基于Halcon标定靶的双目相机高精度标定方法

基于张氏标定原理的传统双目相机标定方法在单一背景下标定精度高,但在复杂背景下不能精确提取特征点坐标,导致相机标定精度受到影响。文中提出一种基于Halcon标定靶感兴趣区域约束的透视变换方法,可以从复杂背景中精确提取特征点坐标,提高双目相机标定精度。首先通过改进的角点提取方法从背景中提取Halcon标定靶上的感兴趣区域,利用透视变换和最小二乘法提取特征点的精确坐标;然后匹配左、右图像中同名的特征点,利用张氏标定原理计算双目相机的参数。实验表明,利用文中方法标定的相机参数,计算特征点平均重投影精度达0.01像素,相比于传统方法平均重投影精度提高0.02像素,提高了双目相机参数标定的精度。     

基于二值几何编码图案的高精度结构光系统参数标定方法研究

该文提出了一种基于空间编码图案的结构光系统参数标定方法。与传统的基于棋盘格图案标 定策略不同的是,该文采用结构光编码图案实现了系统的高精度标定,具体实施步骤包括：(1)根据编码图案的几何分布特性提出了一种编码特征点检测算子,基于检测出的编码特征点构建拓扑结构,利 用仿射变换原理及双线性插值算法提取出编码几何元素图像;(2)将几何元素识别转化为监督分类问题,通过采集大量训练样本训练卷积神经网络,实现编码元素的准确识别和解码过程;(3)利用射影变 换原理建立相机像平面与投影机像平面之间的对应关系,利用此对应关系将标定板上棋盘格角点在相机像平面上的坐标转换至投影机像平面,最终实现了对相机和投影仪内外部参数的同时标定。标定结果显示,该方法对投影仪的标定重投影误差不超过 0.3 像素;三维重建实验结果显示,与传统标定方法相比,该文方法能够显著提升系统的标定和三维重建精度。     

基于激光和CCD外部标定的点云区域分割研究

首先介绍了激光和CCD的外部标定算法,并对该算法进行了改进,提高了标定的精确度.然后提出了一种新的激光点云分割方法,即将点云标定到CCD图像上,通过图像分割的方法实现了快速准确提取感兴趣目标区域内的点云.     

基于投影机-摄像机结构的光照补偿技术综述

随着投影机性能的不断提升以及计算机图形图像技术的不断发展,投影技术被应用到各种场合中,越来越多的日常表面被用作投影表面.通过适当的补偿技术,投影系统可以在几何结构不规则、反射条件不理想的表面上投射出接近于目标图像的画面.文中综述了近年来出现的基于投影机-摄像机结构的光照补偿技术.基于颜色混合矩阵的补偿技术使用少量的校正图案即可计算出系统的光照及反射信息,对于反射情况相对简单的应用可以进行高效的补偿,使系统实时稳定地输出几何、颜色无偏差的目标图像;在此基础上,使用同轴投影机-摄像机结构或者内嵌编码图像的方法进一步缩短标定所需时间,使得光照补偿技术可以扩展到移动投影系统的应用中.基于对目标图像预处理的相关优化技术可以在保证光照补偿精度的同时最大化地利用投影机的能量,尽可能扩大系统的动态范围.基于光线传输矩阵的补偿技术考虑了投影机-摄像机结构中的所有光照效应,采用相关的优化算法可以快速求取出系统光线传输矩阵的广义逆矩阵,以实时计算补偿图像;在此基础上,使用多通道投影系统可以有效地增加系统的分辨率,提高系统的动态范围,使得光照补偿技术可以应用到更多反射条件不理想的表面上.     

