On-line recognition method and apparatus for a handwritten pattern

Claim 2

An on-line recognition method for a handwritten pattern comprising the steps of: sampling (20) successively coordinate information of strokes of a handwritten pattern; segmentalizing (30) the coordinate information of one stroke into line segments consisting of at least either of straight line segments and curved line segments; quantizing (40) the line segments so that the direction of each line segment is classified by one of predetermined angles; normalizing (50) an input pattern constituted by the quantized line segments to determine presence and absence of connections between the line segments; rearranging (60) 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 (300); and calculating (70, 80) 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.

Claim 3

An on-line recognition method according to Claim 1, further comprising, after said difference degree calculating step, a step of altering (90) the number of the line segments to continue the recognition processing when non-matching is detected by the comparison in said difference degree calculating step.

Claim 4

An on-line recognition method according to Claim 2, wherein in said segment number altering step (90), the first or last inputted segment is deleted first to continue the pattern recognition processing.

Claim 5

An on-line recognition method-according to Claim 2, wherein in said segment number altering step (90), the coordinate information of a next stroke is added to the coordinate information of the current stroke to continue the pattern recognition processing.

Claim 6

An on-line recognition method according to Claim 1, wherein in said segmentalizing step (30), seg- mentalization is carried out by calculating an area (A) encircled by a fold line sequentially connecting the coordinate points on the coordinate information of one stroke and a line connecting the start coordinate point and the end'coordinate point of the coordinate information.

Claim 7

An on-line recognition method according to Claim 5, wherein said segmentalizing step (30) includes the substeps of: comparing the calculated area with a predetermined value ( A th) ; determining as a desired line segment the line connecting the start coordinate point and the end coordinate point of the coordinate information when the calculated area is smaller than the predetermined value; and dividing the fold line into two fold lines when the calculated area is not smaller than the predetermined value, to continue the segmentalizing step by comparing with the predetermined value an area encircled by the divided fold line and a line connecting the start coordinate point and the end coordinate point of the divided fold line.

Claim 8

An on-line recognition method according to Claim 5, wherein in said segmentalizing step (30), two contiguous line segments are handled as a portion of a curve, when an absolute difference of angle made by the two segments is smaller than a predetermined angle and a sign thereof is equal to that of the difference of angle made by immediately preceeding two line segments and a length ratio thereof is within a predetermined range.

Claim 9

An on-line recognition method according to Claim 1, wherein in said difference degree calculating step (70), the difference of the quantized angles of each two contiguous rearranged line segments is compared with each corresponding difference of the readout dictionary pattern.

Claim 10

A recognition method for a handwritten pattern comprising the steps of: (a) sampling (20) successively coordinate information of strokes of a handwritten pattern; (b) segmentalizing (30) the sampled coordinate information by carrying out the following substeps: (i) calculating an area (A) 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 (A t h); (iii) determining as a segmentalized straight line of the fold line the line (L) 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 (Fig. 7c) 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.

Claim 11

A recognition method for a handwritten pattern comprising the steps of: (a) sampling (20) successively coordinate information of strokes of a handwritten pattern; (b) segmentalizing (30) the sampled coordinate information by carrying out the following substeps: (i) calculating an area (A) 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 (A t h); (iii) determining as a segmentalized straight line of the fold line the line (L) 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 (Fig. 7c) 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.

Claim 12

A recognition method for a handwritten pattern comprising the steps of: (a) sampling (20) successively coordinate information of strokes of a handwritten pattern; (b) segmentalizing (30) the sampled coordinate information; (c) comparing (70) an input pattern formed by line segments with a dictionary pattern already stored; and (d) when non-matching is detected by the comparison, deleting (90) the first or last inputted line segment first and continue a pattern recognition processing.

Claim 13

A recognition method for a handwritten pattern comprising the steps of: (a) sampling (20) successively coordinate information of strokes of a handwritten pattern; (b) segmentalizing (30) the sampled coordinate information; (c) comparing (70) an input pattern formed by line segments with a dictionary pattern already stored; and (d) when non-matching is detected by the comparison, deleting (90) the first or last inputted line segment first and continue a pattern recognition processing.

Claim 14

An on-line handwritten pattern recognition apparatus comprising: a coordinate input unit (201) for sampling serial coordinate information and pen-up and pen-down information of strokes of a handwritten pattern; a pattern recognition unit (200) 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 (400, 500) for generating reshaped information of the pattern recognized by said pattern recognition unit; said pattern recognition unit (200) including: segmentation means (202) for converting the input information from said coordinate input unit to straight line and curved line segments; quantization data generation means (203) for quantizing the segments in accordance with angles made by lines connecting start points and end points of the respective segments; normalization means (204) for listing presence or absence of connection between the start point and the end point of each of the segments; sequencing means (205) for rearranging the quantized data into one-dimension input data sequence based on said list; difference calculation means (206) 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 (209) 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.

