A method of compressing digital images

摘要

A method (400) of compressing a digital image including a matrix of elements each one consisting of a plurality of digital components of different type representing a pixel, the method comprising the steps of splitting (455) the digital image into a plurality of blocks and calculating, for each block, a group of DCT coefficients for the components of each type, and quantizing (460-465) the DCT coefficients of each block using a corresponding quantization table scaled by a gain factor for achieving a target compression factor; the method further comprises the steps of determining (440) at least one energy measure of the digital image, and estimating (441-450) the gain factor as a function of the at least one energy measure, the function being determined experimentally according to the target compression factor.