交互式自行车模拟器视景仿真系统开发

视景仿真系统是交互式自行车模拟器的重要组成部分。其给骑车者提供逼真的虚拟三维漫游场景。开发的视景仿真系统硬件上采用PowerWall虚拟现实系统，软件上基于自主开发的虚拟现实通用应用开发平台VR Flier，提高了开发的效率。VR Flier采用面向对象方法设计，能够全面地支持小同领域和不同规模的VR应用开发。视景仿真系统通过优化以及动态调度三维场景模型的方法提高了大范围漫游场景的渲染帧率；并对场景路面坡度及视景转向信号进行平滑处理，获得很好的视景仿真效果。     

直升机飞行训练系统的研究与应用

直升机飞行训练系统具有安全、经济、可复现且不受气象条件影响等特点。针对直升机飞行训练的实时仿真问题,开发了一套基于六自由度并联平台和虚拟现实(VR)技术的直升机飞行训练系统。该系统可使飞行员在控制操纵杆体验模拟飞行时,同时具有体感和观感的沉浸感。以六自由度并联平台为运动模拟平台,建立与直升机姿态对应的运动学反解模型;结合VR视景,可以逼真地模拟直升机在实际飞行中的各种环境和动作。该系统可以帮助飞行员完成训练科目,具有承担部分训练工作的功能。该系统可为直升机飞行训练提供新方向。     

基于VR的虚拟视景系统关键技术研究

讨论了虚拟视景系统的应用背景,研究分析了三维视景软件OpenGVS的使用,对基于VR(virtual real)技术进行开发虚拟视景系统平台的总体设计和关键技术的应用进行了研究,介绍了虚拟视景系统平台在总体设计时所涉及的任务分析、任务分解等一些关键问题,着重对虚拟视景系统平台在开发时各仿真功能模块的实现进行了探讨,并对各模块的设计思想、设计方法、设计步骤进行了分析,并完成了整个平台的搭建,测试结果表明,此虚拟视景系统平台具有较高的实用性.     

分布交互环境下的视景系统研究与开发

分析比较了几种常用视景开发工具在分布交互环境下的特点，指出采用MultiGen Creator和Vega进行分布交互环境下的视景仿真系统的开发是一条简单快捷的途径。讨论了分布交互环境下对视景系统的要求，及其所要解决的关键技术。采用MultiGen Creator、Vega以及VR—Link开发出了基于HLA的水下航行器分布交互环境下的视景演示系统，实现了基于Vega的视景仿真系统和HLA系统的互连。     

机场消防车辆模拟器的视景系统研究

为了满足机场消防车训练的要求,提高训练效果,设计并实现了机场消防车训练视景系统。该系统由视景仿真模块、操纵杆数据提取模块和通信模块组成。视景仿真模块采用三个碰撞检测向量确保了消防车运动中准确的位姿;而操纵杆数据提取模块和通信模块分别采用DirectInput技术和UDP通信技术,为视景仿真提供实时数据,确保视景演示的实时性与真实性。实验结果表明,该系统完全满足机场消防训练的要求。     

机载电子对抗视景仿真训练系统设计研究

为了更好地提高电子对抗训练水平,丰富电子对抗的训练手段,针对机载电子对抗作战训练需求设计了机载电子对抗视景仿真训练系统的硬件电路,并将视景仿真技术引入到软件开发中,实现了机载电子对抗全过程的视景仿真训练。     

基于视景仿真的某型飞机武器模拟训练系统的设计

用模拟训练系统代替实装训练是当今武器装备训练的趋势,设计了基于视景仿真技术的武器训练系统,采用PCI总线技术、Creator实体建模、VegaPrime视景仿真控制,使武器训练过程具有良好的人机交互性,对开发相似的半实物视景仿真武器装备模拟训练系统具有一定的借鉴意义.     

基于HLA的平台级视景仿真系统设计研究

随着计算机仿真技术的发展,在大型分布式仿真系统中,单一的视景仿真系统已经不能满足复杂系统仿真的应用需求,基于高层体系结构(HLA)的视景仿真是主要的解决方案.论文结合视景仿真技术和分布式仿真技术设计并实现了一种分布式视景仿真系统,用于武器平台的训练和试验环节,并结合虚拟仿真平台的战术特点,设计实现了相应的武器平台视景仿真系统,对平台操作训练仿真、战术推演验证仿真系统的设计等都具有指导作用.     

