交互式虚拟现实系统的实现

对变互式虚拟现实系统的州论与技术进行了研究。理论研究主要针对二维数据存数捌席中的存储、二维坐标的对应算法及虚拟现实交互式技术的应用。存WEB环境下,能够创造一个实时逼真的虚拟现实环境,并将此环境应用于查询等交互式过程。     

Viability of virtual reality exposure therapy as a treatment alternative

Virtual reality (VR) has garnered the interest of many scientific communities over the last decade. One promising track of research lies in VR exposure therapy (VRET), where gradual exposure to a negative stimulus is used to reduce anxiety. Virtual exposure is desirable in many situations, as it can be less intimidating and less expensive than traditional in vivo treatment with much the same success. Examining the benefits and drawbacks of VRET is an important first step toward an accurate assessment of its viability as a treatment alternative. This paper will review current literature on the topic of VRET and answer several questions regarding the viability of the treatment. It will also provide some additional research direction for improving the case for mainstreaming VRET.     

An Image-Based Virtual Reality Prototype System

The most important goal of virtual reality is to create a virtual world computers where users are allowed to view the environment and control the virtual objects interactively.Traditionally,virtual reality systems use 3D computer graphics to model and render a virtual environment in real time.However,this approach usually requires laborious modeling and expensive special-purpose rendering hardware.Image-based rendering is a new approach in composing a virtual environment in which a set of panoramic images is used to compose the virtual environment and walking in the space is accomplished by “hopping”to different panoramic points.This paper introduces an experimental image-based VR system.The techniques utilized in the system,in particular the authoring and interactive control tools of the system,are described in detail.     

虚拟现实技术在数字化校园中的应用

继多媒体、计算机网络之后,虚拟现实技术成为在教育领域内最具有应用前景的技术。随着该技术的不断发展,它在数字化校园的建设与应用中将发挥其特有的优势。本文将从虚拟现实技术的概念及特点出发,进一步探讨虚拟现实技术在数字化校园中的具体应用。     

Intelligent virtual environments for virtual reality art

The development of virtual reality (VR) art installations is faced with considerable difficulties, especially when one wishes to explore complex notions related to user interaction. We describe the development of a VR platform, which supports the development of such installations, from an art+science perspective. The system is based on a CAVE™-like immersive display using a game engine to support visualisation and interaction, which has been adapted for stereoscopic visualisation and real-time tracking. In addition, some architectural elements of game engines, such as their reliance on event-based systems have been used to support the principled definition of alternative laws of Physics. We illustrate this research through the development of a fully implemented artistic brief that explores the notion of causality in a virtual environment. After describing the hardware architecture supporting immersive visualisation we show how causality can be redefined using artificial intelligence technologies inspired from action representation in planning and how this symbolic definition of behaviour can support new forms of user experience in VR.     

Transfer of training from virtual reality

This experiment compared the value of real-world training, virtual reality training, and no training in the transfer of learning to the same task performed in real-world conditions. Results provide no evidence of transfer from a virtual reality training environment to a real-world task. There was no significant difference between the virtual reality training group and the group that received no training on the task. The group that received real-world training performed significantly better than both of the other two groups. The results question the utility of virtual training and suggest that in the present configuration, individuals learn performance characteristics specific only to the virtual reality context. Needed improvements to virtual reality for the purpose of enabling the transfer of training are indicated.     

Towards a narrative theory of virtual reality

Virtual Reality (VR), by its nature and characteristics, is of specific interest to the AI community, particularly in the domains of Storytelling and Intelligent Characters. We argue that VR must be considered a particular narrative medium alongside Theatre, Literature or Cinema. This paper reviews relevant work in narrative theory from Plato onwards, including the work and theories of literary critics [1], cinema critics [2–4] and theatrical dramaturges [5], and analyses the specific characteristics of VR relevant to this theory. Less studied media such as Live Role Playing Games, improvisational drama and participatory drama are also considered. Finally, this document argues for a participatoryprocess-oriented narrative, with particular attention to the specificities and particularities of stories and their possible representation, adapted to the narrative medium Virtual Reality.     

Tangible authoring of 3D virtual scenes in dynamic augmented reality environment

This paper proposes tangible interfaces and interactions for authoring 3D virtual and immersive scenes easily and intuitively in tangible augmented reality (AR) environment. It provides tangible interfaces for manipulating virtual objects in a natural and intuitive manner and supports adaptive and accurate vision-based tracking in AR environments. In particular, RFID is used to directly integrate physical objects with virtual objects and to systematically support the tangible query of the relation between physical objects and virtual ones, which can provide more intuitive tangibility and a new way of virtual object manipulation. Moreover, the proposed approach offers an easy and intuitive switching mechanism between tangible environment and virtual environment. This paper also proposes a context-adaptive marker tracking method which can remove an inconsistent problem while embedding virtual objects into physical ones in tangible AR environments. The context-adaptive tracking method not only adjusts the locations of invisible markers by interpolating the locations of existing reference markers and those of previous ones, but also removes a jumping effect of movable virtual objects when their references are changed from one marker to another. Several case studies for generating tangible virtual scenes and comparison with previous work are given to show the effectiveness and novelty of the proposed approach.     

