Patent ID: 7551334

Claim:
A method of transforming an original image from a red-green-blue (RGB) color space representation to a luminance-chrominance (Lab) color space representation, comprising: receiving an original image in a red-green-blue color space at an analyzer of a document processing system; converting pixels in the original image from the RGB color space to a luminance chrominance color space using an RGB to Lab converter; determining background pixels in the original image using a background pixel determining processor, including: comparing a luminance value (L) representation of each pixel in the Lab color space to a selectable, adjustable luminance threshold value, comparing a chrominance value (ab) representation to a predetermined chrominance threshold value for each pixel in the Lab color space for which the luminance value representation exceeds the luminance threshold value; and identifying pixels having chrominance value representations less than the predetermined chrominance threshold value as background pixels; and variably adjusting the chrominance value (ab) representation of pixels of the original image for each background pixel in the Lab color space having a chrominance value representation in a neutral chrominance range defined by a start chrominance value less than a neutral chrominance value and an end chrominance value greater than the neutral chrominance value using a background pixel adjusting processor, the variable adjusting based at least in part on a functional relationship of the chrominance value representation to a prespecified chrominance adjustment table associated with the neutral chrominance range.