三维动漫制作与虚拟现实结合技术研究

基于为高校三维动漫教学提供良好的教学技术和实验平台,研究了三维动漫制作与虚拟现实技术相结合的方法,采用三维计算机图形技术CG(Computer Graphics)、影像技术和运动捕捉系统,实现高质量高效率的三维动漫制作。介绍了将动漫技术、虚拟现实VR(Virtual Reality)设备和网络技术相整合的交互动漫虚拟环境建设方案。     

Integration of manufacturing services into virtual environments over the internet

Virtual reality (VR) is a rapidly developing technology that has a wide spectrum of industrial and commercial applications. Networked (distributed or shared) virtual environments (VE) are of growing interest to modern manufacturing industry; a dominating use of networked virtual manufacturing environments (VMEs) is on-line visualisation and collaborative control of 3D information. This has to be supported by real-time data transfer. To meet a broad range of common requirements for Internet-based VE communications, particularly for virtual manufacturing and collaborative design and control, this paper presents a networked virtual environment system that is designed to support networked virtual design and manufacturing. The system is implemented with manufacturing message specification (MMS) standards so as to integrate a range of manufacturing services into networked VEs over the Internet.     

场景语义约束的三维交互技术

针对复杂虚拟环境下的交互需求,从面向高层应用的角度对交互任务进行分析,提出三维交互任务的层次模型。结合应用特点,将虚拟场景中的语义约束引入到三维交互技术的设计中,实现了多种面向高层应用的导航技术和选择操作技术,并在不同交互技术和操作隐喻模式之间实现了自然的融合和平滑的转换。用户界面利用这些语义约束更好地感知和理解用户的交互意图,实现更为直观、高效的三维交互过程。     

虚拟拆卸中多方式交互技术的应用

通过分析虚拟环境下不同人-机交互方式的特点,结合对产品装配体进行人工拆卸的操作活动,提出面向虚拟拆卸的人-机-零件间的多方式交互操作方法,在虚拟环境下研究和利用手抓取操作、手势操作、语音命令和3D虚拟菜单等多种交互方式对产品零部件进行自然、直观的人工拆卸,人机结合进行产品的装配／拆卸序列规划。     

虚拟环境的用户意图捕获

目的虚拟制造环境中需要复杂精确的3D人机交互。目前的虚拟环境(VE)的主要问题是人在交互过程中的认知和操作负荷太重,交互效率亟需提高。解决此问题的重要途径是提高机器的认知能力。方法本文研究了用户意图的分析和抽取,并建立多通道用户意图理解的算法,以此来提高交互效率。结果结合虚拟装配应用给出了典型意图的实验结果并给予分析。通过实验对多通道意图的可用性和可靠性,以及基于意图系统的实时性进行了评估。实验是虚拟装配空间中用户拾取对象意图的实验。当3维鼠标和对象距离为5 000 mm时,传统系统中操作平均耗时5.344 7 s,而基于意图的系统中平均耗时2.326 6 s。基于意图的系统极大地降低了操作的时间和复杂度。结论采用意图驱动的系统情景转换能在虚拟环境工作中有效地降低人的认知负荷,并能很好地帮助系统开发者进行混成系统的建模和分析,降低开发的复杂度。实践结果表明用户意图理解的多通道模型和算法能极大地提高交互式系统的交互自然性和交互效率。该方法不仅适用于本文所用的虚拟装配系统,对于所有的虚拟环境应用场景都有同样的有效性。     

桌面环境下的笔式三维交互框架

笔输入和三维交互结合是研究三维交互范型的一种新方法。提出一个桌面虚拟环境下的笔式三维交互框架,包含交互原语和交互任务构造两个核心组件。首先采用词法到语法的二级封装机制来生成高级事件和交互原语,然后综合交互上下文、用户修正和手势识别实现基本交互任务到复杂交互任务的整合机制。框架中内嵌的手势交互、约束感知和混合交互技术能有效降低任务分解和模式切换带来的认知负担,提高交互自然性。     

结合个性化建模和深度数据的三维人体姿态估计

利用深度传感器估计三维人体姿态是计算机视觉领域的一个重要问题,在人机交互、虚拟现实和动画设计等领域有重要的应用价值.针对该问题的主流方法是自底向上的方法,这类方法一般采用分类、回归或检索技术,可以直接从深度数据中估计三维肢体姿态,在人机交互中得到了很广泛的应用.但是这类方法依赖于大规模的姿态数据库,而且结果不够精确.本文提出一种结合个性化人体建模和深度数据的三维姿态估计方法,首先对运动对象建立三维虚拟人模型,然后利用该个性化的虚拟人模型与深度数据之间的点匹配关系构造姿态优化的目标函数,通过迭代优化目标函数,估计出与深度数据相吻合的三维姿态.与传统方法相比,本文方法不需要任何姿态数据库.实验表明,本文方法得到的结果更加精确.     

