基于虚拟现实的电子沙盘仿真技术研究

对虚拟现实技术、计算机三维图形技术、OpenGL、立体图像生成与显示技术进行了研究,利用计算机三维图形技术和立体显示技术实现沙盘的三维仿真立体沉浸式展示。     

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。     

三维立体显示系统的开发研究

三维立体显示技术是虚拟现实的关键技术之一,同时也是虚拟现实系统最基本的要求E本文中介绍了一 种如何基于现有微机平台的立体显示技术E我们借助立体液晶开关眼镜,运用立体显示技术即可在普通微机屏幕 上观察到具有真三维立体效果的静态画面与立体动画,具有极佳的立体视觉效果.     

虚拟现实近视干预疗法的原理研究与实现方法

本文主要是分析虚拟现实技术对近视治疗的效果,在实验基础上第一次提出了一种全新的近视治疗方法--“虚拟现实近视干预疗法”,即用医学上的双眼合像法结合虚拟现实技术来治疗近视。本文围绕虚拟现实近视干预疗法的原理研究及实现方法进行探讨;分析并阐述了这一医疗方法涉及到的三个理论基础：医学上的双眼合像的理论、非交叉视差形成的沉浸感、根据儿童患者设计的治疗参数;介绍了虚拟现实近视干预疗法的实现方法。用VisualC＋＋和OpenIn-ventor设计编写了能吸引儿童注意力的用立体眼镜观看的立体显示治疗软件,该软件中的图像具有远近移动、立体显示、人机交互等效果和功能。本文为近视的治疗提供了一个有益的创新,在理论和实践上都是十分有意义的
的。     

立体显示的双目模型算法及实现

三维立体显示技术是虚拟现实的关键技术,也是虚拟现实系统必不可少的基本条件,而深度感的正确形成又是立体显示技术的关键。介绍了采用体视原理进行自由立体显示的两种投影系统,并对照了各自的特征。分析了汇聚式双目系统的误差,给出了平行双目投影系统的算法推导和OpenGL的实现。最终以实验印证了算法的可靠性和准确性。     

基于自由立体视频的露天开采虚拟现实的研究与实现

文章结合最新的交互式自由立体视频技术与露天开采虚拟现实技术,设计并实现了一种基于自由立体视频的露天矿开采虚拟现实技术的交互与演示系统。文章利用3DS Max和VRMap软件建立了某露天矿区的虚拟视觉模型,并将这些虚拟视觉模型按照适合立体显示的条件进行场景渲染和视频图象生成,最后结合虚拟场景的三维显示特性设计了交互式自由立体视频软件,通过该软件展示了虚拟现实场景。该系统克服了传统虚拟现实演示的局限性,用较低的成本支持更多的用户进行参与和交互,同时也具有较强的环境拓展性。     

基于VRML文件的立体显示平台及相关技术研究

文章提出了一个基于VRML文件的立体显示平台,实现了一个支持VRML文件立体显示的浏览器。该浏览器包括VRML文件的解析以及立体显示两大部份,立体显示部分采用目前通用的3D图形API标准OpenGL实现。该系统采用面向对象技术构建,因此具有良好的可扩展性。该平台使VRML与虚拟现实技术得到更进一步的结合,从而使VRML在企业产品发布,电子商务等领域具有更广泛的应用。     

三维立体显示系统的开发研究

三维立体显示技术是虚拟现实的关键技术之一，同时也是心现实系统最基本的要求。本文中介绍了一种如何基于现有微机平台的立体显示技术，我们借助立体液晶开关眼镜，运用立体显示技术即可在普通微机屏幕上观察到具有三维立体效果的静态画面与立体劝画，具有极佳的立体视觉效果。     

基于嫦娥一号探月数据虚拟月球立体显示系统

提出一项利用真实月球探测数据来准确构建月球立体虚拟显示系统的技术,在双通道立体环幕投影系统上实现.利用嫦娥一号探月卫星的探月数据,采用多边形细分算法、自动拼接图像算法、渐进网格简化算法等多个关键技术构造具有真实立体感的3D月球模型,在VRP虚拟现实平台上进一步实现立体月球虚拟仿真系统,实现在月球表面的实时虚拟自动或交互漫游,戴上立体眼镜观察月球模型,使人具有身临其境的效果.该系统得到了精度更高的月球模型数据,解决了海量采集数据与实时显示的矛盾.通过该项技术可进一步了解月球表面的真实结构,为月球的科学研究提供基础,可应用于月球环境研究、虚拟漫游、月球科普宣传与展示以及其它月球虚拟现实相关的领域,具有广泛的市场前景.     

