Abstract: The 3D high efficient video coding (3D-HEVC) is the new generation of video coding standard,which adopts depth maps to reduce the number of viewpoints significantly.Depth maps contain geometric information which can improve the video compression efficiency,but the depth image encoding has a heavy computation and takes about 4 times as long as the color image encoding.In this paper,in order to reduce the computational complexity of the depth image coding,a coding unit (CU) partition algorithm based on texture analysis was proposed for 3D-HEVC intra coding.Firstly,the rough texture analysis is performed for the depth map,the global grayscale classification based on the OTSU method is calculated through the texture characteristics of the depth map,and the texture complexity and the direction identification of CTU are determined by the sample points in CTU.Then,the fine texture analysis is performed on a CTU with high texture complexity,and the statistical features of the pixel distribution in the CUs are used to compute the textural division flags from bottom to top for different size of CUs.Finally,the texture complexity of CTU,texture direction flags and CU texture division flags are utilized to predict the depth range of current CTU and decide whether to terminate the division of CU.Compared with the original algorithm in 3D-HEVC test model,the proposed algorithm can reduce 45% encoding time on average with only 0.8% increase in Bjontegaard delta bit rate under the all-intra configuration.Compared with three state-of-the-art algorithms,the proposed algorithm reduces the encoding time by about 12%,% and 4% respectively for overall sequences,and 14%,11% and 10% respectively for the large-resolution sequences,with a similar encoding rate distortion performance.

Key words: 3D-HEVC, Depth map, Intra coding, Texture analysis