US 5,579,031 AGranted

Color matching method and apparatus

AssigneeE. I. Du Pont de Nemours and Company

InventorZhongjie Liang

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Abstract

A process and related apparatus for producing at least two matched color displays of a digital image using two different display devices, comprising using an adaptor to convert the digital information representing the image to digital information such that the displayed image as a result of this converted digital information on one of the devices, appears the same as the image displayed on the other to an average observer when viewed under similar viewing conditions. The adaptor contains a transform LUT constructed using display device modeling to generate corresponding values to preselected input digital image values to map the input color values into the color space of the display device so that image matching is achieved. A output value signals received from a first model are compared to output value signals received from a second model to obtain an error signal used to modify the input color values to the second model, and the modified color values are then used to create the transform LUT for matching the color display of the second display device with that of the first device.

Claims12

Dependent claims

A method for matching the color input signals of at least a first display device and at least a second display device, the first and second display devices having an input, comprising:

(I) creating a transform LUT for converting input color values to output color values by:
(1) producing a first preselected plurality of input color values;
(2) using said plurality of input values to display a plurality of color patches in said first and said second display devices;
(3) obtaining a colorimetric value of each of the displayed color patches in each of the display devices and using said colorimetric values to create a first and a second model for the first and second devices respectively correlating preselected input color values to displayed colorimetric values for each of the two devices;
(4) inputting to said first and second models a second preselected plurality of color values;
(5) comparing an output value signal received from the first model to an output value signal received from the second model to obtain an error signal indicative of the difference between the two output value signals from each of said second plurality of color values;
(6) using the error signal to modify the input color values to the second model and again comparing the output value signal received from the first model to the output value signal received from the second model to obtain a new error signal;
(7) repeating the process of steps (5) and (6) above until the error signal is a minimum;
and
(8) using the modified color values obtaining at the minimum error signal to create the transform LUT correlating input values to the modified color values;
(II) displaying a plurality of source color image values on said first display device;
(III) using the transform LUT to transform the plurality of source color image values to corresponding new image values before inputting
said new image values to the input of the second
display device;
and
(IV) displaying said new color image values on said second display device producing a colorimetric match with the source color image values displayed on the first display device.

13 more elements

Apparatus for generating a transform LUT for converting input color values to output color values, comprising:

(1) digital color image values input means for receiving digital input color image values;
(2) an adder device having (i) a first signal input connected to the input means, (ii) a second, correction error, signal input, and (iii) an output;
(3) a switch circuit having (i) a first signal input connected to the adder device output, (ii) a second control signal input, (iii) a first output, and (iv) a second output;
(4) first and second display model means, each for producing output colorimetric tristimulus image values for input color values, each of said model means having an input and an output, the second model input connected to the first output of the switch circuit;
(5) means, connected to the output of said first and second model means, for comparing the tristimulus values output of the first and second display model means and for producing an error signal;
(6) means for receiving and testing the error signal to determine if said signal is a minimum error signal, and for outputting a correction error signal to the second, correction error, signal input of the adder device and a control signal to the second control signal input of the switch circuit;
and
(7) means also connected to the input means and the second output of the switch circuit for generating a transform LUT correlating digital input color values to modified color values appearing at the second output of the switch circuit when the means for testing determines that the error signal is a minimum.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/389,985Filed 14 Feb 1995 · continuation
Priority: 15 Dec 1992
Granted: 26 Nov 1996
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G06F 3/13
Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for…: digital…
G06F 3/1431
Controlling a plurality of local displays, e.g. CRT and flat panel display: using a single graphics controller
H04N 1/6055
Matching two or more picture signal generators or two or more picture reproducers: using test pattern analysis
G09G 2320/0276
Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping: for the purpose of adaptation to…