基于VR的航天发射视景仿真系统设计与实现

针对如何构建一个虚拟的航天发射训练平台的现实问题,设计出一种基于虚拟现实技术(Virtual Reality,VR)的航天发射视景仿真系统;介绍了该视景仿真系统的逻辑结构和网络结构,采用三角形面片法构建发射场的地形地貌,并通过纹理映射使地形地貌更加逼真;利用图像和3D图形混合建模的方法构建发射场的设施;运用粒子系统原理,设计出发射火箭的火焰模型。通过Vega仿真软件进行系统集成和渲染,使整个仿真系统得到实现;实践证明,该仿真系统能够实时仿真卫星发射的全过程,为实时指挥、判读提供辅助决策支持平台,具有极大的应用价值。     

多机空战战法训练飞行视景仿真系统研究

多机空战战法训练设备研制是适应大规模分布式空战仿真训练的必然趋势.分析了战法训练的虚拟现实技术应用及其优势,对多机空战战法训练设备中飞机仿真平台的功能模型、视景流程和帧渲染顺序进行了总体设计.通过三维建模、虚拟场景配置、虚拟场景实时驱动三个步骤对视景系统进行实现,开发出一套适用于多机空战战法训练的飞行视景仿真系统.测试结果表明,所建立的飞行仿真视景系统能够满足飞行战法训练的要求.     

Development and evaluation of BCI for operating VR flight simulator based on desktop VR equipment

Advancement of brain-computer interface (BCI) has shown its applications in various scenarios, including flight control. Flight simulator is a crucial part for aircraft design or experiment. Desktop virtual reality (VR)-based flight is a perfect choice for overcoming existing problems in head-mounted VR flight simulations, such as dizziness and isolation, which make interaction and sharing very difficult. In this paper, a BCI based on the steady-state visual evoked potential paradigm and a VR flight simulator were developed and integrated. The performance of the developed system was evaluated quantitatively for comparative studies. Experimental results show that the developed system is very convenient and suitable for VR flight simulations. The average operating accuracies with plane and VR visual stimuli are 81.6% and 86.8%, respectively. The VR visual stimuli can improve the average operating accuracy by 5.2% compared with the plane visual stimuli.     

A study of cybersickness and sensory conflict theory using a motion-coupled virtual reality system

Sensory conflict theory explains that motion sickness in virtual reality (VR) systems can be caused due to the mismatch between visual and vestibular senses. This study examines whether coupling physical motions to visual stimuli in VR could reduce this discomfort. A motion-coupled VR system developed on a motion platform, providing vestibular cues to supplement visual roll from a head-mounted display (HMD), was used. Three conditions were tested: visual rotation only (stationary), visual-physical motion synchronised (synchronous), and vestibular motion with a self-referenced visual environment. Results show that when users are placed under a visual-vestibular synchronised condition, their subjective miserable score of cybersickness decreased while their comfort level of the overall experience increased. This indicates that a motion-coupled system, if integrated seamlessly in VR, could mitigate cybersickness symptoms.     

Measuring the likelihood of VR visual fatigue through ocular biomechanics

Immersion in virtual reality is still linked to symptoms of visual fatigue such as eye strain, dizziness, and overall discomfort. Studies have investigated visual fatigue through pre- and post-immersion tests of the visual function. In this work, we extend on our previous study and derive a visual fatigue likelihood metric using biomechanical analysis. Previously, we have investigated the effect of VR on the vergence system during immersion. The proposed visual fatigue metric exhibited a significant correlation to vergence angle variability which was previously linked to vergence accommodation conflict in VR. We also discuss subjective feedback and its relationship with the proposed visual fatigue metric.     

CAVE and fishtank virtual-reality displays: a qualitative and quantitative comparison

We present the results from a qualitative and quantitative user study comparing fishtank virtual-reality (VR) and CAVE displays. The results of the qualitative study show that users preferred the fishtank VR display to the CAVE system for our scientific visualization application because of perceived higher resolution, brightness and crispness of imagery, and comfort of use. The results of the quantitative study show that users performed an abstract visual search task significantly more quickly and more accurately on the fishtank VR display system than in the CAVE. The same study also showed that visual context had no significant effect on task performance for either of the platforms. We suggest that fishtank VR displays are more effective than CAVEs for applications in which the task occurs outside the user's reference frame, the user views and manipulates the virtual world from the outside in, and the size of the virtual object that the user interacts with is smaller than the user's body and fits into the fishtank VR display. The results of both studies support this proposition.     

