基于自适应参考帧模式选择的多视点视频编码方法

基于多视点视频序列相关性,提出独立片的概念,进而提出一种采用自适应参考帧模式选择的多视点视频编码方法.在保证高率失真性能的前提下,应用独立片、自适应算法有效地降低了多视点视频编码计算复杂度,将多种性能进行有机结合,可以根据用户外部设置的参数调整自适应模式.实验结果表明,该方法在保证高压缩效率的前提下,能有效地降低计算复杂度,并改善随机访问性能.     

灵活的多视点视频编码预测结构

多视点视频的时空相关性不仅随着序列的变化而改变,而且视频序列内的相关性特征随着时间的推移也会发生变化,固定的预测结构难以适应复杂情况下多视点视频编码的各种要求。在分析分层B帧预测结构和多视点视频图像中当前帧及其参考帧之间时间相关性和视点间相关性的基础上,提出一种灵活的预测编码结构,根据该多视点视频的时间及视点间相关关系和当前帧与其时间参考帧之间的距离来确定该帧是否采用耗时的视点间预测。实验结果表明,与分层B帧的改进算法——可扩展性预测结构多视点编码算法相比,本文算法在保证编码效率基本不变的前提下,编码复杂度降低了约45%,随机访问性能提高28%,解码图像缓冲区要求降低46%左右。     

一种改进预测结构的多视点视频编码

多视点视频编码是视频编码的研究热点之一。针对联合多视点视频编码（Joint Multi-view Video Coding,JMVC）采用的分层B帧预测结构编码复杂度高,随机访问性能较差等缺点,提出了一种改进的预测结构。所提出的预测结构对B视点中以前一帧作为其时间参考的帧仅采用时间预测,对所有P视点的非关键帧均不进行视点间预测,有效地降低了计算复杂度,提高了随机访问性能。通过选取合适的I视点位置,以减少结构简化带来的编码效率损失。实验结果表明,与分层B帧预测结构相比,所提出的预测结构在保证编码效率损失不大的情况下,显著降低了平均编码时间。改进的预测结构也具有更好的随机访问性能。     

基于H.264标准的多视点视频编码方案的研究

为研究一种新的高效的多视点视频编码方法,提高编码效率,并有效地提高视点间随机切换访问的能力,利用H.264中的新技术多参考帧、SP/SI帧、分层B帧编码等,根据时空预测编码结构的方法,提出了一种基于分层B帧并有利于视点间随机切换访问的多视点视频编码方案.实验结果表明,该方案在提高了编码效率的同时,在视点较多的情况下能够有效地提高视点间随机切换访问的能力.     

支持空域随机访问的多视点视频编码方法

基于H.264/AVC编码框架,提出一种支持空域随机访问功能的多视点视频编码方法,以满足快速虚拟视点绘制的需求.首先采用灵活的GOP时空划分来构建独立时空体,从而在每个时空体内通过限制帧间预测范围来增强解码的独立性,实现压缩域内某一帧特定区域数据的快速定位;进而通过调整预测空间来改善空域随机访问和整帧编码性能之间的关系.实验结果表明,该方法不仅在整帧压缩效率和快速空域随机访问灵活性方面达到了很好的平衡,而且能够通过传输部分码流的方式节省传输带宽.     

基于双目感知的多视点视频快速编码算法

为了减少多视点视频编码过程中多参考帧预测技术巨大的编码复杂度,提出基于双目恰可察觉失真（BJND）的多视点视频多参考帧快速选择算法,通过分析多参考帧选择与BJND之间的统计特性,提前结束多参考帧选择过程。当BJND大于阈值时,确定参考帧列表中时间或者视点上第一参考帧为最优参考帧。实验结果表明,所提出的快速算法在几乎不影响编码率失真性能的情况下,比多视点视频编码校验模型平均节约76%的编码时间。     

基于随机访问的多视点视频编码模式评价模型

运用随机图论、超空间等方法,首先提出了针对编码预测结构的随机访问性能评价函数,对解码端和服务器端的随机访问支持代价进行评价.进而根据实际应用中的带宽、交互限制等多种目标建立了编码策略评价的多目标非线性数学模型,对编码策略在多种性能参数约束条件下如何实现最优策略进行了讨论.利用该非线性多目标规划模型对多视点视频编码策略进行了优化设计,可以获得较好的随机访问性能.     

基于相关性的分布式解码检测优化算法

在分布式视频编解码系统中,由于细节变化丰富而生成的边信息与原始视频帧之间存在较大的差距,降低了解码帧质量。针对如何实现解码帧质量检测,并对低质量的解码帧进行优化以提高系统性能的问题,提出一种基于相关性的分布式解码检测优化算法。在编解码端分别计算相关性,得到置信度值并进行解码检测。对于低质量的像素块根据相关性及运动估计进行重构,最后通过滤波和双向运动补偿产生优化像素块。实验结果表明,所提算法对低质量边信息具有优化作用。     

多视点立体音视频压缩编解码同步研究

为了更好地解决多视点立体视频数据的音视频同步问题,提出了一种基于Direct Show的多视点立体音视频信号压缩编解码同步方案。根据多视点立体视频的光栅显示特点,充分利用了立体视频帧内以及帧问的冗余相关性实现了立体视频数据的无损压缩,同时针对音频数据采用了基于子带编码的方式进行压缩,最后将多视点立体视频与音频数据通过压缩编码后写入立体视频文件,并在解码端通过同步控制机制实现了音视频的同步。实验结果表明,此方法能有效地实现多视点立体音视频同步。     

一种新颖的多视点视频偏色校正算法

针对多视点视频序列中视点间出现偏色的问题,提出了一种偏色校正算法.该算法在编码端只处理目标序列的亮度分量,在解码端利用运动矢量信息和参考序列,使用色彩扩散的方法恢复出目标序列的颜色信息.在完成偏色校正的同时,有效地提高了编码效率.以标准多视点视频测试序列为实验对象,将本文算法与直方图匹配校正、未校正序列进行比较,表明本文算法可以有效校正偏色现象,并获得良好的主观效果.     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.