| US 7,518,757 B2 | ||
| Image reading apparatus and control program therefor | ||
| Noriyoshi Chizawa, Ibaraki (Japan); and Katsuhiro Ishido, Ibaraki (Japan) | ||
| Assigned to Canon Kabushiki Kaisha, (Japan) | ||
| Filed on Sep. 12, 2003, as Appl. No. 10/661,824. | ||
| Claims priority of application No. 2002-267773 (JP), filed on Sep. 13, 2002. | ||
| Prior Publication US 2004/0114827 A1, Jun. 17, 2004 | ||
| Int. Cl. G06K 9/40 (2006.01); H04N 1/58 (2006.01) | ||
| U.S. Cl. 358—461 [358/463] | 9 Claims |
| 9. An image reading apparatus comprising:
a white reference member;
an original document glass;
an image reading device selectively capable of imaging an original document placed on the original document glass and a reference
surface of the white reference member, wherein the image read device generates white reference image data when the image reading
device images the reference surface of the white reference member and generates original image data when the image reading
device images an original document on the original document glass;
a random noise suppressing device that suppresses random noise components in the white reference image data;
a detecting device that detects a location of one or more abnormalities in the white reference image data in which random
noise components have been suppressed by the random noise suppressing device, wherein each abnormality corresponds with the
presence of foreign matter on the reference surface of the white reference member; and
an abnormality identification device that generates an abnormality signal indicative of the detected location of the abnormality.
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