结构相似度的立体视频错误隐藏

针对立体视频传输中右视点整帧丢失,提出了一种基于结构相似度(Structural Similarity,SSIM)的立体视频右视点整帧丢失错误隐藏算法。首先,提出了时域SSIM和视间SSIM的概念。然后,根据视频序列的时域相关性,将前一时刻右视点图像宏块的预测方式作为丢失图像宏块的预测方式。接着,将前一时刻右视点图像以宏块为单位进行时域和视间匹配,求取其以像素为单位的时域SSIM映射图和视间SSIM映射图。最后,计算并比较前一时刻右视点图像每个宏块的时域SSIM和视间SSIM值,得到每个宏块的预测方式,将其预测方式作为丢失帧中宏块的预测方式,从而使用运动补偿预测或者视差补偿预测的方法进行恢复。实验结果表明,与传统的算法和Pang的算法相比,PSNR值分别提高了2.76 dB和3.43 dB,且本文算法主观效果较好。     

基于Matlab小波分析的图像降噪研究

波包理论是在小波基础上发展起来的时频分析理论,在图像降噪中取得了较好的应用。介绍小波分析和小波包的基本理论,分析几种基于小波和小波包的图像降噪的方法,并且在此基础上,利用Matlab R2008b编程与仿真,对其结果进行分析与比较,实验表明,图像降噪效果与阈值的选取密切相关,小波包降噪后的效果比小波更好。     

基于CEEMD的心音信号小波包去噪算法研究

针对传统心音去噪方法易将其部分高频有用信息作为噪声滤除而造成滤波后的心音信号失真及信息丢失的问题,提出了一种基于互补总体经验模态分解(CEEMD)的小波包变换去噪算法。首先通过互补总体经验模态分解将心音信号分解为从高频到低频的不同固有模态函数分量(IMFs),并利用自相关函数客观界定信号的模态分量范围;然后对噪声主导模态分量和混叠模态分量采用小波包变换进行滤波提取有用信息后,与剩余固有模态分量进行重构得到去噪后的信号。实验结果表明,改进的算法不仅可以去除心音中的噪声成分,明显改善心音信号的信噪比和均方根误差,而且能够有效保留信号的高频有用信息,且在不同噪声水平下的去噪性能均优于传统算法,鲁棒性较好。     

影响IP电话话音质量的主要因素及相关技术

分析了影响IP电话话音质量的语音编解码技术、包丢失以及时延和时延抖动等主要因素 ,介绍了当前解决这些问题的相关技术。     

网络控制系统中的时延分析

与传统点对点控制系统相比,由于网络的引入,使得控制系统中出现一些新问题,诸如网络时延、网络调度、包丢失及多包传输等。这些问题的存在使系统性能降低,甚至使控制系统不稳定。主要对以太网中存在的网络诱导时延进行分析和研究。     

基于双树复小波包的发动机振动信号特征提取研究

针对柴油机缸盖振动信号的特征提取问题,提出了一种基于双树复小波包变换和自适应块阈值降噪的标准化相对能量提取方法,双树复小波包利用并行双树实小波变换分解系数达到信息互补,从而获得近似平移不变性和减少了信息的丢失.自适应分块阈值能够随所分析的信号自适应估计最优阈值,达到更好的降噪效果,同时引入消除频率混叠的算法,抑制了双树复小波包分解过程中虚假频率的产生.仿真信号和试验分析该方法能够更有效地消除噪声影响,所提取的相对能量特征具有更好的可区分度.     

EEPROM技术在微机皮带秤中的应用

本介绍在微机皮带秤中，如何利用ＥＥＰＲＯＭ写入数据后掉电不丢失数据的技术，实现保存各种现场调试参数与保存螺计量，零点值等动态数据的双重保护的目的，较好地解决了微机皮带秤常常丢失各种参数与累计量这一难题，提高了皮带秤的可靠性与实用性。     

基于维纳滤波的图像边缘检测方法

针对经典边缘检测方法中存在的精度低、算法复杂等问题,提出了一种基于维纳滤波的图像边缘检测方法。该方法不仅算法简单,而且可以较准确地检测出图像的灰度变化信息,不丢失重要边缘且实际边缘与检测到的边缘之间偏差较小。另外,利用该方法得到的边缘连续性较好,不易产生线段断裂。实验证明该方法可以用于检测图像边缘,尤其对以字符、曲线为主的复杂图像,有较好的检测效果。     

