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CREATION OF UNIFORM GRAY IMAGE

IP.com Disclosure Number: IPCOM000026212D
Original Publication Date: 1990-Oct-31
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 80K

Publishing Venue

Xerox Disclosure Journal

Abstract

The addition of gray to an image is an important copy quality feature for a copier product. Gray is used in monochrome documents as a means of highlighting certain parts of the document, and for drawing attention to the document. Hence, the ability of a copier to reproduce the gray in an original as gray in the output, or to add gray highlights to an all black and white original is of value.

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XEROX DISCLOSURE JOURNAL

CREATION OF UNIFORM GRAY IMAGE U.S. C1.358/450 Paul M. Butterfield
Louis 0. Pepin

Proposed Classification

Int. C1. H04n 5/84

The addition of gray to an image is an important copy quality feature for a copier product. Gray is used in monochrome documents as a means of highlighting certain parts of the document, and for drawing attention to the document. Hence, the ability of a copier to reproduce the gray in an original as gray in the output, or to add gray highlights to an all black and white original is of value.

An original image must be made available for application of gray. The original image might be a source from a scanner or from a local area network. However sourced, the original image would be in the form of a binary bitmap. The creation of the original image must be such that if it were printed in its unaltered form, it would be reproduced asa black and white (no gray) image.

A second image must be created which ccntains a gray halftone bitmap. This bitmap would contain an ordered array of black and white pixels, which if printed would reproduce as a gray print. The source of the gray bitmap could be a scanner or an electronic generation algorithm. However created, the darkness of the gray (controlled by the ratio of black pixels to white) would be modulated to generate the desired darkness.

Schemes for adding gray could include:

1. Pixel-by-pixel combination of some part of the source image with an equivalent part of the gray...