Rotationally desensitized unistroke handwriting recognition

• US 20020009227A1
• Filed: 07/09/2001
• Published: 01/24/2002
• Est. Priority Date: 10/06/1993
• Status: Active Grant

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Reich, Victoria Ann, Goldberg, David, Want, Roy, Weiser, Mark D.
• Granted Patent: US 6,816,859 B2
• Time in Patent Office: Days
• US Class Current: 382/181
• 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 an alphabet of mutually independent 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 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 being rotationally offset from each other by at least 90°

;

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.

2. The method of claim 1 wherein said unistroke symbols are well separated from each other in sloppiness space.

3. 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 directional parameters that are rotationally displaced from each other by at least 90°

;

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 buffer memory in 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 such translating to a utilization device.

4. The handwriting recognition process of claim 3 wherein certain unistroke symbols correlate with natural language alphanumeric symbols, and other unistroke symbols correlate with user invokeable control functions.

5. The handwriting recognition process of claim 4 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 one set of natural language alphanumeric symbols to another set of natural language alphanumeric symbols.