虚拟三维场景与二维电子地图交互系统研究

提出并建立了一个虚拟三维场景与二维电子地图交互系统。介绍了系统的组成和各部分实现的功能。对虚拟场景的数据组织、场景数据读入、观察者位置的确定及交互功能的实现等给出解决方案,给出了实现的代码及画面。该系统利用二维电子地图简洁性、宏观性的特点,通过与虚拟三维场景间的互响应减少观察者在虚拟三维场景中漫游所产生的迷失感,在实际应用中取得了较好的效果。     

三维虚拟场景在车辆导航系统中的应用

城市道路交通网络的日益复杂,使得现有的二维电子地图无法直观的反映道路之间的交错关系,基于二维电子地图的车辆导航系统在复杂的道路交叉口的路径引导也显得无能为力.提出建立复杂道路口的三维虚拟场景和实现场景的指定路径漫游,并以立交桥为例在VC十 6.0中实现二维电子地图与三维虚拟场景的互响应,充分结合二维电子地图在车辆导航过程中的整体性、宏观性与局部三维虚拟场景的直观易懂性等优点,提高现有的车辆导航系统的路径引导效率.     

基于VRML-Java的网络虚拟现实的实现

受到网络速度的限制,传统的网页只能显示文本和图片等二维信息,而网络虚拟现实技术把交互的、逼真的虚拟三维场景引入网络.虚拟现实建模语言（VRML）是一种在互联网上构筑三维虚拟场景的语言标准,通过VRML脚本节点及Java小应用程序实现了用户与虚拟场景更好的交互,并通过Java数据库连接（JDBC）,系统实现了三维场景与二维信息的集成.     

利用VRML技术开发基于网页的三维漫游系统

介绍了利用VRML(Virtual Reality Modeling Language)技术开发基于网页的三维漫游系统的基本原理和实现步骤.针对在网上浏览VRML漫游场景时,由于触发漫游系统运行的时间传感器节点在VRML文件被加载的同时被触发以及网络加载的延时,导致漫游场景不是从起始位置开始运行的问题,提出了利用外部程序控制漫游过程的方法,该方法使用JavaScript外部程序对时间传感器进行相应的控制,使用户浏览漫游场景时,不受网络加载延时的影响能从起始位置开始漫游.最后给出了应用实例.     

虚拟战场环境中的态势标绘与表现

针对军事指挥所现状,设计并实现了一个态势标绘系统,能提供在电子地图上的二维标绘和在虚拟战场环境中的三维标绘两种标绘手段。重点讨论了三维态势标绘中涉及到的地形高程匹配、碰撞检测与碰撞响应、特殊信息和特殊效果的表现等关键技术,并提出了一种二维标绘和三维标绘的实时转换方法,从而实现了二维态势与三维态势的联动表现。     

虚拟现实造型语言VRML2.0总览

一什么是VRML?VRML是“VirtualRealityMedulingLanguge的字首缩写形式，意思是“虚拟现实造型语言”。正如HTML（超文本标记语言）是用于定义可与更多的信息相关联的二维页面的布局和内容的一种文件格式那样，VRML是这样一种文件格式，它用于定义可与更多信息相关联的三维世界的布局和内容。然而与HTML不同，ThML空间比较广阔并且本身具有交互性，因为其空间中都是些彼此间相互作用并能与用户响应的物体。VRML使得信息，包括与其它Web内容相关联的信息，能够在一个交互的三维空间中很容易地被表达出来。VRML能在从PC机到多…     

基于MapXtreme的虚拟漫游2D导航地图建立方法研究

有效的生成三维虚拟场景的2D导航地图,是解决虚拟漫游迷失感、完善虚拟漫游的一个重要问题。基于MapXtreme-Java电子地图开发平台,提出一种虚拟漫游2D导航电子地图的建立方法。通过透视投影法获取场景的平面图,利用MapXtreme for Java在平面图上进行地理数据的添加和扩充,建立平面区域和三维场景坐标的映射关系,支持三维场景与2D地图的互响应。该方法能方便操作人员快速、简洁的建立导航图,指导操作者完成漫游任务,提高了漫游系统的人机交互能力。     

基于VRML的多用户环境通信机制

本文在讨论虚拟社区和基于VRML的多用户环境的基础上,通过Java和VRML的结合以及Java详细论述了虚拟空间生成,系统和用户间通信数据包的构造方法,实现了用户的交互感知、行为共享和持续性.     

基于虚拟现实建模语言的医学体数据三维重建研究

为了临床医学的实际应用,本文尝试运用VRML进行医学体数据的三维可视化工作.基于WEB和网络化是今后数字化医学图像处理的一个发展趋势,而VRML正是基于WEB的虚拟现实建模语言.本文运用VRML进行建模,得到人体头部的三维模型,并对建立的三维模型进行编程实现动态切割等,还利用JavaScript语言实现了三维模型与二维断层图像同时显示的功能,这满足了临床医生在实际应用中的需要.     

