A block-based gradient descent search algorithm for block motion estimation in video coding

A block-based gradient descent search (BBGDS) algorithm is proposed in this paper to perform block motion estimation in video coding. The BBGDS evaluates the values of a given objective function starting from a small centralized checking block. The minimum within the checking block is found, and the gradient descent direction where the minimum is expected to lie is used to determine the search direction and the position of the new checking block. The BBGDS is compared with full search (FS), three-step search (TSS), one-at-a-time search (OTS), and new three-step search (NTSS). Experimental results show that the proposed technique provides competitive performance with reduced computational complexity