Using virtual reality technology for aircraft visual inspection training: presence and comparison studies

The aircraft maintenance industry is a complex system consisting of several interrelated human and machine components. Recognizing this, the Federal Aviation Administration (FAA) has pursued human factors related research. In the maintenance arena the research has focused on the aircraft inspection process and the aircraft inspector. Training has been identified as the primary intervention strategy to improve the quality and reliability of aircraft inspection. If training is to be successful, it is critical that we provide aircraft inspectors with appropriate training tools and environment. In response to this need, the paper outlines the development of a virtual reality (VR) system for aircraft inspection training.

VR has generated much excitement but little formal proof that it is useful. However, since VR interfaces are difficult and expensive to build, the computer graphics community needs to be able to predict which applications will benefit from VR. To address this important issue, this research measured the degree of immersion and presence felt by subjects in a virtual environment simulator. Specifically, it conducted two controlled studies using the VR system developed for visual inspection task of an aft-cargo bay at the VR Lab of Clemson University. Beyond assembling the visual inspection virtual environment, a significant goal of this project was to explore subjective presence as it affects task performance. The results of this study indicated that the system scored high on the issues related to the degree of presence felt by the subjects. As a next logical step, this study, then, compared VR to an existing PC-based aircraft inspection simulator. The results showed that the VR system was better and preferred over the PC-based training tool.     

A study on the factors that improve the velocity perception of a virtual reality‐based vehicle simulator

The Virtual Reality (VR) system of a real‐time VR‐linked vehicle simulator that was used in this study provides visual information and sound effects to participants. The VR system of a VR‐linked vehicle simulator should provide a perceived velocity similar with the perceived velocity in actual driving. To achieve these goals, modeling and rendering methods that offer an improved performance for complex VR applications, such as the 3D road model, were implemented and evaluated. We also evaluated the influences of graphic and engine sound effects on the driver and analyzed each result according to a driver's viewpoint, the dot densities of road texture provided, the lateral distance between a virtual driver and environmental objects, and the engine sound. Each factor was individually analyzed through an experiment that evaluated the influence of visual images or sound effects in the vehicle simulator. Through the experimental evaluation, the research results could be used for improving the effectiveness of VR‐based vehicle simulators.     

虚拟选煤厂三维模型系统的实时性优化

虚拟现实模型系统的优化对于提高运行系统的实时性,保证虚拟现实系统的沉浸、交互等特性具有重要作用.结合虚拟选煤厂三维模型系统的优化,分析和探讨了虚拟现实模型系统实时性优化的几项关键技术,包括优化三维模型结构,节省模型系统的多边形开销,使系统中总多边形数不超过硬件的处理能力;优化纹理数据,在保证必要的纹理细节的前提下,有效节约纹理内存;优化模型数据库和LOD层次结构,改善运行系统的数据筛选性能,提高绘制速度.模型系统优化后系统的剔除和绘制时间曲线表明,优化后系统运行的实时性得到了有效提高.     

Semiotics of virtual reality as a communication process

ABSTRACT

The experience of immersive virtual reality (VR) can be considered as a communication process between human beings, mediated by computer systems, which uses visualisation and other sensory stimulation. In this paper, we analyse how VR characteristics can be explored using semiotic theory and, with methods of generative semiotics, we explore aspects of narrative and interaction in VR. We propose a semiotic analysis of VR communication focusing on syntax, semantics and pragmatics and considering also some principles of generative semiotics. The syntactic level is analysed as determined by the characteristics of the visual communication adopted. The semantic of VR is related to the functional model chosen to realise the virtual system. The pragmatic of VR is based on the human–computer interaction that changes the user's role. We explore how these aspects can be characterised in the context of VR communication design and what principles can be adopted for a VR application, and we present an analysis and a classification of the iconic signs that are being used in VR. Moreover, we present a framework that can be used to classify and describe different kinds of virtual reality systems and to better understand communication in VR, and we use it to classify eight popular systems for e-learning and collaboration.     

基于VR Juggler的空间视景仿真研究与应用

随着空间科学探索在我国的迅速发展,围绕着空间科学任务进行的各种视景仿真研究显得越来越重要.文章基于VR Juggler设计了一个针对空间任务的视景仿真平台,首先详细描述了VR Juggler软件及其性能特点,结合空间任务仿真需要,搭建了包括地球在内的九大行星运行环境,在此基础上,提出了利用终端进行管理和控制场景的操作,实现了多通道多扩展,为空间任务的视景仿真提供了灵活的、可持续扩展的平台.