几何引导的主动式三维感知与交互

随着三维感知设备的发展和大规模三维数据的出现,基于三维重建与理解的视觉感知技术得到了大量关注。与此同时,智能图形逐渐改变了传统图形系统在交互中的被动角色,朝着任务引导的、感知驱动的智能体对真实或虚拟环境的主动交互发展。可以说,计算机图形学正在突破“信息表达”这一传统范畴,逐步拓展迈入“信息感知”领域;图形学的交互技术也由传统的人机交互,逐渐延伸和发展出面向智能任务的主动三维交互。其中,数据驱动三维几何分析与建模的理论和方法,特别是在线重建与分析技术,对三维感知和三维交互形成了重要支撑。本文从图形学和视觉融合的视角,结合研究案例,介绍了主动式三维感知与交互,讨论了“主动式”的特点、优势和挑战,并试图探讨这一方向的开放问题与发展趋势。     

Cognitive,social and teaching presence in a virtual world and a text chat

Using a framework of cognitive, social, and teaching presence, the nature of learning experiences in a three-dimensional virtual world environment (Second Life) and a text-chat learning environment without visuals (TeachNet) were investigated. A mixed method of code frequencies, coherence graphs, interviews, and a survey was used. The results revealed that the TeachNet debates included more cognitive presence codes that indicate higher levels of cognitive processing than in SL debates. The teams were significantly different from each other in the collaboration style for developing arguments and in the ways to use utterances associated with cognitive, social, and teaching presences, and the groups’ collaboration style became more established with more experience with the tasks. The three critical factors–tool, tasks and group cohesion–that affect cognitive, teaching, and social presence are discussed.     

Optical 3D digitizers: bringing life to the virtual world

The purpose of 3D scanning is to bridge the real world with the virtual world. A practical system would not only produce photorealistic models, but would also be inexpensive and easy to use. We took a 3D scanner developer's viewpoint to review different 3D digitizing techniques. We briefly compare existing systems and give special consideration to active optical triangulation-based scanners     

Multimodal interaction for 2D and 3D environments [virtual reality]

The allure of immersive technologies is undeniable. Unfortunately, the user's ability to interact with these environments lags behind the impressive visuals. In particular, it's difficult to navigate in unknown visual landscapes, find entities, access information and select entities using six-degrees-of-freedom (6-DOF) devices. We believe multimodal interaction-specifically speech and gesture-will make a major difference in the usability of such environments     

A multimodal virtual reality interface for 3D interaction with VTK

The object-oriented visualization Toolkit (VTK) is widely used for scientific visualization. VTK is a visualization library that provides a large number of functions for presenting three-dimensional data. Interaction with the visualized data is controlled with two-dimensional input devices, such as mouse and keyboard. Support for real three-dimensional and multimodal input is non-existent. This paper describes VR-VTK: a multimodal interface to VTK on a virtual environment. Six degree of freedom input devices are used for spatial 3D interaction. They control the 3D widgets that are used to interact with the visualized data. Head tracking is used for camera control. Pedals are used for clutching. Speech input is used for application commands and system control. To address several problems specific for spatial 3D interaction, a number of additional features, such as more complex interaction methods and enhanced depth perception, are discussed. Furthermore, the need for multimodal input to support interaction with the visualization is shown. Two existing VTK applications are ported using VR-VTK to run in a desktop virtual reality system. Informal user experiences are presented. Arjan J. F. Kok is an assistant professor at the Department of Computer Science at the Open University of the Netherlands. He studied Computer Science at the Delft University of Technology, The Netherlands. He received his Ph.D. from the same university. He worked as a Scientist for TNO (Netherlands Organization for Applied Scientific Research) and as assistant professor at the Eindhoven University of Technology before he joined the Open University. His research interests are visualization, virtual reality, and computer graphics. Robert van Liere studied Computer Science at the Delft University of Technology, the Netherlands. He received his Ph.D. with the thesis “Studies in Interactive Scientific Visualization” at the University of Amsterdam. Since 1985, he has worked at CWI, the Center for Mathematics and Computer Science in Amsterdam in which he is the head of CWI’s visualization research group. Since 2004, he holds a part-time position as full professor at the Eindhoven University of Technology. His research interests are in interactive data visualization and virtual reality. He is a member of IEEE.     

Human knowledge acquisition from 3D interaction in virtual environments

Recently,virtual environment (VE) based design and planning,which is a kind of interaction intensive computing,has shown great potential.Most users of such systems are specialists or technicians and their 3D interactions with the system embed a great deal of knowledge and skills.Thus,how to integrate human knowledge and skills into VE is a great challenge to researchers in the human computer interaction field.This paper proposes a method for acquiring user knowledge from VE.The main ideas and work include,abstracting the interactive process and formalizing the interactive semantics,as well as providing a semantic model of an interactive information repository,from which user interactive processes can be retrieved and all kinds of application logics can be established.A virtual assembly planning system is introduced as an example of a practical application of this method.Experiments show that the related models can well capture user knowledge and retrieve the interaction process.     

A framework to design 3D interaction assistance in constraints-based virtual environments

The equilibrium of complex systems often depends on a set of constraints. Thus, credible virtual reality modeling of these systems must respect these constraints, in particular for 3D interactions. In this paper, we propose a generic framework for designing assistance to 3D user interaction in constraints-based virtual environment that associates constraints, interaction tasks and assistance tools, such as virtual fixtures (VFs). This framework is applied to design assistance tools for molecular biology analysis. Evaluation shows that VF designed using our framework improve effectiveness of the manipulation task.     

