一种面向Internet信道的H.26L率失真抗误码编码判决策略

从最新的H.26L视频压缩标准出发,提出了一个面向典型Internet误码信道的率失真宏块编码判决策略,通过在宏块编码判决层上引入优化的亮度率失真策略,从而在综合考虑视频编码质量和信道误码扩散导致的解码失真的条件下,使视频流具有更强的自适应误码抵抗能力.实际Internet误码信道下的测试结果充分证明了本率失真判决策略的抗误码优势.     

提高H.26L压缩视频抗误码性能的全局率失真优化方法

该文从较新的H.26L视频压缩编码标准出发,并结合Internet信道的Bernoulli和Gilbert 的包丢失模型,提出了一种全局率失真优化的编码模式判决方法,使编码的视频流具有更强的错误恢复能力。实验证明,在实际的Internet信道误码环境下,此方法具有更强的抗错误和实用性,得到了较好的效果。     

一种基于联合信源信道自适应的不等错误保护方法

针对误码信道和信源编码的统计特性,提出了一种能有效提高基于DCT变换的视频编码码流的抗误码性能的自适应不等错误保护方法.它基于信道误码的反馈信息,选择DCT的量化参数q和信道编码码率,并进行DCT重排和VLC编码,再对数据流进行不等差错保护.通过实验证明,它在高误码信道中性能优于EEP等.     

H．264的信道适应性分析与仿真

H.264通过编码端的差错弹性工具,解码端的误码掩盖措施来增强对误码信道的适应性。分析了H.264为增强抗误码性能而采取的主要措施和H.264的校验模型JM对信道误码的处理方法,提出了一种H.264的信道适应性仿真方法,并使用国际上推荐的测试环境进行了仿真,仿真结果表明H.264能够很好地适应有线和无线误码信道。     

信源信道联合编码技术用于AVS传输的研究

针对误码信道和信源编码的统计特性,提出了一种基于AVS视频序列的联合编码技术,按照重要性对AVS视频层序列码流进行分组重排,信道编码器根据码流信息对其进行比重不等的保护措施,以较低复杂度的运算实现了码率的优化分配.实验表明,与现有的等差错保护相比,在高误码信道中能有效提高AVS码流抗误码性能.     

一种视频编码数据分割方案

数据分割是在无线移动信道等传输视频码流时用于抵御信道误码、提高编码比特流健壮性的一种机制.在对现在流行的视频编码标准中数据分割方案进行研究的基础上,文中提出了一种视频编码中数据分割的新方案.在该方案中,运动矢量信息和头信息分割于不同部分;而且运动矢量的水平和垂直分量也可以分割到不同的部分,从而可以更好地抵御信道误码.在这种分割方案下,又提出了可以改进运动矢量编码效率的新编码方法.实验表明该方法对具有尖峰概率密度函数的情形尤为有效.采用文中数据分割方案具有抗信道误码能力强、运动矢量编码比特位数少、编码效率高等优点.     

无线实时多媒体通信系统

文章设计了一个面向无线应用并综合了实时MPEG-4编码、传输和解码的多媒体通信系统，该系统融合了高级视觉中心编码技术和综合抗误码方法，在高误码的无线信道环境下，提高了解码视频的主客观质量。     

一种无人机遥控信道误码率改进方法研究

与传统的无人机遥控信道改善控制指令传输误码的方式比较,利用卷积码对无人机遥控信道进行编码,在一定信道条件下,其控制指令传输误码有明显下降,在码速率不增加的条件下,无人机系统控制指令传输可靠性得到改善。     

脉冲噪声环境下编码信道抗噪声性能研究

针对现实中多数信道为脉冲噪声环境的特点,以α稳定分布和信道编码理论为基础,并以α稳定分布噪声为脉冲噪声模型,运用M atlab软件研究了脉冲噪声环境下编码信道的抗噪声性能。研究结果表明,SNR较大时脉冲噪声对编码信道所造成的误码影响远大于高斯噪声所造成的误码影响。     