基于集合论思想的协同虚拟环境交互研究

交互技术是协同虚拟环境中实现用户间的多感知（视觉、听觉、触觉等）交流与协作的重要手段。目前,在协同虚拟环境中,由于对存在的交互种类缺乏系统、全面的研究方法,从而用户交互程度明显不足,严重影响了地理协同工作。将集合论思想引入到协同虚拟环境的交互中,首次系统、完备性地分析了协同虚拟环境中存在的交互类型,将复杂的交互研究简化为6类交互的组合。在此基础上,采用Agent技术构建了智能语义物体模型以辅助交互的实现,并应用VTK和Cal3D软件开发包,实现了协同虚拟环境中基于化身的多种交互。     

人体三维运动实时跟踪与建模系统

提出了一种新的人体三维运动实时跟踪与建模系统设计方法,并基于此实现了一套鲁棒的参考应用系统.针对人机交互等对跟踪精度要求不是很高的应用场合,系统在跟踪精确性和简易性与可推广性之间做了很好的折中.系统使用多个摄像头采集图像,实时计算场景深度信息,然后结合使用深度和颜色信息进行人体跟踪.应用一个简易的人体上半身三维模型,并使用基于颜色直方图的粒子滤波算法对头部和手部进行跟踪,从而恢复出模型的各个参数.系统以人脸检测和人手肤色聚类算法为初始化方法.大量实验证明,该系统能在复杂背景下进行人体上半身的跟踪和三维模型恢复,能进行完全自动的初始化,有较强的抗干扰能力和自动错误恢复能力.系统在2.4GHz PC机上能以25帧/秒的速度运行.     

Virtual interpersonal touch: Haptic interaction and copresence in collaborative virtual environments

As digital communication becomes more commonplace and sensory rich, understanding the manner in which people interact with one another is crucial. In the current study, we examined the manners in which people touch digital representations of people, and compared those behaviors to the manner in which they touch digital representations of nonhuman objects. Results demonstrated that people used less force when touching people than other nonhuman objects, and that people touched the face with less force than the torso area. Finally, male digital representations were touched with more force than female representations by subjects of both genders. We discuss the implications of these data to the development of haptic communication systems as well as for a methodology of measuring the amount of copresence in virtual environments.

Approximate resolution of asynchronous conflicts among sequential collaborations in dynamic virtual environments

Asynchronous collaboration for a networked virtual environment (NVE) has emerged as a promising area in collaborative computer‐aided design applications. The concept of asynchronous collaboration is a sequential collaboration of temporal processes in an NVE where the participants are not required to be present at the time of the collaboration. Conflicts in asynchronous collaboration occur because the preceding task of a participant can influence the output of the ensuing task of another participant. The conflicted tasks must be modified manually. However, it requires considerable time and effort to resolve conflicts in a sequential collaboration. In this paper, we present an asynchronous collaborative framework that converts the conflict states of the shared objects into approximately resolved states. We develop a novel approximate resolution algorithm using a task‐based modeling mechanism to resolve the asynchronous conflicts with their corresponding tasks. Moreover, we propose a visual relation editor for convenient management. The participants can set flexible relations among shared objects using the proposed visual editor. The proposed approximate resolution approach can significantly reduce the average resolution time and the number of required manual task resolutions in a virtual environment compared to a manual resolution approach. Copyright © 2015 John Wiley & Sons, Ltd.     

虚拟环境下基于语义的三维交互技术

自然、高效的三维交互技术是虚拟现实系统成功应用的关键.现有的交互技术主要是从几何层次上考虑如何有效实现交互任务,而对面向高层应用的交互任务的支持还不够.借鉴人类在真实世界中的认知原理,虚拟环境中的交互对象不仅具有外观意义上的几何属性,而且包含了与交互有关的规则、约束和供给等语义属性,这些虚拟对象称为语义对象.在系统导航、对象选择/操作等交互任务的执行中,通过语义对象可以实现高层交互语义的封装和解析.从应用角度提高交互技术的效率和可用性,为用户提供"直接操纵"之上的面向高层语义的交互隐喻,屏蔽交互技术的底层实现细节,使用户专注于应用领域相关的高层交互控制.     

面向虚拟环境的装配体模型研究

人机交互是虚拟装配的本质特性和技术瓶颈,能反映交互过程的装配体模型构造,是虚拟装配领域的一个关键问题,给出一种时序的装配体模型,对时序的聚合关系、时序的约束关系以及时序的行为结构给出定义和分析,为实现该模型,还给出了零件的中间模型和对象复杂行为构造,同时对虚拟装配直接操作的交互过程、交互模式及装配工艺知识给出了时序的形式描述,这是连接人机交互与装配体模型以及模型与工艺生成的桥梁．一致的表示模型减少了交互装配信息的冗余性,有利于提高交互信息的复用,为交互生成工艺提出了新方法。     

Effects of 2D wedge design as a wayfinding facilitator in a 3D virtual environment

