Character recognition method
First Claim
1. A method for recognizing a handwritten input character by comparing said handwritten input character with a plurality of templates corresponding to a plurality of various types of characters based on time series information of points characterizing each stroke of said handwritten input character formed from at least one stroke, said handwritten character recognition method comprising the steps of:
- expressing time series information of said points characterizing each stroke as coordinate points in a coordinate system;
calculating, with regard to a plurality of coordinate points within said coordinate system corresponding to a plurality of points characterizing a stroke of said handwritten input character, the relative angles formed by two straight lines formed by means of connecting a coordinate point, used as a reference, characterizing one stroke to two neighboring coordinate points from either a plurality of other coordinate points characterizing the same stroke as this reference coordinate point or a plurality of coordinate points characterizing another stroke, with regard to two neighboring coordinates of all of either of a plurality of other coordinate points characterizing the same said stroke or a plurality of coordinate points characterizing another stroke;
respectively calculating an angle the same as said relative angle using each coordinate point as a reference, with regard to all other coordinate points characterizing the same said stroke as said reference coordinate point of said handwritten input character or all of a plurality of coordinate points characterizing another stroke;
expressing a shape of said handwritten input character by means of a matrix consisting of elements comprising a quantity relating to each of said relative angles calculated with regard to said handwritten input character;
calculating, with regard to a plurality of coordinate points within said coordinate system corresponding to a plurality of points characterizing a stroke of each template, the relative angles formed by two straight lines formed by means of connecting a coordinate point, used as a reference, characterizing one stroke to each of two neighboring coordinate points of either other coordinate points characterizing the same stroke as this reference coordinate point or a plurality of coordinate points characterizing another stroke, with regard to all pairs of neighboring coordinate points of either a plurality of other coordinate points characterizing the same said stroke or a plurality of coordinate points characterizing another stroke;
respectively calculating an angle the same as said relative angle using each coordinate point as a reference with regard to all other coordinate points characterizing the same said stroke as said reference coordinate point of said template or all of a plurality of coordinate points characterizing another stroke;
expressing a shape of each of said templates by means of a matrix consisting of elements comprising a quantity relating to each of said relative angles calculated with regard to said template;
calculating a distance between said handwritten input character and each of said plurality of templates using said matrix expressing a shape for said handwritten input character, and said matrix expressing a shape for each template; and
designating a character corresponding to a template selected based on said distance as a recognition result of said handwritten input character.
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Accused Products
Abstract
The present invention provides a handwritten character recognition method in which neighboring points are connected by straight lines and the segments in-between points are then interpolated using broken lines. Each broken line is equally divided into k segments, and a number is assigned to each division point therein according to the time sequence of the respective point. A (k+1)N×N (N is the number of strokes) matrix P consisting of the elements of row (k+1)(n-1)+1 and column k(m-1)+j comprising angle Ω formed by the straight line connecting division point i of stroke n and division point j of stroke m and the straight line connecting division point i of stroke n and division point j+1 of stroke m, is then calculated. The distance di between handwritten character Cx and matrix Qi (i=1-M) formed in the same manner from M templates corresponding to characters possessing the same number of strokes as character Cx, is calculated as the sum of the squares of each element of matrix P-Qi. The character Cz corresponding to the template Qz with the smallest distance dz is then selected as the recognition result.
