For the majority of object tracking scenario, the emphasis has been put on achieving robust motion estimation under different situations. In this paper, besides introducing a multiple frame based 3D motion
estimation to handle the partial occlusion problem, we present an object shape delineation scheme by dual region growing. As it is well-known, the problem of shape extraction of a moving object undergoing self-occlusion is highly ill-posed. Approaches have been proposed by assuming the similarity of object pixels in the vicinities of the boundaries between the current frame and the previous one. Such an assumption is usually broken down when occlusion occurs; instead, our implementation is based on a stronger assumption. The system consists of (i) a multi-frame motion estimation, (ii) dual-region growing, and (iii) boundary points arbitration. This method is shown to recover favorable object shape during the tracking process.