共查询到17条相似文献,搜索用时 593 毫秒
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分布式视频编码是建立在Slepian-Wolf和Wyner-Ziv信息编码理论基础上的全新视频编码框架,具有编码复杂度低,编码效率较高,抗误码性能好的特点.本文首先简单介绍了一种典型的分布式视频编码实现方案——空间域Wyner-Ziv视频编码,随后提出一种空间域Wyner-Ziv视频编码系统的性能改进算法,该算法在不增加编码复杂度的基础上,在解码端利用双向运动估计预测获取更高质量的边信息,同时采用基于Huber-Markov随机场约束的联合迭代解码算法重建图像.实验结果表明,在相同的输出码流情况下,本文改进算法在解码端重建图像的峰值信噪比与空间域Wyner-Ziv视频编码算法相比平均提高2dB,并且主观效果有所改善. 相似文献
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本文针对互联网和无线信道等不可靠网络的视频传输问题,提出一种基于H.264和双树小波变换的多描述视频编码解决方案.采用分层的多描述视频编码框架,实现H.264和双树小波编码的有机结合.基本层用H.264编码器对视频信号进行低码率编码后,复制到各个描述;增强层用三维双树小波变换对原视频和基本层重建视频的差值进行编码,将产生的四棵三维小波树经噪声整形后两两组合,编码送到不同描述.在解码端,若能够接收到两个描述,则通过中心解码器实现高质量的视频重建;若丢失一个描述,则通过边解码器解码仍可保证一定质量的视频重建.实验结果表明在相同码率下,本算法的视频中心解码和边解码质量优于现有的多描述视频编码算法. 相似文献
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新兴的分布式多视点视频编码通过在解码端使用立体边信息可充分挖掘传统单视点的时间相关性和多视点特有的视间相关性.研究了一种多视点运动预测的立体边信息生成算法,提出了近似视差估计和编码端掩模融合算法.实验证明,解码端采用近似的视差矢量,编码端传递某些先验信息,都能有效提高立体边信息精度,降低计算复杂度. 相似文献
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压缩感知(Compressed Sensing,CS)结合了视频信号的变换和信息压缩过程,为简化编码算法提供了一种新的解决思路.把分布式视频编码(DVC)和CS结合在一起,构建简单的视频编码框架,并利用原始视频帧与边信息之间的相关性进行残差重构,提出了一种基于边信息的分布式视频压缩感知编解码方案.此方法对关键帧采用传统的帧内编、解码;对非关键帧CS进行随机观测提取观测向量,解码端利用优化的边信息和传输的CS观测向量进行联合重构.实验结果表明,该方法在运动较平滑的序列中比参考方案的恢复质量提高了4 ~6 dB. 相似文献
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在分布式多视点视频编码系统中,边信息的质量对于整体的编码效率有重要的影响。在解码端,可以得到两种类型的边信息:时间边信息与视点间边信息。为了能够得到更加准确的边信息,需要对这两种边信息进行有效的融合。文中提出了基于边信息可靠性估计的融合算法,对边信息时间上的连续性与空间结构特性进行挖掘与分析,从而得到边信息误差的预测值并进行边信息融合。实验结果表明了本中提出的算法相对于现有融合算法来说,具有更好的融合效果,可以有效提升分布式编码框架的效率。 相似文献
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在无反馈分布式视频编码系统中,提出了一种Wyner-Ziv帧的顽健重构算法。针对比特面解码错误带来的视频质量下降问题,对DC系数和AC系数使用不同重构方法,特别是对于解码失败的DC系数量化值,利用编码端原始图像的相关信息自适应地调整边信息量化值和解码失败量化值对重构的贡献,从而完成重构。实验结果表明,与最小均方误差重构算法相比,该算法可以有效提高解码视频的平均PSNR(peak signal-to-noise ratio),且解码视频图像的主观质量有明显改善。 相似文献
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针对分布式视频编码(DVC)系统鲁棒传输问题,设计了一种基于层修复的DVC系统传输框架。该传输框架首先对关键帧(K帧)同时采用高效视频编码(HEVC)帧内编码和Wyner-Ziv编码,并将校验信息(Wyner-Ziv码流)作为修复层码流存入缓存中。若当前关键帧有丢失,则向编码端请求该帧对应的层修复码流,在解码端对错误块进行修复,获得关键帧解码质量的提升。同时,研究了层修复码率估计算法,利用已成功解码的位平面辅助完成算法重建。实验结果表明,该传输框架利用关键帧的层修复码流对关键帧失真部分进行了修复,提高了关键帧质量,改善了边信息质量,实现了DVC的鲁棒传输。 相似文献
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Xin HuangSøren Forchhammer 《Signal Processing: Image Communication》2012,27(1):16-30
Distributed Video Coding (DVC) is a new video coding paradigm, which mainly exploits the source statistics at the decoder based on the availability of decoder side information. One approach to DVC is feedback channel based Transform Domain Wyner-Ziv (TDWZ) video coding. The efficiency of current TDWZ video coding trails that of conventional video coding solutions, mainly due to the quality of side information, inaccurate noise modeling and loss in the final coding step. The major goal of this paper is to enhance the accuracy of the noise modeling, which is one of the most important aspects influencing the coding performance of DVC. A TDWZ video decoder with a novel cross-band based adaptive noise model is proposed, and a noise residue refinement scheme is introduced to successively update the estimated noise residue for noise modeling after each bit-plane. Experimental results show that the proposed noise model and noise residue refinement scheme can improve the rate-distortion (RD) performance of TDWZ video coding significantly. The quality of the side information modeling is also evaluated by a measure of the ideal code length. 相似文献
