基于H.264的视频传输中的错误隐藏算法研究

发布时间：2018-03-30 10:50

本文选题：H.264　切入点：受损宏块　出处：《沈阳航空航天大学》2017年硕士论文

【摘要】：当前,下一代视频传输、3G和下一代宽带无线等的推广使用,对视频,多媒体业务和视频传输的需求越来越高,H.264作为视频压缩编码标准的新一代高效编解码标准,已成为多媒体通信领域的亮点与热点。视频图像在获得较高压缩比和较低冗余的同时,也使得其在通信传输中抗误码性能变得十分脆弱。所以,错误隐藏技术已成为图像处理领域一个重要的研究方向,在视频传输、视频监控等领域有着广泛的研究价值和现实意义。论文首先介绍了H.264的基本原理及其关键技术,针对视频图像在传输中发生丢包和产生误码的问题,研究了错误隐藏(Error Concealment)的差错控制方法,并与其他的错误隐藏算法进行了比较。然后针对目前压缩视频码流在无线信道传输过程中由于运动矢量失配导致重构图像质量的问题,提出了一种基于平面拟合(plane fitting)恢复运动矢量的错误隐藏算法。通过把与受损宏块直接相邻的每个分块的运动矢量定义为一个点,采用平面拟合方法表征小范围内相邻运动矢量的变化趋势,不仅避免了传统算法产生的块效应,而且缩短了运行时间,然后利用改进的边界匹配函数,通过计算受损宏块相邻宏块的边界像素值与参考帧中估计宏块相邻宏块中的边界像素值得差值,选取最优的运动矢量对受损图像进行恢复,较传统的BMA算法在计算复杂度保持一致的情况下提高了匹配精度。实验证明了本文所提出的方法较其他方法在不同的RTP丢包概率下峰值信噪比的提升及该方法的有效性。
[Abstract]:At present, with the promotion of 3G and broadband wireless, the demand for video, multimedia services and video transmission is increasing. H.264 is used as a new generation of efficient coding and decoding standards for video compression and coding. It has become a bright spot and hot spot in multimedia communication field. Video images not only obtain high compression ratio and low redundancy, but also make their error resistance performance in communication transmission very fragile. Error concealment technology has become an important research direction in the field of image processing. It has extensive research value and practical significance in the field of video transmission and video surveillance. Firstly, this paper introduces the basic principle and key technology of H.264. Aiming at the problem of packet loss and error code generation in video image transmission, the error control method of error concealment is studied. Compared with other error concealment algorithms, this paper aims at the problem of reconstructed image quality due to motion vector mismatch in the current compressed video stream transmission in wireless channel. In this paper, an error concealment algorithm based on plane fitting algorithm for motion vector restoration is proposed. By defining the motion vector of each block directly adjacent to the damaged macroblock as a point, The method of plane fitting is used to characterize the variation trend of adjacent motion vectors in a small range, which not only avoids the block effect produced by the traditional algorithm, but also shortens the running time, and then uses the improved boundary matching function. By calculating the boundary pixel value of the adjacent macroblock in the damaged macroblock and estimating the boundary pixel value in the adjacent macroblock in the reference frame, the optimal motion vector is selected to restore the damaged image. Compared with the traditional BMA algorithm, the matching accuracy is improved with the same computational complexity. The experiments show that the proposed method is more effective than other methods in raising the PSNR under different RTP packet loss probability and the effectiveness of the proposed method.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.81

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