A non-iterative motion vector based global motion estimation algorithm

Global motion compensation (GMC) is a coding tool introduced in MPEG-4 advanced simple profile (ASP); it can improve the coding efficiency on video sequences with global motion. Conventional pixel-domain iterative global motion estimation (GME) algorithms for estimating the perspective transform model parameters are very computationally demanding, and thus its applicability is restricted. A fast non-iterative GME algorithm is proposed for estimating the perspective transform global motion parameters from the motion vectors (MV) obtained from the block matching process. The proposed algorithm first fits multiple global motion models from groups of input MVs, then, a robust estimate is formed by a histogram-based postprocessing. Simulation results show the proposed algorithm can achieve superior coding performance while using much fewer computations compared to the iterative approaches.