Pattern recognition system for hand-written characters operating on an on-line real-time basis

• US 4,317,109 A
• Filed: 04/17/1980
• Issued: 02/23/1982
• Est. Priority Date: 05/18/1979
• Status: Expired due to Term

• Current Assignee: Nippon Telegraph and Telephone Corporation
• Original Assignee: Nippon Telegraph and Telephone Corporation
• Inventors: Masuda, Isao, Odaka, Kazumi
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US06/140,448
• Time in Patent Office: 677 Days
• Field of Search: 340/146.3 SY, 340/146.3 SG, 340/146.3 AC
• US Class Current: 382/187
• CPC Class Codes: G06V 10/20 Image preprocessing
• CPC Class Codes: G06V 10/46 Descriptors for shape, contour or point-related descriptors, e.g. scale invariant feature transform [SIFT] or bags of words [BoW]; Salient regional features colour feature extraction G06V10/56
• CPC Class Codes: G06V 10/75 Organisation of the matching processes, e.g. simultaneous or sequential comparisons of image or video features; Coarse-fine approaches, e.g. multi-scale approaches; using context analysis; Selection of dictionaries

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_i 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_i, (g) means for operating the members (e) and (f) repetitively for all the strokes of the j'"'"'th reference character, (h) means for detecting the minimum value p_min among the stroke difference p_i 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 p_min to provide the value dθ _j, which is the pattern difference between the input character and the j'"'"'th reference character, (j) a storage for storing the value dθ_j , (k) means for operating the members (i), and (j) repetitively for all the reference characters to provide the set of dθ_j for the given input character, and (l) means for detecting the minimum value among the values dθ_j and determining the input character as the reference character which provides the minimum value of dθ_j.

Claims

1. A pattern recognition system for handwritten characters operating on an on-line real-time basis comprising:

(a) a character input unit for providing the coordinates of a plurality of points of an input character, the input character being formed by a plurality of strokes,

(b) a pre-process unit for normalizing the size and the position of said input character,

(c) means for providing a plurality of 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 a plurality of reference characters,

(e) a stroke difference calculator for providing a stroke difference p_i which is the sum 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, where i, j and k are integers,

(f) a storage for storing the stroke difference p_i,

(g) means for operating the members (e) and (f) repetitively by incrementing the value i for all the strokes of the j'"'"'th reference character,

(h) means for detecting the minimum value p_min among the stroke differences p_i thus stored,

(i) means for operating the members (e), (f), (g) and (h) repetitively for by incrementing the value k all the strokes of the input character, and accumulating the value p_min to provide the value dθ

_j, which is the pattern difference between the input character and the j'"'"'th reference character,

(j) a storage for storing the value dθ

_j,

(k) means for operating the members (i) and (j) repetitively for all the reference characters to provide the set of dθ

_j for the given input character,

(l) means for detecting the minimum value among the values dθ

_j, and determining the input character as the reference character which provides the minimum value of dθ

_j.

2. A pattern recognition system for hand-written characters according to claim 1, wherein the predetermined number of feature points for each stroke of the input character is three and those three feature points are the initial point, the center point and the end point of each stroke.