基于OP通道的远程交互操作流量分析

基于OP通道的远程交互操作在减少网络传输流量方面有很大的优越性。文章介绍基于OP通道的人人交互系统的模型、原理及应用程序实例五子棋游戏;给出网络流量的规定方法,分别对OP通道方式及传统的共享协作方式的网络传输流量进行定量测定;最后对OP信息流量进行详细的分析,并与传统的共享协作方式进行对比。     

实时交互的带浮雕纹理的三维模型构建方法

为了快速生成带浮雕纹理的三维模型,提出一种实时交互的浮雕纹理模型构建方法。方法分两步：第一步,将生成浮雕的源模型或图像转换为初始深度图,并进一步转换为梯度图,再通过梯度域的压缩、过滤,求解线性方程重建出整体连续的浮雕深度图;第二步,借助基于网格求交的浮雕纹理映射算法将浮雕深度图贴在目标模型表面,并通过移动、旋转、缩放等操作实时在目标模型三维空间上修改浮雕效果,最终重建目标模型网格,生成浮雕纹理模型。实验表明,所提方法可快速实现在一个目标模型上生成凹浮雕、凸浮雕、多浮雕等效果,所得模型无需经过其他处理,可直接应用于3D打印,打印效果较好。     

Demonstrating the Cognitive Plausibility of Interactive System Specifications

Much of the behaviour of an interactive system is determined by its user population. This paper describes how assumptions about the user can be brought into system models in order to reason about their behaviour. We describe a system model containing reasonable assumptions about the user as being ‘cognitively plausible’. Before asserting the plausibility of a model however we must first be able to make the assumptions made in that model inspectable. There is a tension between the inspectability of user assumptions and the tractability of models; inspectable models tend to not be very tractable and vice versa. We describe how we can get round this tension, by deriving tractable models from explicit user assumptions. The resulting models may not of themselves be very inspectable to human-factors workers, but the process by which they are derived is inspectable. Hence we claim that we can have both tractability and inspectability. We exemplify our claims using a simple cognitive model and ‘Meeting Maker’, an interactive electronic diary system. Received March 2000 / Accepted in revised form July 2000     

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.     

A system for desktop conceptual 3D design

In the traditional design process for a 3D environment, people usually depict a rough prototype to verify their ideas, and iteratively modify its configuration until they are satisfied with the general layout. In this activity, one of the main operations is the rearrangement of single and composite parts of a scene. With current desktop virtual reality (VR) systems, the selection and manipulation of arbitrary objects in 3D is still difficult. In this work, we present new and efficient techniques that allow even novice users to perform meaningful rearrangement tasks with traditional input devices. The results of our work show that the presented techniques can be mastered quickly and enable users to perform complex tasks on composite objects. Moreover, the system is easy to learn, supports creativity, and is fun to use.     

运输态势交互模型及其CSP形式化研究

人机交互（HCI）技术的迅猛发展为自然高效和谐的HCI提供了基础支持,随着HCI行为的日益复杂,如何验证其过程的正确性成为研究HCI领域的重心。根据双手触摸光感应触控平台在运输态势的HCI,提出一种体现用户操作与设备响应相结合的运输态势HCI模型,该模型采用通信顺序进程形式化描述,并结合甘特图验证其单用户操作的逻辑正确性和稳定性。     

人眼立体视觉空间与虚拟三维空间的几何映射关系理论分析

虚拟三维空间是现实世界的数字化三维空间,而人眼立体视觉空间则是人眼视觉系统对于现实世界或虚拟世界所形成的三维立体构象。传统上人眼直接观察现实世界,确立了人眼立体视觉空间与现实世界之间的几何对应关系。而人眼立体视觉空间与虚拟三维空间是否也存在对应的几何关系？以人眼立体视觉和虚拟三维场景为研究对象,根据双目视差原理,论述了人眼立体视觉的几何模型及视觉三维模型的表示形式。通过分析虚拟空间三维点元、屏幕视差及网膜视差等三者之间的内在几何关系,利用矩阵代数建立了虚拟空间与视觉空间之间的几何映射关系。这一映射关系表明视觉三维模型与虚拟三维模型之间存在一一对应关系,也反映了人眼视觉系统在虚拟空间中的可测量性质。本文创新性之处在于得到了视觉三维模型的完整表示,突破了传统上立体显示的定性感知,提供了定量分析的基础。这一工作对于在虚拟空间中的立体体验、虚拟交互以及立体测量等实践活动具有一定理论参考价值。     

A semi-interactive panorama based 3D reconstruction framework for indoor scenes

We present a semi-interactive method for 3D reconstruction specialized for indoor scenes which combines computer vision techniques with efficient interaction. We use panoramas, popularly used for visualization of indoor scenes, but clearly not able to show depth, for their great field of view, as the starting point. Exploiting user defined knowledge, in term of a rough sketch of orthogonality and parallelism in scenes, we design smart interaction techniques to semi-automatically reconstruct a scene from coarse to fine level. The framework is flexible and efficient. Users can build a coarse walls-and-floor textured model in five mouse clicks, or a detailed model showing all furniture in a couple of minutes interaction. We show results of reconstruction on four different scenes. The accuracy of the reconstructed models is quite high, around 1% error at full room scale. Thus, our framework is a good choice for applications requiring accuracy as well as application requiring a 3D impression of the scene.     

