Video coding using spatial extrapolation based motion field segmentation

Temporal image prediction using motion compensation techniques has been used successfully to encode digital image sequences. In current standards (MPEG and H.263) block matching is used for motion estimation and only translational motion and motion discontinuities (MD) at block edges can be described. To overcome this problem the spatial-transform was introduced. Using affine, geometric transforms these schemes are capable of describing rotation, shear, and change in scale. Due to the underlying continuous motion model problems arise at the MDs. We propose a two step local MD estimation scheme. In the first step motion estimation is performed, in the second step the MDs are computed for every block. The dense motion fields on both sides of a discontinuity line are extrapolated from their respective neighbours. The selection of the optimal position of the MD yields a higher coding efficiency and an improved visual quality. Although the MDs have to be transmitted as additional side information a coding gain is achieved compared to conventional coders