Browse Prior Art Database

VARIATIONS ON DOT-CENTERED HALFTONE CHARACTERIZATION

IP.com Disclosure Number: IPCOM000027683D
Original Publication Date: 1998-Oct-31
Included in the Prior Art Database: 2004-Apr-08
Document File: 4 page(s) / 155K

Publishing Venue

Xerox Disclosure Journal

Abstract

U.S. Patent 5,469,267 to Wang discloses a system of mathematically characterizing any kind of halftone pattern. In the scheme of this patent, any image containing halftones is characterized as comprising a large number of square cells. Each of these cells is considered to have, at one corner thereof, a location where a halftone dot is possibly centered. Under this scheme, only seven types of cells could possibly exist, and any kind of halftone pattern, such as created by a digital printer, could be characterized as a combination of any number of these seven types of cells. This characterization scheme, as explained in the patent, enables relatively quick and simple techniques for analyzing halftone patterns obtained in various ways, and can be used to calibrate digital printers.

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XEROX DISCLOSURE JOURNAL

VARIATIONS ON DOT-CENTERED HALFTONE CHARACTERIZATION Shen-ge Wang
David A. Mantell

Proposed Classification
U. S. CL 3581298 Int. C1. H04n 01/21

Fig. 1

XEROX DISCLOSURE JOURNAL - Vol. 23, No. 5 SeptembedOctober 1998 225

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VARIATIONS ON DOT-CENTERED HALFTONE CHARACTERIZATION(CONT'D)

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Fig. 2

U.S. Patent 5,469,267 to Wang discloses a system of mathematically characterizing any kind of halftone pattern. In the scheme of this patent, any image containing halftones is characterized as comprising a large number of square cells. Each of these cells is considered to have, at one corner thereof, a location where a halftone dot is possibly centered. Under this scheme, only seven types of cells could possibly exist, and any kind of halftone pattern, such as created by a digital printer, could be characterized as a combination of any number of these seven types of cells. This characterization scheme, as explained in the patent, enables relatively quick and simple techniques for analyzing halftone patterns obtained in various ways, and can be used to calibrate digital printers.

Proposed here is a number of variations on the basic method shown in the '267 patent. Whereas the original patent described square cells, with each comer of the square being centered on one pixel area, alternate cell configurations can provide practically superior results, such as in calibration and halftone development. Figure 1 shows how four pixels forming...