Method and device for estimating and hierarchically coding the motion of sequences of images

A method for estimating and hierarchically coding the motion of sequences of images, comprising the steps of:

• at a first step, partitioning a current image into 2.sup.P+1 .times.2.sup.P+1 pixel macroblocks, where p is an integer, and determining first field of motion vectors, which is associated with this partition into macroblocks, by using an iterative and recursive estimation algorithm initialized by field of motion vectors estimated for a preceding image;
• at a second step, partitioning into quadrants each of the macroblocks and determining, for the blocks which result therefrom, second field of motion vectors by using the interactive and recursive estimation algorithm but initialized by vectors from the field of motion vectors which were estimated at the preceding level;
• at an ith step, i=3 to D, where n is an integer, partitioning each of the blocks of the i-1 level into quadrants and determining, for the blocks which result therefrom, an ith field of motion vector by using the iterative and recursive estimation algorithm initialized by vectors from the field of motion vectors which were estimated at the preceding level, the blocks of minimum size being 2.sup.l+1 .times.2.sup.l+1 pixel blocks, where l is an integer;
• determining a final motion vector field from the n resulting field of motion vectors by choosing a lowest level of partition for which the field of motion vector associated with the corresponding block leads to a minimization of a criterion reflecting differences of brightness between blocks communicating in the successive images via the estimated displacement vectors.