共查询到18条相似文献，搜索用时 531 毫秒
1.
许志良 《深圳信息职业技术学院学报》2008,6(2):48-51
为了解决视频图像在传输过程中产生运动矢量丢失问题,本文提出一种新的后处理差错掩盖算法。我们在DCT域进行边缘检测,把与丢失块相邻的图像块分为边缘块和平滑块,同时把丢失块周围的图像块运动矢量的大小和方向分成九类。结合边缘检测与运动矢量分类,我们提出一种加权运动矢量恢复算法。仿真结果表明对不同视频序列,此算法都能比传统的方法恢复出质量更高的图像。 相似文献
2.
多视点视频编码是当前视频编码领域的研究热点之一。在有限的网络带宽下,合理的码率分配可以提高视频主观视觉质量。本文提出一种基于结构相似度的码率分配方法,首先对视频帧提取基于结构相似度的显著图,然后结合显著图对重要宏块和非重要宏块分配不同的QP值,以达到码率分配的目的。实验结果表明,本文方法在有限的带宽下能有效的提高多视点视频的视觉主观质量。 相似文献
3.
本文分析研究了MGS编解码技术及其码流结构,利用FMO（Flexible Macroblock Order灵活宏块顺序）编码技术实现MGS质量可伸缩的视觉敏感区域编码,提出改进的码流提取规则来达到保护视觉敏感区域。并对视频敏感区域码流提出新的容错方法,避免MGS首片层系数丢失导致的敏感区域保护失效。 相似文献
4.
刘彦甲 《商丘师范学院学报》2009,25(9):75-78
随着通信技术、网络技术、计算机技术的发展,传输信道的差错,不仅严重影响视频业务质量,甚至会使通信系统崩溃,因此差错复原技术就成为易发生差错信道下视频编码的重要组成.该文对目前各种新的视频编码标准中所应用的一些差错复原技术,如重同步;数据分割;可逆变长编码;图像分割;可伸缩视频编码;多描述编码;差错掩盖等的内容、原理进行了详细的叙述.并对信道模型进行了差错复原技术的实验.结果表明,在应用了差错复原技术后,重建图象的主客观质量均得到了明显的改善. 相似文献
5.
对高清视频序列而言,H.264/AVC视频编码器性能优异,但同时其计算复杂度也较高。帧间和帧内预测模式的选择是H.264/AVC待优化的主要技术。鉴于此,根据选定的帧间预测模式和帧内模式选择之间存在的相关性,提出了基于最佳帧间预测模式的H.264高清基本档次编码器的快速帧内模式选择算法。对该算法的评估是基于率失真、峰值信噪比(PSNR)的改变量、执行时间以及所跳过的intra4×4和intra16×16模式占全搜索算法的百分比进行的。经720p(1280×720)和1080p(1920×1088)高清视频序列测试,在不损失PSNR、不增加码率的前提下,该算法能节省60%的帧内预测计算时间,并对16×16宏块和4×4子块帧捏模式选择部分的跳过率分别达到了16%和83%。 相似文献
6.
针对区域级背景减除问题,提出一种基于图像块对比度直方图特征的背景减除方法。对于已输入的一段视频,将每一帧视频分割成图像块,并提取对比度直方图特征。在该特征上通过自描述方式将前景作为噪声误差项与背景分离,随后使用稀疏子空间聚类方法构建关于对比度直方图特征的聚类,而对于特征聚类的主成分分析给出了关于背景特征的多个子空间,并以此作为区域级背景模型。在后续输入视频帧中提取对比度直方图特征,将其投影到各子空间中计算重构误差,以此作为前背景的决策依据。实验结果表明,该方法能够有效减除视频中的背景。 相似文献
7.
把高斯混合模型(GMM)用于视频流的错误隐藏技术中,并对此进行了分析、论证、研究。GMM依据邻近的时域和空域的信息,用最小均方差来估计丢失像素的区域;如部分视频数据丢失,根据丢失视频数据邻近的时-空域信息通过GMM做一个最小均方差估计;如丢失宏块周围的时域信息也随之丢失,则采用反复迭代估计的方法来解决。和现有的基于时-空域的错误隐藏方法相比,基于GMM的错误隐藏方法提高了PSNR,且对于大范围内的丢包率都是有效的。仿真实验也证实了基于GMM的错误隐藏方法能较好地提高和改善视频的主客观质量。 相似文献
8.
