Global motion estimation in image sequences using robust motion vector field segmentation

In this paper we propose an algorithm for the purpose of video indexing which estimates the global motion caused by camera movement. Since motion estimation is a computationally expensive process, we are using information already computed in block based video encoders such as the displacement vectors of the blocks and the computed SAD values of the blockmatching process. With this approach we could significantly speed up the determination of the parameters of a chosen global motion model. The accuracy of the algorithm is improved further by introducing a reliability measure. To achieve a robust computation with respect to object motion, an effective and straightforward segmentation of this vector field is implemented. Finally, the modeling of the global motion is evaluated using MPEG-7 test data.