Discrete-cosine/sine-transform based motion estimation
A new motion estimation scheme, discrete-cosine/sine-transform based motion estimation (DXT-ME) utilizing the principle of orthogonality of cosine and sine functions to estimate, in the transform domain, displacements from the motion information contained in the pseudo-phases of the images of moving objects, is proposed. The computational complexity of this method is only O(N2)+Odct for an image of size N×N in comparison to O(N4), the complexity of the full search block matching approach, where Odct is the complexity of DCT/DST coding. Furthermore, incorporation of DXT-ME with DCT-based video standards achieves further savings of computations and makes symmetric codecs feasible. Unlike the pel-recursive algorithm, this scheme is not susceptible to noise. For complicated scenery or large moving objects, simple preprocessing is performed on images to extract the features of moving objects before applying DXT-ME. Simulation on some video sequences is presented to compare this scheme with the block matching method.