多投影机非平面自动几何校正

非平面投影以其高度的沉浸感、多样的表现形式和灵活的场景布局,近年来越来越多地应用在虚拟现实、数字娱乐、展览展示等领域。非平面投影与平面投影相比,由于涉及到投影机位姿标定以及失真图像校正等问题,实现难度较高。目前的投影校正方法虽然可以通过重建或者非重建方法实现非平面屏幕投影的几何校正,但是它们多少都存在成本高昂,步骤复杂,需要人工干预,适用面窄等问题。针对非平面屏幕中最常使用的柱幕面型,提出一种非重建的多投影机投影几何校正方法,此方法可自动实现柱幕环境的几何投影校正,并且可对柱幕在加工中引入的倾斜、表面起伏等外形偏差予以修正,实现了复杂柱幕环境下多投影机高精度、短时间投影几何校正。提出的方法不仅适用于柱幕,还可扩展应用于其他可参数化描述的面型,如球面、双曲面、抛物面等面型的投影环境,具有广泛的适用性。     

光栅投影式3维照相系统中光栅投影仪的标定

提出了一种光栅投影式立体照相系统中光栅投影平面的标定方法。将光栅投影到已知目标平面,通过数字摄影得到光栅平面与目标平面相交的光栅图像。根据光栅图像记录的信息,在每条交线上提取两点,作为对应光栅平面拟合用的两点。按一定规律移动目标平面,即可得到每个光栅平面上若干对点。利用最小二乘法分别拟合出每个光栅平面的空间平面方程。     

自适应复杂环境的投影图像校正算法

为实现投影仪在任意表面上的自适应投影,提出一种可以在日常环境光照条件下进行自动几何校正和色彩补偿的投影图像校正算法.该算法使用基于二进制编码结构光的离散映射集合方法,通过计算对应像素映射关系消除投影图像的几何畸变;然后应用一种优化的朗伯特反射模型构造投影表面的纹理空间,对原始投影图像进行预处理和全局亮度补偿,最终实现投影图像的颜色补偿.实验结果表明,基于文中算法在复杂环境中进行投影,可以在不规则几何表面上投影出符合视觉期望的无变形图像,并能够有效地消除投影表面固有纹理和环境光照对投影图像的干扰;将自适应复杂环境的投影图像校正算法应用于传统投影机摆脱了投影机对投影幕布的依赖,可以在任意环境中实现近似于白色平板幕布的投影效果.     

一种基于投影不变量的目标交接改进方法

在多摄像机视频监控系统中,图像之间的视点对应以及目标的交接是重要的研究内容。不需要标定摄像机的参数,该文提出了一种利用尺度不变特征变换（SIFT：scale-invariant features transform）及融合颜色信息的投影不变量实现目标交接的方法。利用SIFT方法自动生成图像间匹配的特征点对,并由此生成视野分界线,然后利用融合颜色信息的投影不变量方法完成对多摄像机之间目标身份的确认。     

多投影显示系统结构光几何校正算法

针对带有非规则曲面显示墙的多投影显示系统的几何校正问题,提出一种基于结构光投影技术的自动非线性几何校正算法.该算法首先用结构光投影技术计算出每个投影机与显示墙的映射关系;其次使用相机拍摄显示墙上的经纬度点阵;最后通过提取拍摄的图像特征计算得到投影机帧缓存中每个像素点在全局坐标系下的经纬度值,并将其转换为纹理坐标,从而实现了非线性几何校正.模拟仿真实验和虚拟机场系统中的实际应用结果表明,文中算法能够有效地提高系统的几何校正精度,且无需进行相机的标定和具有显示墙解析式的先验知识,适用于任意光滑的曲面显示墙.     

复杂表面投影几何校正技术研究

当投影仪将图像投影到复杂表面时,为使观察者观看到不失真图像,提出了基于角点检测的几何校正方法。该方法利用对复杂表面投影白色区域图像的阈值分割来提取校正区域;进行横纵特征条纹的提取和处理,获取投影系统中特征点的坐标;通过对观察者所需的理想图像进行变换获得投影仪所需预变形图像。编写了基于OpenCV的校正软件。实验表明,该方法可以有效消除复杂表面引起的几何畸变,得到良好的观看效果。     

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.