Browse Prior Art Database

METHOD FOR ESTIMATING COLOR GAMUT MAPPING ON A DISPLAY DEVICE

IP.com Disclosure Number: IPCOM000026506D
Original Publication Date: 1992-Jun-30
Included in the Prior Art Database: 2004-Apr-06
Document File: 4 page(s) / 266K

Publishing Venue

Xerox Disclosure Journal

Abstract

Color images prepared and displayed on one color device are often disappointing when reproduced on a different device because of the incorrect reproduction of one or more colors. It is desirable to have a method for easily and quickly previewing and predicting, on a color source device, the reproduction of a color on a target device. There is proposed herein a method for quickly and inexpensively determining an estimated, or roughly predicted, target color for each of one or more original colors, on a selected printer or other color output device, taking into account the color reproducing characteristics of that device. The estimated target colors are displayed on the user's display (source device) as a preview of roughly how the colors will be reproduced on the selected target device. This allows the user to determine whether the target device will provide colors appropriate for the user's purposes before actually printing the illustration or palette of colors, thereby saving the expense, time, and computational power involved in preparing one or more printed drafts.

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XEROX DISCLOSURE JOURNAL

METHOD FOR ESTIMATING COLOR GAMUT MAPPING ON A DISPLAY DEVICE
Giordano Bruno Beretta

Y

Proposed Classification

U.S. C1.358/080

Int. C1. G04n 1/04

 Prepare Rough Prediction Model

/32

i

Green

.1 .2 .3 .4 .5 .6 .7 .8

 Select Uncalibrated Target Device Colors Corresponding to Source Primary Colorants

  Prepare Target Device Color Samples From Selected

Yes

Fig. I

stop

Fig. 2

XEROX DISCLOSURE JOURNAL - Vol. 17, No. 3 May/June 1992 171

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METHOD FOR ESTIMATING COLOR GAMUT MAPPING ON A DISPLAY DEVICE(Cont'd)

Color images prepared and displayed on one color device are often disappointing when reproduced on a different device because of the incorrect reproduction of one or more colors. It is desirable to have a method for easily and quickly previewing and predicting, on a color source device, the reproduction of a color on a target device. There is proposed herein a method for quickly and inexpensively determining an estimated, or roughly predicted, target color for each of one or more original colors, on a selected printer or other color output device, taking into account the color reproducing characteristics of that device. The estimated target colors are displayed on the user's display (source device) as a preview of roughly how the colors will be reproduced on the selected target device. This allows the user to determine whether the target device will provide colors appropriate for the user's purposes before actually printing the illustration or palette of colors, thereby saving the expense, time, and computational power involved in preparing one or more printed drafts.

An internationally recognized color specification standard established by the

CIE (the Commission Internationale de YEclairage) uses tristimulus values to define, independent of any color reproduction device, the appearance of a color based on the spectral reflectance and spectral power distribution of a colored object. It is generally known that the linear mathematical transform of Equation (1) maps red, green, and blue colorant values for a color in the RGB color space of a color monitor into XYZ tristimulus values in tristimulus space:

k]

p:

A,

f;] A,

. b]

(1)

where R, G, and B are each in a range from 0 to 1 and represent the coordinates of the color in the monitor's RGB color space; X, Y, and 2 are the tristimulus values of the color; A17A2,A3,A4,A5,A6,A7,A8, and A9 are the constant coefficients of the transformation matrix, and 0 signifies matrix multiplication.

The method disclosed herein is based on the discovery that, despite the fact that target devices such as printers do not use additive color reproduction technology, an adequate estimation or rough prediction of original monitor colors to be reproduced on a particular printer may be obtained, without actually printing the colors, by treating the printer as though it were a device having a set of primary colorants which beha...