On-line recognition method and apparatus for a handwritten pattern
First Claim
1. An on-line recognition method for a handwritten pattern comprising the steps of:
- sampling successively coordinate information of strokes of a handwritten pattern;
segmentalizing the coordinate information of one stroke into line segments consisting of at least either of straight line segments and curved line seg- ments;
quantizing the line segments so that the direction of each line segment is classified by one of predetermined angles;
normalizing an input pattern constituted by the quantized line segments to determine presence and absence of connections between the line segments;
rearranging the order of the quantized line segments in accordance with a predetermined connection sequence, on the basis of the determination result of the preceeding step;
reading out a dictionary pattern already stored in a memory; and
calculating degree of difference between the input pattern and the readout dictionary pattern by comparing the both on the basis of the quantized angles and the rearranged order of the quantized line segments, to thereby recognize the input pattern.
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Abstract
Coordinates of a handwritten pattern drawn on a tablet are sequentially sampled by a pattern recognition unit to prepare pattern coordinate data. Based on an area encircled by segments created by the sampled pattern coordinate data of one stroke and a line connecting a start point and an end point of the one-stroke coordinate data, the sampled pattern coordinate data of the one stroke is converted to a straight line and/or curved line segments. The converted segments are quantized and normalized. The segments of the normalized input pattern are rearranged so that the input pattern is drawn in a predetermined sequence. Differences between direction angles for the rearranged segments are calculated. Those differences are compared with differences of the direction angles of the dictionary patterns read from a memory to calculate a difference therebetween. The matching of the input pattern and the dictionary pattern is determined in accordance with the difference. If the matching fails, the first or last inputted segment of the input pattern is deleted or the sampled pattern coordinate data of the next stroke is added, to continue the recognition process.
122 Citations
27 Claims
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1. An on-line recognition method for a handwritten pattern comprising the steps of:
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sampling successively coordinate information of strokes of a handwritten pattern; segmentalizing the coordinate information of one stroke into line segments consisting of at least either of straight line segments and curved line seg- ments; quantizing the line segments so that the direction of each line segment is classified by one of predetermined angles; normalizing an input pattern constituted by the quantized line segments to determine presence and absence of connections between the line segments; rearranging the order of the quantized line segments in accordance with a predetermined connection sequence, on the basis of the determination result of the preceeding step; reading out a dictionary pattern already stored in a memory; and calculating degree of difference between the input pattern and the readout dictionary pattern by comparing the both on the basis of the quantized angles and the rearranged order of the quantized line segments, to thereby recognize the input pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A recognition method for a handwritten pattern comprising the steps of:
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(a) sampling successively coordinate information of strokes of a handwritten pattern; (b) segmentalizing the sampled coordinate information by carrying out the following substeps; (i) calculating an area encircled by a fold line formed by the sampled coordinate information and a line connecting the start coordinate point and the end coordinate point of the fold line; (ii) comparing the calculated area with a predetermined value; (iii) determining as a segnentalized straight line of the fold line the line connecting the start coordinate point and the end coordinate point of the fold line when the calculated area is smaller than a predetermined value, and returning to the substep (i); and (iv) dividing the fold line into two fold lines and returning to the substep (i); and (c) after the segmentalizing step, carrying out a pattern recognition processing on the basis of the line segments.
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10. A recognition method for a handwritten pattern comprising the steps of:
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(a) sampling successively coordinate information of strokes of a handwritten pattern; (b) segmentalizing the sampled coordinate information; (c) comparing an input pattern formed by line segments with a dictionary pattern already stored; and (d) when no-matching is detected by the comparison, deleting either one of the first and last line segments from the inputted line segments and then continuing a pattern recognition processing on the basis of the inputted line segments in which one line segment has been deleted.
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11. An on-line handwritten pattern recognition apparatus comprising:
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a coordinate input unit for sampling serial coordinate information and pen-up and pen-down information of strokes of a handwritten pattern; a pattern recognition unit for comparing the input information from said input unit for each input stroke starting from pen-down and ending at pen-up with standard pattern information stored in a memory to determine analogy therebetween; a pattern generation unit for generating reshaped information of the pattern recognized by said pattern recognition unit; said pattern recognition unit including; segmentation means for converting the input information from said coordinate input unit to straight line and curved line segments; quantization data generation means for quantizing the segments in accordance with angles made by lines connecting start points and end points of the respective segments; normalization means for listing presence or absence of connection between the start point and the end point of each of the segments; sequencing means for rearranging the quantized data into one-dimension input data sequence based on said list; difference calculation means for rearranging the standard pattern data into one-dimension standard data sequence by said sequencing means and comparing the one-dimension standard data sequence with the one-dimension input data sequence to calculate the analogy therebetween; and number of segments altering means for increasing or decreasing the number of segments to be compared with the standard pattern information when the difference is smaller than a predetermined value, to continue a pattern recognition processing. - View Dependent Claims (12, 13, 14)
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15. An on-line handwritten pattern recognition apparatus for evaluating analogy between a handwritten pattern and each of stored dictionary patterns, and of a pattern recognized to be identical to the handwritten pattern is found in the dictionary patterns, outputting that dictionary pattern as a recognized pattern, and if such a pattern is not found, repeating the above process for a next input handwritten pattern, characterized by that:
the handwritten pattern is divided into a plurality of segments in accordance with a value of an area encircled by a straight line connecting two of a plurality of sample points on the handwritten pattern and the sample points interposed between said two points and tracing said handwritten pattern. - View Dependent Claims (16, 17, 18, 19, 20)
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21. An on-line handwritten pattern recognition apparatus for evaluating analogy between a handwritten pattern and each of stored dictionary patterns, and if a pattern recognized to be identical to the handwritten pattern is found in the dictionary patterns, outputting that dictionary pattern as a recognized pattern, and if such a pattern is not found, repeating the above process for a next input handwritten pattern, characterized by that:
combinations consisting of portions of or entire handwritten pattern are compared with the dictionary patterns, the combinations consist of segments of the handwritten patterns, and the combination having a larger number of segments is compared first. - View Dependent Claims (22, 23, 24, 25, 26, 27)
Specification