Method and device for coding an image signal with redundancy reduction with locally uniform distortion.

摘要

Method of image signal coding, the image being subdivided into blocks to be coded in sequence; first a two-dimensional linear transformation is applied to each of said blocks, obtaining a set of transformation coefficients Cij. The coding is carried out iteratively by coding at each iteration one of the coefficients of the block with an additional bit as compared to the preceding iteration, and evaluating at each iteration the global error value made if the image block is reconstructed starting from the total number of bits till now given to the block. The iterations relating to a block start from the coding of all its coefficients with zero bits and terminate when said global error becomes lower than a predetermined threshold error. A device is also described to implement the method.