视触觉融合的增强现实三维注册方法

增强现实技术是近年来人机交互领域的研究热点。在增强现实环境下加入触觉感知,可使用户在真实场景中看到并感知到虚拟对象。为了实现增强现实环境下与虚拟对象之间更加自然的交互,提出一种视触觉融合的三维注册方法。基于图像视觉技术获得三维注册矩阵;借助空间转换关系求解出触觉空间与图像空间的转换关系;结合两者与摄像头空间的关系实现视触觉融合的增强现实交互场景。为验证该方法的有效性,设计了一个基于视触觉增强现实的组装机器人项目。用户可触摸并移动真实环境中的机器人零件,还能在触摸时感受到反馈力,使交互更具真实感。     

三维单目虚实物体球对面碰撞检测算法

为加强增强现实的沉浸感与真实性,实时地进行虚实物体间的碰撞检测至关重要.因此,提出一种基于增强现实和单目视觉的任意形状虚实物体碰撞检测估计算法.通过改进现有的单目二维虚实碰撞检测及响应算法,针对现有碰撞检测算法存在的计算复杂度高的问题,提出一种仅需计算实际物体4个特征点的三维碰撞检测算法;并通过对象分割、特征点提取、碰撞检测和碰撞响应等过程取得与真实世界物理特性一致的三维虚实碰撞响应估计效果.在增强现实有标记和无标记环境下分别进行实验结果表明,碰撞检测的计算量与二维算法相近,且具有景深效果,实现了基于单目视觉的增强现实三维虚实碰撞响应预测和处理.     

虚拟现实的力触觉交互技术发展现状与趋势

虚拟现实通过模拟人的视觉、听觉、力触觉等,使人处于一种与真实世界非常逼真的虚拟世界中,来感受、体验和评价虚拟世界中的场景和设备。力触觉在虚拟现实环境中有其突出优越性,力触觉使得虚拟现实环境变得真实,是唯一的既可接受周围环境输入又可以对周围环境输出的感知通道,可极大增强可视化表达的效果。虚拟现实的力触觉交互技术包括力触觉再现技术和虚拟环境的力触觉建模。介绍了这两方面的发展现状、存在的问题和今后的发展趋势。     

计算机触觉:虚拟现实环境的力触觉建模和生成

触觉是人类5种感觉通道之一,在日常生活中发挥着不可缺少的作用.在虚拟现实和增强现实系统中,力触觉反馈的引入有望显著提高人机交互的沉浸感和交互性.文中综述了虚拟现实环境中力触觉感受的建模和生成方法,从力触觉生成与视觉生成的差异性出发,回顾了计算机触觉的发展历史和国内外研究现状,重点分析了虚拟物体建模、碰撞检测、碰撞响应、变形计算等关键技术,并提出了力触觉生成技术的未来发展趋势和技术挑战.     

基于HoloLens的变电站运维仿真培训系统

HoloLens增强现实(Augmented Reality, AR)眼镜为现实世界叠加了逼真的3D全息影像,因此其常被采用为平台来开发基于增强现实技术的变电设备运维仿真培训系统。以HoloLens的主相机作为变电站图像采集设备,采用ASIFT设备局部特征识别方法、人工编码标识识别方法和基于光学字符识别技术（OCR）的设备标牌识别方法相结合,实现变电站不同大小和不同形状设备的可靠识别;通过视觉方法寻找人工标识特征点或设备特征点对目标设备进行精确定位和初始化注册,并利用HoloLens的空间锚点（Anchor）技术,实现目标设备的快速跟踪和注册;构建基于增强现实的变电设备运维学习、训练和考核环境,并进行示范验证。本文通过拓展现有实训系统的功能,提升了现有实训系统的实用性、交互性与体验感,提高了培训的效果和效率。     

增强现实技术在图书馆导视系统设计中的应用

随着信息技术的不断发展,增强现实技术逐渐成为一个热门的研究领域。图书馆是一个重要的文化场所,其导视系统的设计对读者使用体验具有重要影响。文章主要探讨了增强现实技术在图书馆导视系统中的应用,包括增强现实技术、语音识别技术以及无线传输技术等。通过对这些技术的介绍和分析,文章提出了一种基于增强现实技术和语音识别技术的图书馆导视系统设计方案,并通过实验验证了该方案的可行性和有效性。研究对于改善图书馆导视系统的用户体验和提升图书馆服务质量具有重要的意义。     

