Patent ID: 6614941
Filing Date: 2003-09-02
Classification: H04N

Abstract:
Apparatus for generating quantisation values for use in quantisation of regions of an input image, comprising:a plurality of non-final stages, each said non-final stage including (i) means for generating a test quantisation value in dependence on a basic quantisation value and an activity value indicative of a degree of detail in a current region; (ii) means for compressing frequency separated image data from said current region in accordance with said test quantisation value; (iii) means for comparing said resulting quantity of compressed data with a desired quantity of data; and (iv) means for adjusting said basic quantisation value to be used by a next stage in dependence on whether said quantity of compressed data is greater than or less than the desired quantity; and a final stage, said final stage being operable to generate a final quantisation value for use in quantising said image data for said current region in dependence on said basic quantisation value and said activity value indicative of a degree of detail in said current region.