AN INTEGRATED APPROACH TO BLOCK BASED MOTION ESTIMATION FOR VIDEO CODING

In video communication systems motion compensation techniques allow to remove temporal redundancy among frames in order to achieve strong re ductions in bitrate. Block based approaches are widely used for such a task, since they offer a good balance between performances and comple xity; however, resulting motion fields still present spatial and tempo ral redundancies, the exploitation of which would allows a greater bit rate reduction. The motion estimation method proposed in this paper at tains such a goal maintaining the block based partitioning of the resu lting field. It uses a spatio-temporal prediction followed by a lossy coding of the residual field by vector quantization. The prediction is based on autocompensation, enhanced with the aid of some additional p arameters so that it provides a stationary error field. The statistica l distribution of such a residual field allows vector quantization to perform efficiently, even when the method is applied to video sequence s with extremely varying motion activities. Both the prediction and th e vector quantization simply use an index for each block to code its m otion vector. Finally, the indexes are spatially organized in two sing le images that are coded with a region based technique.