Image processing apparatus capable of efficient coding of complex shape ...

United States Patent m

Onokera

[54] IMAGE PROCESSING APPARATUS

CAPABLE OF EFFICIENT CODING OF
COMPLEX SHAPE INFORMATION

[75] Inventor: Ken Onokera, Yokohama, Japan

[73] Assignee: Canon KabushiH Kaisha, Tokyo, Japan

[21] Appl. No.: 387,627

[22] Filed: Feb- 13,1995

Related U.S. Application Data

[63] Continuation-in-part of Ser. No. 90,629, Jul. 12, 1993, abandoned, which is a continuation of Ser. No. 811,913, Dec. 23, 1991, abandoned, which is a continuation of Ser. No. 449,149, Dec. 15, 1989, abandoned, which is a continuation of Ser. No. 176,272, Mar. 31, 1988, abandoned.

[30] Foreign Application Priority Data

Apr. 6, 1987 [JP] Japan 62-083007

Apr. 6, 1987 [JP] Japan 62-083008

[51] Int CI.6 G06K 9/48

[52] U.S. CI 382/199

[58] Field of Search 345/144; 395/142,

395/143; 382/187, 199, 201, 203, 232

[56] References Cited

U.S. PATENT DOCUMENTS

4,542,412 9/1985 Fuseetal 382/13

4,550,438 10/1985 Convis et al 382/56

4,620,287 10/1986 Yam 340/728

4,653,107 3/1987 Shojimaetal 382/22

4,674,059 6/1987 Schrieber 364/523

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US005644654A [ii] Patent Number: 5,644,654 [45] Date of Patent: Jul. 1, 1997

4,686.632 8/1987 Schrieber 340/728

4,771,474 9/1988 Takashima et al 382/23

FOREIGN PATENT DOCUMENTS

2147474 5/1985 United Kingdom H04N 1/411

8302179 6/1983 WTPO G06F 3/00

Primary Examiner—Jose L. Couso

Attorney, Agent, or Firm—Fitzpatrick, Cella, Harper & Scinto

[57] ABSTRACT

There is provided an image processing apparatus for approximating the contour of a character or the like by a set of function curves or straight lines, thereby compressing the image data by contour decision information. This apparatus comprises: a designating section to designate a curve portion of a contour line; a section to obtain slopes and coordinates of the curve portion at the initial and terrninative points thereof or of each interval which is obtained by dividing the curve portion designated by the designating section; a section to determine a dividing point in the interval or on the curve portion; a section to obtain the coordinates of the dividing point; an approximating section to approximate the curve portion on the basis of the slopes of the curve portion and on the basis of the coordinates of the initial and terminative points and the dividing point; and a coder to encode the codes corresponding to the coordinates of a plurality of special points on the approximated curve into the coded data of the curve or interval. The approximating section performs the curve approximation by using a Bezier cubic curve and stores as the contour data of four special points on the Bezier cubic curve. Thus, the contour of image data can be approximated at a high speed and the image data can be easily compressed.

24 Claims, 11 Drawing Sheets