The purpose of this study is to investigate users' wayfinding task performance and subjective preference in a three‐dimensional (3D) virtual environment. The research variables are interaction mode (touch sensitive vs body movement modes), viewing perspective [first‐person perspective (1PP) versus third‐person perspective (3PP)], and gender (man versus woman). Three difficult levels of tasks were conducted, i.e., A, A‐P, and A‐A types. The experiment is 2 × 2 × 2 between‐subject design. Participants needed to complete three wayfinding tasks and fill out subjective preference questionnaires regarding task fluency, satisfaction, system usability scale, and NASA Task Load Index (NASA‐TLX). Fifty‐six participants (28 men and 28 women) were invited using convenient sampling method. The results are as follows: (1) Participants adopting touch‐sensitive mode performed better than body movement mode. (2) Participants using touch‐sensitive mode could have better task fluency and higher SUS score, and with less effort and frustration. (3) Participants adopting 3PP had better wayfinding task performance than first‐person perspective. They also had higher system usability scale score and spent less effort for having wider viewing perspective. (4) The gender variable only showed significant effect in A‐P type of wayfinding task. Men performed better than women. It is concluded that adopting touch‐sensitive interaction and 3PP designs can better facilitate users' wayfinding tasks.     

Poster3D: a system for three-dimensional authoring and presentation in immersive virtual environments

We developed a simple system for three-dimensional (3D) authoring and presentation in immersive virtual reality environments. Our system enables a user to create and edit content both through direct manipulation using hand gestures in an immersive environment, and by using a 2D GUI on a PC desktop. The system also exploits various features of 3D information visualization to produce effective and interactive presentations. In a system trial, users found that the system enhanced their experience. The system helps users create 3D educational materials more easily and learn through the materials with greater interest and motivation. Noritaka Osawa received his B.S., M.S. and Ph.D. degrees in information science from the University of Tokyo in 1983, 1985, and 1988 respectively. After working for a software company and the University of Electro-communications, he has been at the National Institute of Multimedia Education since 1998. He has also been jointly appointed at the Graduate University for Advanced Studies since 2001. He now works for them as a Professor. His current research interests include human–computer interfaces using virtual reality technologies, information visualization, and system software. Sangtae Kim received B.A. degree in Visual Communication from YougIn University, Korea, in 1996, and M.A. and Ph.D. degrees in Design, from the University of Tsukuba, 2001, and 2004, respectively. He is currently an Assistant Professor of the institute of Art and Design, The University of Tsukuba, Ibaraki, Japan. His research interests include visual communication, dynamic information graphics, multimedia systems, 3DCG, and Web3D technology. He planned for the MDD (Multi-Dynamic Documentation) project in 2003. At present, he is involved in the development of Web3D contents (Interactive Anatomy system) that uses MDD technology.     

Characteristics and usage patterns of older people in a 3D online multi-user virtual environment

3D online multi-user virtual environments (MUVEs) have a lot of potential in supporting older people in their daily lives, yet little research has been conducted to explore how older people engage with this type of technology. This paper aims to investigate the characteristics, user groups and activity patterns (particularly social networks and gift giving behaviour) of older users within a 3D online multi-user virtual environment. Data from approximately 5000 online user profiles of older and younger users from a 3D MUVE, namely IMVU, was collected for analysis. Overall, we identified several distinct patterns of use (e.g. size of social ties, level of reciprocity, etc.) among older users when compared with younger users. We also found that despite the capabilities of 3D MUVEs to provide the users immersion in alternative realities, a feature well embraced by younger users in this study, older users seemed more interested in activities which serve as an extension to their physical life.     

Analyzing place metaphors in 3D educational collaborative virtual environments

In the recent years, the usage of three dimensional (3D) collaborative virtual environments (CVEs) for educational purposes has increased. The metaphors behind the design of virtual places are quite diverse, from replication of real universities to art museums and scientific labs. This paper reports the results of a case study where the students of our university, as a part of their course assignment, analyzed place metaphors used in a range of 3D educational CVEs vs. the corresponding educational goals. The students suggested a design for a virtual campus representing the Norwegian University of Science and Technology (NTNU). The results of this study provide some suggestions concerning the characterization of different design features in educational CVEs and the suitability of such features for different educational goals. Also, a preliminary set of design guidelines for an ideal virtual campus representing a real university is presented. Finally, some challenges associated with using 3D CVEs in various educational situations are discussed.     

虚拟博物馆的三维场景构造及交互漫游实现

虚拟现实技术日趋成熟,针对虚拟场景的构造、交互漫游系统的实现过程展开讨论.系统对徐悲鸿博物馆的主要建筑物、生前作品及其雕塑进行了三维重建,实现了整个博物馆的虚拟漫游.探讨了构建虚拟博物馆三维场景及交互漫游实现过程中的若干关键技术问题,同时为虚拟博物馆系统的建立提供了一种切实可行的途径.     

基于3D Widgets的三维人机交互平台的设计与实现

随着人机交互技术的不断发展,对三维人机交互的支持在三维图形软件中占有越来越重要的地位,而在医学影像处理与分析领域,它对于更方便、准确地使用可视化的结果辅助医生进行诊断具有重要意义。该文针对医学影像处理与分析领域中三维交互的需求与特点,设计并实现了一个基于3D Widgets的三维人机交互软件平台,包括以3D Widgets为核心的交互框架、各功能模块以及一些实用的Widgets的设计和实现,并给出了一组应用实例。其最终目的是为医学影像处理与分析领域提供一个灵活可靠和可扩展的三维交互平台。