Current Issue Cover
基于分层视差估计的立体图象编码

安平1, 张兆扬1(上海大学通信与信息工程学院,上海 200072)

摘 要
基于立体视频数据压缩的目的,提出了一种基于分层视差估计/补偿的立体图象编码方案。该方案是采用JPEG标准独立编码参数图象,并利用视差估计/补偿技术编码目标图象,应用分层马尔可夫随机场(MRF)模型。率失真(RD)模型以及交叠块匹配的混合视差估计/补偿算法,可得到光滑准确的视差场,与通常的变尺寸块匹配(VSBM)相比,该算法得到的视差补偿图象的峰值信噪比(PSNR)可提高2.5dB左右;双向半像素精度的视差估计/补偿的性能要比单向整像素搜索提高3dB,实验结果表明,该立体图象编码方案能有效地压缩立体图象数据,并可推广到立体序列图象的编码压缩中。
关键词
Stereo Image Coding Based on Hierarchical Disparity Estimation

()

Abstract
To compress the stereo video data, we propose an algorithm for stereo image coding based on hierarchical disparity estimation/compensation. A stereo image pair consists of a reference image and a target image. The reference image is coded by method using JPEG standard, while the target image is coded using the disparity estimation/compensation technique. We apply the wavelet transformation to code the created residual image, and use DPCM(difference pulse coding modulation) to code the disparity fields. Hierarchical Markov Random Field(MRF) model, Rate-Distortion(RD) model and the overlapped block matching/compensation are applied in the hybrid disparity estimation method to obtain a smooth and consistent disparity field. In terms of peak signal to noise ratio(PSNR) of the disparity compensated image, the proposed disparity estimation algorithm achieves about 2 5 dB higher PSNR, as compared to conventional variable size block matching. The experimental results also show that the disparity estimation/compensation in half pixel accuracy and dual-direction can obtain a 3dB higher performance than that of integer pixel accuracy only in horizontal direction. In the same quality of reconstructed image, our coding system can obtain 0 387 bits reduction in terms of coding bit rate of the target image compared to VSBM based scheme, and 1 003 bits reduction compared to the one using JPEG standard to code the target image. The proposed hierarchical model for disparity estimation effectively improves the efficiency of stereo image coding.
Keywords

订阅号|日报