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US 6,665,441 B1Granted
Pattern matching method and apparatus
AssigneeKeyence Corporation
InventorYoshiaki Nishio
Life of this patent
Estimating the term…
Abstract
A pattern recognition matching processing method and apparatus uses expansion processing with dictionary data as a matching candidate (pattern image). Contraction processing may be performed for the pattern image, and a differential image between the expanded and contracted images can be found. A mask image is prepared based on the differential image, and matching processing of the image containing a character to be recognized with the pattern image is performed with respect to pixels in an area other than the prepared mask image.
Claims16
A pattern matching method comprising the steps of:
- performing expansion processing for a preset pattern image used as a matching candidate so as to prepare a first pattern image;
- performing contraction processing for the preset pattern image so as to prepare a second pattern image;
- finding a differential image between the first and second pattern images;
- preparing a mask image based on the differential image;
- performing matching processing of an image containing a character to be recognized with respect to pixels in an area other than those pixels in the prepared mask image;
- and
- performing at least one step of determining an expansion processing ratio for said expansion processing based on a line width of the character to be recognized and determining a contraction processing ratio for said contraction processing based on a line width of the character to be recognized.
4 more elements
A pattern matching apparatus comprising:
- first pattern image preparation means for performing expansion processing for a preset pattern image used as a matching candidate so as to prepare a first pattern image;
- second pattern image preparation means for performing contraction processing for the preset pattern image so as to prepare a second pattern image;
- differential image preparation means for preparing a differential image between the first and second pattern images;
- mask image preparation means for preparing a mask image based on the differential image prepared by said differential image preparation means;
- matching processing means for performing matching processing of an image containing a character to be recognized with respect to pixels in an area other than those pixels in the mask image prepared by the mask image preparation means;
- and
- at least one of a means for determining an expansion processing ratio for said expansion processing based on a line width of the character to be recognized and a means for determining a contraction processing ratio for said contraction processing based on a line width of the character to be recognized.
4 more elements
A pattern matching method comprising the steps of:
- performing expansion processing for a preset pattern image used as a matching candidate so as to prepare a first pattern image;
- using the preset pattern image as a second pattern image;
- finding a differential image between the first and second pattern images;
- preparing a mask image based on the differential image;
- performing matching processing of an image containing a character to be recognized with respect to pixels in an area other than those pixels in the prepared mask image;
- and
- the step of determining an expansion processing ratio for said expansion processing based on a line width of the character to be recognized.
4 more elements
A pattern matching apparatus comprising:
- first pattern image preparation means for performing expansion processing for a preset pattern image used as a matching candidate so as to prepare a first pattern image;
- second pattern image preparation means using the preset pattern image as the second pattern image;
- differential image preparation means for preparing a differential image between the first and second pattern images;
- mask image preparation means for preparing a mask image based on the differential image prepared by said differential image preparation means;
- matching processing means for performing matching processing of an image containing a character to be recognized with respect to pixels in an area other than those pixels in the mask image prepared by the mask image preparation means;
- and
- means for determining an expansion processing ratio for said expansion processing based on a line width of the character to be recognized.
4 more elements
Dependencies are inferred from the claim text.