理想投影椭圆约束下的鱼眼镜头内部参数标定

目的 鱼眼镜头是发展轻、小型全方位视觉系统的理想光学传感器,但由于镜头焦距短、视场大及光学原理约束,鱼眼图像存在严重畸变,为此提出一种高精度、应用方式灵活的鱼眼镜头内部参数标定方法,以期将鱼眼图像转换成符合人眼视觉习惯的平面透视投影图像。方法 从球面透视投影模型出发,首先分析给出空间直线在水平面上的理想投影椭圆约束,进而结合椭圆严格几何特性建立误差方程对鱼眼相机等效焦距f,纵横比A及径向畸变参数k₁,k₂进行最小二乘估计,最后利用估计参数对鱼眼图像进行立方盒展开实现平面透视纠正目的。结果 对某型号定焦鱼眼相机的棋盘格影像多视标定及网上鱼眼图像单视自标定结果表明,本文方法标定参数对鱼眼图像不同区域的平面透视纠正效果稳健、精度高。多视标定参数均方根误差（RMSE）约0.1像素,纠正影像上直线拟合误差RMSE约0.2像素,总体效果略优于对比文献方法;单视自标定参数误差RMSE约0.3像素,影像纠正范围、直线透视特性保持明显优于对比文献方法及商业软件DXO（DXO Optics Pro）。结论 本文方法标定参数少、计算过程简单且对标定参照物要求不高,对于具有大量直线的人工场景理论上可实现自标定,应用价值较高。     

二维机器视觉测量中的图元识别

采用视觉测量方法对工件的各种断面尺寸参数进行测量时,需要在采集到的图像中找到被测量对象。文章给出了一种识别测量对象的图像匹配方法。该方法首先采用Canny方法从工件图像中提取出宽度为单像素的连续边缘图像,并根据工件的原理图纸生成待匹配的模板图像;对模板图像进行缩放和旋转,使之能在匹配率的约束下和边缘图像实现匹配;原理模板中包含图元的编码信息,据此可以在边缘图像中识别出工件的图元信息。实验结果表明,文中提出的方法能适用于一般工件的断面图元识别。     

基于立体视觉的汽车安全气囊装配精度测评方法

本文提出了一种基于双目立体视觉检测而实现汽车安全气囊装配精度测评的方法,将CCD摄像机提供的待测安全气囊的图像与标准安全气囊的三维数模相结合,建立了汽车安全气囊轮廓检测点的位置公差V_x、V_y、V_z以及点所在轮廓曲线段的形状公差K作为装配精度参数的评价指标,自动完成轮廓尺寸参数的计算,判定待测安全气囊是否合格.实际验证结果表明,所建立的立体视觉安全气囊装配精度测评方法和指标可以快捷精确的评价汽车安全气囊的装配质量.     

基于计算机视觉的工件表面三维测量系统

该文根据计算机视觉原理,提出了一种工件表面三维测量技术。该技术利用图像坐标与空间坐标的变换关系,采用LOG算子和快速HOUGH变换,对角点进行提取。并利用核线约束,实现图像的精确匹配,最终完成对工件表面的自动测量。     

基于HALCON的双目立体视觉工件尺寸测量

为了实现对大批量生产工件尺寸的精密测量,该文基于双目立体视觉视差原理,设计了一种工件尺寸实时测量系统;系统通过两个工业数字摄像头实时采集工件不同角度的两幅图像,并基于机器视觉软件HALCON的HDevelop开发环境,对两幅图像进行相关预处理,获取感兴趣区域。提出一种基于canny的亚像素边缘检测、边缘细化、基于atukey权重函数的最小二乘法边缘拟合及边缘均匀取点算法获取精确的边缘特征点,并通过双目系统标定、极线约束与NCC相结合的立体匹配、世界坐标转换、几何计算相结合的非接触式双目视觉方法进行尺寸测量。通过大量实验证明,该方法可有效地获取工件特征点的三维坐标值,不借助外部测量仪器实现工件关键尺寸的高精度实时检测,检测精度达±0.2mm以上,简单快捷,具有较好的准确性和实时性。     

Dixon结式在密码学中的应用

针对密码学中的多变元多项式二次方程系统求解问题,基于扩展Dixon结式提出了一种求解算法DR(Dixon resultants).基本思想为对于MQ(multivariate quadratic)问题,把x₁,x₂,…,x_n-1当作变元,而把x_n当作参数,然后利用和改进扩展Dixon结式方法求解该类系统.分析了该算法对于一般情况的复杂度,并且基于实验证据猜测:对于某些稀疏问题,新算法的复杂度很有可能也是多项式的.实验结果表明,对于m=n的一般和稀疏的问题,DR效率优于已有的两种算法.除了高效性,新算法还具有复杂度容易度量、计算时间可以预测的优点.     