基于网络的虚拟现实技术

网络虚拟现实技术代表着未来计算机的应用技术,它为地理上分散的用户提供了一种可以交流与合作的共享空间,文章概述了虚拟现实的三要素、替身和显示技术,以及实现网络虚拟现实的一些关键技术,诸如网络联结、通讯协议、通讯方式、推测技术等。最后,介绍了一种用于Ｗｅｂ上的虚拟现实建模语言ＶＲＭＬ。     

Impact of parallax and interpupillary distance on size judgment performances of virtual objects in stereoscopic displays

Effective interactions in both real and stereoscopic environments require accurate perceptions of size and position. This study investigated the effects of parallax and interpupillary distance (IPD) on size perception of virtual objects in widescreen stereoscopic environments. Twelve participants viewed virtual spherical targets displayed at seven different depth positions, based on seven parallax levels. A perceptual matching task using five circular plates of different sizes was used to report the size judgment. The results indicated that the virtual objects were perceived as larger and smaller than the corresponding theoretical sizes, respectively, in negative and positive parallaxes. Similarly, the estimates from participants with small IPDs were greater than the predicted estimates. The findings of this study are used to explain human factor issues such as the phenomenon of inaccurate depth judgments in virtual environments, where compression is widely reported, especially at farther egocentric distances. Furthermore, a multiple regression model was developed to describe how the size was affected by parallax and IPD.

Practitioner Summary: The study investigates the effects of parallax and interpupillary distance on size perception of virtual targets in a stereoscopic environment. Virtual objects were perceived as larger in negative and smaller in positive parallax. Also, size estimates were greater than the theoretical sizes for participants with smaller IPD. A multiple-regression model explains the impact of parallax and measured IPD. Abbreviations IPD interpupillary distance

VR virtual eality

HMD head mounted-displays

2AFC two-alternative forced choice

IOD interocular distance

PD pupillary distance

ANOVA analysis of variance

     

Image correction based on homography in stereoscopic projection display

Abstract— Stereoscopic and autostereoscopic projection‐display systems use projector arrays to present stereoscopic images, and each projector casts one parallax image of a stereoscopic scene. Because of the position shift of the projectors, the parallax images have geometric deformation, which influences the quality of the displayed stereoscopic images. In order to solve this problem, a method based on homography is proposed. The parallax images are pre‐transformed before they are projected, and then the stereoscopic images without geometric distortion can be obtained. An autostereoscopic projection‐display system is developed to present the images with and without calibration. Experimental results show that this method works effectively.     

Distance estimation with mixed real and virtual targets in stereoscopic displays

In this paper we investigated the accuracy of center-to-center distance perception in near field augmented reality visual targets viewed by stereoscopic glasses. One real and one virtual targets were presented in four layout or target orientations (two horizontal and two vertical, by altering the relative positions of real and virtual targets) at three different parallax conditions (on screen, 5 cm from screen and 10 cm from screen) and four levels of scaled between targets’ distance (10–20 cm, 20–30 cm, 30–40 cm and 40–50 cm). The result revealed overall underestimation with an accuracy of about 84%. Interestingly, it was noticed that the main effects of layout, parallax and center-to-center distance were significant. Generally, accuracy improves when targets put vertical, close to observers’ position and smaller separation of targets. Significant interactions among the three main factors were also reported. The results are of great importance as it provides guide for the developers to decide where to present targets depending on the need for relative accuracy of judgment. Some engineering implications of the result are also discussed in this paper.     

Ergonomic evaluation of interaction techniques and 3D menus for the practical design of 3D stereoscopic displays

There has been a recent commercialization of 3D stereoscopic displays in order to implement them in a virtual reality environment. However, there is a lack of extensive research into user interfaces for 3D applications on stereoscopic display. This study focused on three representative interaction techniques (ray-casting, keypad and hand-motion techniques) utilizing a head-mounted display and 3D CAVE. In addition, the compatibility with 3D menus was also investigated based on performance and subjective assessment. Nine 3D menus were designed for the experiment in regards to three 2D metaphors (pop-up, pull-down and stack menus) and three structural layouts (list, cubic and circular menus). The most suitable technique for the 3D user interface on a stereoscopic display was the ray-casting technique and the stack menu which provided the user with good performance and subjective response. In addition, it was found that the cubic menu was not as effective as other menus when used with the three interaction techniques.Relevance to industryThis research describes a distinctive evaluation method and recommendations that guarantee the suitability for interactive 3D environments. Therefore, the results will encourage practitioners and researchers that are new to the area of 3D interface design.     