混合跟踪技术在增强现实系统中的应用

跟踪技术是增强现实的一个重要研究方向,它致力于解决虚拟信息与真实环境的精确配准问题,构建稳定、高效的增强现实系统。通过分析增强现实系统的跟踪需求,指出单一跟踪存在的不足,说明采用混合跟踪技术的必要性,论述了基于视觉一惯性的混合跟踪技术及其在增强现实中的应用,实现了一种基于VisTracker视觉-惯性混合跟踪器的增强现实实验系统,并给出调试结果。     

基于松组合的视觉惯性SLAM方法

研究了一种基于松组合的视觉惯性即时定位与同步构图(SLAM)方法。针对视觉特征点匹配率低问题,研究基于ORB(Oriented FAST and Rotated BRIEF)特征点的提取方法;基于ORB-SLAM的输出,结合SINS提出了一种具有回环检测功能的SLAM/SINS组合方法。利用最小二乘法估计视觉SLAM算法的尺度因子;构建SLAM/SINS的非线性卡尔曼滤波器,将视觉SLAM系统输出的位置信息经过尺度变换后作为观测量进行卡尔曼滤波,修正惯导的误差。最后利用标准数据集证明与开源的SLAM算法进行对比,结果表明,所提出的算法有比较高的定位精度,并且在移动设备上开发了增强现实软件,以增强现实为实验手段验证在较大的空间范围和环境干扰下,这种组合方法具备较好的漂移消除能力。     

图像局部纹理特性的静电力触觉渲染

目的 触摸触觉设备感知物体时,需要实现视觉-力触觉同步反馈,其中图像-力触觉反馈难点在于再现更真实的纹理触感的触觉渲染过程。本文提出了一种基于图像局部纹理特征的静电力触觉渲染模型,实现了更加清晰、触感真实的图像纹理的静电力触觉反馈。方法 首先,采用局部傅里叶变换方法强化局部纹理特征,提取傅里叶变换系数分离出表征形状和局部纹理、边缘的频域分量。其次,对局部纹理特征进行力触觉渲染,建立局部纹理特征与驱动信号的映射模型,采用比例模型将局部纹理特征值转化为同等级的静电力表达。最后,根据静电力与驱动信号的心理学模型,由局部纹理特征控制不同驱动信号的输出产生静电力触觉。结果 进行纹理触觉对比感知实验验证算法有效性,62.5%的实验参与者偏爱基于图像局部纹理的触觉渲染算法反馈的纹理触感,本文算法可以模拟多种图像的纹理、边缘的触感。结论 算法在频域分离图像局部纹理、边缘和形状特征,建立纹理-力触觉渲染模型,针对大多数图片可以有效地增强纹理触感,提升触觉再现交互技术的沉浸感。     

引入力触觉的数字文物多模交互方法

目的 针对当前文物资源由传统的实体文物向虚拟展示和数字文物进行扩展的趋势,如何提供一种多模态的信息呈现方式就显得尤为重要。通过将力触觉技术引入3维文物展示领域,提出一种基于多模感知的3维文物交互式呈现的算法框架。在对文物的基本特征进行视、听、触觉多通道分析的基础上,依据用户与文物模型的接触状态对多通道信息进行计算和整合。方法 在力触觉计算渲染方面,基于嵌入深度构建弹簧系统模拟轮廓形状的接触过程,引入动摩擦和静摩擦因数来反映表面摩擦力这一材质特征,通过法线贴图来实现文物表面纹理的触觉处理;针对交互的环境由2维平面拓展至立体空间,结合力触觉设备将操作时的行为和状态映射为虚拟环境中的操作代理,借助操作代理构建"旋转"和"选择-移动-释放"两种基本的操作范式来实现用户意图;最后,物理引擎的引入将物体的基本运动规律集成至虚拟场景,提升场景交互的真实感.结果 使用Phantom Omni手控器搭建面向馆藏文物的多模感知实验系统,抽取志愿者对实验系统进行测评。实验结果表明：运用本文方法,用户可从视觉、听觉、触觉多个通道对数字文物的整体和细节信息进行感知,且交互的整体过程简单、自然、有效。结论 本文提出的基于多模感知的数字文物交互式呈现方法,可有效实现对各类数字遗产特别是3维文物的多模重现,在保证较高实时性的同时拥有良好的可用性和情感体验效果。     

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.