Patent ID: 8125687
Filing Date: 2012-02-28
Classification: H04N

Abstract:
1. A method for determining colorant values for color patches in a printable target that contains plural such color patches, wherein the printable target is printable by a color printer having multiple colorant channels including a black channel and multiple non-black channels, and wherein the printable target is thereafter usable for color characterization of the color printer, wherein the method comprises: printing a black ramp using the black channel; measuring color values of the black ramp to obtain measured color values thereof; selecting substantially uniform steps on the black ramp as determined in a printer independent color space, by applying principal component analysis (PCA) to the measured color values or color values derived from the measured color values of the black ramp, and by using a first principal component from PCA thereof to select the substantially uniform steps, wherein the substantially uniform steps are substantially invariant to small variations in the first principal component of the measured color values on the black ramp; performing, for multiple ones of the substantially uniform steps on the black ramp, the following steps (a) through (c) of: populating colorant values of the color patches in the printable target by using multiple combinations on the substantially uniform steps on the black ramp and on the chromatic ramps that meet an ink limiting threshold.