实时立体视觉系统中的深度映射

目的 为减少立体图像中由于水平视差过大引起的视觉疲劳。针对实时渲染的立体视觉系统,给出了一种非均匀深度压缩方法。方法 该方法在单一相机空间内,通过不同的投影变换矩阵生成双眼图像,水平视差由投影变换来控制。为减少深度压缩造成的模型变形而带来的瑕疵,将不同深度区域内物体施以不同的压缩比例;将相机轴距表示为深度的连续函数,通过相机轴距推导出在单一相机空间内获取双眼图像的坐标变换,将深度压缩转换为模型的坐标变换,从而保证压缩比例的连续变化。结果 实验结果表明,该方法能有效提高立体图像的质量。结论 该方法简单、高效,可应用于游戏、虚拟现实等实时立体视觉系统。     

Quality assessment for virtual reality technology based on real scene

Virtual reality technology is a new display technology, which provides users with real viewing experience. As known, most of the virtual reality display through stereoscopic images. However, image quality will be influenced by the collection, storage and transmission process. If the stereoscopic image quality in the virtual reality technology is seriously damaged, the user will feel uncomfortable, and this can even cause healthy problems. In this paper, we establish a set of accurate and effective evaluations for the virtual reality. In the preprocessing, we segment the original reference and distorted image into binocular regions and monocular regions. Then, the Information-weighted SSIM (IW-SSIM) or Information-weighted PSNR (IW-PSNR) values over the monocular regions are applied to obtain the IW-score. At the same time, the Stereo-weighted-SSIM (SW-SSIM) or Stereo-weighted-PSNR (SW-PSNR) can be used to calculate the SW-score. Finally, we pool the stereoscopic images score by combing the IW-score and SW-score. Experiments show that our method is very consistent with human subjective judgment standard in the evaluation of virtual reality technology.

     

在虚拟现实中快速应用立体显示

提出了立体照相机的概念,通过立体照相机分析了平行立体投影法的视差性质、瞳距大小及视点的视图和投影变换,最后给出了开发立体显示的步骤.实验表明,程序开发者只需遵循给定的步骤开发支持立体显示的虚拟现实程序,不必经过多次的尝试便可以体验良好的立体视觉效果,大大缩短了程序开发时间.     

Effects of displays on a direct reaching task: A comparative study of head mounted display and stereoscopic widescreen display

This study was conducted to investigate the virtual display effects on direct interaction performance metrics such as accuracy, task completion time, and comfort. Eighteen participants performed tapping (pointing) tasks in the coronal plane by directly reaching for tapping targets at three egocentric distance levels, with three indices of difficulty at each egocentric distance. The position data and severity of cybersickness symptoms were collected with a motion system and a symptom questionnaire, respectively. The results indicated that accuracy was higher with the stereoscopic widescreen display than with the head mounted display. However, no significant differences in task completion time, throughput, and cybersickness were observed between the two VR displays. In addition, increasing the egocentric distance improved accuracy and lengthened the task completion time, whereas increasing the task difficulty lengthened the task completion time but did not affect the accuracy. The findings are important and informative for users in choosing between the two virtual reality displays. Generally, the stereoscopic widescreen display can be recommended for tasks requiring high egocentric distance accuracy in the coronal plane. Furthermore, developers may refer to these findings in designing interfaces that allow a more natural way of interaction for users.     

Virtual toed‐in camera method to eliminate parallax distortions of stereoscopic images for stereoscopic displays

Abstract— The parallax images captured by a toed‐in camera have positive and negative horizontal parallax for stereoscopic displays, but they also have parallax distortions including horizontal and vertical distortions. The virtual toed‐in camera method can eliminate the horizontal distortion and reduce the vertical distortion. The parallax formulae for the corrected‐parallax images were deduced. The experiments were carried out and the results proved that the method was accurate. Good stereoscopic images without horizontal distortion and with little vertical distortion were presented on an autostereoscopic display.