Patent ID: 6031630
Filing Date: 2000-02-29
Classification: H04N

Abstract:
A method for undercolor removal (UCR) from a multi-color image represented by N color planes of non-black pixel image color values and replacement of removed undercolor by black values, said method comprising the steps of:a) obtaining a corrected black color plane of initial maximum black color values by replacing each black color value with a black color value that is a function of an initial maximum black color value and N-1 of logically corresponding non-black pixel image color values;b) revising page strip portions of said corrected black color plane so that each pixel black color value thereof is converted to a UCR value by deriving said function of said each pixel black color value and a logically corresponding, Nth color plane non-black pixel image color value;c) subtracting from respective ones of Nth color plane non-black pixel image color values, logically corresponding UCR values for each page strip and feeding each said page strip to a print engine for rendering of resultant Nth color plane non-black pixel image color values;d) subtracting from remaining ones of said N-1 color plane non-black pixel image color values, logically corresponding UCR values for each page strip and feeding each said page strip to the print engine for rendering of each resultant color plane of resultant non-black pixel image color values; ande) employing said UCR values from said black color plane as derived in step b) to enable rendering of black by said print engine.