Image scanner

United States Patent [19]

Mita

[54] IMAGE SCANNER

[75] Inventor: Kikuo Mita, Yokohama, Japan

[73] Assignee: Eastman Kodak Company, Rochester, N.Y.

[21] Appl. No.: 805,692

[22] Filed: Dec. 11, 1991

[30] Foreign Application Priority Data

Mar. 4, 1991 [JP] Japan 3-037637

[51] Int. CI.' H04N 1/38

[52] U.S. CI 358/464; 358/463;

358/447; 358/465; 358/448; 358/445; 382/51 [58] Field of Search 358/464, 463, 447, 462,

358/465, 454, 443, 471, 474, 445; 382/51, 50

[56] References Cited

U.S. PATENT DOCUMENTS

4,903,316 2/1990 Hongo et al 358/464

4,919,736 12/1990 Weiman el al 382/51

4,931,881 6/1990 Matsui et al 358/464

4,975,768 12/1990 Takayaga 358/464

5.048.096 9/1991 Beato 358/464

5,055,944 10/1991 Shibahara 358/464

5,081,691 1/1992 Chesley 382/51

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US005329382A

[ii] Patent Number: 5,329,382 [45] Date of Patent: Jul. 12, 1994

5,119,211 6/1992 Sakurai 358/444

5.138,674 8/1992 Sugawa 382/51

5,144,566 9/1992 Anderson et al 382/51

5,157.740 10/1992 Klein et al 382/51

5,166,810 11/1992 Sorimachi et al 358/463

5,166,986 11/1992 Mizuoka et al 382/51

FOREIGN PATENT DOCUMENTS

57-57089 4/1982 Japan 358/463

Primary Examiner—Edward L. Coles, Sr.

Assistant Examiner—Fan Lee

Attorney, Agent, or Firm—Raymond L. Owens

[57] ABSTRACT

A document image scanner that converts scanned images for output as bilevel images is provided with a bilevel image filter. The bilevel image filter counts the number of continuous pattern elements in each direction, vertical, horizontal and diagonal, from a specific point and compares the results with a predetermined reference. Patterns falling below the reference value are regarded as resulting from background noise and are erased.

3 Claims, 4 Drawing Sheets