Handwritten word recognition based on geometric decomposition
First Claim
1. A method of recognizing a handwritten word of cursive script, said method comprising:
- providing a template of previously classified words;
optically reading a handwritten word so as to form an image representation thereof comprising a bit map of pixels;
extracting an external pixel contour of said bit map;
detecting vertical peak and minima pixel extrema on upper and lower zones of said external contour respectively;
determining respective feature vectors of said vertical peak and minima pixel extrema and comparing said feature vectors with said template so as to generate a match between said handwritten word and a said previously classified word.
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Abstract
A method of recognizing a handwritten word of cursive script comprising providing a template of previously classified words, and optically reading a handwritten word so as to form an image representation thereof comprising a bit map of pixels. The external pixel contour of the bit map is extracted and the vertical peak and minima pixel extrema on upper and lower zones respectively of this external contour are detected. Feature vectors of the vertical peak and minima pixel extrema are determined and compared to the template so as to generate a match between the handwritten word and a previously classified word. A method for classifying an image representation of a handwritten word of cursive script is also provided. Also provided is an apparatus for recognizing a handwritten word of cursive script. This apparatus comprises a template of previously classified words, a reader for optically reading a handwritten word, and a controller being linked thereto for generating a match between the handwritten word and the previously classified words. Two algorithms are provided for respectively correcting the skew and slant of a word image.
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Citations
59 Claims
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1. A method of recognizing a handwritten word of cursive script, said method comprising:
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providing a template of previously classified words;
optically reading a handwritten word so as to form an image representation thereof comprising a bit map of pixels;
extracting an external pixel contour of said bit map;
detecting vertical peak and minima pixel extrema on upper and lower zones of said external contour respectively;
determining respective feature vectors of said vertical peak and minima pixel extrema and comparing said feature vectors with said template so as to generate a match between said handwritten word and a said previously classified word. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method for classifying an image representation of a handwritten word of cursive script, said method comprising:
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optically reading a handwritten word so as to form an image representation thereof comprising a bit map of pixels;
extracting a pixel contour of said bit map;
detecting vertical peak and minima pixel extrema on upper and lower zones of said contour respectively;
organizing said peak and minima pixel extrema into respective independent peak and minima sequences, determining the respective feature vectors of said peak and minima sequences; and
classifying said word image according to said peak and minima feature vectors. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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44. An apparatus for recognizing a handwritten word of cursive script, said apparatus comprising
a template of words having been previously classified according to feature vectors, a reader for optically reading a handwritten word, and a controller being linked to said template and said reader; wherein said controller;
forms an image representation of said handwritten word comprising a bit map of pixels;
extracts a pixel contour of said bit map;
detects vertical peak and minima pixel extrema on upper and lower zones of said contour respectively;
determines respective feature vectors of said peak and minima sequences; and
compares said feature vectors with said template so as to generate a match between said handwritten word and a said previously classified word.- View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. A method for correcting a slant of an image representation of a handwritten word of cursive script comprising a bit map of pixels, said method comprising:
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pre-computing a look-up table of the image representation that maps Cartesian coordinates to polar coordinates;
performing a Radon transform in the polar domain of the image representation; and
calculating a slant angle from the Radon transform in the polar domain. - View Dependent Claims (57)
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58. A method for correcting the skew of an image representation of a handwritten word comprising a bit map of pixels, said method comprising:
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pre-computing a look-up table of the image representation that maps Cartesian coordinates to polar coordinates;
prerforming a Radon transform in the polar domain of the image representation calculating a skew angle from the Radon transform. - View Dependent Claims (59)
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Specification