Methods and apparatus for determining a total colorant limit for digital imaging devices
AssigneeElectronics for Imaging, Inc.
InventorsMario Kühn, Samer Mady
Life of this patent
Estimating the term…
Abstract
Methods and apparatus are provided for calibrating a digital color imaging device to a printing press by determining a total colorant limit, per-channel colorant limits, and channel linearization tables using colorimetric and/or spectrophotometric techniques. In addition, for digital color imaging devices that use multi-hue colorants, methods and apparatus are provided for determining distribution functions for the multi-hue colorants as a function of input values.
Claims24
A system for calibrating a digital color imaging device, the system comprising:
- a color output device for printing an image file including a test pattern, the test pattern comprising a plurality of strips, each strip comprising a plurality of test patches, the test patches for each strip comprising scales of percentages of a fixed number of at least two C, M, Y, and K colorants;
- a measurement device that measures each of the test patches for colorimetric data;
- a processor for calculating the total colorant limit by:
- receiving the colorimetric data from the measurement device based upon the colorimetric data;
- selecting one patch in each strip with a minimum lightness;
- determining, for each patch in each strip that was selected by the processor as having a minimum lightness, a total area coverage (TAC), the TAC comprising a sum of the percentages of colorants used to produce the patch;
- selecting a maximum TAC from the TAC determined for each patch in each strip that was selected by the processor as having the minimum lightness;
- and
- the processor setting the total colorant limit to the maximum TAC selected by the processor.
A computer-implemented method for calibrating a digital color imaging device, the method comprising:
- printing a test pattern, the test pattern comprising a plurality of strips, each strip comprising a plurality of test patches, the test patches for each strip comprising scales of percentages of a fixed number of at least two C, M, Y, and K colorants;
- measuring each of the test patches for colorimetric data;
- receiving the colorimetric data from the measurement device;
- selecting, with a processor, one patch in each strip with a minimum lightness;
- based on the patches selected in the previous step, determining, with the processor, a total area coverage (TAC), the TAC comprising a sum of the percentages of colorants used to produce the patch;
- based on the patches for which TAC was determined in the previous step, selecting, with the processor, the patch with a maximum TAC;
- and
- setting, with the processor, the total colorant limit to the maximum TAC that was determined in the previous step.
Dependencies are inferred from the claim text.