Method and circuit for scaling raster images

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US007565031B2

(12) United States Patent

Loew

(io) Patent No.: (45) Date of Patent:

US 7,565,031 B2 Jul. 21, 2009

(54) METHOD AND CIRCUIT FOR SCALING RASTER IMAGES

(75) Inventor: Andreas Loew, Gross-Gerau (DE)

(73) Assignee: Thomson Licensing, Boulogne Billancourt (FR)

( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 618 days.

(21) Appl.No.: 10/806,734

(22) Filed: Mar. 23, 2004

(65) Prior Publication Data

US 2004/0218835 Al Nov. 4, 2004

(30) Foreign Application Priority Data

Apr. 3, 2003 (DE) 103 15 442

(51) Int. CI.

G06K 9/32 (2006.01)

(52) U.S. CI 382/298; 345/660; 348/581;

348/704; 358/451; 708/208

(58) Field of Classification Search 382/298

See application file for complete search history.

(56) References Cited

U.S. PATENT DOCUMENTS

5,097,518 A * 3/1992 Scott etal 382/298

5,530,482 A * 6/1996 Gove et al 348/441

5,561,725 A 10/1996 Degi et al.

5,825,367 A 10/1998 Shyuetal.

2002/0114535 Al * 8/2002 Luo 382/282

2003/0185451 Al * 10/2003 Jung 382/233

FOREIGN PATENT DOCUMENTS

EP 0497494 8/1992

* cited by examiner

Primary Examiner—Matthew C Bella

Assistant Examiner—David P Rashid

(74) Attorney, Agent, or Firm—Robert D. Shedd; Robert B.

Levy

(57) ABSTRACT

A method is proposed which enables high-resolution raster images to be represented on lower-resolution displays. The method according to the invention selects support points in lines and columns of the original image, which have a smallest possible variation of their distances and approximate the set scaling at least in ranges. Consequently, rational scaling ratios can also be achieved in an advantageous manner. In order to represent fine details of the original image in the scaled image as well, the adjacent pixels of the support points are also incorporated into the calculation of the pixels that are output. Furthermore, a circuit for scaling a raster image inreal time is proposed. Moreover, a film scanner having a scaling device in accordance with the method according to the invention is proposed.

5 Claims, 6 Drawing Sheets