自适应格状编码调制

介绍了多维格状编码调制（MTCM）及其自适应格状编码调制的设计方法,并模拟了固定码率TCM与自适应TCM在衰落信道中的误码性能。     

A new interpretation on the MMSE as a robust MEE criterion

The minimum mean-square error (MMSE) and minimum error entropy (MEE) are two important criteria in the estimation related problems. The MMSE can be viewed as a robust MEE criterion in the minimax sense, as its minimization is equivalent to minimizing an upper bound (the maximum value) of the error entropy. This note gives a new and more meaningful interpretation on the robustness of MMSE for problems in which there exists uncertainty in the probability model. It is shown that the MMSE estimator imposes an upper bound on error entropy for the true model. The upper bound consists of two terms. The first term quantifies the “MMSE performance” under nominal conditions, and the second term measures the “distance” between the true and nominal models. This robustness property is parallel to that of the risk-sensitive estimation. Illustration examples are included to confirm the robustness of MMSE.     

改进的蜂群算法评定空间直线度误差

建立了直线度误差的最小区域评定模型,提出了一种改进的蜂群算法并将其应用到直线度误差评定中。阐述了基本蜂群算法的原理,给出了评定直线度的目标函数,利用混沌序列的全局遍历性,混沌初始化蜜源位置,以期提高蜂群算法的鲁棒性。比较改进蜂群算法与两种典型群智能算法的实例计算结果,证明该算法评定球度误差时不仅收敛速度快、评价精度高,而且鲁棒性高,适用于形位误差的优化评定。     

失真补偿量化索引调制水印的性能分析

该文分析了基于量化索引调制的失真补偿水印方案中量化步长的伸缩因子与失真度、鲁棒性和检测误码率之间的关系。在高分辨率量化的假设前提下,推导出失真补偿量化索引调制水印算法在加性高斯白噪声信道下的误码率计算公式,并提出了一个失真-鲁棒性函数来度量算法的抗噪鲁棒性和失真度与鲁棒性之间的代价关系。通过计算机仿真,比较了不同失真补偿量化索引调制水印方案下算法的失真-鲁棒性能和误码率性能;并以一段音频数据三级小波细节系数为载体嵌入水印信息,统计检测时的位错误率。实验结果验证了在低量化步长范围内,理论预测误码率与实验检测误码率较为吻合,失真-鲁棒性函数能够很好地度量高分辨率量化前提下的算法抗噪鲁棒性和失真度与鲁棒性之间的代价关系。     

一种面向健壮性的瞬时功耗建模方法

为了支持通用系统的功耗建模,提出一种以健壮性为目标的RT级瞬时功耗建模方法,即在特定的误差限制下,可以适用于更多的应用情况。对于一个给定的电路模块,首先构造反映电路结构特征的启发式函数进行功耗分类,对每个分类采用常数标识功耗;然后对启发式进行组合,进一步提高功耗模型的健壮性。从实验结果来看,健壮性比已有的功耗模型提高了10％到20％。     

Effect of Mismatch on the Reliability of ON/OFF-Programmable CNNs

In this paper, the reliability of computation of ON/OFF-programmable cellular nonlinear networks (CNNs) is analyzed. This paper redefines the classical concept of robustness (tolerance to physical imperfections) in ON/OFF-programmable CNNs so that it can be used to predict the computation reliability of a physical realization. Also, a systematic approach to improve robustness is described, and guidelines for optimizing reliability with the given resources are given. Random mismatch is identified as the main source of errors in a physical realization. At the presence of random mismatch, we describe the probability of a cell producing an error with specific inputs and the error probability when processing random data. In addition, we show how the error probability could be defined in case the cell needs to work correctly with all possible input combinations.     

