虚拟现实辅助机器人遥操作技术研究

本文以水下机器人的遥操作作业为应用背景,提出并实现了虚拟现实技术和视觉感知 信息辅助机器人遥操作实验系统．该系统使用了CAD模型和立体视觉信息完成遥操作机器人 及其作业环境的几何建模和运动学建模,实现了虚拟作业环境的生成和实时动态图形显示． 采用了基于立体视觉的虚拟环境与真实环境的一致性校正、图形图像叠加、作业体与环境位 姿关系建立、基于网络的监控通讯等关键技术．在这个实验系统中,操作人员可利用所生成 的虚拟环境,在多视点、多窗口作业状态图形和图像显示帮助下,实时动态地进行作业观测 与机器人遥操作与运动规划,为先进遥操作机器人系统的实现提供了经验和关键技术．     

虚拟环境暴露后与用户视觉相关的模拟器病致因

为了优化虚拟环境设计,增强虚拟现实系统的可用性,对虚拟环境暴露后用户出现的与视觉相关的模拟器病症状进行了研究.在分析双眼视觉感知机理和虚拟环境立体显示基础上,给出了视差型立体图像显示的深度感知控制公式;通过比较用户在实际环境、平面显示和虚拟立体显示中的视觉感知差异,得出了调节固定的显示模式是虚拟环境暴露后用户视觉感知冲突并诱发视觉相关模拟器病症状的重要致因.最后通过虚拟飞行实验前后用户双眼调节性辐辏AC/A的变化和虚拟环境暴露后模拟器病问卷调查,对上述结论进行验证,并提出虚拟环境优化设计和合理安排模拟训练的原则和建议.     

基于语言描述的三维虚拟场景构建研究

三维虚拟环境被广泛的应用于各个领域并发展成为了一个故事表达的新媒介，然而如何构建这类的虚拟环境仍需要专业人士，这在一定程度上限制了虚拟环境技术的应用。由于意识到以传统的菜单界面为主的三维场景制作软件的局限性，采用自然语言为用户界面的三维虚拟环境制作技术受到了研究者的重视。本文介绍了一种方法，该方法通过基于文字的输入并对环境的视觉特征进行操作，进而能使非专业人员制作一个可交互的三维虚拟环境。我们提出了将文字的含义作为视觉再现的主要资源，这种文字 - 概念 - 视觉信息的直接联想模式可用来对知识的再现展示，建立一个可扩展的视觉语义的数据表现模型中间层的来联结语 言含义和视觉图形的再现。     

基于分布式的坦克仿真系统的框架设计

文章在分析两个经典的分布式虚拟现实系统的基础上,结合坦克仿真的具体情况,从通用性和开放性角度考虑,提出了分布式坦克仿真（DTS）系统的软件体系结构。然后从人机交互、网络通信、实体管理、多视觉通道图形显示等方面详细介绍了DTS系统的设计情况。     

基于Xen的虚拟显示性能测试与评价

针对虚拟化环境下图形显示的特点,该文充分考虑了在虚拟化环境下显示性能的特殊性,选取了六个不同的应用,将其作为评价虚拟化环境下显示性能的重要指标;与此同时提出了一个虚拟化环境下虚拟机显示性能的评价标准,作为判断虚拟环境下虚拟机显示性能好坏的依据。     

基于Xen的虚拟显示性能测试与评价

针对虚拟化环境下图形显示的特点,该文充分考虑了在虚拟化环境下显示性能的特殊性,选取了六个不同的应用．将其作为评价虚拟化环境下显示性能的重要指标;与此同时提出了一个虚拟化环境下虚拟机显示性能的评价标准．作为判断虚拟环境下虚拟机显示性能好坏的依据。     

面向机器人应用的桌面虚拟环境生成与显示技术

本文主要研究了利用微机网络的并行计算能力来实现桌面机器人虚拟环境生成的结构和算法．此系统的性能价格比高，只需少量的投资，这为研究ＶＲ技术在机器人中的应用提供了一种新的途径．实时三维图形的生成与显示是产生虚拟环境的基础和关键，要实时产生三维图形，需要计算机有非常高的运算速度，文中详细地介绍了在基于局域网的分布式网络系统上，如何利用网络的计算能力来完成三维图形的实时生成．同时在立体显示技术上作了改进，消除了利用液晶光闸眼镜来观察立体图像给人造成的严重闪烁感     

虚拟现实中的视觉系统与其实现技术

视觉系统是实现虚拟现实的关键部分。本文探讨了虚拟环境中视觉系统的设计思想，并介绍了现时流行的虚拟环境中视觉系统的实现方案。     

虚拟环境中立体图像的生成

虚拟环境是用计算机生成三维的视觉、听觉、触觉的感觉世界其三维立体图像的生成则是虚拟环境的一项关键技术。本文对三维立体图的生成，显示的原理和方法进行了介绍，并根据其原理和算法，绘制了一个简单的室内布置的三维立体图。     

多通道技术在视景仿真系统中的应用

视觉通道是虚拟环境系统中最重要的人机交换界面,利用三通道投影可以得到更广阔的视角效果,增强“沉浸感”.详细分析了Vega模块Dvega的实现原理,给出了视锥偏移计算公式,同时给出了利用Vega编程实现三通道视景的具体方法.     