刘晓阳 《济南职业学院学报》2014,(5)
本文提出了一种基于时域信息代表图像和希尔伯特曲线顺序特征的哈希算法。先从视频段中获取时域信息的代表图像,再对代表图像进行分块,将各块按照希尔伯特曲线的顺序排列,计算出时域信息代表图像上相邻块的灰度关系排序特征,进而生成视频哈希。本文中对多种视频攻击(比如剪切,丢帧,模糊,滤波,添加logo等)下的多类视频(包括纪录片、新闻、体育、人文、动画等)进行了鲁棒性与区分性的试验。实验结果表明本文所提算法较现有哈希算法有更好的检测性能。 相似文献
9.
介绍了统计可变形模型的建立过程和使用建立的统计模型来恢复缺失数据的算法.并将该算法用于肝脏CT图像实验了三种不同分辨率下的恢复效果,结果表明:使用该方法恢复肝脏CT图像,可将误差控制在1%以下. 相似文献
10.
为了提高视频流传输效率,本文提出一种基于视觉注意的数据包优先级排序策略。本文排序策略主要包括三个过程：首先,根据率失真理论计算数据包客观重要性;其次,通过分析视频镜头中视觉转移特性确定视频帧的时空显著图,采用灵活宏块排序技术将显著区域与背景区域分离,并根据数据包所包含区域的时空显著度确定数据包主观重要性;最后综合数据包主客观重要性得出数据包的最终优先级。实验结果表明,本文方法能够有效提高视频流的主观重建图像质量。 相似文献
11.
INTRODUCTION In typical video transmission systems, a video signal is compressed, and the resulting bit stream is transmitted over an error-prone channel. The errors may consist of symbol errors caused by fading, as observed for wireless channels, or packet erasures caused by congestion, as observed in the Internet. If a received video packet contains errors, then the portion of the video signal contained in the packet is lost and must be concealed. Error concealment schemes alone cannot … 相似文献
12.
一种新的无线视频传输帧内刷新策略 总被引：1，自引：0，他引：1
首先分析了无线信道突发性出错和二阶Markov无线信道模型. 根据该模型和视频编码器的编码方式推导了突发性出错引起的帧内编码和帧间编码的信道失真. 然后提出了一种新的速率失真率(R-D)框架内的帧内刷新策略. 该策略一方面对无线视频传输系统的容错性能和编码效率进行了优化, 另一方面可有效阻止帧间错误传播, 减小信道失真. 在不同传输信道中的仿真结果验证了该策略在无线视频传输容错方面的性能改进. 相似文献
13.
The emergence of third generation mobile system (3G) makes video transmission in wireless environment possible, and the latest 3GPP/3GPP2 standards require 3G terminals support H.264/AVC. Due to high packet loss rate in wireless environment, error resilience for 3G terminals is necessary. Moreover, because of the hardware restrictions, 3G mobile terminals support only part of H.264/AVC error resilience tool. This paper analyzes various error resilience tools and their functions, and presents 2 error resilience strategies for 3G mobile streaming video services and mobile conversational services. Performances of the proposed error resilience strategies were tested using off-line common test conditions. Experiments showed that the proposed error resilience strategies can yield reasonably satisfactory results. 相似文献
14.
为增强无线多跳网络（Ad hoc网络）中视频传输的抗误码性能,提出了一种面向Ad hoc网络的视频多描述编码及其传输方法。首先,通过判断两个相邻帧运动矢量的差值,自适应地在视频序列中插入参考帧以提高帧间编码效率;然后分别抽取出视频序列中的奇数帧和偶数帧形成两个描述;最后,在确保传输路径可靠性的基础上,选取两个质量较高的节点不相交路径分别传输视频序列的两个描述,以提高视频传输的可靠性。OPNET Modeler中的仿真实验结果表明,与目前Ad hoc网络中典型的多描述编码及传输方法MDC_AODV相比,本文提出的方法有效地增强了视频传输的抗误码性,提高了接收端的视频质量。 相似文献
15.
