A robust global motion estimation scheme for sprite coding

A new global motion estimation technique for sprite coding is presented in this paper. The proposed system manages to accurately register frames to a sprite without referencing the sprite. This allows motion estimation process to be performed in an environment free from the adverse influence of the sprite which is usually blurred by the erroneous motion estimation. Furthermore, our proposed system can figure out the frame having the highest resolution, base frame, in the video sequence and project all other frames to the space of this base frame. This can avoid the loss of information due to decimation. Moreover, the determination of the size of the sprite can be conducted before construction of the sprite which avoid clumsy process of manual sprite memory allocation. Experimental results show that our proposed technique manages to estimate global motion in high accuracy and indicate a good robustness against estimation error which is suitable for the sprite coding application in MPEG-4.