Different approaches for motion estimation

The motion estimation and compensation technique is widely used for interframe video coding applications, but the real-time high quality motion estimation is not easy due to its enormous computations. There are many computional effective block motion estimation algorithms but with trade-off between the algorithm accuracy and algorithm speed. Different block motion estimation algorithms are available, which include full search or exhaustive search algorithm, the fast search algorithm, such as three step search, two dimentional logarithmic search, binary search, etc. Also motion estimation in DCT domain & motion estimation in wavelet domain give better performance. DCT based motion estimation has low computational complexity than full search block matching approach. Wavelet based coding has better performance than traditional DCT based coding, since it reduces artifacts in the DCT coding. In this paper, all above algorithms are explained & implementation of full search motion estimation & three step search motion estimation is done. Also comparison between these two algorithms is shown on basis of computational complexity & PSNR. From the results, it is concluded that computational complexity of three step search is almost 10 times less than full search algorithm while PSNR of three step search is less only by one-two percent than full search method .