Reference frame modification techniques for temporal and spatial scalability

Compressed video is usually transmitted over channels which are not necessarily error free. Channel errors can result in a mismatch between the encoder and the decoder, and because of the predictive structures used in video coding, the errors will propagate both temporally and spatially. Consequently, the quality of the received video at the decoder may degrade significantly. In order to improve the quality of the received video, several error resilient methods have been proposed. In this paper, the introduced mismatch is reduced by modifying the prediction structure and forming a more robust reference frame. The proposed technique combines error robustness of previous Intra coded blocks, better prediction achieved using the previous reference frame, and exponential decay of error propagation caused by the leaky prediction. This technique was examined with the scalable extension of H.264/AVC. Furthermore, the technique was also used in combination with random Intra refresh and error resilience mode decision techniques to achieve better robustness. Simulation results show the effectiveness of our scheme, especially for medium and high motion sequences.     

基于准循环LDPC码在数字水印技术的研究

鲁棒性是数字水印的重要指标之一,提出将准循环LDPC码的前向纠错技术应用于数字版权的保护中,利用准循环LDPC码较强的前向纠错能力,来提高数字水印的鲁棒性。实验结果表明,经准循环LDPC码编码后的数字水印应用于数字水印技术中,水印图像的鲁棒性得到了极大的提高,且经JPEG压缩后,图像水印也能较好地恢复出来。     

基于F范数的二维主成分分析算法及焊缝表面缺陷识别研究

针对传统二维主成分分析(two-dimensional principal component analysis, 2DPCA)算法应用于焊缝表面缺陷识别中存在重构性能及鲁棒性较弱等问题,本文将最大化投影距离和最小化重构误差引入到目标函数中,提出了一种基于F范数的非贪婪二维主成分分析算法(non-greedy 2DPCA with F-norm, NG-2DPCA-F),该算法具有良好的鲁棒性和较低的重构误差。为了进一步提取图像的结构信息和求解出维数更小的特征矩阵,进而提出一种基于F范数的非贪婪双向二维主成分分析算法(non-greedy bilateral 2DPCA with F-norm, NG-B2DPCA-F)。最后,以含有不同噪声块的焊缝表面图像数据集进行实验,结果表明,本文所提算法在平均重构误差、重构图像与分类识别实验中均表现出良好的鲁棒性能。     

A joint encoder–decoder error control framework for stereoscopic video coding

Stereoscopic video coding (SSVC) plays an important role in various 3D video applications. In SSVC, robust stereoscopic video transmission over error-prone networks is still a challenge problem to be solved. In this paper, we propose a joint encoder–decoder error control framework for SSVC, where error-resilient source coding, transmission network conditions, and error concealment scheme are jointly considered to achieve better error robustness performance. The proposed joint encoder–decoder error control framework includes two parts: an error concealment algorithm at the decoder side and a rate–distortion optimized error resilience algorithm at the encoder side. For error concealment at the decoder side, an overlapped block motion and disparity compensation based error concealment scheme is proposed to adaptively utilize inter-view correlations and temporal correlations. For error resilience at the encoder side, first, the inter-view refreshment is proposed for SSVC to suppress error propagations. Then, an end-to-end distortion model for SSVC is derived, which jointly considers the transmission network conditions, inter-view refreshment, and error concealment tools at the decoder side. Finally, based on the derived end-to-end distortion model, the rate–distortion optimized error resilience algorithm is presented to adaptively select inter-view, inter- or intra-coding for SSVC. The experimental results show that the proposed joint encoder–decoder error control framework has superior error robustness performance for stereoscopic video transmission over error-prone networks.     

带有自校正功能的异步电动机转差型矢量控制系统（一）

为了提高异步电动机转差型矢量控制系统对鲁棒性，从而提高整个调速系统的动态性能，本文介绍了一种具有自校正的转差型矢量控制系统。在分析了前馈矢量控制系统中存在问题的基础上，给出了修正的Gabriel自校正方法的自校正律，利用相关函数的方法证明了这种自校正方法的正确性，以及对转速测量误差和负载变化的鲁棒性。[编者按]