摄像机标定系统的设计

为了解决摄像机在视觉测量中的应用这一问题,必须实现摄像机的高精度标定,设计了摄像机标定系统。首先,从摄像机标定技术的基础理论研究出发,对摄像机标定技术的原理和所采用的张正友标定法的基本原理进行了分析总结。然后,利用Matlab 标定工具箱和一张8x12,正方形边长为26mm的黑白棋盘格,对设计的摄像机系统进行标定。最后,分析了标定系统中的误差,对该系统的设计进行验证。实验结果表明：摄像机的主点坐标误差为：[-0.01186;0.03393];摄像机外部参数标定像素误差达到[0.22981; 0.16846]。基本满足视觉测量的稳定可靠、精度高、抗干扰能力强、可移植性强等要求,为后续应用到视觉测量中奠定了基础。     

基于序列图像的摄像机自标定方法

提出了一种新的结合摄影测量和计算机视觉相关理论的摄像机自标定方法。首先通过序列图像的匹配点对,利用计算机视觉理论中的8点法求得摄像机基础矩阵F,通过矩阵F利用Kruppa方程求得矩阵C,对矩阵C进行Cholesky分解得到摄像机的内参数矩阵K,然后将求出的内参数作为初始值,利用摄影测量理论进行相对定向和绝对定向,最小二乘前方交会计算得到匹配点对的三维空间坐标,最后由匹配点对的三维空间坐标及其图像坐标,采用三维直接线性变换和光束法平差方法解算出摄像机内、外参数及畸变系数。该方法不依赖于特定的场景几何约束条件,只要序列图像之间有匹配点对,就可以进行自标定工作,具有广泛的适用性。模拟数据和真实图像的实验结果表明：该方法计算过程简单,标定精度高,是一种值得借鉴的摄像机自标定方法。     

基于分块的二维视觉测量系统标定

为了满足高速动态拉伸试验机的的应变测量系统对于高精度的要求,研究了一种基于计算机视觉测量系统的标定技术。应用二次多项式曲面拟合技术,采用了一种基于分块的摄像机模型参数标定方法,不仅能够对摄像机的镜头的畸变进行校正,并且能够获得较高的测量精度。通过对试件的拉伸试验表明:采用基于分块的摄像机模型参数标定方法能取得较高的图像测量精度。     

基于嵌入式Linux的双目测距系统研究

根据嵌入式系统的特点,设计了以ARM为核心的双目立体视觉测距系统。系统使用双目立体摄像头采集图像数据,可设置图像的多种属性。利用开源计算机视觉库Open CV对采集的图像数据进行处理,分别完成了两台摄像机标定、匹配、重建等工作,最后实现摄像机测距功能。实验结果表明,该系统测量结果合理,工作稳定,同时可用Qt/Embedded实时显示图像和数据,具有良好的人机交互功能和跨平台移植性。     

图像中心点预标定方法研究与应用

在应用视觉测量系统中,视觉传感器即CCD摄像机的标定是必要的步骤。目前大部分标定算法都需要事先给出图像中心点,文中讨论该参数的求取方法。介绍了目前几种常用的图像中心的标定方法,有重点地介绍了各种方法的原理和实现流程,对其实现原理的复杂性、实验仪器的精密性、操作方法的难易度进行了综合比较,最后给出相应的实验结果及其结论。对各种视觉测量系统及摄像机标定精度要求不同的场合,可以根据其实验条件及要求选取最合适的方法进行图像中心点的求取。     

双目立体视觉系统的精度分析

为提高双目立体视觉系统的测量精度,分析双目视觉系统的工作原理以及该系统各个环节的误差模型.通过提高标定模板的精度、增加标定图像,可以减小标定误差及图像校正行对齐误差.分析图像识别误差对视觉系统测量精度的影响,导入视觉系统的结构参数与测量误差之间的关系,从而确定结构参数对测量精度的作用.讨论物距对测量精度的影响,并给出合...     

基于视觉定位的带电作业锁杆无线遥控操作技术

利用视觉定位能精确转换图像坐标为真实位置的能力,结合机器人技术,提出基于视觉定位的带电作业锁杆无线遥控操作技术。根据视觉定位原理,使用VisionHAWK智能相机采集带电作业锁杆图像,运用Visionscape软件分析及处理获取的图像,采用像素网格划分法计算所得图像坐标,通过摄像机标定方法,利用Visionscape软...     

基于投影仪和摄像机的结构光视觉标定方法

为实现基于投影仪和摄像机的结构光视觉系统连续扫描,需要计算投影仪投影的任意光平面与摄像机图像平面的空间位置关系,进而需要求取摄像机光心与投影仪光心之间的相对位置关系。求取摄像机的内参数,在标定板上选取四个角点作为特征点并利用摄像机内参数求取该四个特征点的外参数,从而知道四个特征点在摄像机坐标系中的坐标。利用投影仪自身参数求解特征点在投影仪坐标系中的坐标,从而计算出摄像机光心与投影仪光心之间的相对位置关系,实现结构光视觉标定。利用标定后的视觉系统,对标定板上的角点距离进行测量,最大相对误差为0.277%,表明该标定算法可以应用于基于投影仪和摄像机的结构光视觉系统。     

图像中心点预标定方法研究与应用

在应用视觉测量系统中，视觉传感器即CCD摄像机的标定是必要的步骤。目前大部分标定算法都需要事先给出图像中心点，文中讨论该参数的求取方法。介绍了目前几种常用的图像中心的标定方法，有重点地介绍了各种方法的原理和实现流程，对其实现原理的复杂性、实验仪器的精密性、操作方法的难易度进行了综合比较，最后给出相应的实验结果及其结论。对各种视觉测量系统及摄像机标定精度要求不同的场合，可以根据其实验条件及要求选取最合适的方法进行图像中心点的求取。     

基于HALCON的机器人手眼标定精度分析与反演方法

通过视觉引导机器人完成抓取任务,机器人手眼标定的精度直接影响了抓取任务作业精度和抓取成功率。对于基于位置的机器人视觉引导系统,手眼标定的任务则是确定机器人坐标系与相机坐标系之间的位姿关系。通过HALCON平台,使用线性标定法实现了6DOF机器人的手眼标定。对手眼标定的结果进行反演,直观地展示了手眼标定的精确程度。最后通过采集多组不同数量的图片,在HALCON平台下验证了不同摄像机模型对手眼标定的精度影响,以及同种摄像机模型在不同数量图片的情况下手眼标定的标定精度。实验证明,根据位姿矩阵中待求解的未知量个数采集合适数量的图片和使用更精确的摄像机模型能够提高手眼标定的精度。     

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。     

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。     

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.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.