Robust global motion estimation and novel updating strategy for sprite generation

A new global motion estimation technique for sprite coding systems is presented. The proposed system can accurately register frames to a sprite without referencing to the sprite. This allows the motion estimation process to be performed in an environment independent of the quality of the sprite. The frame having the highest resolution of the scene is determined and all other frames can be projected on to the space of this chosen frame such that information loss due to decimation can be avoided. The static sprite is strategically updated, according to the major camera motion during decoding, to alleviate the problem of error propagation from the sprite image. Experimental results indicate that the proposed technique is very accurate and robust, which makes it suitable for MPEG-4 sprite coding