Apparatus for recognizing input character strings by inference

60 Pages·2013·3.23 MB·English

US006751605B2
United States Patent
(12) (10) Patent N0.: US 6,751,605 B2
Gunji et al. (45) Date of Patent: Jun. 15, 2004
(54) APPARATUS FOR RECOGNIZING INPUT 5,321,833 A * 6/1994 Chang et al. ................ .. 707/5
CHARACTER STRINGS BY INFERENCE 5,377,281 A 12/1994 Ballard et al.
5,787,197 A 7/1998 Beigi et al. ............... .. 382/229
(75) Inventors: Keiko Gunji, Mito (JP); Koyo 5,826,260 A * 10/1998 Byrd et al. .. ...... .. 707/5
Katsura, Hitachiohta (JP); Soshiro 5,909,510 A 6/1999 Nakayama .. 382/229
Kuzunuki, Hitachinaka (JP); Masaki 6,041,323 A * 3/2000 Kubota ........................ .. 707/3
Miura, Hitachi (JP); Toshimi Yokota, FOREIGN PATENT DOCUMENTS
Hitachiohta (JP)
JP 02308384 12/1990
(73) Assignee: Hitachi, Ltd., Tokyo (JP) JP 07093467 4/1995
* cited by examiner
(*) Notice: Subject to any disclaimer, the term of this
Primary Examiner—Sanjiv Shah
patent is extended or adjusted under 35
U.S.C. 154(b) by 157 days. (74) Attorney, Agent, or Firm—Antonelli, Terry, Stout &
Kraus, LLP
(21) Appl. No.: 09/789,820 (57) ABSTRACT
(22) Filed: Feb. 22, 2001 A character recognition apparatus for inferring the entire
character string solely from a user-input handwritten key
(65) Prior Publication Data
Word and displaying the inferred result as a candidate
US 2001/0028742 A1 Oct. 11, 2001 character string.
Related US. Application Data The apparatus of the invention comprises: a Word string
includes a Word hierarchy and for recognizing each of the
(62) Division of application No. 08/859,410, ?led on May 20, Words Within the hierarchy; a character transition probability
1997, now Pat. No. 6,097,841. table a4 storing probabilities of transitions from any one
(51) Int. Cl.7 .............................................. .. G06F 17/30 character to another, and those pieces of the Word identi?
(52) US. Cl. 707/1; 707/3 cation information Which correspond to combinations of
(58) Field of Search .............................. .. 707/1, 2, 3, 4, characters resulting from the transitions; and an optimization
unit for using the character transition probability table in
707/5, 6, 10, 102, 103; 706/52
optimizing candidate character strings obtained by a recog
(56) References Cited nition unit. The Word dictionary is searched for a Word
de?ned by the Word identi?cation information Which corre
U.S. PATENT DOCUMENTS sponds to the optimized candidate character string, Whereby
the searched Word is retrieved Which applies to the hierarchy
4,654,875 A 3/1987 Srihari et al.
information and Which has yet to be input.
5,020,019 A * 5/1991 Ogawa ...................... .. 706/52
5,067,165 A 11/1991 Nishida 382/229
5,297,042 A * 3/1994 Morita ........................ .. 707/5 10 Claims, 40 Drawing Sheets
211312
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U.S. Patent Jun. 15,2004 Sheet 1 0f 40 US 6,751,605 B2
FIG.1
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APPEARANCE TRANSITION
RECOGN'T'ON PROBABILITY PROBABILITY WORD I
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U.S. Patent Jun. 15,2004 Sheet 2 0f 40 US 6,751,605 B2
FIG.2
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U.S. Patent
Jun. 15,2004 Sheet 3 0f 40 US 6,751,605 B2
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U.S. Patent Jun. 15,2004 Sheet 4 0f 40 US 6,751,605 B2
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PROBABILITY PROBABILITY
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U.S. Patent Jun. 15,2004 Sheet 5 0f 40 US 6,751,605 B2
FIG.7 _
mono DICTIONARY?
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U.S. Patent Jun. 15,2004 Sheet 6 6f 40 US 6,751,605 B2
FIG.8
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CHARACTER
APPEARANCE
COUNT TABLE
APPEARANCE
CHARACTER COUNT
El 27
TOTAL
CHARACTER
COUNT
89274
U.S. Patent Jun. 15,2004 Sheet 7 0f 40 US 6,751,605 B2
FIG.9
d6
CHARACTER TRANsnm
COUNT TABLE /
CHARACTER TRANSITION CANDIDATE
TRANSITION COUNT WORD NO.
(Eli-*7?‘ 2 A11,A12
f)‘—*@ 1 A12
U.S. Patent Jun. 15,2004 Sheet 8 0f 40 US 6,751,605 B2
FIG. 10
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APPEARANCE d8
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CHARACTER PROBABILITY fxggéxéwéé ...................... u-“
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! 18 T_O_TAL CHARACTER COUNT
it 89274
15
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1 1
75 89274
U.S. Patent
Jun. 15,2004 Sheet 9 0f 40 US 6,751,605 B2
FIG. 11
CHARACTER TRANSITION
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PROBABILITY TABLE F/
CHARACTER TRANSITION CANDIDATE
TRANSITION PROBABILITY WORD NO.
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APPEARANCE COUNT (E1)
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