Applying virtual reality for trust-building e-commerce environments

The application of virtual reality in e-commerce has enormous potential for transforming online shopping into a real-world equivalent. However, the growing research interest focuses on virtual reality technology adoption for the development of e-commerce environments without addressing social and behavioral facets of online shopping such as trust. At the same time, trust is a critical success factor for e-commerce and remains an open issue as to how it can be accomplished within an online store. This paper shows that the use of virtual reality for online shopping environments offers an advanced customer experience compared to conventional web stores and enables the formation of customer trust. The paper presents a prototype virtual shopping mall environment, designed on principles derived by an empirically tested model for building trust in e-commerce. The environment is evaluated with an empirical study providing evidence and explaining that a virtual reality shopping environment would be preferred by customers over a conventional web store and would facilitate the assessment of the e-vendor’s trustworthiness.     

Two-handed assembly with immersive task planning in virtual reality

Assembly modelling is the process of capturing entities and activity information related to assembling and assembly. Currently, most CAD systems have been developed to ease the design of individual components, but are limited in their support for assembly designs and planning capability, which are crucial for reducing the cost and processing time in complex design, constraint analysis and assembly task planning. This paper presents a framework of a two-handed virtual assembly (VA) planner for assembly tasks, which coordinates two hands jointly for feature-based manipulation, assembly analysis and constraint-based task planning. Feature-based manipulation highlights the important assembling features (e.g. dynamic reference frames, moving arrow, mating features) to guide users for the ease of assembly and in an efficient and fluid manner. The users can freely navigate and move the mating pair along the collision-free path. The free motion of two-handed input in assembly is further restricted to the allowable motion guided by the constraints recognised on-line. The allowable motion in assembly is planned by the logic steps derived from the analysis of constraints and their translation in the progress of assembly. No preprocessing or predefined assembly sequence is necessary since the planning is produced in real-time upon the two-handed interactions. Mating features and constraints in databases are automatically updated after each assembly to simplify the planning process. The two-handed task planner has been developed and experimented for several assembly examples including a drill (12-parts) and a robot (17-parts). The system can be generally applied for the interactive task planning of assembly-type applications.     

From sensory substitute technology to virtual reality research

This paper describes research into sensory substitutes for the disabled, and proposes one basic research approach to assistance technology. It also reports on how the technology is related to virtual reality research.     

Using virtual reality for industrial design learning: a methodological proposal

ABSTRACT

Nowadays, the different computer tools available enable designers to create complex industrial prototypes. The use of these tools is constrained by the limitations imposed by common devices, such as screens and displays. Recently emerged virtual and augmented reality techniques have started being used as supports in many learning and industrial environments. Beyond the new possibilities that these tools offer for designing industrial objects, the underlying question is whether these new technologies could improve the creativity of designers to enable them to get a better understanding of the designing process itself. This paper presents a methodological proposal for the deployment of an industrial design engineering course aimed not only at learning different design techniques, but also at assessing the creativity skills of students. The practical contents include the use of virtual reality devices, to help the designer overcome the limitations of prototype visualisation and make better designing decisions. Moreover, a creativity test will be performed at the beginning and at the end of the course to assess the changes in creativity skills taking place within the experiment group versus the changes in a traditional learning (control) group.     

Integrated manufacture: A role for virtual reality?

Virtual Reality (VR) is fast becoming an affordable technology with potentially wide-ranging applications in many professions including education, medicine and industry. Its advantages over existing technology are primarily that users can visualise, feel involvement and interact with virtual representations of real world activities in real time.

A recently completed study, funded by the EPSRC, examined the feasibility of VR as a tool for UK manufacturing industry. Of primary interest was whether manufacturers perceive a use for VR in their inudstry and, if so, what impact they envisage it will have within their company. A national survey was distributed to over 2,000 UK manufacturing companies randomly selected and interviews carried out with existing users of VR technology. A brief summary of these results is presented.

A demonstration application was developed in desktop VR representing the manufacture of a consumer product in which various stages of the manufacturing process were featured including initial design, manufacture, and testing. The demonstration application is described in detail and user assessments are presented. On the basis of these findings, the potential future role of VR in integrated manufacture is discussed. Relevance to industry

In only a short time, virtual environments have become a focus of serious consideration as a tool for manufacturing and other industry. In order that VR has greatest industrial utility we need to examine and develop its potential as a specialism-free integrating medium within a simultaneous engineering approach.     

A methodology for solid modelling in a virtual reality environment

This paper presents a methodology for solid modelling in a virtual reality (VR) environment. Solid modelling in the VR environment is precisely performed in an intuitive manner through constraint-based manipulations. A hierarchically structured and constraint-based data model is developed to support solid modelling in the VR environment. Constraint-based manipulations are realized by allowable motions for precise 3D interactions in the VR environment. A mathematical matrix is presented for representing allowable motions. A procedure-based degree-of-freedom combination method for 3D constraint solving is presented for deriving the allowable motions from constraints. A rule-based constraint recognition engine is developed for both constraint-based manipulations and implicitly incorporating constraints into the VR environment. A prototype system has been implemented to testify the feasibility of the presented methodology.     

