Patent ID: 7382923

Claim:
Method of processing a coded digital signal including a set of samples obtained by coding a set of original samples representing physical quantities using a multiresolution coding format, and including a set of information relating to a size w, h of the set of original samples and its resolution res, comprising the steps of: locating a subset of original samples of given size zulx, zuly, zh, zw and resolution zres in the set of original samples according to the set of information relating to the size w, h and the resolution res of this set; determining, amongst coefficients of a low-frequency sub-band LL O of a last decomposition level obtained by decomposition into frequency sub-bands of the set of original samples, a number of coefficients per dimension of the signal which correspond to the located subset; deciding, at the decoding side, to modify or not to modify the size of the located subset according to the determined number of low-frequency sub-band coefficients before restoring the located subset, said deciding step including taking into account at least one predetermined criterion representing a quality level for the restored subset of original samples of the digital signal; and modifying the size of the located subset of original samples, in which the modification is an increase in the size of the subset of original samples, wherein by representing, in a space of dimensions corresponding to the dimensions of the digital signal, a position of the coefficients of the low-frequency sub-band of the last decomposition level and a position of the subset of original samples delimited by a boundary, the increase in the size of the subset consists of moving the boundary so as to add to the subset at least one coefficient of the low-frequency sub-band per dimension of the digital signal, the at least one added coefficient being situated close to the boundary before the movement thereof.