Quantization of the colors in a digital image within a color space is achieved by successively dividing the colour space into a number of compartments in a number of steps, each compartment containing a subset of the colors of the image. Each step comprises: determining the variance in a predetermined...http://www.google.co.uk/patents/US6781593?utm_source=gb-gplus-sharePatent US6781593 - Method and apparatus for color quantization