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Citations
19 Claims
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1. A method for recognizing a handwritten input character by comparing said handwritten input character with a plurality of templates corresponding to a plurality of various types of characters based on time series information of points characterizing each stroke of said handwritten input character formed from at least one stroke, said handwritten character recognition method comprising the steps of:
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expressing time series information of said points characterizing each stroke as coordinate points in a coordinate system; calculating, with regard to a plurality of coordinate points within said coordinate system corresponding to a plurality of points characterizing a stroke of said handwritten input character, the relative angles formed by two straight lines formed by means of connecting a coordinate point, used as a reference, characterizing one stroke to two neighboring coordinate points from either a plurality of other coordinate points characterizing the same stroke as this reference coordinate point or a plurality of coordinate points characterizing another stroke, with regard to two neighboring coordinates of all of either of a plurality of other coordinate points characterizing the same said stroke or a plurality of coordinate points characterizing another stroke; respectively calculating an angle the same as said relative angle using each coordinate point as a reference, with regard to all other coordinate points characterizing the same said stroke as said reference coordinate point of said handwritten input character or all of a plurality of coordinate points characterizing another stroke; expressing a shape of said handwritten input character by means of a matrix consisting of elements comprising a quantity relating to each of said relative angles calculated with regard to said handwritten input character; calculating, with regard to a plurality of coordinate points within said coordinate system corresponding to a plurality of points characterizing a stroke of each template, the relative angles formed by two straight lines formed by means of connecting a coordinate point, used as a reference, characterizing one stroke to each of two neighboring coordinate points of either other coordinate points characterizing the same stroke as this reference coordinate point or a plurality of coordinate points characterizing another stroke, with regard to all pairs of neighboring coordinate points of either a plurality of other coordinate points characterizing the same said stroke or a plurality of coordinate points characterizing another stroke; respectively calculating an angle the same as said relative angle using each coordinate point as a reference with regard to all other coordinate points characterizing the same said stroke as said reference coordinate point of said template or all of a plurality of coordinate points characterizing another stroke; expressing a shape of each of said templates by means of a matrix consisting of elements comprising a quantity relating to each of said relative angles calculated with regard to said template; calculating a distance between said handwritten input character and each of said plurality of templates using said matrix expressing a shape for said handwritten input character, and said matrix expressing a shape for each template; and designating a character corresponding to a template selected based on said distance as a recognition result of said handwritten input character. - View Dependent Claims (2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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3. A method for recognizing a handwritten input character by comparing said handwritten input character with a plurality of templates corresponding to a plurality of various types of characters based on time series information of points characterizing each stroke of said handwritten input character formed from at least one stroke, said handwritten character recognition method comprising the steps of:
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expressing time series information of a pen movement, which is a horizontal direction component and a vertical direction component of an acceleration vector of said pen movement occurring at each time during pen movement when inputting a handwritten character, as coordinate points in an acceleration coordinate system in which the coordinate values of a horizontal axis and a vertical axis are a horizontal direction component and a vertical direction component of a pen movement acceleration vector; calculating, with regard to a plurality of coordinate points within said coordinate system corresponding to a plurality of points characterizing a stroke of said handwritten input character, the relative angles formed by two straight lines formed by means of connecting a coordinate point, used as a reference, characterizing one stroke to two neighboring coordinate points from either a plurality of other coordinate points characterizing the same stroke as this reference coordinate point or a plurality of coordinate points characterizing another stroke, with regard to two neighboring coordinates of all of either of a plurality of other coordinate points characterizing the same said stroke or a plurality of coordinate points characterizing another stroke; respectively calculating an angle the same as said relative angle using each coordinate point as a reference, with regard to all other coordinate points characterizing the same said stroke as said reference coordinate point of said handwritten input character or all of a plurality of coordinate points characterizing another stroke; expressing a shape of said handwritten input character by means of a matrix consisting of elements comprising a quantity relating to each of said relative angles calculated with regard to said handwritten input character; calculating, with regard to a plurality of coordinate points within said coordinate system corresponding to a plurality of points characterizing a stroke of each template, the relative angles formed by two straight lines formed by means of connecting a coordinate point, used as a reference, characterizing one stroke to each of two neighboring coordinate points of either other coordinate points characterizing the same stroke as this reference coordinate point or a plurality of coordinate points characterizing another stroke, with regard to all pairs of neighboring coordinate points of either a plurality of other coordinate points characterizing the same said stroke or a plurality of coordinate points characterizing another stroke; respectively calculating an angle the same as said relative angle using each coordinate point as a reference with regard to all other coordinate points characterizing the same said stroke as said reference coordinate point of said template or all of a plurality of coordinate points characterizing another stroke; expressing a shape of each of said templates by means of a matrix consisting of elements comprising a quantity relating to each of said relative angles calculated with regard to said template; calculating a distance between said handwritten input character and each of said plurality of templates using said matrix expressing a shape for said handwritten input character, and said matrix expressing a shape for each template; and designating a character corresponding to a template selected based on said distance as a recognition result of said handwritten input character. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification