面向视频播放场景的屏幕编码码率控制方法

针对屏幕中同时出现视频和文字图片时现有码率控制方法的局限性,提出一种新的码率控制方法。以视频缓存检验器和恒定码率因子控制模式为基础,通过视频窗口检测算法将屏幕内容划分为视频区域和非视频区域,并对不同的区域采取不同的码率控制算法。结合视频区域识别算法,新的码率控制方法分别对帧层和宏块层采用如下方法实现优化:对于帧层,若当前帧为P帧且在I帧周围一定范围内,则该帧通过采用P_SKIP模式降低非视频区域的帧率以补偿I帧的整体质量,提高屏幕视频序列的整体视觉效果;对于宏块层,则根据当前宏块所处区域(视频区域或非视频区域)对宏块量化参数及其波动范围作一定调整。实验结果表明,与x264原有的VBV+CRF模式相比,新的码率控制方法获得的主观评价评分要高40%。     

基于非局部低秩和自适应量化约束先验的HEVC后处理算法

经高效视频编解码标准HEVC压缩后的视频在高压缩比、低码率的情况下存在明显的压缩效应。针对该问题,提出了一种基于非局部低秩(Non-local Low-rank,NLLR)和自适应量化约束(Adaptive Quantization Constraint,AQC)先验的HEVC后处理算法。该算法首先构造在最大后验概率框架下的优化问题,然后利用解码后的压缩视频和量化参数QP获取非局部低秩和自适应量化约束先验信息,最后利用split-Bregman迭代算法来解决所提的优化问题,从而有效去除压缩效应,提升重建视频质量。其中,非局部低秩先验通过构建基于相似块聚类的非局部低秩模型来获得;自适应量化约束先验通过联合不同量化参数QP下的约束特性与视频的DCT域块活动性来获得。实验结果表明,在同等码率的情况下,与HEVC标准相比,所提算法在帧内编码模式下可以达到平均0.2597 dB的PSNR提升,在帧间编码模式下可以达到平均0.2828 dB的PSNR提升。     

基于压缩感知的改进MPEG-2编码方案

为寻找压缩感知在视频编码上的应用并提高MPEG-2的编码效率,提出了基于压缩感知和MPEG-2的改进方案。该视频编码改进方案从标准重构方法与像素域最小全变分重构算法中选出最终重构方法,使最终重构出的图像具有较小均方误差和。像素域最小全变分重构算法的提出,基于原始图像的梯度比残差图像的梯度更稀疏这个特征。实验结果表明,所提出的方案对于各类序列都有性能的提升。对于有比较锐利边缘物体的序列,平均峰值信噪比(PSNR)提高0.5dB以上;而对于具有较多平坦区域或复杂纹理的序列,平均PSNR也有0.26dB~0.41dB的提高。     

基于非均匀量化的小波域分布式深度图视频编码

针对分布式多视点加深度格式(DMVD)的视频编码中深度图视频解码质量问题,提出一种结合子带层及子带系数的小波域分布式深度视频非均匀量化方案,通过给边缘分配更多比特来提升深度图的边缘质量。结合深度图经小波变换后系数分布特性,对第N层的低频小波系数采用均匀量化方案,对其他层高频小波系数采用非均匀量化方案。针对高频系数的非均匀量化,对处于"0"左右的高频系数采用较大的量化步长,随着高频系数幅度值的增大,量化步长逐渐减小,量化逐渐精细,从而提升深度图中的边缘细节质量。实验结果表明,对于边缘较多且变化较明显的"Dancer"和"PoznanHall2"深度序列,该算法能够有效地提高二者的边缘信息质量从而提高其率失真(R-D)性能,最高可达1.2 dB;而对于边缘区域较小且较为模糊的"Newspaper"和"Balloons"深度序列,系统的R-D性能也能被提升0.3 dB左右。     

