Zoom motion estimation for color and depth videos using depth information

In this paper, two methods of zoom motion estimation for color and depth videos by using depth information are proposed. Color and depth videos are independently estimated for zoom motion. Zoom for color video is scaled by spatial domain, and depth video is scaled by both spatial and depth domains. For color video, instead of existing methods of zoom motion estimation that apply all of possible zoom ratios for a current block, the zoom ratio of the proposed method is determined as the ratio of the average depth values of the current and reference blocks. Then, the reference block is resized by multiplying the zoom ratio and the reference block is mapped to the current block. For depth video, the reference block is first scaled in the spatial direction by the same methodology used for color video and then scaled by a distance ratio from a camera to the objects. Compared to the conventional motion estimation method, the proposed method reduces MSE by up to about 30% for the color video and up to about 85% for the depth video.