Rotationally desensitized unistroke handwriting recognition

• US 6,816,859 B2
• Filed: 07/09/2001
• Issued: 11/09/2004
• Est. Priority Date: 10/06/1993
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Goldberg, David, Want, Roy, Weiser, Mark D.
• Primary Examiner(s): Mizrahi, Diane D.
• Assistant Examiner(s): Mofiz, Apu M
• Application Number:
  US09/901,406
• Publication Number:
  US 20020009227A1
• Time in Patent Office: 1,219 Days
• Field of Search: 707/6, 707/4, 382/186, 382/188, 382/189, 382/313, 382/315, 345/158, 345/860, 715/541, 715/540
• US Class Current: 1/1
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text
• CPC Class Codes: G06V 30/1423 the instrument generating sequences of position coordinates corresponding to handwriting preprocessing or recognising digital ink G06V30/32
• CPC Class Codes: G06V 30/228 of three-dimensional handwriting, e.g. writing in the air
• CPC Class Codes: Y10S 707/99936 Pattern matching access

Abstract

A Unistrokes symbollogy in which strokes of like profile (i.e., strokes that are distinguished from each other by their rotational orientation) are rotationally offset from each other by at least 90° is provided. This provides a sufficient tolerance for disambiguating these strokes when they are written into hand-held pen computers and the like by users having widely divergent hand writing styles.

Claims

1. A machine implemented method for interpreting handwritten text comprising

writing said text in sequential time order using a natural language alphabet of mutually independent alphanumeric unistroke symbols to spell out said text at an atomic level, each of said unistroke symbols conforming to a respective graphical specification that includes a stroke direction parameter, some of said unistroke symbols being rotationally differentiated symbols which are characterized by having graphical specifications that differ from each other essentially only on the basis of their respective stroke direction parameters, with said respective stroke direction parameters of all of said rotationally differentiated symbols being rotationally offset from each other by at least 90°

and no more than 180°

;

signaling a predetermined, symbol independent delimiter between successive ones of said unistroke symbols in said time order;

capturing the stroke direction of each of said unistroke symbols as an ordered list of coordinates;

disambiguating said unistroke symbols from each other based upon predetermined criteria, including the stroke directions of the respective symbols;

wherein the natural language alphabet of mutually independent alphanumeric unistroke symbols is defined by a first set of unistroke symbols and a second set of unistroke symbols.

2. The method of claim 1 wherein the natural language is English.

3. The method of claim 1 wherein the first set of unistroke symbols represent alphabetic characters from the group comprising:

a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, and z.

4. The method of claim 3 wherein the second set of unistroke symbols represent numeric symbols from the group comprising:

0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

5. The method of claim 1 wherein the second set of unistroke symbols represent numeric symbols from the group comprising:

0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

6. The method of claim 1 wherein the first set of unistroke symbols and the second set of unistroke symbols have at least one identical unistroke symbol.

7. The method of claim 6 wherein the first set of unistroke symbols represent alphabetic characters from the group comprising:

a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, and z.

8. The method of claim 7 wherein the first set of unistroke symbols includes unistroke symbols that represent numeric symbols from the group comprising:

0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

9. A handwriting recognition process for pen computers, said process comprising the steps of

correlating unistroke symbols with natural language alphanumeric symbols, each of said unistroke symbols being fully defined by a single continuous stroke that conforms geometrically and directionally to a predetermined graphical specification, with certain of said unistroke symbols having graphical specifications that are distinguished from each other solely by their respective stroke directional parameters, all of said unistroke symbols that are distinguished from each other solely by their respective stroke directional parameters being rotationally offset from each other by at least 90°

and no more than 180°

;

entering user written unistroke symbols into buffer memory in sequential time order, successive ones of said unistroke symbols being delimited from each other by a predetermined, symbol independent delimiting operation;

reading out said unistroke symbols from said buffer memory in said sequential time order to provide buffered unistroke symbols;

translating each buffered unistroke symbol that correlates with a natural language symbol into said natural language symbol; and

outputting any natural language symbols that are produced by said translating step to a utilization device;

wherein the natural language alphabet of mutually independent alphanumeric unistroke symbols is defined by a first set of unistroke symbols and a second set of unistroke symbols.

10. The handwriting recognition process of claim 9 wherein certain unistroke symbols correlate with said natural language alphanumeric symbols, and other unistroke symbols correlate with user invokeable control functions.

11. The handwriting recognition process of claim 10 wherein at least one of said other unistroke symbols correlates with a control function that shifts the correlation of at least some of said certain unistroke symbols from a first set of natural language alphanumeric symbols to a second set of natural language alphanumeric symbols.

12. The handwriting recognition process of claim 11 wherein the first set of natural language alphanumeric symbols are lower case characters and the second set of natural language alphanumeric symbols are upper case characters.

13. The handwriting recognition process of claim 12 wherein the lower case characters and upper case characters are characters from the group comprising:

a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, and z.

14. The handwriting recognition process of claim 9 wherein the natural language is English.

15. The handwriting recognition process of claim 9 wherein the first set of unistroke symbols represent alphabetic characters from the group comprising:

a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, and z.

16. The handwriting recognition process of claim 15 wherein the second set of unistroke symbols represent numeric symbols from the group comprising:

0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

17. The handwriting recognition process of claim 9 wherein the second set of unistroke symbols represent numeric symbols from the group comprising:

0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

18. The handwriting recognition process of claim 9 wherein the first set of unistroke symbols and the second set of unistroke symbols have at least one identical unistroke symbol.

19. The handwriting recognition process of claim 18 wherein the first set of unistroke symbols represent alphabetic characters from the group comprising:

a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w, x, y, and z.

20. The handwriting recognition process of claim 19 wherein the second set of unistroke symbols represent numeric symbols from the group comprising:

0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.