A method for determining a number of colors in a digital image includes receiving a digital image and determining a total number of pixels in the digital image. A proportion of the total number of pixels is selected as having an infrequent color and a respective color for each one of a first portion...http://www.google.com/patents/US7266237?utm_source=gb-gplus-sharePatent US7266237 - System and method for a heuristics-based approach for determining a number of colors in an image
