Method for the encoding of data for assistance in the reconstruction of a sub-sampled moving electronic image

A method for encoding assistance data for use in the reconstruction of an electronic image belonging to a sequence of images using a compressed image signal, wherein the compression of the image signal comprises the steps of:

• dividing the electronic image into elementary image blocks containing a fixed number of pixels,
• selecting an optimal processing operation from among several concurrent compression processing operations achieved in parallel for each elementary image block, the processing operations comprising at least one compression processing operation by image filtering and at least one compression processing operation by motion compensation,
• segmenting the image into substantially homogeneous superblocks of variable size i.times.i for which all elementary image blocks are defined collectively, and classifying each superblock according to the level of segmentation from a minimum size containing a single elementary image block, each level corresponding to the regrouping of four lower level adjacent blocks, the encoding method comprising the steps of:
• generating for at least two levels of segmentation a first code for each superblock representing the homogeneity of the superblock, the compression processing employed, and the level of segmentation,
• generating a second code for each superblock representing a motion vector where motion compensation compression processing is employed and the level of segmentation, and
• multiplexing the codes together under the control of a sequencing means locked into a pre-determined image scanning procedure such that segmentation information is retained only for superblocks containing more than one elementary image block, and motion vector information is expressed only for blocks where motion compensation compression processing is employed.