In this work, we present an evaluation of the performance and error robustness of RTP-based broadcast streaming of high-quality high-definition (HD) H.264/AVC video. Using a fully controlled IP test bed (Hillestad et al., 2005), we broadcast high-definition video over RTP/UDP, and use an IP network emulator to introduce a varying amount of randomly distributed packet loss. A high-performance network interface monitoring card is used to capture the video packets into a trace file. Purpose-built software parses the trace file, analyzes the RTP stream and assembles the correctly received NAL units into an H.264/AVC Annex B byte stream file, which is subsequently decoded by JVT JM 10.1 reference software. The proposed measurement setup is a novel, practical and intuitive approach to perform error resilience testing of real-world H.264/AVC broadcast applications. Through a series of experiments, we evaluate some of the error resilience features of the H.264/AVC standard, and see how they perform at packet loss rates from 0.01 % to 5%. The results confirmed that an appropriate slice partitioning scheme is essential to have a graceful degradation in received quality in the case of packet loss. While flexible macroblock ordering reduces the compression efficiency about 1 dB for our test material, reconstructed video quality is improved for loss rates above 0.25%. 相似文献
16.
In this work, we present an evaluation of the performance and error robustness of RTP-based broadcast streaming of high-quality high-definition (HD) H.264/AVC video. Using a fully controlled IP test bed (Hillestad et al., 2005), we broadcast high-definition video over RTP/UDP, and use an IP network emulator to introduce a varying amount of randomly distributed packet loss. A high-performance network interface monitoring card is used to capture the video packets into a trace file. Purpose-built software parses the trace file, analyzes the RTP stream and assembles the correctly received NAL units into an H.264/AVC Annex B byte stream file, which is subsequently decoded by JVT JM 10.1 reference software. The proposed measurement setup is a novel, practical and intuitive approach to perform error resilience testing of real-world H.264/AVC broadcast applications. Through a series of experiments, we evaluate some of the error resilience features of the H.264/AVC standard, and see how they perform at packet loss rates from 0.01% to 5%. The results confirmed that an appropriate slice partitioning scheme is essential to have a graceful degradation in received quality in the case of packet loss. While flexible macroblock ordering reduces the compression efficiency about 1 dB for our test material, reconstructed video quality is improved for loss rates above 0.25%. 相似文献
17.
Although H.264 video coding standard provides several error resilience tools, the damage caused by error propagation may still be tremendous. This work is aimed at developing a robust and standard-compliant error resilient coding scheme for H.264 and uses techniques of mode decision, data hiding, and error concealment to reduce the damage from error propagation. This paper proposes a system with two error resilience techniques that can improve the robustness of H.264 in noisy channels. The first technique is Nearest Neighbor motion compensated Error Concealment (NNEC) that chooses the nearest neighbors in the reference frames for error concealment. The second technique is Distortion Estimated Mode Decision (DEMD) that selects an optimal mode based on stochastically distorted frames. Observed simulation results showed that the rate-distortion performances of the proposed algorithms are better than those of the compared algorithms. 相似文献
18.
Concerning inter4v mode employed widely in MPEG-4 video, a new temporal error concealment scheme for MPEG-4 video sequences is proposed, which can selectively interpolate one or four motion vectors (MVs) for the missing macroblock (MB) according to the estimated MB coding mode. Performance of the proposed scheme is compared with the existing schemes with multiple testing sequences at different bit error rates. Experimental results show that the proposed algorithm can mask the impairments caused by transmission errors more efficiently than 0 MV and average MV methods by consuming more time for different bit error rates. It has an acceptable image quality close to that obtained by the selective motion vector matching (SMVM) algorithm, while taking less than half of cycles of operations. The proposed concealment scheme is suitable for low complexity video real-time implementations. 相似文献