Global bi-directional motion compensation frame interpolation algorithm

A frame interpolation algorithm for the application of low-bit-rate video coding is proposed in this paper. The global motion vectors are first estimated by computing global sum of absolute differences between frames. Then the block motion estimation is carried out according to the modified weighted correlation index criteria. The estimation is further adjusted around the moving object based on the modified weighted correlation index criteria but with a smaller factor k so that the global motion estimation is less influential to the movement vector estimation for the moving objects. Finally the motion estimation outliers are determined by the Box-and-Whisker analysis, and removed by two methods. Method 1 redoes the bi-directional estimation with a larger factor k; Method 2 computes the movement vectors of the outliers using neighboring movement vectors. The experiments showed that the proposed method can improve the peak signal to noise ratio for four test video sequences. Visual inspection also shows better frame interpolation quality.