压缩视频图像质量的客观测量方法

介绍了基于特征的视频质量客观测量方法，给出了一种利用时空和颜色特征实现的视频质量客观测量方法（OVQM）。实验结果表明，在测量压缩损伤方面，OVQM比MSE具有更大的优势。     

无线视频错误控制技术研究

无线视频传输中误码和丢包会导致视频质量的严重下降,研究了视频传输中的错误控制相关技术。对已有的无线视频错误控制方法进行了详细分析,在此基础上提出了一种更加有效的无线视频传输中的错误控制框架。将无线误码丢包和拥塞丢包准确区分,改进了以往算法带宽估计公式不准确的问题。并且对视频内容根据在解码端重要性的不同区分保护。在错误控制的同时进行了拥塞控制。     

媒体资产管理系统中的视频图像质量评价研究

首先介绍了图像质量的主观评价和客观测量方法,具体分析了双刺激连续质量标度法和双刺激损伤标度法,根据媒资系统中各种视频图像的不同特点,针对性地提出了对应的图像质量评价方法,为当前电视台媒资系统性能的测试与评价提供参考。     

MPEG-2中TS码流传输损伤测量方法研究与设计

MPEG-2标准规定的传输流(TS)结构是我国数字电视领域普遍使用的一种基带码流形式。经过不同传输网络承载的TS码流会出现不同程度的时延、抖动、丢包等信道损伤,目前针对TS码流的传输损伤缺少标准的测量方法。基于IP标准测试仪表、码流分析仪、软件实现的测试仪器与硬件实现的测试仪器等角度设计了数种测量方法,并逐个进行了可行性分析,最后介绍了基于硬件实现的TS码流损伤测量方法的实现过程。     

多媒体视频质量测量的研究和标准化

多媒体视频是电信运营商的重要业务,如何准确地测量多媒体视频质量,反馈给运营商,更好的监测管理,提升客户体验,至关重要.本文将从多媒体视频质量测量的应用需求、主观评价方法、客观测量方法、标准化等几个方面展开研究,重点分析视频视觉质量(PVQ)测量技术,其中无参考测量技术是目前国际研究和标准化的重点.在PVQ测量的基础上,...     

高清视频联网系统中一种新的丢包率分析方法

为了提高系统性能并最大限度降低算法实现复杂度,本文提出了一种新的高清视频联网系统中丢包率的更优近似分析方法,重点研究包长度对丢包率的影响。首先使用马尔可夫链模型估算数据包的误码率,进而得出数据包网络时延的概率分布,最后计算出基于包长度的丢包率的理论表达式。仿真结果表明,通过减小发包大小可以有效降低丢包率,同时基于包长度的丢包率的理论分析方法可以有效地运用到高清视频联网系统的分析研究中。     

数字电视传送流丢包和丢包率研究

定义了数字电视传送流丢包,并通过实验指出丢包对电视信号有重要影响,建议把定义的丢包率作为评价数字电视信号传输质量的客观指标之一.为此,提出了两种分析丢包和统计丢包率的算法,并进行了实验验证.     

3D视频的错误隐藏快速算法

具有独特编码结构的3D视频在不可靠信道上传输时遭遇丢包后极易造成错误传播,因此研究基于3D视频的错误隐藏技术十分必要。而且,压缩后传输的3D视频数据量仍然较大,这对解码器的解码速度提出了很高的要求。如何在解码端加速进行错误隐藏是研究重点,通过快速定位静止宏块的方法加速错误隐藏速度。实验结果表明该算法在保证不降低视频的主、客观质量的同时,能有效地降低错误隐藏算法的复杂度。     

SDI信号及带模数转换的数字播控系统视频测量

对数字播控系统传输的SDI信号的工作原理进行了分析,详细介绍了SDI信号主要指标的测量方法并如何用于对带模数转换的数字播控系统视频指标的客观评价,有普遍的指导意义.     

H_265编码视频质量评价

本文着重研究了H．265编码的高清视频质量评价方法,以用于未来测试H．265编码器的性能。根据ITUVQEG的最新研究进展,介绍了高清视频的主观评价和客观测量方法,并且分析了目前已有的客观测量技术的主要实现方法和与主观评价方法相关度的结果,最后给出H．265编码视频质量测量技术的发展建议,并指出针对H．265编码器的测试,实验室环境,全参考的方法是首选,而无参考的方法是研究趋势。     

A Geometric Approach to Improving Active Packet Loss Measurement

Measurement and estimation of packet loss characteristics are challenging due to the relatively rare occurrence and typically short duration of packet loss episodes. While active probe tools are commonly used to measure packet loss on end-to-end paths, there has been little analysis of the accuracy of these tools or their impact on the network. The objective of our study is to understand how to measure packet loss episodes accurately with end-to-end probes. We begin by testing the capability of standard Poisson-modulated end-to-end measurements of loss in a controlled laboratory environment using IP routers and commodity end hosts. Our tests show that loss characteristics reported from such Poisson-modulated probe tools can be quite inaccurate over a range of traffic conditions. Motivated by these observations, we introduce a new algorithm for packet loss measurement that is designed to overcome the deficiencies in standard Poisson-based tools. Specifically, our method entails probe experiments that follow a geometric distribution to 1) enable an explicit trade-off between accuracy and impact on the network, and 2) enable more accurate measurements than standard Poisson probing at the same rate. We evaluate the capabilities of our methodology experimentally by developing and implementing a prototype tool, called BADABING. The experiments demonstrate the trade-offs between impact on the network and measurement accuracy. We show that BADABING reports loss characteristics far more accurately than traditional loss measurement tools.     