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Wyner-Ziv Video Coding (WZVC) is considered as a promising video coding scheme for Wireless Video Sensor Networks (WVSNs) due to its high compression efficiency and error resilience functionalities, as well as its low encoding complexity. To achieve a good Rate-Distortion (R-D) performance, the current WZVC paradigms usually adopt an end-to-end rate control scheme in which the decoder repeatedly requests the additional decoding data from the encoder for decoding Wyner-Ziv frames. Therefore, the waiting time of the additional decoding data is especially long in multihop WVSNs. In this paper, we propose a novel progressive in-network rate control scheme for WZVC. The proposed in-network puncturing-based rate control scheme transfers the partial channel codes puncturing task from the encoder to the relay nodes. Then, the decoder can request the additional decoding data from the relay nodes instead of the encoder, and the total waiting time for decoding Wyner-Ziv frames is reduced consequently. Simulation results validate the proposed rate control scheme. 相似文献
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We present in this paper a new distributed video coding (DVC) architecture for wireless capsule endoscopy. It is based on the state of the art DVC systems, but without using key frames. Instead, it uses an adapted vector quantization (VQ) with a searching complexity that is shifted to the decoder. VQ allows creating a good side information (SI) by exploiting the similarities in human anatomy. Thus, SI is created from a codebook (CB) rather than by motion compensated prediction. This approach decreases largely the complexity of the encoder, which codes only Wyner-Ziv frames, and allows a progressive decoding. The encoder of the proposed DVC generates only a simple hash that is used by the decoder to select the corresponding VQ codeword. The obtained experimental results show that rate-distortion results are better than those of JPEG, and show the possibility of using scalable coding to control the used rate and energy. 相似文献
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To minimize the errors of the reconstructed values and improve the quality of decoded image,an efficient reconstruction scheme for transform domain Wyner-Ziv (WZ) video coding is proposed.The reconstruction scheme exploits temporal correlation of the coefficient bands,the WZ decoded bits stream and the side information efficiently.When side information is outside the decoded quantization bin,the reconstructed value is derived using expectation of the WZ decoded bit stream and the side information.When side information is within the decoded quantization bin,the reconstructed value is derived using the biased predictor.Simulation results show that the proposed reconstruction scheme gains up to 1.32 dB compared with the commonly used boundary reconstruction scheme at the same bit rates and similar computation cost. 相似文献
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码率分配是无反馈分布式视频编码中的关键技术之一.本文研究编码端快速边信息生成方法,基于边信息和Wyner-Ziv帧各个位平面误码率,提出了一种编码端码率分配算法(Bitplane Error Probability based Encoder Rate Control,BEP_ERC).还提出在编码端精确估计拉普拉斯-柯西混合分布(Laplace-Cauchy Mixture Distribution,LCMD)模型参数α和μ的思想.实验表明本文算法与现有算法相比,率失真性能提升0.1~0.4dB,且降低了编码端计算复杂度. 相似文献