A method and apparatus for block quantization for color halftoning is
described. In one embodiment, the method comprises dividing an input
image and an output image into blocks, wherein each block in the output
image corresponds to one block in the input image. The method also
includes dividing each block into subblocks if an edge exists in said
each block, calculating a color average of each input block, and
calculating a set of output colors for each block in the output image to
match the color average of its corresponding block in the input image.