Browse Prior Art Database

ILLUMINATOR APERTURE FOR DIGITAL IMAGE SCANNER

IP.com Disclosure Number: IPCOM000026640D
Original Publication Date: 1993-Feb-28
Included in the Prior Art Database: 2004-Apr-06
Document File: 2 page(s) / 72K

Publishing Venue

Xerox Disclosure Journal

Abstract

The figure depicts the illumination and optics components of an image input terminal, having a platen 4 upon which a document to be scanned is placed. The document image will be converted to an electrical representation by a charge coupled device (CCD)

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XEROX DISCLOSURE JOURNAL

ILLUMINATOR APERTURE FOR Proposed Classification DIGITAL IMAGE SCANNER U.S. C1.350/319 Richard M. Baran Int. C1. G02B 5/00, G02B

7/00, G02B 27/00

8 L /

XEROX DISCLOSURE JOURNAL - Vol. 18, No. 1 January/February 1993 31

[This page contains 1 picture or other non-text object]

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ILLUMINATOR APERTURE FOR DIGITAL IMAGE SCANNER(Cont'd)

The figure depicts the illumination and optics components of an image input terminal, having a platen 4 upon which a document to be scanned is placed. The document image will be converted to an electrical representation by a charge coupled device (CCD) 8 mounted on a movable optics carriage which reciprocates back and forth under platen 4 in the slow scan direction indicated by arrow 6. Scattered light from illuminator lamp 7 reaching the document on platen 4 is reflected and re-enters the illumination cavity 10 causing non- uniformity of the automatic gain correction (AGC) pixels in the slow scan direction. Large dark areas on the input document, near the slow scan registration edge, can cause a lower signal at the automatic gain correction pixels, similar to lower output of the lamp 7. The error in the AGC pixel level due to this scattered light has been measured to approach seven percent.

To avoid or reduce the scattered light causing this effect, an illuminator aperture 9 located near the platen 4 and extending across the width of the platen is used. This illuminator aperture 9 has been found to red...