Haptics-based virtual reality periodontal training simulator

This paper focuses upon the research and development of a prototype dental simulator for training of periodontal procedures. By the use of virtual reality and haptics technology, the periodontal simulator allows trainees to learn performing diagnosis and treatment of periodontal diseases by visualizing a three-dimensional virtual human mouth and feeling real tactile sensations while touching the surface of teeth, gingiva, and calculi with virtual dental instruments. Since periodontics requires dentists to depend primarily on tactile sensations to perform diagnostic and surgical procedures, the use of haptics is unquestionably crucial for a realistic periodontal simulator. The haptics-based virtual reality periodontal training simulator has been validated by a experiment conducted by the College of Dentistry at University of Illinois at Chicago (UIC) with faculty members and dental students, which demonstrates the scientific contribution and usefulness of the simulator as a vital part of the curriculum of the Department of Periodontics at UIC.

Effects of virtual presence and learning outcome using low-end virtual reality systems

Low-cost technology is essential to integrate Virtual Reality (VR) into educative institutions around the world. However, low-cost technology usually refers to low-end technology, which may compromise the level of immersion of the VR system. This study evaluates whether low-end and high-end VR systems achieve a comparable learning outcome regardless their immersion level. We also analyze the relationship between virtual presence and the learning outcome arising from a VR educational experience. An evaluation with 42 participants was conducted. We measured learning outcome and virtual presence under three different configurations, namely: a desktop computer, a low-end VR system, and a high-end VR system. The impact of simulator sickness was also analyzed. Results revealed a lower learning outcome in the less immersive configuration (i.e. desktop) and a similar learning outcome in both low-end and high-end VR systems. Even though low-end VR systems are less immersive and produce a lower level of virtual presence than high-end VR systems, the results support the use of low-end VR systems for educative applications.     

Experiencing immersive virtual reality in museums

Virtual Reality (VR) has been regarded as a highly effective technology that enables people to gain enjoyable and immersive information about museum collections. Drawing from the four realms of the experience economy, we assume absorptive experiences influence immersive experiences, overall museum VR tour experience, and intention to visit a museum. The results show that all the hypotheses are supported. Furthermore, we compared and tested the proposed model and its rival model (postulating the direct influence of the four realms of the experience economy on museum VR experience) and found that the proposed model is better than the rival model.     

Application of virtual reality in hospital facilities design

The airborne particles present in certain hospital environments, such as the tuberculosis isolation or operating rooms, can be extremely harmful for patients and/or hospital personnel. An important issue during the design of hospital facilities is an efficient airborne particle removal system. A near-optimal setup of the parameters that affect the airflow, and consequently the airborne particle trajectories within the room is desirable. Computational Fluid Dynamics (CFD) is an alternative to tedious and time-consuming experimental investigations during the design phase, when a large number of alternatives need to be evaluated. The main limitations of CFD application in building design are the high level of skill required, the complexity of the setup phase, and the difficulty of output data interpretation using common 2D (two-dimensional) display devices. A virtual reality (VR) environment can help in overcoming some of these limitations. A CFD/VR procedure for design of contaminant-free hospital facilities is presented in this paper. By means of a VR preprocessing step, inferior solutions can be discharged to drastically reduce the number of configurations to investigate. Then, a CFD/VR tool is used to explore the restricted set of room layouts. The 3D (three-dimensional), immersive visualisation of an indoor space and of the particle motion inside it allows the user to really see the particle flows and consequently understand the effects of room parameters on particle motion throughout the room. In this way a close-to-optimal configuration of the room layout and of the ventilation system can be achieved more speedily and more conveniently compared to traditional CFD investigations.     

GeoVR: a web-based tool for virtual reality presentation from 2D GIS data

A tool called GeoVR has been designed and developed under a client/server architecture to enable the interactive creation of a 3D scene and virtual reality modeling language (VRML) model from 2D spatial data by integrating Internet geographical information system (GIS) and HTML programming. The client front-end of this tool provides an HTML form to set properties for building 3D scenes, while the server back-end supported by off-the-shelf software: ArcView Internet Map Server and ArcView 3D Analyst through Avenue programming, processes the parameters and generates a 3D scene. This 3D scene is then transformed into a VRML model, which, together with its legend, is sent back to the VRML-enabled WWW browser for display and navigation. It is demonstrated that this tool, not only automates the conversion of the conventional 2D GIS data into VRML, but also adapts the current GIS 3D capabilities to the increasingly popular Web environment. The development of GeoVR offers new opportunities for geoscientists to build applications that benefit from virtual reality presentation based upon the existing GIS spatial databases.     

Diffractive optics for virtual reality displays

Abstract— Near‐to‐eye (NTE) displays are generally systems where the imaging optics of a microdisplay is brought close to the eye, like a magnifying glass. In portable NTE terminals, the challenges are in achieving low power consumption as well as low weight and small size. Part of the problem is related to the microdisplay, but the optics also plays a major role. A study on how diffractive optical elements (DOEs) on planar waveguides can be used to miniaturize the optics of NTE displays is presented and the performance of the system is analyzed.