Fast Global Motion Estimation in Two Sampling Steps

An important technique in image and video processing is global motion estimation (GME). The common GME methods can be classified in direct and indirect categories. Whereas the direct global motion estimation techniques boast reasonable precision they tend to suffer from high complexity. As with indirect methods, though presenting lower complexity, they mostly exhibit lower accuracy than their direct counterparts. In this paper, the authors introduce a robust algorithm for GME with near identical accuracy and almost 50-times faster than MPEG-4 verification model (VM). This approach entails two stages in which, first, motion vector of sampled block is employed to obtain initial GME then Levenberg-Marquardt algorithm is applied to the subsampled pixels to optimize the initial GME values. As will be shown, the proposed solution exhibits remarkable accuracy and speed features with experimental results distinctively bearing them out.