实现牙体预备触觉交互仿真的图形显示

介绍了在牙科手术训练触觉交互系统的虚拟手术环境中,通过材料去除速率控制构成牙齿的网格变形实现牙齿被切削时材料去除过程的图形仿真.针对牙体预备操作和触觉交互装置输出力的特点,在交互系统的虚拟环境中,当工具与牙体模型发生接触时,所有进入工具空间范围的顶点都会沿着其外法线的反方向进行投射,投射量受控于材料去除速度,且网格变形速度不超过真实的牙齿材料去除速度,同时针对网格的变形位置绘制虚拟工具.通过限制网格变形可以动态的实现牙齿被切削过程的形状变化,图形显示逼真同时没有滞后.     

Vision‐tangible interactive display method for mixed and virtual reality: Toward the human‐centered editable reality

Building a human‐centered editable world can be fully realized in a virtual environment. Both mixed reality (MR) and virtual reality (VR) are feasible solutions to support the attribute of edition. Based on the current development of MR and VR, we present the vision‐tangible interactive display method and its implementation in both MR and VR. We address the issue of MR and VR together because they are similar regarding the proposed method. The editable mixed and virtual reality system is useful for studies, which exploit it as a platform. In this paper, we construct a virtual reality environment based on the Oculus Rift, and an MR system based on a binocular optical see‐through head‐mounted display. In the MR system about manipulating the Rubik's cube, and the VR system about deforming the virtual objects, the proposed vision‐tangible interactive display method is utilized to provide users with a more immersive environment. Experimental results indicate that the vision‐tangible interactive display method can improve the user experience and can be a promising way to make the virtual environment better.     

基于Web GIS的虚拟校园综合体系研究

随着虚拟现实技术、计算机图形图像技术的不断发展进步和互联网的日益普及,虚拟校园将成为各教育教学机构展示自己教学、科研水平和对外宣传的主要渠道之一。在简单分析当前虚拟校园相关发展技术的基础上着力论述基于Web GIS的虚拟校园综合体系,提出了Web GIS环境下对虚拟校园景观进行群组图片特效展示、全景展示、虚拟仿真展示等多种方式进行综合展示的思路,并进行了必要的实践。     

Egocentric depth judgments in optical, see-through augmented reality

A fundamental problem in optical, see-through augmented reality (AR) is characterizing how it affects the perception of spatial layout and depth. This problem is important because AR system developers need to both place graphics in arbitrary spatial relationships with real-world objects, and to know that users would perceive them in the same relationships. Furthermore, AR makes possible enhanced perceptual techniques that have no real-world equivalent, such as X-ray vision, where AR users are supposed to perceive graphics as being located behind opaque surfaces. This paper reviews and discusses protocols for measuring egocentric depth judgments in both virtual and augmented environments, and discusses the well-known problem of depth underestimation in virtual environments. It then describes two experiments that measured egocentric depth judgments in AR. Experiment I used a perceptual matching protocol to measure AR depth judgments at medium and far-field distances of 5 to 45 meters. The experiment studied the effects of upper versus lower visual field location, the X-ray vision condition, and practice on the task. The experimental findings include evidence for a switch in bias, from underestimating to overestimating the distance of AR-presented graphics, at ~ 23 meters, as well as a quantification of how much more difficult the X-ray vision condition makes the task. Experiment II used blind walking and verbal report protocols to measure AR depth judgments at distances of 3 to 7 meters. The experiment examined real-world objects, real-world objects seen through the AR display, virtual objects, and combined real and virtual objects. The results give evidence that the egocentric depth of AR objects is underestimated at these distances, but to a lesser degree than has previously been found for most virtual reality environments. The results are consistent with previous studies that have implicated a restricted field-of-view, combined with an inability for observers to sc     

The virtual wind tunnel

The design and implementation of a virtual environment linked to a graphics workstation for the visualization of complex fluid flows are described. The system user wears a stereo head-tracked display, which effectively displays 3-D information, and an instrumented glove to intuitively position flow-visualization tools. The visualization structures and their interfaces in the virtual environment and the implementation hardware and software are described. The performance of the virtual wind tunnel is reviewed using the flow past a tapered cylinder as an example. Performance issues and future directions for the system are discussed     

Real world teleconferencing

We've been exploring how augmented reality (AR) technology can create fundamentally new forms of remote collaboration for mobile devices. AR involves the overlay of virtual graphics and audio on reality. Typically, the user views the world through a handheld or head-mounted display (HMD) that's either see-through or overlays graphics on video of the surrounding environment. Unlike other computer interfaces that draw users away from the real world and onto the screen, AR interfaces enhance the real world experience. For example, with this technology doctors could see virtual ultrasound information superimposed on a patient's body.     

The Panda3D graphics engine

Disney's VR Studio developed Panda3D, a graphics engine and programming environment, to be flexible enough to support everything from real-time graphics applications to the development of high-end virtual reality theme park attractions or video games. The acronym itself lists Panda's primary features as platform-agnostic, networked, display architecture. As a result of its powerful and flexible design, much of the Panda system's architecture reflects the occasionally opposing goals of performance and versatility.     

近距离3D人机交互技术研究实现

3D人机交互技术是计算机图形学、虚拟现实和模式识别的交叉融合领域,可分为虚拟环境的显示和三维物体识别。该研究将虚拟环境显示和三维物体识别整合成一个完整的解决方案并应用到1∶1模拟虚拟场景的近距离交互。研究了虚拟现实之间的坐标转换;分析了影响虚拟物体立体显示的三个主要因素：OpenGL中摄像机的张角,摄像机间距和立体图像对的产生;并实现了基于Intel Perceptual Computing的三维物体识别。实验结果显示：该方案在1∶1模拟虚拟场景方面具有良好的3D显示效果,同时在手势识别方面有较高的识别率。