Claim 15

An on-line handwritten pattern recognition apparatus comprising: a coordinate input unit (201) for sampling serial coordinate information and pen-up and pen-down information of strokes of a handwritten pattern; a pattern recognition unit (200) 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 (400, 500) for generating reshaped information of the pattern recognized by said pattern recognition unit; said pattern recognition unit (200) including: segmentation means (202) for converting the input information from said coordinate input unit to straight line and curved line segments; quantization data generation means (203) for quantizing the segments in accordance with angles made by lines connecting start points and end points of the respective segments; normalization means (204) for listing presence or absence of connection between the start point and the end point of each of the segments; sequencing means (205) for rearranging the quantized data into one-dimension input data sequence based on said list; difference calculation means (206) 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 (209) 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.

Claim 16

An on-line handwritten pattern recognition apparatus according to Claim 11 wherein said segmentation means includes: calculation means for calculating an area encircled by segment pattern sequentially connecting points on the input stroke and a line connecting the start point and the end point of the segment pattern; first decision means for determining whether the segment pattern is to be regarded as a straight line or not based on the area calculated by said calculation means; and second decision means for determining whether the segments determined as the straight line by said first decision means are a portion of a curved line.

Claim 17

An on-line handwritten pattern recognition apparatus according to Claim 11 wherein said sequencing means includes means for selecting one segment from said segments and arranging the quantized data in one direction starting from the quantized data of said selected segment, based on said list.

Claim 18

An on-line handwritten pattern recognition apparatus according to Claim 11-wherein said number of segments altering means includes a start pointer and an end pointer for the segments to be compared, means for incrementing or decrementing said pointers, and segment updating means for replacing the segments by new segments pointed by said pointers.

Claim 19

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: the handwritten pattern is divided into a plurality of segments in accordance with an area encircled by a line connecting two of a plurality of sample points on the handwritten pattern and a group of segments connecting said two points and tracing said handwritten pattern.

Claim 20

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: the handwritten pattern is divided into a plurality of segments in accordance with an area encircled by a line connecting two of a plurality of sample points on the handwritten pattern and a group of segments connecting said two points and tracing said handwritten pattern.

Claim 21

An on-line handwritten pattern recognition apparatus according to Claim 15 wherein the handwritten pattern is divided into a plurality of segments by substituting said handwritten pattern by a segment when said area is smaller than a predetermined threshold, and if said area is larger than the predetermined threshold, the line connecting.the sample points is repeatedly shortened until said area becomes smaller than said threshold.

Claim 22

An on-line handwritten pattern recognition apparatus according to Claim 16 wherein the line connecting the sample points is shortened by dividing each stroke of the handwritten pattern into n segments (n ? 2, an integer), and if an angle difference of m contiguous segments (n Z m ≧ 2, an integer) is smaller than a predetermined angle, reducing the m segments to ℓ (m > ℓ, an integer) segments.

Claim 23

An on-line handwritten pattern recognition apparatus according to Claim 15 wherein the handwritten pattern is divided in accordance with a ratio of the length of the line connecting the two of the sampling points on the handwritten pattern and a sum of lengths of the segments tracing the handwritten pattern.

Claim 24

An on-line handwritten pattern recognition apparatus according to Claim 18 wherein the handwritten pattern is substituted by a segment when said ratio is within a predetermined range, and if said ratio is not within the predetermined range, the line connecting the sample points on the handwritten pattern is repeatedly shortened until said ratio comes into said range.

Claim 25

An on-line handwritten pattern recognition apparatus according to Claim 19 wherein the line connecting the sample points is shortened by dividing each stroke of the handwritten pattern into n (n ≧ 2, an integer) segments, and if an angle difference of m (n ≧ m ≧ 2, an integer) contiguous segments is smaller than a predetermined angle, reducing m segments to & (m > ℓ, an integer) segments.

Claim 26

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.

Claim 27

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.

Claim 28

An on-line handwritten pattern recognition apparatus according to Claim 21 wherein said segments are time-serially numbered, the segment having the smallest or largest number is deleted and the remaining segments are used as one of said combination.

Claim 29

An on-line handwritten pattern recognition apparatus according to Claim 22 wherein the number of segments to be deleted is limited to n (0 S n < number of input segments, an integer), and the opposite ends of the segment number sequence are alternately deleted.

Claim 30

An on-line handwritten pattern recognition apparatus according to Claim 22 or 23 wherein a plurality of segments are deleted in one step when said segments include segments connected at an angle larger than a predetermined angle.

Claim 31

An on-line handwritten pattern recognition apparatus according to Claim 22 or 23 wherein segments connected at an angle larger than a predetermined angle in said segments are deleted in one step.