Abstract: Disclosed is a method to achieve a sub-sampling of pictures, making it possible to optimize the spatial and temporal definition of the compressed signal, so as to enable a most faithful possible reconstruction of the picture received with said compressed picture signal and, if necessary, with complementary assistance data. A field of speed vectors is defined for at least each picture to be sub-sampled, and said pictures to be sub-sampled are sub-sampled by eliminating certain picture points, the preserved picture points being chosen so as to avoid selecting a picture point which corresponds spatially to the approximate projection of a source point preserved during the sub-sampling of the preceding sub-sampling picture, said projection resulting from the application, to said source point, of the associated shift vector.

Abstract: A method for the estimation of the motion of electronic picture points, in the plane of the picture, by means of fast, convergent and adaptive processing, notably in order to enable subsequent, efficient processing, by sub-sampling, of the picture sequence without harming the psycho-visual quality of the picture reconstructed from the sub-sampled picture. To each electronic picture point, there is assigned a displacement vector, computed according to a WALKER and RAO type of algorithmic process of prediction/correction, the predicted value of motion of the current point being the value of the original displacement vector associated with a point of origin of the preceding picture, so that said current point is the approximate projection of said point of origin along said original displacement vector.