Knowledge contribution in virtual communities: accounting for multiple dimensions of social presence through social identity

Integrating social presence theory and social identity theory, this study brings system design and social influence aspects together to explain their joint effects on knowledge contribution in virtual communities (VCs). Different from most prior information systems (IS) research that adopts a uni-dimensional approach and restricts social presence to be the subjective nature of media, we developed and empirically tested a model explaining the effects of multi-dimensional social presence on social identification processes and knowledge contribution. An online survey was conducted with four different VCs of interest. The results showed the difference in relative contribution of social presence dimensions on social identity as well as knowledge contribution. Both practical and theoretical implications are discussed.     

X3D虚拟场景与Java交互研究

介绍了X3D规范之一的场景访问接口（Scene Access Interface,SAI）的概念及其提供的功能服务,并介绍了X3D虚拟场景通过SAI和Java交互的两种方法的原理和实现过程：通过Script节点的方法和直接与外部程序交互的方法,并举例说明了两种交互方式。应用表明,虚拟场景通过SAI和Java的交互是一种行之有效的交互方法。通过X3D和Java的结合,开发人员能够获得Java功能强大的逻辑控制和网络通信能力以增强虚拟场景的交互性,构建功能更加强大的网络虚拟现实系统应用。     

Physical and social presence in collaborative virtual environments: Exploring age and gender differences with respect to empathy

Collaborative virtual environments (CVEs) hold the immense potential of enhancing social inclusion and social support not only in younger but especially also in older people. However, there is still considerably little knowledge about the experiences of elderly when using CVEs. Additionally, there is reason to assume that men and women regardless of their age might also differ in their perceptions of CVEs, with this difference very likely being mediated by empathic abilities. Consequently, the main objective of the current study was to evaluate gender specific experiences of social and physical presence in a group of older (N = 62) and younger adults (N = 62) with respect to possible mediating influences of empathy. Results indicate no differences in physical and social presence between the two age groups, yet they support past findings that men experience more spatial presence, involvement and a higher sense of being there than women. Also, the empathy scale Fantasy considerably mediated gender differences in spatial presence, thus strengthening the theoretical assumption of a relationship between presence and empathy. Implications and future directions of these findings are discussed in detail.     

Place presence, social presence, co-presence, and satisfaction in virtual worlds

This study investigated the relationship among three types of presences, including place presence, social presence, and co-presence in virtual worlds and their relationship with satisfaction and immersive tendencies of students. Students’ scores on a subjective questionnaire were analyzed. The results indicated that there was a significant relationship among the place presence, social presence, and co-presence. While social presence seemed to affect the satisfaction most, place and co-presence also affected students’ satisfaction in the virtual world. Moreover, immersive tendencies of the students were related to their place and co-presence but not to their social presence. Findings highlighted the important issues for the design of virtual world environments to increase presence and satisfaction of students.     

Exploring individual user differences in the 2D/3D interaction with medical image data

User-centered design is often performed without regard to individual user differences. In this paper, we report results of an empirical study aimed to evaluate whether computer experience and demographic user characteristics would have an effect on the way people interact with the visualized medical data in a 3D virtual environment using 2D and 3D input devices. We analyzed the interaction through performance data, questionnaires and observations. The results suggest that differences in gender, age and game experience have an effect on people’s behavior and task performance, as well as on subjective user preferences.     

Interaction with a desktop virtual environment: a 2D view into a 3D world

With the development of computer software and hardware in the past few years, it has been possible to produce effective training virtual environments on everyday personal computers with little expert training required for users or designers. However, the development of the equipment that enables this has brought little coinciding research on what features to include when designing these environments. Despite these increased advances in PC capabilities for desktop virtual environments (VEs), there are still limitations on the number of objects that can be programmed to be interactive, usually due to restrictions on programming time and cost. As a result, it is often left to the programmer to decide which of the objects included to increase the realism of the environment will be interactive and which aesthetic. The work presented in this paper is an experiment that aims to establish a guide for environment designers to aid effective environment interaction development by identifying key elements in a VE design.

一种基于三维建图和虚拟现实的人机交互系统

以提高人机共融水平为目的,以救援机器人为背景,提出并实现基于三维建图和虚拟现实(VR)技术的人机交互系统.在该系统中,救援机器人基于多线激光雷达和惯性测量单元(IMU)实时构建环境的三维点云地图,并将建图结果增量式地表示为3D-NDT地图,实时传输至操作台的虚拟现实系统中可视化;同时,操作人员利用虚拟现实系统的交互设备生成机器人的控制指令,控制机器人运动,构成一个完整的人在回路的人机交互系统.该系统在将机器人环境实时在虚拟现实中可视化的基础上,可以给操作人员以极强的沉浸感,有利于操作人员更直接地理解机器人所处环境.此外,该系统作为一种新的人机交互方式,为提高人与机器人的自然交互水平提供了新思路,对促进人机交互技术的发展具有重要意义.     

An evaluation of multimodal interaction techniques for 3D layout constraint solver in a desktop-based virtual environment

We propose a new approach to the 3D layout problems based on the integration of constraint programming and virtual reality interaction techniques. Our method uses an open-source constraint solver integrated in a popular 3D game engine. We designed multimodal interaction techniques for the system, based on gesture and voice input. We conducted a user study with an interactive task of laying out room furniture to compare and evaluate the mono- and multimodal interaction techniques. Results showed that voice command provided the best performance and was most preferred by participants, based on the analysis of both objective and subjective data. Results also revealed that there was no significant difference between the voice and multimodal input (voice and gesture). Our original approach opens the way to multidisciplinary theoretical work and promotes the development of high-level applications for the VR applications.     

Multimodal perception study on virtual 3D curved textures with vision and touch for interactive multimedia systems

Multimedia Tools and Applications - Understanding the multimodal rendering of 3D shapes is becoming an important research topic as multimedia and virtual reality technologies are rapidly advancing....