引入三维阴影及镜面反射的两步光源检测算法

现有基于光照模型的增强现实逆向光源检测算法要求校准物体的表面是纯漫反射体,检测出的位置误差较大.针对这一问题,提出一种引入投影阴影三维形状特征及镜面反射分量的两步光源检测算法.算法分为光源位置和强度检测两个部分,在光源位置已知的条件下引入带有镜面反射分量的Cook-Torrance模型检测强度,并采用随机采样分区、误差处理等机制.同时使用投影阴影三维形状特征代替平面阴影角点特征,然后利用光线跟踪检测光照位置.实验表明该算法检测光源位置更加准确,检测光强有效,较好地解决了点光源位置检测不准确和受校准物材质限制问题.     

建筑造型及其环境图象的渲染技术

本文提出一个用于建筑物及其周围场景真实感图形生成的图形图象综合光线跟踪算法采用综合处理图形和图象的光线跟踪技术，对建筑物及其场景中插人的景物图象（如树木、人物等）可以根据光源、视点的位置，生成合理的阴影和倒影。由于引入了虎视点及位置纹理映射的方法，景物图象在造型表面上的倒影及景物图象上被其它物体遮挡的阴影效果更加逼真。提出的天空背景的处理方法，使得背景可以反射、透射到建筑物表面上，并在视点变化时天空背景可以正确地移人或移出视野。此外本文还在表现建筑物表面材料的连续纹理映射、模拟地面积水的局部反射效果等问题上给出了解决方法。     

基于Visual C++平台的光线追击模拟模型

光线追踪算法可以模拟出场景中光源或环境光在物体表面的反射、折射透射等现象,给观察者一种真实的视觉效果,因此文中开发了一个基于Visual C++平台的光线跟踪系统。采用模块化方式是基于分层组织的思想,从而设计了一个通用、可扩展的光线追踪系统,为可视化提供了一个基础框架。采用统一的面向对象的模型来模拟环境中的物体,以及光源发出的光线在物体表面所产生的镜面反射、漫反射或是介质中产生的折射等光学现象,从而实现复杂特效的渲染。最后提出光线追迹的发展趋势。     

一种基于光线跟踪的软阴影算法

提出了一种基于光线跟踪的软阴影算法。该算法生成的阴影更具真实感,并可克服阴影映射算法产生的锯齿现象的问题。实验结果表明,该算法对较复杂物体仍能够保证良好的绘制视觉效果,满足虚拟现实应用的要求。     

基于离散点的光线跟踪的研究

在计算机图形中,光线跟踪是获得具有正确的反射、折射和阴影等效果的更加真实的图像的一个有效方法.研究了基于离散点造型的光线跟踪方法,探讨了在只有物体的离散采样点集合而没有点之间的连接信息的情况下,如何进行光线与物体求交的具体过程.     

一种基于背景模型的运动目标检测与跟踪算法

本文提出了一种静止摄像机条件下的运动目标检测与跟踪算法．它以一种改进的自适应混合 高斯模型为背景更新方法，用连通区检测算法分割出前景目标，以Kalman滤波为运动模型实 现对运动目标的连续跟踪．在目标跟踪时，该算法针对目标遮挡引起的各种可能情况进行了 分析，引入了对运动目标的可靠性度量，增强了目标跟踪的稳定性和可靠性．在对多个室外 视频序列的实验中，该算法显示了良好的性能，说明它对于各种外部因素的影响，如光照变 化、阴影、目标遮挡等，具有很强的适应能力．     

摄影入门必看数码相机拍摄技巧

拍室内摄景物时，要让拍摄对象尽量远离墙壁或物体根据光线的投影原理，当拍摄对象离墙壁或其它物体较近时，室内原有的灯光和自然光无法照射或反射到拍摄对象后的墙壁等物体，当强光源闪光灯照射时，就会使被拍摄对象在其后的墙壁等物体上留下闪光阴影。所以，在不影响构图的情况下，让拍摄对象尽量远离白色的墙壁或在其后面的物体，保持一定的空间和距离，闪光阴影就会明显减弱。     

低照度摄像机的认识与应用

在光线较差的环境中,低照度摄像机无需辅助光源即能识别目标物体,发挥着重要的作用,受到越来越多用户的青睐。本文就从其COD与配套技术、DSP等方面进行描述,为读者介绍当前低照度摄像机的发展与应用情况。     

低照度摄像机的认识与应用

在光线较差的环境中,低照度摄像机无需辅助光源即能识别目标物体,发挥着重要的作用,受到越来越多用户的青睐。本文就从其CCD与配套技术、DSP等方面进行描述,为读者介绍当前低照度摄像机的发展与应用情况。     

多层阴影图轮廓边背投软影算法

在场景深度和物体分布复杂时,针对轮廓边背投软影算法中的可见性因子计算存在误差,从而导致过阴影和光渗等绘制瑕疵的问题,提出一种基于掩码的多层阴影图遮挡物轮廓边背投软影算法.该算法通过计算光源掩码的深度复杂函数获得更准确的可见性因子,解决了轮廓边背投软影算法中存在的过阴影问题;将光源掩码计算与多层阴影图结合以解决光渗问题,最终生成更高质量的光滑软影.实验结果表明,在保证绘制效率的前提下,文中算法可以产生更为准确、真实的软影效果.     

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。     

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。