Depth map-sequence coding algorithm based on fractal
Zhu Shi-pin · Journal of Optoelectronics·laser · 2014
Depth map compression is the crucial technology in three dimentional video(3DV)coding system.To obtain high compression efficiency and low encoding complexity for depth map-sequence,this paper proposes a novel coding algorithm for depth map-sequence based on fractal.This applicable scheme for depth map-sequence coding is proposed by adequately exploiting local similarity between adjacent frames in depth map-sequence and combining intra-prediction method in H.264.In the proposed scheme,the I frame in depth map-sequence is encoded by adopting intra-prediction structure in H.264,while the P frame is encoded by fractal compression method.Firstly,the theoretical basis of fractal coding is presented.Then,a new motion-vector-field-based adaptive hexagon search algorithm,which is applicable to fractal coding,is proposed by improving unsymmetrical multi-level hexagon search(UMHexagonS)method.Finally,the P frame prediction structure based on fractal in depth map-sequence coding is formed.Experimental results indicate that the proposed coding system can improve the overall performance of the H.264coding system with an average Bjontegaard delta peak signal-to-noise ratio(BDPSNR)gain of 3.54dB and an average Bjontegaard delta bit rate(BDBR)reduction of 40.98%.Furthermore,the computational complexity is reduced and the entire encoding time on average is saved by 85.27%.In addition,the proposed algorithm shows certain advantages compared with other international representation methods in this field.