Abstract: An arrangement for estimating motion in a sequence of picture comprising first, second and third picture stores (10, 20, 30) arranged in series to ensure the permanent storage of three respective consecutive pictures denoted, for example, by their rank 2k, 2k+1, 2k+2 in the sequence of pictures, and a recursive displacement estimator (40) receiving the outputs of said first and third picture stores to update at each extension of the classifying tree the displacement vectors relating to the junctions of the tree and the send them to a delayed-decision circuit (50), said delayed-decision circuit receiving said updating information and also the outputs of said picture stores and supplying, for each block preceding the current block of L blocks, the information of the group in which this preceding block and the information of the corresponding displacement vector is finally classified.

Abstract: A receiver for a high definition television signal in which the signal prior to transmission is sub-sampled on a block-by-block basis according to the movement has an input (39) which receives the sub-sampled signal which is applied to a shuffler (40) which shuffles the pixels of blocks in a manner which is the inverse to that performed prior to transmission. The correctly positioned pixels are applied to means (43,44,45) for adaptive switched interpolation filtering capable of providing spatial frequency filter responses which approximate those at the transmitter, for sub-sampling blocks of the interpolated picture are sub-sampled but where pixels adjacent but outside a block are sub-sampled with the same structure as that of the block and for non-adaptive switched interpolation filtering for providing spatial frequency filter responses which substantially correspond to those at the transmitter. An output (46) provides the reproduced high definition television signal.