具有模态词□φ=□1V□2φ且可靠与完备的公理系统

提出具有模态词□φ=□₁V□₂φ的命题模态逻辑,给出其语言、语法与语义,其公理化系统是可靠与完备的,其中,□₁与□₂是给定的模态词.该逻辑的公理化系统具有与公理系统S5相似的语言,但具有不同的语法与语义.对于任意的公式φ,□φ=□₁V□₂φ;框架定义为三元组W,R₁,R₂,模型定义为四元组W,R₁,R₂,I;在完备性定理证明过程中,需要在由所有极大协调集所构成的集合上构造出两个等价关系,其典型模型的构建方法与经典典型模型的构建方法不同.如果□₁的可达关系R₁等于□₂的可达关系R₂,那么该逻辑的公理化系统变成S5.     

优先级驱动的短任务优先RTOS进程调度算法

针对目前普遍采用的基于静态优先级轮转调度算法的不足,提出一种静态优先级驱动的短任务优先动态时间片轮转调度算法,称之为LC调度算法。该算法采用短任务优先的调度策略,动态分配时间片,为每个静态优先级设置两个就绪队列RQ₀和RQ₁,将burst time短的进程插入RQ₁,长的插入RQ₀。当RQ₀上有进程等待时间过长则会自动提升到相应的RQ₁上。模拟实验表明：LC算法在各种条件下都能保持优秀的性能,它充分考虑了调度的开销、性能、响应速度和公平性,并且对burst time预测精度不敏感,相对于其他改进的RR算法具有更好的表现。     

强边缘导向的盲去模糊算法

目的 在图像的获取过程中,成像设备与拍摄场景发生了相对位移,导致获取的实际图像存在信息丢失、模糊退化的现象,这极大地影响了图像的质量和人们的视觉体验,也影响了图像的后续处理。盲去卷积旨在从观测图像中估计模糊核并获得清晰图像,为此提出了一种基于强边缘的运动图像盲去模糊算法。方法 结合图像梯度稀疏性,采用自适应l₀范数约束待估计图像梯度的强边缘;针对模糊核稀疏性和连续性,以l₀-l₂范数分别约束模糊核的像素和梯度,同时把模糊核归一化先验作为正则项引入模型中,以强边缘指导模糊核估计。在去模糊阶段,结合全变分与超拉普拉斯正则化方法的优点,将两种方法复原的图像取平均,以减轻复原图像中的振铃效应,同时保留更多的图像细节。结果 为了检验本文算法的有效性,对Levin测试集和实际拍摄的模糊图像分别进行仿真,并同现有算法进行比较。Levin测试集上的实验结果表明,提出的盲反卷积成功率为100%且在对比算法中具有最高PSNR;实际彩色图像的盲反卷积实验表明,相比于其他算法,本文算法获得的模糊核具有更准确的支撑和较少的噪点,获得的清晰图像具有较优的视觉效果。结论 该方法从定量和定性比较上都体现了较好的去运动模糊能力,可适用于遥感、医学等领域。     

独立多处理机任务静态调度问题的近似算法

研究独立多处理机任务静态调度问题P_m|fix|C_max,即在m个处理机系统中调度n个多处理机任务,每个任务指派到所需一组处理机上不可剥夺地执行.该问题应用广泛但早已证明为NP难问题,而且也不存在常数近似算法.分析了问题P_m|fix|C_max和其中所有任务都是单位处理机时间的特殊情形P_m|fix,p=1|C_max的调度,并利用实例划分(split scheduling,简称SS)、首次满足优先(first fit,简称FF)和最大宽度优先(large wide first,简称LWF)等方法,构造了问题P_m|fix,p=1|C_max的√2m +1近似算法和问题P_m|fix|C_max的2√m 近似算法,优于目前已有文献的最好结果.     

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.