Image analysis – Pattern recognition – Unconstrained handwriting
Reexamination Certificate
1999-05-05
2002-04-02
Popovici, Dov (Department: 2622)
Image analysis
Pattern recognition
Unconstrained handwriting
C382S187000
Reexamination Certificate
active
06366697
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to handwriting recognition and, more particularly, to handwriting recognition for hand-held pen computers and the like.
BACKGROUND OF THE INVENTION
The basic Unistrokes application describes a handwriting recognition system and methodology which utilizes continuous, explicitly delimited strokes for representing natural language symbols at the atomic level (i.e., alphanumeric characters for English and other orthographic natural language representations, and phonemes for phonetic systems). Additional strokes of like type can be interspersed with these symbol representing strokes for control purposes, such as for switching between look-up tables for lower and upper case characters and for less frequently utilizes punctuation marks, text editing functions and special constructs (e.g., equations). See, for example, a copending, commonly assigned U.S. patent application of Dennis Venable, which was filed Jan. 3, 1995 under Ser. No. 08/368,122 on “SELF-DELIMITING SPECIFICATION OF MULTIDIMENSIONAL CHARACTER CONSTRUCTIONS FOR PEN COMPUTERS.” (now abandoned) Furthermore, the usual single stroke per natural language symbol characteristic of the Unistroke alphabet may be relaxed if desired to permit some or all of the natural language symbols to be represented by multiple, separately delimited strokes, such as may be needed or desired for applications involving larger natural language symbol sets. See, for example, a copending, commonly assigned U.S. patent application of Robert R. Buckley, which was filed Jan. 3, 1995 under Ser. No. 08/368,136 on “EXTENDED SELF-DELIMITING DATA ENTRY FOR PEN COMPUTERS,” (now abandoned).
Successive Unistroke symbols are positively delimited from each other by a predetermined, intervening, stroke independent delimiting operation, such as the waiting for writing these symbols into a pen computer or the like. This positive delimiting of successive Unistroke strokes significantly simplifies the recognition process by parsing the respective strokes completely independently of their spatial relationship while capturing the logical ordering of these strokes based on the time order in which they are written. Thus, the Unistroke symbollogy and recognition process are well suited for applications in which spatial ordering of stroke-by-stroke cyclical changes in the pressure atypical user causes a stylus or electric pen to exert against a writing surface during and following, respectively, while symbols is difficult to achieve or assure, such as “heads-up” writing and/or for applications requiring the writing of symbols on small writing surfaces that are too small to maintain an easily recognizable spatial separation between logically ordered symbols that are written on a scale that is natural and comfortable to the ordinary user.
The basic Unistrokes application recognizes that the symbol recognition process is further simplified if the Unistroke symbols are well separated from each other in “sloppiness space.” As set forth in the basic Unistrokes application, this “sloppiness space” notion can best be understood by recognizing that each alphanumeric symbol is defined by some number of features (say, d features). Thus, each symbol nominally resides at a unique point in a d-dimensional space which is referred to herein as “sloppiness space.” From this it follows that the amount of overlap, if any, that occurs in the positioning within this d-dimensional space of the normal variants of the symbols of a given alphabet determines how well separated those symbols are in sloppiness space. If there is little, if any, overlap between the variants of different symbols, the symbols are “well separated from each other in sloppiness space.” This goal is well met by the Unistroke alphabet that is disclosed in the basic Unistrokes application when the symbols are written by different users under reasonably consistent conditions. In practice, however, it has been found that the tilt angle at which different users tend to write strokes on easily rotatable writing surfaces, such as the input interfaces of hand-held computers, is a user dependent variable which varies significantly from user-to-user. Some users intuitively compensate for rotational tilt of the writing surface by generally referencing their strokes to the principal axis of the writing surface, but other users tend to reference their strokes to other features of their environment, such as the principal axis of their bodies. Thus, the rotational tilt of the writing surface sometimes introduces an unwanted ambiguity that reduces the reliability of the character recognition process. Accordingly, it would be desirable to avoid this ambiguity, especially if that can be done without interfering with the users' normal work practices.
SUMMARY OF THE INVENTION
To that end, the present invention defines 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°. 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.
