A multiresolution motion estimation technique with indexing
In the multiresolution motion estimation (MRME) techniques originally proposed by Zhang and Zafar, four MRME algorithms have been proposed. In one of these algorithms, the motion vectors in the low-pass subband are properly scaled and used as the final motion vectors for all the other subbands, and, in another, the properly scaled motion vectors in the first algorithm are used as predictions and further refined. The former algorithm requires a much lighter computational load and fewer coding bits for the motion vectors than the latter; on the other hand, the latter is able to provide a better MRME performance than the former. In this paper, we propose a new MRME technique that takes advantage of both of the above algorithms. In the proposed algorithm, the sum of absolute difference associated with each of the scaled motion vectors as in the first algorithm is calculated, and the result compared with the sum of the absolute values of the amplitudes of the wavelet coefficients within the motion block to be compensated. The outcome of the comparison decides if these scaled motion vectors are accepted as the final ones. For the coding of motion information, the motion vectors used for the prediction and their patterns of applicability to higher resolution levels, called the indices, are coded.