Pattern recognition system for hand-written characters operating on an on ...

United States Patent [i9]

Odaka et al.

[ii] 4,317,109 [45] Feb. 23, 1982

[54] PATTERN RECOGNITION SYSTEM FOR HAND-WRITTEN CHARACTERS OPERATING ON AN ON-LINE REAL-TIME BASIS

[75] Inventors: Kazumi Odaka, Tokorozawa; Isao Masuda, Higashi-Kurume, both of Japan

[73] Assignee: Nippon Telegraph & Telephone Public Corp., Tokyo, Japan

[21] Appl. No.: 140,448

[22] Filed: Apr. 17, 1980

[30] Foreign Application Priority Data May 18, 1979 [JP] Japan 54-61146

[51] Int. C1.3 G06K 9/46

[52] U.S. CI 340/146.3 AC; 340/146.3 J

[58] Field of Search 340/146.3 SY, 146.3 SG,

340/146.3 AC

[56] References Cited

U.S. PATENT DOCUMENTS

3,111,646 11/1963 Harmon 340/146.3 SG

3,133,266 5/1964 Frishkopf 340/146.3 SG

4,024,500 5/1977 Herbst et al 340/146.3 SG

4,028,674 6/1977 Chuang 340/146.3 SY

OTHER PUBLICATIONS

Hanaki et al., "An On-Line Character Recognition . . . ", Pattern Recognition, vol. 8, Apr. 1976, pp. 63-71. Arakawa et al., "On-Line Recognition of Handwritten Characters", Review of the Electrical Communication Laboratories, vol. 26, Nos. 11-12, Nov.-Dec. 1978. Groner et al., "On-Line Computer Classification of

Handprinted Chinese Characters", IEEE Trans, on
Electronic Computers, Dec. 1967, pp. 856-860.

Primary Examiner—Leo H. Boudreau
Attorney, Agent, or Firm—Armstrong, Nikaido,
Marmelstein & Kubovcik

[57] ABSTRACT

The present system comprises (a) a character input unit for providing the coordinates of a plurality of points of an input character, (b) a pre-process unit for normalizing the size and the position of said input character, (c) three points approximate unit for providing three feature points for each stroke of the input character, (d) a reference pattern storage for providing the coordinates of the feature points for each stroke of the reference characters, (e) a stroke difference calculator for providing the sum p; of the length between the feature points of the k'th stroke of the input character and the feature points of the i'th stroke of the j'th reference character, (f) a storage for storing the stroke difference p/, (g) means for operating the members (e) and (0 repetitively for all the strokes of the j'th reference character, (h) means for detecting the minimum value pm,„ among the stroke difference p/ thus obtained, (i) means for operating the members (e), (f), (g) and (h) repetitively for all the strokes of the input character, and accumulating the value pmj„ to provide the value dOj, which is the pattern difference between the input character and the j'th reference character, (j) a storage for storing the value dOj , (k) means for operating the members (i), and (j) repetitively for all the reference characters to provide the set of dfyfor the given input character, and (1) means for detecting the minimum value among the values 60j and determining the input character as the reference character which provides the minimum value of ddj.

2 Claims, 6 Drawing Figures