REFERENCES:
patent: 3108254 (1963-10-01), Dimond
patent: 3145367 (1964-08-01), Crane
patent: 3199078 (1965-08-01), Gaffney, Jr. et al.
patent: 3462548 (1969-08-01), Rinder
patent: 3500323 (1970-03-01), Funk et al.
patent: 3626368 (1971-12-01), Lee
patent: 3699518 (1972-10-01), Greenough et al.
patent: 3784982 (1974-01-01), Schlang
patent: 3835453 (1974-09-01), Narayanan
patent: 3903502 (1975-09-01), Moss
patent: 3930229 (1975-12-01), Crane et al.
patent: 3996557 (1976-12-01), Donahey
patent: 4047010 (1977-09-01), Perotto et al.
patent: 4139837 (1979-02-01), Liljenwall et al.
patent: 4156911 (1979-05-01), Crane et al.
patent: 4241409 (1980-12-01), Nolf
patent: 4262281 (1981-04-01), Buckle et al.
patent: 4365235 (1982-12-01), Greanias et al.
patent: 4400697 (1983-08-01), Currie et al.
patent: 4475239 (1984-10-01), van Raamsdonk
patent: 4542526 (1985-09-01), Satoh et al.
patent: 4561105 (1985-12-01), Crane et al.
patent: 4562304 (1985-12-01), Ward et al.
patent: 4573196 (1986-02-01), Crane et al.
patent: 4608658 (1986-08-01), Ward
patent: 4641354 (1987-02-01), Fukunaga et al.
patent: 4656317 (1987-04-01), Tsugei et al.
patent: 4718102 (1988-01-01), Crane et al.
patent: 4731857 (1988-03-01), Tappert
patent: 4751741 (1988-06-01), Mochinaga et al.
patent: 4839634 (1989-06-01), More et al.
patent: 4860372 (1989-08-01), Kazunuki et al.
patent: 4953225 (1990-08-01), Togawa et al.
patent: 4972496 (1990-11-01), Sklarew
patent: 4985929 (1991-01-01), Tsuyama
patent: 5005205 (1991-04-01), Ellozy et al.
patent: 5022081 (1991-06-01), Hirose et al.
patent: 5022086 (1991-06-01), Crane et al.
patent: 5034989 (1991-07-01), Loh
patent: 5038382 (1991-08-01), Lipscomb
patent: 5049862 (1991-09-01), Dao et al.
patent: 5109352 (1992-04-01), O'Dell
patent: 5121441 (1992-06-01), Chefalas et al.
patent: 5125039 (1992-06-01), Hawkins
patent: 5133076 (1992-07-01), Hawkins et al.
patent: 5140645 (1992-08-01), Whitaker
patent: 5148155 (1992-09-01), Martin et al.
patent: 5150424 (1992-09-01), Aguro et al.
patent: 5194852 (1993-03-01), More et al.
patent: 5197810 (1993-03-01), Zhang et al.
patent: 5214428 (1993-05-01), Allen
patent: 5285505 (1994-02-01), Kim et al.
patent: 5313527 (1994-05-01), Guberman et al.
patent: 5315667 (1994-05-01), Fujisaki et al.
patent: 5333209 (1994-07-01), Sinden et al.
patent: 5341438 (1994-08-01), Clifford
patent: 5347295 (1994-09-01), Agulnick et al.
patent: 5491495 (1996-02-01), Ward et al.
patent: 5521986 (1996-05-01), Curtin, II et al.
patent: 5550930 (1996-08-01), Berman et al.
patent: 5596656 (1997-01-01), Goldberg
patent: 5610996 (1997-03-01), Eller
patent: 5940535 (1999-08-01), Huang
patent: 0 107 196 (1984-05-01), None
patent: 0 114 248 (1984-08-01), None
patent: 0 135 615 (1984-08-01), None
patent: 0 120 481 (1984-10-01), None
patent: 0 243 925 (1987-11-01), None
patent: 0 391 044 (1
Goldberg David
Want Roy
Weiser Mark D.
Popovici Dov
Xerox Corporation
LandOfFree
Rotationally desensitized unistroke handwriting recognition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Rotationally desensitized unistroke handwriting recognition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rotationally desensitized unistroke handwriting recognition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2913267