Method for calibrating a color printer using a scanner for color measurements
First Claim
1. A method of calibrating a color reproduction device, comprising the steps of:
- (a) scanning a standard target using a subject scanning means to generate a first plurality of color signals;
(b) obtaining a second plurality of color signals, said second plurality of color signals generated by an object measurement means using said standard target;
(c) creating scanner tables for said subject scanning means dependent on said first plurality of color signals and said second plurality of color signals;
(d) scanning a subject target using said subject scanning means to generate a third plurality of color signals;
(e) generating a fourth plurality of color signals using said third plurality of color signals and said scanner tables;
(f) obtaining a fifth plurality of color signals, said fifth plurality of color signals representing desired color signals; and
,(g) creating calibration curves for a subject color reproduction device dependent on said fourth plurality of color signals and said fifth plurality of color signals.
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Abstract
The present invention is a method for calibrating color reproduction devices such as printers and for stabilizing the print colors generated by a computer controlled color reproduction device. Further, the present invention acts to standardize the print colors produced across a family or series of color reproduction devices. It may be incorporated into a color management system used to produce consistent colors across a variety of reproduction devices. In the first embodiment of the present invention, an object scanning device and an object color reproduction device are used. In the second embodiment, an object densitometer is used as the measuring device to measure densities. In yet another embodiment, an object colorimeter is used as the measuring device to measure CIE values. The present invention enables generation of a set of calibration curves for correcting the color output of the color reproduction device. The calibration curves provide modification functions for each of the individual color print channels of the color reproduction device (e.g., CMYK). The calibration curves are used to alter the rendering of color reproductions, and thereby achieve a desired result. The calibration curves may be downloaded to a color management system to alter the rendering of color images, pages, documents, etc., and thereby achieve a desired result. The calibration curves may also be downloaded directly to the controller of the color reproduction device. The present invention further provides an improved method of measuring ink values using a subject scanner by defocusing or diffusing a target.
178 Citations
53 Claims
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1. A method of calibrating a color reproduction device, comprising the steps of:
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(a) scanning a standard target using a subject scanning means to generate a first plurality of color signals; (b) obtaining a second plurality of color signals, said second plurality of color signals generated by an object measurement means using said standard target; (c) creating scanner tables for said subject scanning means dependent on said first plurality of color signals and said second plurality of color signals; (d) scanning a subject target using said subject scanning means to generate a third plurality of color signals; (e) generating a fourth plurality of color signals using said third plurality of color signals and said scanner tables; (f) obtaining a fifth plurality of color signals, said fifth plurality of color signals representing desired color signals; and
,(g) creating calibration curves for a subject color reproduction device dependent on said fourth plurality of color signals and said fifth plurality of color signals. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of modifying reproduction means, comprising the steps of:
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(a) generating first measured data of a standard target using a first scanning means; (b) obtaining first reference data of said standard target; (c) creating scanner tables for first color channels of said first scanning means; (d) generating second measured data of a subject target using said first scanning means, said subject target produced by a first reproduction means; (e) computing third measured data dependent on said second measured data and said scanner table; (f) obtaining second reference data of an object target; (g) modifying second color channels of said first reproduction means dependent on said second reference data and said third measured data. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48)
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49. A method of generating color signals using a scanning means, comprising the steps of:
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(a) disposing a target on a scanning means, said target comprising a plurality of single-colorant patches; (b) disposing a distortion means connected to said scanning means and to said target; (c) generating a plurality of scan signals using said scanning means and distorting means, said plurality of scan signals dependent on said target. - View Dependent Claims (50, 51, 52, 53)
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Specification