coherent light to a two-dimensional image so as to automatically recognize and measure a particular pattern, comprising:
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
means for Fourier transforming the joint coherent image to produce a joint Fourier transform image of each said reference image and each said input image;
means for converting the joint Fourier transform image into an intensity distribution signal;
means including a spatial light modulator of the electrically addressed type receptive of the intensity distribution signal for recording an intensity distribution image corresponding to the intensity distribution signal;
means for reading the image recorded in the spatial light modulator of the electrically addressed type by using coherent light;
means for Fourier transforming the read image into a correlation image;
means for converting the correlation image into correlation signals;
means for processing the correlation signals to determine a correlation coefficient between each said reference image and each said input image; and
means including another spatial light modulator adjacent to a plane of each said reference image for changing an intensity of the coherent light passing through the plane of each said reference image before the joint coherent image is Fourier transformed again by the means for Fourier transforming the joint coherent image, the intensity of the coherent light being changed according to the determined correlation coefficient between each said reference image and each said input image to thereby effect correction of the correlation coefficient through feedback.
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
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3. An optical pattern recognition apparatus for applying optical correlation processing using coherent light to a two-dimensional image so as to automatically recognize and measure a particular pattern, comprising:
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
means for Fourier transforming the joint coherent image to produce a joint Fourier transform image of each said reference image and each said input image;
means including a binary spatial light modulator for converting the joint Fourier transform image into a binarized intensity distribution image and for recording the binarized intensity distribution image on the binary spatial light modulator;
means for reading the binarized intensity distribution image on the spatial light modulator by using coherent light;
means for further Fourier transforming the read binarized intensity distribution image into a correlation image;
means for converting the correlation image into correlation signals;
means for processing the correlation signals to determine a correlation coefficient between at least one said reference image and at least one said input image; and
means including another spatial light modulator adjacent to a plane of each said reference image for changing an intensity of the coherent light passing through the plane of each said reference image before the joint coherent image is Fourier transformed again by the means for Fourier transforming the joint coherent image, the intensity of the coherent light being changed according to the determined correlation coefficient between each said reference image and each said input image to thereby effect correction of the correlation coefficient through feedback. - View Dependent Claims (4, 5, 14)
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
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6. An optical pattern recognition apparatus for applying optical correlation processing using coherent light to two-dimensional image so as to automatically recognize and measure a particular pattern, comprising:
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
means for Fourier transforming the joint coherent image to produce a joint Fourier transform image of each said reference image and each said input image;
means including a spatial light modulator for converting the joint Fourier transform image into an intensity distribution image and recording the same on the spatial light modulator;
means for reading the intensity distribution image recorded on the spatial light modulator by using coherent light;
means for Fourier transforming the read intensity distribution image into a correlation image;
means for converting the correlation image into correlation signals;
means for processing the correlation signals to determine a correlation coefficient between each said reference image and each said input image; and
means including a masking device adjacent to a plane of each said reference image for changing the intensity of the coherent light passing through the plane of each said reference image before the joint coherent image is Fourier transformed again by the means for Fourier transforming the joint coherent image, the intensity of the coherent light being changed according to one of (1) a segment ratio of each said reference image and each said input image, and (2) an incident light intensity component through each said reference image, so as to normalize a Fourier transform intensity for each said reference image. - View Dependent Claims (7, 8, 9, 10, 11, 12, 15, 17)
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
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13. An optical pattern recognition apparatus for applying optical correlation processing using coherent light to a two-dimensional image so as to automatically recognize and measure a particular pattern, comprising:
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
means for Fourier transforming the joint coherent image to produce a joint Fourier transform image of each said reference image and each said input image;
means including a spatial light modulator for converting the joint Fourier transform image into an intensity distribution image and for recording the intensity distribution image on the spatial light modulator;
means for reading the intensity distribution image recorded on the spatial light modulator by using coherent light;
means for Fourier transforming the read intensity distribution image into a correlation image;
means for converting the correlation image into correlation signals;
means for processing the correlation signals to determine a correlation coefficient between each said reference image and each said input image; and
means including a masking spatial light modulator adjacent to a plane of each said reference image for changing an intensity of the coherent light passing through the plane of each said reference image before the joint coherent image is Fourier transformed again by the means for Fourier transforming the joint coherent image, the intensity of the coherent light being changed in a nonlinear relation to the determined correlation coefficient between each said reference image and each said input image to thereby effect correction of the correlation coefficient through feedback. - View Dependent Claims (16)
- means for converting at least three images comprised of at least one reference image and at least one input image into a joint coherent image;
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18. An apparatus for optical pattern recognition by iterative processing, comprising:
- first converting means for converting at least three images comprised of at least one reference image and at least one input image into a joint image;
first transforming means for Fourier transforming the joint image into a Fourier transform image;
recording means for perceiving and recording the Fourier transform image as an intensity distribution image;
reading means for reading the intensity distribution image from the recording means and Fourier transforming the read image into a correlation image;
computing means receptive of the correlation image for determining a correlation coefficient for each said reference image correlated with each said input image and producing a correlation signal in response thereto;
feed-back means operable with each iteration for changing the light intensity of each said reference image before the joint image is Fourier transformed again by the first transforming means, the light intensity being changed in response to the correlation signal so as to correspondingly alter the perception of each said reference image by said recording means to thereby effect optical pattern recognition to each said input image by repetitively reducing with each iteration the perception of each said reference image that does not have the highest corresponding correlation coefficient. - View Dependent Claims (19, 20, 21, 26, 27)
- first converting means for converting at least three images comprised of at least one reference image and at least one input image into a joint image;
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22. An apparatus for optical pattern recognition according to claim 22;
- wherein said computing means includes normalizing means for determining a normalized value for each respective said correlation coefficient based on the size of each said reference image, and said computing means produces the correlation signal in response to the normalized value and the correlation coefficient corresponding to each said reference image.
- View Dependent Claims (23, 24, 25)
Specification