Ni60-Ni包MoS_2-Ni包C复合自润滑涂层的结合强度及摩擦学性能

镍基合金涂层材料具有良好的耐磨性和耐蚀性.在其中加入适量复合固体润滑剂可有效改善合金的摩擦学性能,并保持一定的结合强度.以Ni60为基体粉末,Ni包MOS2和Ni包C(石墨)为复合自润滑粉末,以均匀设计方法设计喷涂粉末配比,采用超音速火焰喷涂技术制备涂层,测试了涂层的抗拉结合强度、摩擦系数和磨损失重,并对涂层的结合强度、摩擦系数和磨损失重进行了回归分析.结果显示:回归方程均具有较好的拟合性;Ni包MoS2与Ni包C具有协同效应,对Ni60涂层的性能具有显著的影响;当Ni包MoS2为33%(质量分数)、Ni包C为13%(质量分数)时,复合涂层的结合强度大于30 MPa,摩擦系数和磨损失重最小,表明涂层具有较好的结合性能及最佳的摩擦学性能.     

扩展方向树的遥感图像小波包压缩算法

针对遥感图像纹理丰富、空间相关性弱,普通压缩算法容易造成高频信息丢失的特点,本文利用小波包优良的高频分析能力,提出一种结合SPIHT的小波包编码算法.该算法采用类似SPIHT算法的零树结构,通过重新定义方向树,即扩展方向树,改变小波包各节点之间的对应关系,解决小波包分解时产生的"父冲突"问题.同时,对扩展方向树的合理性进行了实验验证,并结合SPIHT算法实现了整个编解码.实验结果表明,对于富含纹理的遥感图像,在1bpp的压缩率下,该算法峰值信噪比(PSNR)超出SPIHT算法0.5-1dB,且视觉效果更好.     

电子稳像在计算机视频辐射信息再现中的应用

介绍了计算机视频辐射信息再现的基本原理，然后分析了产生图像左右飘移的原因，并提出了一种基于图像特征跟踪的电子稳像方案。该方案根据被接收的视频信息，找到图像的特征，实现图像的稳定再现。经过实验证明，该方案的稳像误差最大不超过1个像素。     

Video Transmission for Third Generation Wireless Communication Systems

This paper presents a twin-class unequal protected video transmission system over wireless channels. Video partitioning based on a separation of the Variable Length Coded (VLC) Discrete Cosine Transform (DCT) coefficients within each block is considered for constant bitrate transmission (CBR). In the splitting process the fraction of bits assigned to each of the two partitions is adjusted according to the requirements of the unequal error protection scheme employed. Subsequently, partitioning is applied to the ITU-T H.263 coding standard. As a transport vehicle, we have considered one of the leading third generation cellular radio standards known as WCDMA. A dual-priority transmission system is then invoked on the WCDMA system where the video data, after being broken into two streams, is unequally protected. We use a very simple error correction coding scheme for illustration and then propose more sophisticated forms of unequal protection of the digitized video signals. We show that this strategy results in a significantly higher quality of the reconstructed video data when it is transmitted over time-varying multipath fading channels.     

一种用间接法推定摄像机光谱特性的误差特性方法

本文提出一种利用间接法来推定摄像机光谱特性的误差特性新方法。介绍了这种方法的原理，给出了误差特性表达式。利用最小二乘法还推出了误差特性的估算公式。     

Traffic scheduling for multimedia transmission over IEEE 802.11e wireless LAN

As the demand for broadband multimedia wireless is increasing, improving the quality of service (QoS) of the widely deployed IEEE 802.11 wireless LAN has become crucial. In order to attain the QoS required by a wide range of applications, the IEEE 802.11 working group has denned a new standard - the IEEE 802.lie. However, very limited work has been performed to address the QoS transmission problem of real-time video over IEEE 802.11e. A novel measurement-based dynamic transmission opportunity (MBDTXOP) scheme is proposed, which adaptively allocates resources to a variable bit rate (VBR) video on the basis of the estimation of future traffic demand to support efficient QoS transmission of VBR video. The novelty of the proposed scheme, when compared with existing methods, lies in estimating the required network resources by exploiting the characteristics of digital video; this capability enables the MBDTXOP scheme to substantially increase network utilisation while preserving the required QoS for the transmission of VBR video. Simulations comparing the proposed scheme with other mechanisms clearly demonstrate the outstanding performance of the former.     

