Patent ID: 7382915

Claim:
A method, comprising: high pass filtering at least one chrominance component of a color image to compute at least one high pass filtered chrominance component; applying a high pass filter to a luminance component of the color image to compute a high pass filtered luminance component; weighting the at least one high pass filtered chrominance component by a weighting factor based upon the high pass filtered luminance component, wherein the weighting factor includes a sign factor, wherein the sign factor is negative one when a polarity of the high-pass filtered chrominance information is opposite that of the high-pass filtered luminance signal, and wherein the sign factor is positive one when the polarity of the high-pass filtered chrominance information is the same as that of the high-pass filtered luminance signal; modifying a luminance component of the color image based upon the weighted at least one high pass filtered chrominance component; and generating a monochrome output image based upon the modified luminance component.