基于H.264的转码初始量化参数自适应选择

针对不同的视频内容造成编码前几帧质量低下的问题,提出一种基于I帧复杂度的初始量化参数(QP)选择算法。在编码前利用解码码流中得到的I帧宏块模式信息,运用宏块中的3种不同帧内预测模式判断I帧的复杂度,并采用目标码率和初始QP的关系重新拟合新的初始QP的选择方法。实验结果表明,在相同的码率下,该算法避免了传统码率控制中初始QP选择算法的弊端,可提高视频的客观质量,降低判断I帧的复杂度,客观峰值信噪比值比现有相关算法平均提高0.6 dB,最高提高1.69 dB。     

基于ROI的动态FMO视频抗差错算法研究

本文提出了一种基于感兴趣区域(ROI)的动态FMO(DFMO)的视频抗差错算法,该算法采用分层编码的思想,对于ROI区域采用抗差错性能好的FMO模式,而非ROI区域则采用抗差错性能次之的FMO模式,以此达到抗差错性能和编码效率的平衡。仿真结果表明,相比于传统FMO模式,本文提出的DFMO算法在保证较低额外比特开销的情况下,可以有效地提高重建视频的主客观质量。     

基于块分类的深度图运动估计及其并行实现

针对三维高效视频编码(3D high efficiency video coding,3D-HEVC)深度图在运动估计过程中没有充分利用平坦区域数据特性而导致的计算量大、编码时间长等问题,提出一种基于块分类的深度图运动估计优化方法.依据编码块像素分布特征,将其分类为平坦或者边缘区域,自适应地为不同类型编码块分配不同的搜索算法,减少整体计算开销.实验结果表明,优化后的算法相比于全搜索算法,平均峰值信噪比(peak signal to noise ratio,PSNR)的损耗仅为0.0870 dB;相比于TZSearch(test zone search)算法,运动搜索次数平均减少12.04％.为进一步提升编码速度,基于视频阵列处理器对优化后的算法设计并行实现方案.实验结果表明,所设计的并行方案串/并平均加速比达到2.8940.     

基于H.264压缩域的视频盲水印算法

为了解决H.264视频信息的版权保护问题,提出了一种基于即时解码刷新(IDR)帧离散余弦变换(DCT)域的盲水印算法。该算法首先分析IDR帧的纹理特征,利用滑动矩形窗根据图像的梯度特性提取出复杂纹理区域;然后,计算该区域内每个宏块的16个4×4子块能量,得到能量最高子块;最后,通过自适应修改子块的一个交流(AC)系数幅值以达到嵌入水印的目的。实验结果表明：对CIF分辨率视频测试序列嵌入水印后,视频图像的峰值信噪比(PSNR)平均下降0.15dB,码率平均增加了0.49%,水印检测准确率达到91%以上,并且该算法能够有效抵抗不同量化参数(QP)的重复编码攻击。     

基于重建编码信息的视频ROI提取算法

针对H.264/AVC视频编码标准计算复杂度高、难以实时应用的缺陷,利用重建块的运动矢量和帧间预测模式,并结合人类视觉感知特征,提出一种视频感兴趣区域快速提取算法及其优化编码方案。仿真结果表明,与H.264/AVC算法相比,该算法能够在码率平均增加0.17%、峰值信噪比平均下降0.052 dB的前提下,节省53.11%的编码时间。     

视频编码中自适应的初始量化参数预测算法

通过分析在H.264/AVC中预测初始量化参数的方法过于简单,导致视频序列整体编码量化参数和重建图像PSNR的波动,甚至PSNR急剧下降的问题,利用基于Cauchy分布的R-Q模型,结合I帧图像复杂度建立R-C-Q模型,提出了自适应的初始量化参数预测算法。该算法能够根据不同视频序列的特性,准确地预测I帧的初始量化参数,有效地抑制视频序列的整体量化参数及PSNR的波动,从而提高码率控制精度和重建图像质量。     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

基于AD9626的模拟信号采集存储卡设计

自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

A human-computer interface for non-computer specialists

The COM teleconferencing system was designed to be easy to use for both beginners and people with much computer experience. A number of design choices in organizing the human-computer interface were considered very carefully. These design problems are not unique for teleconferencing applications, but will appear in many other developments of human-computer interfaces for non-computer specialists. This report discusses naming conventions, menu format, user commands, help facility and the treatment of ‘type ahead’ from the users.