An Efficient Half Pixel Motion Estimation Algorithm Based on Spatial Correlations

Abstract

Motion estimation is an important part of video encoding systems, because it can significantly affect the output quality and the compression ratio. Motion estimation which consists of integer pixel motion estimation and half pixel motion estimation is very computationally intensive part. To reduce the computational complexity, many methods have been proposed in both integer pixel motion estimation and half pixel motion estimation. For integer pixel motion estimation, some fast methods could reduce their computational complexity significantly. There remains, however, room for improvement in the performance of current methods for half pixel motion estimation. In this paper, an efficient half pixel motion estimation algorithm based on spatial correlations is proposed to reduce the computational complexity. According to spatially correlated information, the proposed method decides whether half pixel motion estimation is performed or not for the current block. Experimental results show that the proposed method outperforms most of current methods in computation complexity by reducing the number of search points with little degradation in image quality. When compared to full half pixel search method, the proposed algorithm achieves the search point reduction up to 96% with only 0.01 ~ 0.1 (dB) degradation of image quality.