Method and microprocessor for preprocessing handwriting having characters composed of a preponderance of straight line segments
First Claim
Patent Images
1. A method of preprocessing a handwritten pen input for characters composed of a preponderance of straight line segments, comprising the steps of:
- A) receiving the handwritten input as a sequence of (x, y) points where x and y are coordinates in a two dimensional coordinate system;
B) determining a change in angle at each of the points;
C) identifying potential segmentation points as each of the points having a local maximum of angle change exclusive of any other points and an angle change exceeding a preset threshold;
D) removing spurious segmentation points to provide useful segmentation points, where spurious segmentation points are each of the potential segmentation points which is less than a preset distance from another of the potential segmentation points; and
E) determining a sequence of straight line strokes to represent the handwritten input from the useful segmentation points.
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Abstract
The method and microprocessor of the present invention includes a step of calculating the angle changes, in the handwritten input. The method then selects potential segmentation points in the input whose angle change exceeds a predetermined threshold. The segmentation points are used to determine a sequence of straight line strokes that may be used by a recognizer for interpretation of the handwritten input.
70 Citations
30 Claims
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1. A method of preprocessing a handwritten pen input for characters composed of a preponderance of straight line segments, comprising the steps of:
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A) receiving the handwritten input as a sequence of (x, y) points where x and y are coordinates in a two dimensional coordinate system; B) determining a change in angle at each of the points; C) identifying potential segmentation points as each of the points having a local maximum of angle change exclusive of any other points and an angle change exceeding a preset threshold; D) removing spurious segmentation points to provide useful segmentation points, where spurious segmentation points are each of the potential segmentation points which is less than a preset distance from another of the potential segmentation points; and E) determining a sequence of straight line strokes to represent the handwritten input from the useful segmentation points. - View Dependent Claims (2, 3, 4, 5)
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6. A method of recognizing a handwritten character comprising the steps of:
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A) receiving the handwritten input as a sequence of (x, y) points where x and y are coordinates in a two dimensional coordinate system; B) determining a change in angle at each of the points; C) identifying potential segmentation points as each of the points having a local maximum of angle change exclusive of any other points and an angle change exceeding a preset threshold; D) removing spurious segmentation points to provide useful segmentation points, where a spurious segmentation point is a potential segmentation point which is less than a preset distance from another of the potential segmentation points; E) determining a sequence of straight line strokes to represent the handwritten input from the useful segmentation points; and F) using the sequence of straight line strokes to determine the identity of said handwritten character. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A device/handwriting recognition microprocessor for, upon receiving handwritten character input as a sequence of (x,y) points where x and y are coordinates in a two dimensional coordinate system, recognizing a handwritten character composed of a plurality of (x,y) values, comprising:
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A) an angle change determiner for determining a change in angle at each of the sequence of (x,y) points; B) a potential segmentation point identifier, operably coupled to the angle change determiner, for identifying potential segmentation points as each of the points having a local maximum of angle change exclusive of any other points and an angle change exceeding a preset threshold; C) an artifact remover, operably coupled to the potential segmentation point identifier, for removing spurious segmentation points to provide useful segmentation points, where a spurious segmentation points is a potential segmentation point which is less than a preset distance from another of the potential segmentation points; and D) a stroke determiner, operably coupled to the artifact remover, for determining a sequence of straight line strokes to represent the handwritten input from the useful segmentation points. - View Dependent Claims (15, 16, 17, 18)
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19. A device/handwriting recognition microprocessor for, upon receiving handwritten character input as a sequence of (x,y) points where x and y are coordinates in a two dimensional coordinate system, recognizing a handwritten character composed of a plurality of (x,y) values, comprising:
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A) an angle change determiner, operably coupled to receive the sequence of (x,y) points, for determining a change in angle at each of the sequence of (x,y) points; and B) a point to stroke delineator, operably coupled to the angle change determiner, for determining useful segmentation points, where useful segmentation points are each of the sequence of points where the change in angle exhibits a local maximum exclusive of any other points and where the change in angle exceeds a preset threshold but is at least a preset distance from another of the sequence of points that has the change of angle exceeding the preset threshold, and generating a sequence of straight line strokes between the useful segmentation points to represent the handwritten input. - View Dependent Claims (20, 21)
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22. A method comprising the steps of:
