US Patent 7154637 Dither volume for cell location

While a general large layer dither volume provides great flexibility in dither cell design, by decoupling different intensity levels, they are inefficient to access since each color component requires the retrieval of a different bit from the volume. Therefore in a multi threshold dither volume for digital halftoning a contone color image, in the form of an array of contone color pixel values to bi-level dots, there is allocated for each dither cell location a fixed set of n thresholds defining n+1 intensity intervals within which said dither cell location is defined to be alternatively not set and set.