Segment-based video coding using an affine motion model

This paper describes a segment-based motion compensation (MC) method where object motion is described using an affine motion model. In the proposed MC method, the shape of the objects is obtained using 5D K-mean clustering (employing three color components and two coordinates). Motion estimation and compensation employing the affine motion model are performed on each arbitrarily shaped object in the current frame. By using the affine motion model, rotation and scaling of objects can be compensated for in addition to translational motion. The residual between the current frame and the predicted one is DCT-coded and multiplexed with the motion and shape parameters. Simulation results show that the interframe prediction error is significantly reduced compared to the conventional block-based method. The SNR of the coded sequences obtained using the proposed method (modified MPEG1 with segment-based affine MC) is about 0.8 - 2 dB higher than that using the conventional one (original MPEG1 with block-based MC).