Patent ID: 6930693

Claim:
A method of image signal processing wherein a signal defining a pixellated multi-level image is defined by a first plurality of binary strings in a memory, the strings having associated therewith respective weightings and defining respective bit planes each bit plane corresponding to a digitised pixelwise intensity distribution, such that the weighted pixelwise intensity distribution over all said plurality of bit planes corresponds to said multi-level image, comprising the steps of: storing said strings in sequential locations in said memory in decreasing order of weighting; and making a succession of read cycles from the stored strings, each read cycle consisting of reading at least one of the stored strings in sequence as stored, commencing with the string for the highest weighting, the numbers of the strings read in the read cycles being varied so that at the end of the succession of read cycles each string has been read out a number of times proportional to its associated weighting.