Patent ID: 8294952
Filing Date: 2012-10-23
Classification: H04N

Abstract:
1. A halftoning process for printing digital images, said halftoning process comprising: receiving CMYK input pixel data that define an input pixel of an input digital image in terms of continuous tone input data values for cyan, magenta, yellow, and black colors, wherein I(C), I(M), I(Y), I(K) respectively correspond to said continuous tone input data value for said cyan, magenta, yellow, and black colors; converting said CMYK input pixel data to modified CMYKRGB* pixel data that define said input pixel in terms of error-adjusted continuous tone data values for said cyan, magenta, yellow, and black colors, and also in terms of red, green and blue colors, wherein I*(C), I*(M), I*(Y), I*(K), I*(R), I*(G), I*(B) respectively correspond to said error-adjusted converted continuous tone input data values for said cyan, magenta, yellow, black, red, green, blue colors; quantizing said modified CMYKRGB* pixel data to derive intermediate output CMYKRGB pixel data in which said cyan, magenta, yellow, black, red, green, and blue colors are each defined by either a first quantized value that represents no color or a second quantized pixel value that represents full color, wherein O′(C), O′(M), O′(Y), O′(K), O′(R), O′(G), O′(B) respectively define said intermediate output pixel data for said cyan, magenta, yellow, black, red, green, and blue colors, and wherein said intermediate output CMYKRGB pixel data define an output pixel that corresponds to said input pixel; converting said intermediate output CMYKRGB pixel data to CMYK output data in which said output pixel is defined in terms of CMYK output values O(C), O(M), O(Y), O(K) respectively for said cyan, magenta, yellow, and black colors, wherein each of said CMYK output values is defined by either a first output value representing no color or a second output value representing full color.