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sampling points of handwriting input to a handwriting recognizer wherein vectors are formed between the points; determining for each one of the points a change of angle between two of the vectors joining at the one of the points; comparing the change of angle for each one of the points with a preset threshold and identifying points as potential segmentation points where, exclusive of any other points, the change of angle for each one of the potential segmentation points is a maximum vis-a-vis the change of angle at adjacent points and is greater than the preset threshold; removing spurious segmentation points where spurious segmentation points are each of the potential segmentation points having a change of angle that is a local maximum and is greater than the preset threshold but is less than a preset distance from another of the potential segmentation points having a change of angle that is a local maximum and is greater than the preset threshold; and determining a sequence of straight line strokes between the potential segmentation point for each one of the points. - View Dependent Claims (23, 24, 25)
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26. A handwriting recognizer comprising:
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an angle change determiner wherein for each of a set of points sampled along handwriting input to a handwriting recognizer wherein vectors are formed between each of the set of points, the angle change determiner determines a change of angle between two of the vectors joining at each one of the set of points; a potential segmentation point identifier coupled to the angle change determiner which compares the change of angle for each one of the set of points with a preset threshold and identifies points as potential segmentation points where, exclusive of any other points, the change of angle for each one of the potential segmentation points is a maximum vis-a-vis the change of angle at adjacent points and is greater than the preset threshold; an artifact remover coupled to the potential segmentation point identifier which removes spurious segmentation points where spurious segmentation points are each of the potential segmentation points having a change of angle that is a maximum vis-a-vis the change of angle at adjacent points and is greater than the preset threshold but is less than a preset distance from another of the potential segmentation points having a change of angle that is a maximum vis-a-vis the change of angle at adjacent points and is greater than the preset threshold; and a stroke determiner coupled to the artifact remover which determines a sequence of straight line strokes between the potential segmentation point for each one of the set of points. - View Dependent Claims (27)
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28. A method of preprocessing a handwritten pen input for characters composed of a preponderance of straight line segments, comprising the steps of:
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A) receiving the handwritten input as a sequence of (x, y) points where x and y are coordinates in a two dimensional coordinate system; B) determining a change in angle at each of the points; C) identifying useful segmentation points from points having an angle change exceeding a preset threshold; D) determining a sequence of straight line strokes to represent the handwritten input from the useful segmentation points; E) inserting a straight line stroke between any two consecutive useful segmentation points having a pen-up segment between them; and F) using the sequence of straight line strokes to determine the identity of the handwritten character.
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29. A method of preprocessing a handwritten pen input for characters composed of a preponderance of straight line segments, comprising the steps of:
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A) receiving the handwritten input as a sequence of (x, y) points where x and y are coordinates in a two dimensional coordinate system; B) determining a change in angle at each of the points; C) identifying potential segmentation points as each of the points having an angle change exceeding a preset threshold; D) removing spurious segmentation points to provide useful segmentation points, where spurious segmentation points are each of the potential segmentation points having an angle change exceeding the preset threshold but are less than a preset distance from another of the potential segmentation points having an angle change exceeding the preset threshold; and E) determining a sequence of straight line strokes to represent the handwritten input from the useful segmentation points; and F) inserting a straight line stroke between any two consecutive useful segmentation points having a pen-up segment between them.
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30. A device/handwriting recognition microprocessor for, upon receiving handwritten character input as a sequence of (x,y) points where x and y are coordinates in a two dimensional coordinate system, recognizing a handwritten character composed of a plurality of (x,y) values, comprising:
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A) an angle change determiner for determining a change in angle at each of the sequence of (x,y) points; B) a potential segmentation point identifier, operably coupled to the angle change determiner, for identifying potential segmentation points as each of the sequence of points whose angle change exceeds a preset threshold; C) an artifact remover, operably coupled to the potential segmentation point identifier, for removing spurious segmentation points to provide useful segmentation points; and D) a stroke determiner, operably coupled to the artifact remover, for determining a sequence of straight line strokes to represent the handwritten input from the useful segmentation points, wherein the stroke determiner inserts a straight line stroke between any two useful consecutive segmentation points having a pen-up segment between them.
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Specification