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Proceedings Paper

Scanner show-through reduction using reflective optics
Author(s): Xiao-fan Feng
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Paper Abstract

Document scanners are used to convert paper documents to digital format for document distribution or archiving. Scanners are also used in copier and fax machine to convert document to electrical signal in analog and digital format. Most document scanners use white backing to avoid black border or black hole in scanned images. One problem with white backing is that show-through from the backside is visible for duplex printed (two sided) documents. This paper describes an optical method to eliminate show-through without reverting back to the black border or black hole. The scanner cover is made into a saw-tooth shaped mirror surface. The surface is oriented so that it reflects the light from the scanner lamp to the scanner lens. When scanning the scanner cover as in the case of a hole in the paper, it reflects light (specular reflection) from the scanner lamp directly to the scanner lens. Because the scanner lamp is much brighter than the reflected light from the document, only a small portion of the reflected light is needed to have the same output as scanning a piece of white paper. Radiometric calculation shows that this new approach can reduce the overall reflection from the scanner cover to 8% when scanning a document, and yet, appear to be white when no document is in between the cover and scan bar. The show-through is greatly reduced due to this reduced overall reflection from the scanner cover.

Paper Details

Date Published: 18 December 2003
PDF: 10 pages
Proc. SPIE 5293, Color Imaging IX: Processing, Hardcopy, and Applications, (18 December 2003); doi: 10.1117/12.527623
Show Author Affiliations
Xiao-fan Feng, Sharp Labs. of America, Inc. (United States)

Published in SPIE Proceedings Vol. 5293:
Color Imaging IX: Processing, Hardcopy, and Applications
Reiner Eschbach; Gabriel G. Marcu, Editor(s)

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