Adaptive motion estimation order for frame rate up-conversion

This paper proposes an adaptive motion estimation (ME) order for frame rate up-conversion (FRUC). Almost all existing FRUC methods adopt a raster scan order for ME. The ME is performed from top-left blocks to bottom-right blocks in raster scan order. Such an order can propagate some wrongly estimated motion vectors (MV) through a frame. The proposed method first detects the blocks rich in features (feature blocks) and estimates their MVs. Then ME is performed on the other blocks according to their distance to feature blocks. The closer a block to feature blocks is; the earlier the ME is performed on it. In this adaptive order, MVs of feature blocks are propagated to its neighbors. It makes the estimated motions of a frame close to the true motions. In order to demonstrate the efficiency of the proposed method, we estimate the MVs with diamond search in the proposed adaptive ME order. In the experiments, the quality of frame rate up converted videos have been significantly improved compared with the ones using traditional raster scan order. Moreover, the adaptive ME order can be easily combined with various ME methods applied in previous FRUC.