Abstract: In a method in which the data related to the image are read in successive blocks, then subjected to orthogonal transformation, the coefficients of the transform obtained being quantized and analyzed according to a certain order and applied in the form of binary signals to a redundancy reducing coder, the signals representing the coefficients of the transform are stored in a memory organized in several blocks, and the contents of said memory are analyzed such that the signals applied to the redundancy reducing coder comprise sets of signals of coefficients taken from a group of blocks, the signals of each coefficient in each set being taken from a separate block belonging to said group of blocks.