40 Gbit/s packet bit error ratio and loss real-time measurement for ultrahigh-speed packet switched network

A novel packet bit error rate (BER) and loss measurement method and system is proposed. A proposed 40 Gbit/s packet BER and loss measurement system is expressed in detail. A 40 Gbit/s BER and loss measurement with various conditions is demonstrated experimentally. In real time, only the payload part of a packet and burst stream with fluctuated guard time is evaluated. The BER and packet loss of a randomly received packet sequence due to routing and buffering can be also evaluated by the measurement system. A 10 Gbit/s packet BER and loss measurement with optical label switching, buffering, and preamble-free optical packet 3R are demonstrated experimentally.     

基于双边线性预测的信包丢失隐藏算法

本文提出了一种基于双边线性预测的信包丢失隐藏算法。该方法利用丢失信包的前一信包或邻接信包(在后一信包可获得的情况下)预测丢失信包。线性加权双边线性预测的样点获得最终的重建信号。使用重叠相加和幅度调整操作平滑重建信号和真实信号之间的边界。经过非正式试听和ITU-T P.862协议所推荐的PESQ算法测试,本文建议算法的重建语音信号质量,与其他四种流行重建算法相比有了较为明显的改善。     

单向时延测量中的时间同步问题

网络性能测量一直是人们所关注的话题。通过对网络的连通性、时延、丢包率、带宽等的测量去掌握网络实时的运行动态。在网络单向时延测量中,由于各个主机时钟误差的存在使得测量结果精确性不高。针对两种不同类型的误差设计了两种方法,并且实验也证实了这两种方法的可行性及正确性。     

WSN data gathering algorithm based on compressive sensing and matrix completion technique

The unreliable links and packet losing are ubiquitous in WSN.The performance of data collection algorithm based on compressive sensing is sensitive to packet losing.Firstly,the relationship between packet loss rate and CS-based reconstruction precision was analyzed,and the sparsest block measurement (SBM) matrix was formulated to keep the data gathering consumption smallest and make sure the low-rank property of measurements.Then,combined with the matrix completion (MC) and compressive sensing (CS),the CS data gathering algorithm based on sparsest block measurement matrix (CS-SBM) algorithm was proposed.CS-SBM gathered data in a period and recovered the loss data based on MC to weaken the impact of packet loss on data gathering.CS-SBM reconstructed data based on CS to reduce measurement number and energy consumption and prolong the network lifetime.Simulation analysis indicates that the proposed algorithm reconstruct the whole data with high-accuracy under 50% packet loss rate,resisting unreliable links effectively.     

一种语音信号重建算法

为了减轻因信包丢失而造成的语音失真,提出了一种基于双边线性预测的信包丢失隐藏算法。这种方法利用丢失信包的前一信包或邻接信包(在后一信包可获得的情况下)预测丢失信包,通过线性加权双边线性预测的样点获得最终的重建信号,使用重叠相加和幅度调整操作平滑重建信号和真实信号之间的边界。经过非正式试听和ITU-T P.862协议所推荐的PESQ算法测试,该算法的重建语音信号质量与其他四种流行重建算法相比,有了较为明显的改善。     

Trajectory Sampling With Unreliable Reporting

We define and evaluate methods to perform robust network monitoring using trajectory sampling in the presence of report loss. The first challenge is to reconstruct an unambiguous set of packet trajectories from the reports on sampled packets received at a collector. In this paper we extend the reporting paradigm of trajectory sampling to enable the elimination of ambiguous groups of reports, but without introducing bias into any characterization of traffic based on the surviving reports. Even after the elimination, a proportion of trajectories are incomplete due to report loss. A second challenge is to adapt measurement based applications (including network engineering, path tracing, and passive performance measurement) to incomplete trajectories. To achieve this, we propose a method to join multiple incomplete trajectories for inference, and analyze its performance. We also show how applications can distinguish between packet and report loss at the statistical level.     

无感知分组丢失下的无线传感器网络链路质量评估模型

针对现有链路质量评估方法没有考虑到不完整分组对链路产生的影响,将无线传感器网络的链路分组丢失分为感知分组丢失和无感知分组丢失,分析了无感知分组丢失产生的原因,在对无感知分组丢失进行度量的基础上,提出一种无感知分组丢失下的链路质量评估模型。该模型采用卡尔曼滤波对获取的CCI进行降噪处理,基于Cubic模型、最小二乘法拟合出CCI与无感知分组丢失率的关系模型。实验结果表明,无感知分组丢失下的链路质量评估模型是合理的,通过该模型求得的无感知分组丢失率与实测值接近。     

一种基于分组丢失率测量的差错容忍式拥塞控制算法

空间通信的TCP大多数是基于Vegas算法,该算法需要对往返时延进行较为精确的测量,这在具有极长且可变时延的信道特征的深空通信环境中很难实现。提出一种基于分组丢失率测量的差错容忍式拥塞控制算法,该算法采用数据块的形式发送数据,依据历史数据设定差错容忍度,利用分组丢失率测量值进行拥塞状态判断及发送窗口大小调整,从而使用较小的开销达到较高的传输效率。最后,利用数学建模方法,证明基于分组丢失率测量的差错容忍式拥塞控制算法的吞吐量比传统TCP的Tahoe算法提高34%,比Reno算法提高22%。     

Modelling and performance of packet synchronization in A data communications system

This paper deals with some problems of packet synchronization in a slotted packet-radio communications system. The problems considered are bit-synchronization and unique word detection for bursty systems. The necessary overhead for synchronization purposes is dimensioned for applications in land-mobile satellite communication systems. The performance of synchronization is evaluated using hardware measurement equipment, including a commercial bit-synchronizer. Using these results, the performance loss of communication systems due to packet synchronization effects can be estimated. This is done for the additive white Gaussian noise channel and the class of land-mobile satellite channels.