时差定位的传感器位置分布研究

提高目标的定位精度一直以来都是无源定位关注的主要问题,通过分析目标位置误差的Fisher信息矩阵以及对应的Cramer-Rao下界与传感器位置及数量的关系,得到使定位误差最小的传感器分布情况.给出了目标距离较远时,在二维及三维定位中基于时差定位方法的传感器最佳分布.     

用VRML和Java实现虚拟小区的交互漫游

为了实现虚拟小区的交互漫游,在系统实现过程中采用了几种方式的交互技术,文中对这些交互技术进行了讨论和实现。阐述了在虚拟小区中交互漫游的两种方式,即由用户交互控制视点和由计算机自动控制视点的方式,并对这两种交互漫游方式给出了VRML编码的具体实现;最后采用外部编程接口（EAI）实现了用户界面中的二维平面图和三维场景图的交互。     

基于X3D的动态交互式虚拟社区技术研究

三维虚拟社区具有强大的功能和广泛的商业价值,是虚拟现实技术的应用之一。X3D是新一代互联网3D图形规范,为构建基于Web的3D应用提供了解决方案。本文从虚拟场景建模、动态交互的实现技术和虚拟场景优化三个方面讨论基于X3D构建动态交互式虚拟社区的技术。     

Optimizing Heuristic Evaluation Process in E-Commerce: Use of the Taguchi Method

This article proposes a 3-dimensional (3D) vision-based ambient user interface as an interaction metaphor that exploits a user's personal space and its dynamic gestures. In human-computer interaction, to provide natural interactions with a system, a user interface should not be a bulky or complicated device. In this regard, the proposed ambient user interface utilizes an invisible personal space to remove cumbersome devices where the invisible personal space is virtually augmented through exploiting 3D vision techniques. For natural interactions with the user's dynamic gestures, the user of interest is extracted from the image sequences by the proposed user segmentation method. This method can retrieve 3D information from the segmented user image through 3D vision techniques and a multiview camera. With the retrieved 3D information of the user, a set of 3D boxes (SpaceSensor) can be constructed and augmented around the user; then the user can interact with the system by touching the augmented SpaceSensor. In the user's dynamic gesture tracking, the computational complexity of SpaceSensor is relatively lower than that of conventional 2-dimensional vision-based gesture tracking techniques, because the touched positions of SpaceSensor are tracked. According to the experimental results, the proposed ambient user interface can be applied to various systems that require real-time user's dynamic gestures for their interactions both in real and virtual environments.     

A Sensorized Garment Controlled Virtual Robotic Wheelchair

This paper presents the design and performance of a body-machine-interface (BoMI) system, where a user controls a robotic 3D virtual wheelchair with the signals derived from his/her shoulder and elbow movements. BoMI promotes the perspective that system users should no longer be operators of the engineering design but should be an embedded part of the functional design. This BoMI system has real-time controllability of robotic devices based on user-specific dynamic body response signatures in high-density 52-channel sensor shirt. The BoMI system not only gives access to the user’s body signals, but also translates these signals from user’s body to the virtual reality device-control space. We have explored the efficiency of this BoMI system in a semi-cylinderic 3D virtual reality system. Experimental studies are conducted to demonstrate, how this transformation of human body signals of multiple degrees of freedom, controls a robotic wheelchair navigation task in a 3D virtual reality environment. We have also presented how machine learning can enhance the interface to adapt towards the degree of freedoms of human body by correcting the errors performed by the user.     

An Interactive Designing System with Virtual Sculpting and Virtual Woodcut Printing

In this paper, we propose an interactive designing method and a system based on it to create 3D objects and 2D images. This system consists of two subsystems for virtual sculpting to create a 3D shape and virtual printing to produce a picture with a printing block. In the virtual sculpting subsystem, a user can form solid objects with curved surfaces as if sculpting them. The user operates virtual chisels, and can remove or attach arbitrary shapes of ellipsoids or cubes from or to the workpiece. A 3D object generated by virtual sculpting looks like a real wooden sculpture. If using a board as a workpiece, a user can generate a virtual printing block. In the virtual printing subsystem, a user can synthesize a woodcut printing image from the virtual printing block mentioned above, a virtual paper sheet, and a printing brush. The user can synthesize a realistic woodcut print with a procedure similar to the actual woodcut printing.     

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。     

Interactive digital graffiti canvas system

This paper presents an interactive digital painting system that allows a user to draw graffiti on a virtual 3D canvas with a digital spray can. The system visualizes a stereoscopic representation of the canvas by tracking the user's head. It also emulates real‐time spray painting by tracking the spray can in the user's hand as well as sensing the button pressure of the spray device. After painting a 3D object, the user can interact with the object on the display and see it flying in the 3D environment through a tracked head‐mounted display. As demonstrated in the results of our evaluation, we verified that the system resembles real graffiti in regard to a natural and realistic graffiti experience. Copyright © 2015 John Wiley & Sons, Ltd.