一种低硬件消耗的CABAC编码器研究与实现

基于上下文的自适应算术编码(CABAC)是H.264标准中的一个重要创新.通过算术编码与自适应上下文模型的结合使其可以获得很高的压缩比,相对于CAVLC其可以获得9%～14%码率的降低.CABAC作为一种新型的熵编码方法,其将自适应技术、上下文模型化和二进制算术编码有效的结合在了一起,并采用查表的乘法与概率估计,使得CABAC在硬件实现方面比较方便.在此提出了一种适用于1080P(@30Hz)的低硬件消耗的CABAC编码器,采用SMICO.18μmCMOS工艺实现,其理想速度可以达到200MHz.该编码器可以应用于高清视频编码领域.     

改进的CABAC与SPIHT编码算法研究

为提高图像压缩效率,提出了分段自适应二进制算术编码CABAC与SPIHT算法相结合的混合编码算法,并从理论和仿真实验两个方面证明了该算法的有效性。根据SPIHT算法产生码流概率的特点及二进制熵编码的特性将SPIHT算法产生的二进制码流分为符号和数据两段,并按照SPIHT编码阈值对数据码流再次分段,采用优化的CABAC对各二进制码流段分别编码,在不增加计算量的情况下能够得到更好的图像压缩效果。     

一种提前进行模式选择的H.264编码优化算法

H.264编码标准利用基于各种不同大小块的运动估计和补偿,从而显著的提高了编码效率.但运动估计和离散余弦变换(DCT)也大大的增加了计算复杂度,使编码时间随之增加.本文提出了一种提前进行模式选择的算法,先进行16×16大小全零块的检测,然后在此基础上预先进行模式选择的判断,用以控制编码复杂度.实验结果显示在信噪比略有下降的同时,总的编码时间平均可以节省75.11%,而用以进行运动估计的时间平均可以节省84.25%.     

一种基于H.264的可变块快速运动估计算法

H.264是最新的视频编码标准,它相对于以前的视频编码标准在编码效率上有了巨大的提高。高编码效率得益于采用了一系列新的编码技术,这也导致了较高的计算复杂度。H.264运用了可变块运动估计方法,这也是H.264编码过程中最耗时的模块。提出了一种基于H.264的可变块快速运动估计算法。该算法基于以下3种策略:静止块的预测、非静止块的预测搜索和合并过程中的自适应精细搜索。试验结果证明,该算法能够将计算复杂度降低到快速全搜索运动估计算法的3%,而PSNR和码率几乎与快速全搜索算法得到的结果相当。     

H．264／AVC中计算复杂度可调的快速模式选择算法

H．264／AVC视频编码标准采用多模式编码技术虽显著提高了编码效率，但由于该技术计算复杂度极高，因此为了降低计算复杂度，提出了一种计算复杂度可调的快速模式选择算法。该算法依据编码模式的特点和最佳模式分布规律，利用运动活性及已测试模式所得残差的量化系数来预测尚未测试模式的编码性能，并略过不必要测试的模式，通过选择恰当的阈值即可实现计算复杂度的调整。实验表明，与全模式选择算法相比，采用该算法编码速度可以提高2～4倍，而且重建质量和编码效率损失极小。     

低码率视频编码的优化方法

采用的低码率视频编码方法是以全局运动补偿和局部运动补偿为核心的混合编码方法.主要针对MPEG-4中原有算法计算量大、复杂度高的特点进行了编码系统优化,将这一编码方法实用化.该优化方法是针对占编码系统70%计算量的全局运动估计进行的,采用了基于运动特征的运动估计方法和鲁棒的目标函数,并在优化方法中引入了三级金字塔的分层计算.从对比实验结果来看,优化方法对不同运动类别视频的编码都是有效的,系统编码速度提高了3倍以上.目前,这项优化方法已经被MPEG-4视频编码优化小组采用.     

基于时空相关性的宏块编码模式预测算法

与以往的各种视频编码标准相比，H．264视频编码标准在编码效率上获得了最大50％的提高．但这是以提高编码的计算复杂度为代价的，其中运动估计和模式选择的计算复杂度最大．文中提出一种基于时空相关性的宏块编码模式预测算法，该算法首先检查根据时空相关性预测得到的模式，再根据相应的阈值判断是否结束模式选择过程。而不用对所有的模式进行全搜索．试验结果证明：在保持相近率失真性能的同时，该算法可以有效地降低编码的计算复杂度．     

一种快速帧内预测算法

为进一步提高帧内预测的编码性能,提出一种新的帧内预测算法。该算法对用于预测的参考像素进行相似度检测,当参考像素相似度高时,直接使用平均模式预测,省去了用于编码预测模式的比特,节省了码率,并降低了计算复杂度。实验结果表明,该算法在同样的峰值信噪比(PSNR)下,平均码率降低了1.42%,编码速度提高了32.1%。     

基于CABAC和去耦合码率估计技术的H.264/AVC帧内模式选择方法研究

本文提出了一种简单有效的帧内模式选择方法,通过分析CABAC熵编码中色度分量与量度分量的交织信息,去除耦合,同时在率失真优化过程中部分引入部分码率估计方法,降低模式选择的计算复杂度,提高模式选择速度。大量的实验结果表明,本文提出的方法对全I帧序列能够带来66.4%的时间节省,同时几乎不损失编码图像质量;对IBBP序列能够达到平均10%的时间节省,同时部分序列甚至比JM有更好的R-D曲线。     

立体视频编码中运动和视差联合估计算法的研究

立体视频编码不仅要在同一个视点间进行运动估计,还要在相邻视点间进行视差估计,计算复杂度非常高.如何有效地结合运动估计和视差估计,降低运算复杂度是当前亟待解决的问题.本文详细分析了立体视频左右通道视频流之间的相关性,提出一种运动和视差联合估计快速算法.根据运动—视差模型,结合时空域的多参考帧来进行联合的运动和视差估计,实现对数据的有效编码压缩.实验证明,该算法与传统的全搜索算法相比,能在保证率失真性能基本不变的前提下,降低96.45%的运算复杂度,大大提高编码速度.     

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     

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.     

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。