Patent ID: 9036213
Filing Date: 2015-05-19
Classification: G06K,H04N

Abstract:
1. A method for image processing a digital color image, the method comprising the steps of: generating from the digital color image for each of a number of predetermined process colors a digital separation image, each digital separation image specifying for each pixel of said digital color image a color density value for the associated process color; associating with each individual digital separation image a separate array of threshold values for converting the digital separation image into a print signal that indicates for each pixel whether a dot of marking material of the corresponding process color is to be applied, wherein the separate arrays of thresholds are mutually uncorrelated; adding up, for each pixel, the color density values of all said process colors to determine a total density value; splitting, for each pixel, the color density value of each process color into a basic part and an excess part, if the total density value exceeds a predetermined density threshold, wherein the predetermined density threshold is lower than 100% and a sum of the basic parts does not exceed the predetermined density threshold; converting the basic part, or the color density value if the total density value does not exceed the density threshold, of each process color into a print signal using a dither technique and a first array of threshold values, said dither technique and first array of threshold values being associated with one of the process colors, and converting the excess part of each process color into a print signal using a dither technique and an array of threshold values that is associated with the digital separation image corresponding to the process color.