从视频中恢复三维人脸的实时方法

三维人脸恢复是视觉交互的一个难点问题,提出了一种从视频中实时恢复三维人脸的新方法.该方法利用主动形状模型进行人脸特征点提取和跟踪,确保了三维形状恢复和特征跟踪的有效性和一致性;采用非刚体形状和运动估计方法构建三维形变基,有效地适应人脸形状变化的多样性;采用非线性优化算法估算人脸姿态和三维形变基参数,实现了三维人脸形状和姿态的实时恢复.实验结果表明,该方法不仅能从视频中实时恢复三维人脸模型,而且可有效跟踪人脸各种姿态的变化.     

Generating 3D interaction techniques by identifying and breaking assumptions

Researchers have created 3D interaction techniques for immersive virtual worlds, but existing techniques represent just part of the design space. While exploring other parts of the design space might yield more effective techniques, conducting that exploration is difficult and time-consuming. Analyzing the particular task, user, and hardware characteristics for any given problem is straightforward, but only suggests the shape of a potential technique; generating the technique itself still requires a creative breakthrough. We propose extending existing approaches to generating 3D interaction techniques by focusing more explicitly on identifying and breaking assumptions about the real world to inspire potential technique ideas. We describe our approach, suggest an initial list of assumptions to consider, and present a case study of applying the process to create a technique for navigation with visible landmarks and place representations.     

一种用于虚拟校园漫游的三维引擎的研究

在对三维引擎技术OSG进行分析和研究的基础上,提出并实现了一种用于虚拟校园漫游的三维引擎系统,该系统使用OSG所提供的类和接口,实现了虚拟校园场景的渲染以及漫游的交互控制功能,同时在引擎中添加了语音介绍功能,丰富了浏览者的视听感受。实践证明,该引擎具有良好的移植性与通用性,为虚拟校园漫游技术向虚拟校园系统和虚拟学习平台方面的迁移提供了支持。     

Evaluating autostereoscopic 3D baseball games using signal detection theory and receiver operating characteristic space

This study investigates the effects of display technique (2D, autostereoscopic 3D), ball speed (138, 140 km/h), and operation time (5, 10, 15 min) on the four outcomes of signal detection theory (SDT) (i.e., hit, miss, false alarm, correct rejection), β, d’, receiver operating characteristic (ROC) space, Simulator Sickness Questionnaire (SSQ), and the iGroup Presence Questionnaire (IPQ). The results indicated that the display technique was significant on the hit rate, SSQ, and IPQ, where a higher hit rate, visual fatigue, and IPQ were found in the 3D technique. The results also showed that the ball speed was significant on the miss rate and d’, where a low miss rate and high d’ were found in the higher speed of 138 km/h. The results further demonstrated that the operation time was significant on the false alarm rate, correct rejection rate, d’, SSQ, and IPQ, with a long operation time being associated with a better performance for every variable, except the SSQ.Relevance to industryFrom the results obtained regarding the ROC space, this study found that the possibility of participants’ misjudgements was low, and the accuracy of this research is considered reliable. The results of this study could serve as a reference for N3DS and game manufacturers in designing future products.     

3D Z-string: A new knowledge structure to represent spatio-temporal relations between objects in a video

In this paper, we propose a new knowledge structure called 3D Z-string, extended from the 2D Z-string, to represent the spatial and temporal relations between objects in a video and to keep track of the motions and size changes of the objects. Since there are no cuttings between objects in the 3D Z-string, the integrity of objects is preserved. The string generation and video reconstruction algorithms for the 3D Z-string representation of video objects are also developed. The string generated by the string generation algorithm is unique for a given video and the video reconstructed from a given 3D Z-string is unique too. The experimental results show that the 3D Z-string is more compact and efficient than the 3D C-string in terms of storage space and execution time.     

