 Data acquisition system and method with a selectable sampling rate |
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| Model train control system |
| OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a model train control system 10 includes a ... |
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| Control, sound, and operating system for model trains |
| The present invention provides a model train operating, sound and control system that provides a ... |
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| Control, sound, and operating system for model trains |
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| Integrated circuit testing device with dual purpose analog and digital channels |
| What is claimed is: 1. An apparatus for performing tests on integrated circuits, each integrated ... |
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| Equalization system for modems in a polled arrangement |
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| Latched fedback memory finite-state-engine |
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| Integrated sample and hold circuit |
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Color printer calibration architecture
| Details |
Inventors: Rolleston, Robert J.; Maltz, Martin S.; Stinehour, Judith E.;
Assignee:
Primary Examiner: Brinich; Stephen
Assistant Examiner: Grant, II; Jerome
Attorney, Agent or Firm:
In a printer which produces images as a function of the combination of cyan (C), magenta (M), yellow (Y) and black (K) colorants on an output color print, responsive to device independent colorimetric description of an image, there is provided a method of calibrating the response of the printer to an image described in terms of colorimetric values, including the steps of first, gray balancing or linearizing colorant signals; secondly, adding black to an ideal device dependent description of a color image in accordance with a predetermined black addition process, and thirdly, providing a color correction transformation process, where the color correction transformation is accomplished via a method of interpolating printer responses from a look-up table indexing colorimetric descriptions of measured real responses, which take into account subsequent black addition and signal linearization. |
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DETAILED DESCRIPTION We claim: 1.
A method of calibrating a color printer so that color images defined in terms of colorimetric color signals may be printed on a color printer responsive to printer colorant signals to render color prints with a set of three primary colorants and black on a substrate, the calibration method comprising the ordered steps of: a) linearizing the printer response by: i) producing a set of printer colorant signals to print a corresponding test pattern set of varying density samples of each of the three primary colorants and black on a substrate, ii) measuring the density of each printed density sample, and iii) generating a printer linearization table for each of the three primary colorants and black, whereby a linear increase in a colorant signal produces a linear increase in a printer colorant signal; b) determining, for a given density characteristic of a combination of primary colorant signals to generate a color on the substrate, a black colorant signal, to add black to a color print; c) producing a color transform and correction table by: i) producing a second set of printer colorant signals of colors from combinations of the three primary colorants, with black colorant signals added in accordance with the determined density characteristic of the combination of primary colorant signals, to print a corresponding second test pattern set of color samples from combination of the three primary colorants and black on a substrate, ii) measuring the color of each printed color sample in terms of colorimetric color signals, and iii) generating a color transformation table mapping measured colors in terms of the three primary colorants used to generate the color samples to colorimetric color signals; d) storing an addressable mapping of colorimetric color signals to colorant signals in a printer memory.
2.
A method as defined in claim 1, and including the further step, after determining the black colorant signal, and prior to producing a color transform and correction table, determining an amount by which each colorant can be correspondingly reduced for under color removal
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