一种结合时间轴滤波的视频消噪新方法

为了提高含噪视频图像的质量,提出了一种二维小波域自适应滤波与时域时间轴滤波相结合的视频图像消噪新方法。首先,对视频序列的各帧在二维小波域中进行自适应滤波,之后在时域中进行时间轴滤波。对于二维小波域滤波算法,提出了一种高效的自适应阈值选取方案;时间轴滤波器则是结合了运动检测和递归平均。实验结果表明,其消噪效果要优于单纯的二维小波域滤波方法。     

面向运动估计器硬件实现的加权块匹配检测算法

在各种视频处理算法中，运动补偿型算法大大提高了各种视频处理效果。运动估计器的硬件实现是各种运动补偿视频处理算法在实际系统中运用的关键。由于块匹配运动估计算法较低的运算复杂度和硬件实现难度以及块匹配检测标准函数很高的调用频率，已经广泛应用到各种实际系统中。文中提出了加权最小最大误差的匹配检测标准，能够降低运动估计器的运算复杂度，减少估计器的硬件面积，提高硬件速度，而且能够降低递归搜索块匹配运动估计算法固有误差传递带来的负面影响。     

Image compression by vector quantization with noniterative derivation of a codebook: applications to video and confocal images

We demonstrate an image-compression technique that uses what we believe is a new noniterative codebook generation algorithm for vector quantization. The technique supports rapid decompression and is equally applicable to individual images or to a set of images without the need for interframe processing. Compression with a single-image codebook is tested on (1) ten confocal images of the hindbrain of a mouse embryo, (2) video images of a polystyrene microsphere that is manipulated by a focused laser light, and (3) five fluorescence images of the embryo eye lens taken at different magnifications. The reconstructions are assessed with the normalized mean-squared error and with Linfoot's criteria of fidelity, structural content, and correlation quality. Experimental results with single-image compression show that the technique produces fewer local artifacts than JPEG compression, especially with noisy images. Results with video and confocal image series indicate that single-image codebook generation is sufficient at practical compression ratios for producing acceptable reconstructions for mouse embryo analysis and for viewing optically trapped microspheres. Experiments with the magnified images also reveal that the compression scheme is robust to scaling.     

Generic nonsinusoidal phase error correction for three-dimensional shape measurement using a digital video projector

A structured light system using a digital video projector is widely used for 3D shape measurement. However, the nonlinear gamma of the projector causes the projected fringe patterns to be nonsinusoidal, which results in phase error and therefore measurement error. It has been shown that, by using a small look-up table (LUT), this type of phase error can be reduced significantly for a three-step phase-shifting algorithm. We prove that this algorithm is generic for any phase-shifting algorithm. Moreover, we propose a new LUT generation method by analyzing the captured fringe image of a flat board directly. Experiments show that this error compensation algorithm can reduce the phase error to at least 13 times smaller.     

Prediction-Correction Scheme for Decoupled Forward Backward Stochastic Differential Equations with Jumps

By introducing a new Gaussian process and a new compensated Poisson random measure, we propose an explicit prediction-correction scheme for solving decoupled forward backward stochastic differential equations with jumps (FBSDEJs). For this scheme, we first theoretically obtain a general error estimate result, which implies that the scheme is stable. Then using this result, we rigorously prove that the accuracy of the explicit scheme can be of second order. Finally, we carry out some numerical experiments to verify our theoretical results.     

视频分层组织方案和技术

数字视频是多媒体信息系统中重要的数据类型。传统的视频表示方法仅是一个时间序列－－媒体流,所以对计算机来说,很难在内容层次上认知视频。为了有效地访问和利用视频信息,合适的视频数据组织非常重要。章提出将视频划分成四个层次即视频节目、情节、镜头和图像帧的组织方法。这样一种分层结构提供了紧凑和有意义的视频目录,方便了视频非线性浏览和基于内容的检索。为了得到这样一种组织,不仅要检测出镜头和情节这些视频单元的边界,还要提取镜头关键帧和选择情节有代表性的镜头和代表帧。章介绍一系列分割视频和组织视频的准则和方法,并把它们结合起来组成了一个原型实验系统。中还给出了一些对实际视频进行组织的结果,它们表明该组织形式是非常有效的。