The influence of polarized 3D display on autonomic nervous activities

The spectral analysis of Heart Rate Variability (HRV) can be used for assessing the autonomic nervous activities and further the physiological conditions of subjects. This study intended to explore whether or not people would have fatigue, faintness and other kinds of uncomfortable conditions after watching a 3D film by using HRV measures as the objective physiological indices, in addition to other subjective physiological indices.Twenty men aged 22 ± 2 experienced watching 3D films and 2D films and were served as the controls of themselves. As the controls, the subjects had to rest at the same place. All subjects were are randomized for taking different experiences, and the electrocardiographic (ECG) signals were recorded during the whole process. The researchers could obtain the indices of the autonomic nervous activities before and after experiencing 3D and 2D movies with the help of spectral HRV analyses, along with the objective physiological information. The subjects were requested to fill out the questionnaire for the subjective feelings after the movie experiences.It was found that the subjects’ high-frequency power (HFP) representing parasympathetic nervous activities decreases after watching a 3D film. The sympathetic and parasympathetic nerve activities before and after watching a 2D film were not significantly different. The subjects complained that they felt dizzy, had headaches, and got visual fatigue while watching a 3D film.This study found that the subjects’ parasympathetic nerve activities were reduced after watching a 3D film, indicating that watching a 3D film would make people uncomfortable and tired. This result was the same as that of the questionnaire. Thus, HRV analyses could be an objective physiological index for discomfort as viewing 3D films.     

基于Web的三维交互系统的设计与实现

介绍利用Java3D技术,构建一个基于Web的三维交互系统,实现与用户进行交互,并给出了部分实现细节。     

基于Web的三维交互系统的设计与实现

介绍利用Java3D技术,构建一个基于Web的三维交互系统,实现与用户进行交互,并给出了部分实现细节。     

An efficient method for fully automatic 3D digitization of unknown objects

Our goal is to develop a complete and automatic scanning strategy with minimum prior information about the object shape. We aim to establish a methodology for the automation of the 3D digitization process. The paper presents a novel approach to determine the Next Best View (NBV) for an efficient reconstruction of highly accurate 3D models. Our method is based on the classification of the acquired surfaces into Well Visible and Barely Visible combined with a best view selection algorithm based on mean shift, which avoids unreachable positions. Our approach is applicable to all kinds of range sensors. To prove the efficiency and the robustness of our method, test objects are first scanned manually by experts in 3D digitization from the VECTEO company. The comparison of results between manual and automatic scanning shows that our method is very efficient and faster than trained experts. The 3D models of the different objects are obtained with a strongly reduced number of acquisitions while moving efficiently the ranging device. The obtained results prove the effectiveness and the versatility of our 3D reconstruction approach for industrial applications.     

Parallel decoupled terminal-edge bisection method for 3D mesh generation

We present a practical and stable algorithm for the parallel refinement of tetrahedral meshes. The algorithm is based on the refinement of terminal-edges and associated terminal stars. A terminal-edge is a special edge in the mesh which is the longest edge of every element that shares such an edge, while the elements that share a terminal-edge form a terminal star. We prove that the algorithm is inherently decoupled and thus scalable. Our experimental data show that we have a stable implementation able to deal with hundreds of millions of tetrahedra and whose speed is in between one and two order of magnitude higher from the method and implementation we presented (Rivara et al., Proceedings 13th international meshing roundtable, 2004).Maria-Cecilia Rivara and Carlo Calderon's work was partially supported by Fondecyt 1040713.Andriy Fedorov’s work is supported in part by ITR #ACI-0085969, and NGS #ANI-0203974.Nikos Chrisochoides’s work is supported in part by NSF Career Award #CCR-0049086, ITR #ACI-0085969, NGS #ANI-0203974, and ITR #CNS-0312980.     

基于HLA的三维虚拟环境

在分析了HLA体系结构及运行支撑框架(RTI)的基础上,提出了一个基于HLA的三维虚拟环境的设计和实现方案。阐明了此类系统的设计方法,着重分析了系统实现中涉及的仿真对象模型、信息交互机制、程序控制逻辑、坐标转换、实时性等关键技术问题和解决方案。最后在使用WindowsNT4.0的PIII高档微机平台上实现了该系统。实验表明,在综合分布交互系统SSS中,该分系统可实现与其它分系统的正确交互,场景刷新速率最高可达20帧/秒,基本满足实时性要求。     

3D street art illusions: embedding chalk stylized rendering of 3D objects into a pavement photo

Three dimensional street art illusions have become more popular in recent years. Many of them are drawn on pavement such as streets, sidewalks, and town squares. It is often known as 3D chalk art, where a 2D artwork is drawn on the street, giving the viewer a 3D optical illusion from a certain perspective. This paper supplies chalk stylized renderings for 3D models and synthesizes 3D objects into a realistic photograph. Users can input one photo for the 3D model. First, a camera position is achieved by using a camera calibration algorithm. Second, a chalk stylized rendering was applied to create an artistic image of the 3D models using the same camera position. Then, the non‐photorealistic rendering image is composited into a source photograph using a modified Poisson approach. All of the enhanced pavement texture details are also blended into the object's image. The major contribution of this paper is providing a user to create any interesting and attractive 3D illusionary art without physically drawing pictures on the pavement. Finally, the proposed method is demonstrated using various experimental 3D street art illusion images. Copyright © 2014 John Wiley & Sons, Ltd.