Interframe coding using two-stage variable block-size multiresolution motion estimation and wavelet decomposition

We propose a two-stage variable block-size multiresolution motion estimation (MRME) algorithm. In this algorithm, a method to reduce the amount of motion information is developed, and a bit allocation method minimizing the sum of the motion information and the prediction error is obtained in the wavelet transform domain. In the first stage of the proposed scheme, we utilize a set of wavelet components of the four subbands in the lowest resolution. These motion vectors are directly used as motion vectors for the lowest subband, and are scaled into the initial biases for other subbands at every layer of the wavelet pyramid. In the second stage, the bottom-up construction of a quadtree based on the merge operation is performed. The proposed scheme reduces the uncompressed bit rate of 8 bits/pixel into 0.212 bits/pixel at 41.1 dB of PSNR for the "Claire" sequence, which can be regarded as nearly an 11% reduction compared with the conventional method.