Complex-subband transform for subband-based motion compensation

A new method called complex subband transform (CST) is introduced for subband signals decomposition, the motion estimation, and the subband image sequence coding. There are two subband-based methods proposed which combine the process of motion compensation and the process of subband decomposition namely out-band and in-band compensation. We modify the M-band perfect reconstruction modulation filter (PRMF) and propose a so-called complex subband transform (CST). We also derive a method using CST-based phase correlation functions to calculate motion vectors for overlapped windowed regions. In the experiments, we show that the CST-based motion estimation generates a more accurate and coherent motion field than the conventional block matching methods