A coding technique for the contours in smoothly perfect eight-connectivity based on two-stage motion compensation

In this paper, a new contour-coding technique for object-oriented video coding is proposed. In our approach, the two-stage motion compensation technique is considered, in order to cope with the rather complex motion of the object. While the object-based motion compensation is performed in the first stage, the second-stage motion compensation is carried out to search the best match of the contours, which are not motion compensated in the first stage. Also, by introducing the notion of the error band, the current contours can be properly fitted to the motion-compensated contours using the interframe relationship of the contours. In addition, an efficient technique for encoding the contours, simplified by the majority filter, is also proposed. From the simulation result, it is shown that the proposed technique provides better performance than the content-based arithmetic encoding, especially when lossy encoding is allowed. Moreover, by varying the width N of the error band, it is shown that the bit amount for the shape information can be adjusted according to the channel condition.