【作者】 陈阵；

【导师】 贾庆轩； 孙汉旭；

【作者基本信息】 北京邮电大学 ， 机械设计及理论， 2008， 硕士

【摘要】 对多投影面沉浸式虚拟环境的研究一直是虚拟现实领域一个重要的研究方向。但是,由于此类系统的构建大多基于专业图形工作站和高端投影设备,高昂的成本使其应用范围受到很大限制。近年来,随着PC性能的快速发展,构建以PC集群驱动的多投影面沉浸式虚拟环境成为新的研究热点。但是,现有的并行绘制系统多应用于可视化仿真,并不适于虚拟设计制造等动态变化的交互式应用,这也影响了虚拟现实技术在制造业的发展和推广。本文从虚拟设计的特点和需求出发,对分布式并行绘制系统中LOD(Level of detail)及渐进式传输技术进行了研究。论文对面向虚拟设计的多投影面沉浸式虚拟环境的软件体系结构、并行绘制系统中LOD技术和渐进式传输等问题进行了深入的研究,论文的主要研究工作如下:首先,在分析比较了国内外虚拟环境系统研究基础之上,针对虚拟设计的特点,研究了面向虚拟设计的虚拟环境体系结构,并对Client-Server和Master-Slave两种常见的分布式并行绘制体系结构进行了比较,重点研究了北京邮电大学的五通道环幕立体显示系统,并给出了基于环幕的并行绘制系统设计方案。其次,在研究了二次误差度量模型简化算法基础上,提出了一种基于协方差度量的改进算法,针对两种算法设计开发了相应的三维模型简化软件,并对模型简化的结果进行了分析比较。同时,研究了LOD结构分类、动态管理及模型间平滑过渡等技术。再次,对三维模型渐进式传输技术进行了研究,给出了渐进网格的定义及实现步骤,重点研究了Client-Server并行绘制体系结构,提出了一种基于Client-Server模型的渐进式传输方案,在基于联网PC的分布式并行绘制系统中实现模型的渐近传输并进行实时绘制。在五通道环幕立体显示系统上,基于Master-Slave和Client-Server模型,搭建了面向虚拟设计的分布式并行绘制平台。基于Master-Slave,结合LOD技术,开发了虚拟装配应用实例;基于Client-Server,利用渐进式传输技术,开发了虚拟设计应用环境。最后对全文进行了总结和展望。更多还原

【Abstract】 The research of Multi-Projector immersive virtual environment of virtual reality has been an important area. However, because such systems are based on the construction of professional graphics workstations and high-end projection equipment, the high cost makes its scope of application are largely limited. In recent years, with the rapid development of PC’s performance, to establish a PC Cluster driven Multi-Projector immersive virtual environment as a hot spot of study. However, the existing parallel rendering systems are used in visual simulation, but unsuitable for dynamic interactive applications like virtual design and manufacturing, which has also affected the virtual reality technology in the development and promotion of the manufacturing sector.Combining the features and needs of virtual design, bring forward to the research on LOD and progressive transmission technology of parallel rendering system for virtual design. The paper on virtual design-oriented multi-Projector immersive virtual environment software architecture, Parallel Rendering System LOD technology and progressive transmission issues an in-depth study, the main research work are as follows:Firstly, based on the analysis and comparison of the research of virtual environment systems at home and abroad, in view of the characteristics of virtual design, researched of virtual design-oriented virtual environment architecture, and compared Client-Server and Master-Slave two common distributed parallel rendering architecture, focused on the five-channel cylinder screen stereoscopic display system of the Beijing University of Posts and Telecommunications, and gave the parallel rendering system design scheme based on cylinder screen.Secondly, based on the research of quadric error metric model simplification algorithm, put forward the covariance-based improved algorithm, for two algorithms designed and developed relevant model simplification software, and the results of the model simplification were compared. In addition, we studied the classification, dynamic management of LOD model and smooth transition techniques between models.Thirdly, raised the research of the model progressive transmission technology, given the progressive meshes’ definition and realization, focus on the research of Client-Server parallel rendering architecture, based on Client-Server, and presented a scheme of progressive transmission. Based on distributed parallel rendering system of PC Cluster, implemented the progressive transmission of 3D model and real-time rendering.On the five-channel cylinder screen stereoscopic display system, based on Master-Slave and Client-Server, we constructed virtual design-oriented distributed parallel rendering platform. Based on Master-Slave, combining LOD technology, developed the virtual assembly application instance. Based on Client-Server, take use of progressive transmission technology, developed a virtual design application platform.Finally, make a summary and outlook for this paper.更多还原