基于边界匹配的增强多权重差错掩盖方法研究*

提出了一种基于边界匹配的增强多权重差错掩盖算法,通过受损宏块周围时空域相邻宏块的相关信息在增强候选运动矢量集中进行运动矢量选取,采用多权重的边界匹配方法使之在物体边界处能够获得更准确的运动矢量,并专门对连续图像片丢失或整帧丢失的情况进行时域掩盖处理。基于H.26L的仿真实验表明,该方法可有效地抑制视频差错的扩散,取得较好的差错掩盖效果。     

基于边界匹配的增强多权重差错掩盖方法研究

提出了一种基于边界匹配的增强多权重差错掩盖算法,通过受损宏块周围时空域相邻宏块的相关信息在增强候选运动矢量集中进行运动矢量选取,采用多权重的边界匹配方法使之在物体边界处能够获得更准确的运动矢量,并专门对连续图像片丢失或整帧丢失的情况进行时域掩盖处理。基于H．26L的仿真实验表明,该方法可有效地抑制视频差错的扩散,取得较好的差错掩盖效果。     

H.264中基于多宏块模式的时域误码掩盖算法

视频压缩码流在信道传输时,由于受到信道带宽或者稳定性的影响,容易发生数据的损坏或者丢失,这样不仅会对当前的视频帧产生影响,而且差错会延续到随后的视频帧,因此,需要采用某种技术来降低差错的影响.新一代视频压缩标准H.264支持多种分块大小的运动补偿,分块大小范围从16×16到4×4,因此,在H.264中一个宏块最多可能有16个运动矢量,这些信息都可以用于时域的误码掩盖.为此,提出了一种基于多宏块分割模式的时域误码掩盖算法,根据相邻宏块的分割模式,每个丢失宏块被自适应的划分为大小不同的子块进行掩盖.实验结果表明,该算法可以得到比传统算法更好的视频质量.     

基于SVC的空域增强层帧级错误掩盖算法

基于SVC空域增强层宏块编码模式的特点,提出一种增强层帧级错误掩盖算法,综合利用层间预测信息和时域直接模式TD下的运动信息,预测丢失帧中的宏块是否采用TD模式编码运动信息。对于符合判决条件的宏块,使用TD模式来产生其运动矢量,以提高运动矢量恢复的精确度,从而提升丢失帧的错误掩盖效果。实验结果表明,与原JSVM算法相比,该算法以很小的运算复杂度,使增强层序列的解码PSNR平均提高了0.23 dB。     

一种适用于H.264的时域差错掩盖算法

为了克服视频传输中因传输错误引起的视频质量下降,结合H.264的编码特性,提出一种基于运动矢量自适应修复的时域差错掩盖算法。首先利用正确接收的宏块信息估计丢失块邻域内运动矢量的变化强度,据此自适应采用边界运动矢量差值最小法或多项式插值法恢复丢失块的运动矢量,然后根据恢复的运动矢量对丢失块进行补偿替代。仿真结果表明,该算法同传统的时域差错掩盖算法相比,在相同网络丢包的环境下PSNR值提高了0.2~2.5dB,同时解码的图像也获得较好的主观视觉效果。     

IP网络MPEG-4视频流的自适应差错掩盖算法

针对IP网络上的MPEG-4视频传输,采用面向差错控制的打包方案,提出了一种结合时域差错恢复和空域差错恢复方法的快速自适应差错恢复混合算法。该算法根据视频帧的编码模式、丢失宏块的邻域宏块的编码模式、运动程度和运动矢量一致性自适应地选择差错恢复方法。仿真实验结果验证了自适应算法具有较好的差错恢复能力。     

基于可变尺寸块运动矢量恢复的H.264时域差错掩盖算法

针对H.264帧间预测编码的新特点,提出了一种基于可变尺寸块运动矢量恢复的时域差错掩盖算法。该算法首先利用相邻宏块编码模式的相关性,根据周围宏块的编码模式判断受损宏块的编码模式及运动矢量恢复的宏块划分方式,分别对各个划分的子块进行运动矢量的恢复;然后利用相邻块运动矢量参考帧的相关性,根据相邻块运动矢量的参考帧确定匹配使用的参考帧;最后采用边缘失真匹配方法恢复运动矢量。实验结果表明,该算法同传统的差错掩盖算法相比,由于支持不同尺寸块运动矢量的恢复,因此,算法对差错信号能够获得更好的恢复效果。     

一种基于H.264的帧间错误掩盖算法

H.264采用混合编码算法.视频流的传输错误将会导致解码错误在时间和空间上扩散,直接影响重构图像的质量.本文充分结合H.264的编码特性,利用宏块的空间或时间相关性来确定丢失宏块的类型,根据相邻块的运动矢量建立一个描述小区域内运动矢量变化趋势的多项式模型,更精确的恢复出丢失宏块的运动矢量,提高重构图像的质量.仿真结果表明:该算法优于以往的边界匹配算法,在同等宏块丢失率下,恢复的视频序列Y分量的PSNR值能提高0.75～1.5dB.     

利用改进的图像修复的联合帧间差错隐藏算法

针对图像修补的不足和视频帧间编码的特点,提出利用改进的图像修复的帧间差错隐藏联合算法.根据丢失宏块的周围宏块的运动相关性和正确接收情况对丢失宏块进行运动性和可用性判断,如果丢失宏块属于静止宏块且可用性不为零,则采用改进的图像修补隐藏帧间差错,否则采用外边界匹配准则进行差错隐藏;并在图像修补中对置信度、等照度和修复方向等方面进行了改进.该算法既发挥了图像修复对纹理丰富区域的修复优势,也克服了图像修补对运动区域的隐藏效果不好的缺陷.实验结果表明,该算法可以带来主观和客观质量上的提高,并且明显克服了外边界匹配算法带来的视频抖动.     

自适应时域差错掩盖方法

差错掩盖作为视频传输中的重要技术之一,可以有效地弥补视频在传输过程中,因为传输环境等原因造成的数据丢失及数据错误,最大程度地保证视频在到达接收端后可以保持令人满意的质量。通过提出一种可应用于基于块编码系统的自适应时域差错掩盖方法,同时估计丢失宏块的运动及丢失宏块中的像素运动,并根据每个像素的不同情况,自适应地将两个估计的运动结合,获得最终的像素恢复值。实验结果表明,该方法相比原有方法,在主观和客观质量上都有较大的提高。     

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。     

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.     

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.     

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     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

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。