基于视觉的增强现实运动跟踪算法

增强现实系统不仅具有虚拟现实的特点同时具有虚实结合的新特性，为实现虚拟物体与真实物体间的完善结合，必须实时地动态跟踪摄像与真实物体间的相对位置和方向，建立观测模,墼是而通过动态三维显示技术迅速地将虚拟物体添加到真实物体之上，然而目前大多数增强现实系统的注册对象均匀静物体，运动物体的注册跟踪尚很少有人涉足。该算法通过标志点的光流场估计真实环境中运动物体的运动参数，根据透视投影原理和刚体的运动特性确定摄像机与运动物体间的相对位置和方向，实现增强现实系统的运动目标跟踪注册。该算法构架简单、实时性强，易于实现，扩展了增强现实系统的应用范围。     

基于增强现实技术中虚拟物体投影的应用研究

增强现实技术是近年来的一个研究热点。增强现实是把计算机产生的虚拟物体或其他信息合成到用户感知的真实世界中的一种技术。它是对真实世界的补充,而不是完全替代真实世界。显示技术和跟踪注册技术是增强现实系统关键技术,也是研究的重点。本文简要介绍了显示技术以及跟踪注册技术。     

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。     

增强现实系统及其关键技术研究

首先概要介绍了增强现实技术的概念、相关特性,指出了视觉一致性是增强现实系统最需要解决的问题;接着给出了增强现实系统的总体结构,概略介绍了各组成部分的功能以及对应的关键技术;然后在此基础上论述了关键技术中的显示技术和跟踪注册技术,并以跟踪注册为重点介绍了的增强现实系统基于跟踪器的方法、视觉跟踪方法和复合跟踪法等多种方案,并分析了不同方法不同实现的特性和应用场合,最后对增强现实的当前应用和未来趋势做出了概要总结.     

移动增强现实中视觉三维注册方法的实现

为了提高移动增强现实注册技术的性能,采用了一种基于计算机视觉的注册算法。该方法利用ARToolkit中的标识检测法查找相关的标识和特征点,然后基于视觉三维注册算法得到模型视图矩阵,最后在相应位置绘制虚拟物体。实验结果表明这种注册方法在实时性、稳定性、抗遮挡性方面效果良好,满足移动增强现实系统高精度三维注册的要求。     

增强现实系统中的深度检测技术研究

增强现实技术是虚拟现实的一个分支,它将虚拟的增强信息融合到真实场景中去。对于增强现实系统而言,融合过程中虚实的遮挡关系需要根据真实环境的深度信息来判断。为了实时获取真实环境的深度信息,文中根据双目立体视觉原理,构建了一个完整的增强现实深度检测系统,该系统安装要求低,通过对系统进行标定和校正,使其达到双目立体规范结构,为对应点的匹配搜索提供了很大的方便。从实验的结果可以看出,文中的深度检测系统算法快速稳定,左右视差图效果良好,可以为虚实遮挡提供可靠的深度信息。     

增强现实中的跟踪技术

增强现实是一种正在发展的新技术,它将由计算机产生的虚拟场景或信息准确叠加到真实环境中,可以增强用户对真实世界的感知与交互能力;对用户视场及视点的跟踪是增强现实中实现虚、实场景配准的关键技术之一;通过对增强现实中跟踪技术性能要求的讨论,介绍了基于磁场、声学、惯性、光学传感等多种跟踪技术,分析了各种方法的跟踪性能与局限性,认为以基于视觉跟踪为主的混合跟踪技术将是增强现实系统的主流跟踪技术,重点论述了基于视觉的跟踪与基于视觉一惯性的混合跟踪技术及其有待解决的问题,并针对户外增强现实中的跟踪技术做了专门讨论。     

基于全景成像的增强现实系统

建立完整的基于全景成像的增强现实系统,将全景图像采集系统放置在场景中采集真实图像,佩戴头盔显示器和头部跟踪器的观察者可以在其他地方观看在真实图像中添加了虚拟信息的增强图像,解决图像采集装置与头盔显示器分离时增强现实系统的技术难点。实验结果表明,全景成像方法对于亮度差异较大的图像有较好的拼接效果,适用于室外复杂环境的图像拼接,全景图像的局部增强显示效果良好。     

头盔显示器发展综述

随着虚拟现实与增强现实技术的快速发展,近年来越来越多的虚拟现实与增强现实相关应用走入大众视野.在众多显示设备中,头盔显示器以其高沉浸感、实时交互性及其广阔的应用领域在虚拟现实与增强现实技术中占据重要地位.文中介绍了头盔显示器光学系统成像原理;分析总结了从不同的技术角度解决的传统头盔显示器体积与质量大、调焦与辐辏不匹配等问题的3种新型头盔显示器,包括自由曲面头盔显示器、波导型头盔显示器和真实立体感头盔显示器,阐述了用户佩戴头盔显示器的视疲劳主观和客观评测方法;最后对头盔显示器的未来发展趋势进行了展望.     

沉浸式环境中多场景视觉提示信息可视化方法综述

沉浸式环境是通过虚拟现实（virtual reality,VR）等技术为用户呈现趋近于真实的环境体验。虚拟现实是通过计算机生成现实世界的模拟环境,可以为用户提供丰富的沉浸感、交互性和想象力体验。用户在虚拟现实场景中,通过视觉可以快速熟悉环境,获取场景内外的信息,还可以通过视觉完成与场景的交互,增强用户的感知。增强现实（augmented reality,AR）会将虚拟信息放置在真实场景中,用户可以与真实场景中的虚拟信息进行交互。为了充分了解视觉提示信息在虚拟现实等不同沉浸式场景中的研究,探究视觉信息提示方法的本源,本文按照信息提示位置的不同、功能和应用的不同进行区分,首先综述近年来在普通二维场景中的方法,通过技术对比和改进深入讨论了在三维虚拟现实或增强现实环境下对视觉提示信息可视化方法的研究。分析在虚拟现实或增强现实环境下与普通二维场景中显示的异同,同时展开视觉提示信息在多场景下对用户注意力等使用功能方面的研究介绍,以及全景视频观看等实际场景中的应用研究说明。本文通过对二维和三维场景视野外、场景中标签布局和注意力引导,以及全景视频观看等实际应用中的讨论,可以更详细地展示视觉提示信息在沉...     

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.