Diamond Search for Block Motion Estimation

Definition:Diamond search technique for block motion estimation is based on diamond search patterns.

The process of block matching motion estimation is to find out a candidate block, within a search area in the previous frame, which is most similar to the current block in the present frame. To speed up the search process, a number of fast search algorithms have been developed in the past two decades. It is shown that the diamond search (DS) algorithm [1] [2] can achieve a better compromise between the complexity and prediction performance among different methods.

Diamond search makes use of the center-biased motion characteristics of video sequences and uses diamond search patterns (Figure 1) instead of rectangular as most of other search methods. It also uses the halfway stop criterion to allow early termination of the search. The detailed steps of DS are shown below. Figure 2 shows an example how DS locates the motion vector.

• Step 1 The initial large diamond search pattern is...