【作者】 张铎；

【导师】 陈定方； 李勋祥；

【作者基本信息】 武汉理工大学 ， 计算机应用技术， 2008， 硕士

【摘要】 虚拟现实技术是二十世纪末兴起的一门综合性信息及计算机应用技术,它融合了计算机图形学、三维实时动画技术、计算机接口技术、传感技术,人工智能等多个信息及计算机应用技术的分支,是人们通过计算机对复杂数据进行可视化操作与交互的一种全新方式。将虚拟现实技术应用于汽车驾驶模拟训练系统,通过计算机生成汽车行驶过程中的虚拟场景、音响效果和运动仿真,可以使操作者沉浸在虚拟驾驶环境中,根据虚拟驾驶环境提供的视觉、听觉、触觉感受,执行相应驾驶动作,体验、认识和学习现实世界中的汽车驾驶,具有节能、安全、经济等优点,而且培训不受时间、气候、场地的限制,训练效率高,培训周期短。论文结合汽车驾驶模拟器视景系统的开发,对虚拟场景中的几何建模技术、声音建模技术进行了研究。系统采用MultiGen Creator和3DS Max作为建模工具,采用VC++和OSG构建了仿真开发平台。论文对图形绘制流水线的三个阶段进行了研究;分析各种流水线的瓶颈问题,总结查找瓶颈的典型方法,对常用的图形绘制加速原理和方法进行介绍;讨论了基于GPU的图形绘制流水线和它的一些优化。针对实时视景仿真的特点,提出了场景模型建立和组织过程中应该遵循的原则。对场景建立过程进行了描述,指出了其中应该注意的问题。在场景建模过程中,运用了一系列先进的建模技术,如LOD技术、纹理映射技术、实例技术以及外部引用技术等,在实现逼真视觉效果的同时,减少系统资源耗费,提高系统的运行性能。本文重点研究了三维声效建模中的关键技术问题,包括声音的空间定位原理,声音的距离消减模型,声音的多普勒效应等;对虚拟空间声效模拟系统开发工具,如课题中使用到的OpenAL开发库,进行了必要的介绍,并深入探讨了汽车驾驶模拟器中的声效模块设计及其实现方式。在所开发的驾驶模拟器视景仿真模块中,文中讨论的建模技术和方法已经获得了成功的应用,兼顾了实时仿真中的沉浸性、实时性和交互性的要求,取得了较好的仿真效果;同时,三维空间声音加入到实时场景中,增加了驾驶者的听觉体验,加强了系统沉浸感。更多还原

【Abstract】 Virtual Reality is a comprehensive technology that rised at the end of the 20^th century. It fused many branches of information and computer application technology, such as computer graphics, 3D real-time animation, computer interface, sensor, artificial inteligence and so on. It is a new mode for people to handle and interact with complex data in a visulized way through computer. When Virtual Reality technology is applied in vehicle simulation system to create virtual scene, 3D sound and movement, operators will immerse in the virtual driving environment, as is driving a real car. According to the virtual vision, hearing and touch feelings obtained from the driving environment, operators can conceive driving reactions, experience and study how to drive in the real world. Obviously, it has a lot of advantages to adopt Virtual Reality technology in vehicle simulation system, such as low-costs, safety, no limitations for time, climate and field, and he training period is short and will be very effective too.The thesis studies the VR modeling techniques of virtual scene and 3D sound according to the development of Visual Vehicle Simulation System. Firstly, the modeling tools is determined by system requirement, and VisualC++ and OpenSceneGraph（OSG） are adopted to construct simulation platform, and then the system development blue print is put forward on the basis of them. The thesis studies the three phases of graphics rendering pipeline; analyses bottlenecks of the pipeline, and give some methods to find which bottleneck it is in a given hardware architecture. The principles of some graphic rendering accelerating methods is introduced. The pipeline based on GPU and it’s optimization methods are discussed too. Some important scene modeling and organising rules are brought forward according to real-time simulation system requirement. Scene modeling process, and issues about scene modeling that should be awared are discussed. In the modeling process, a lot of advanced modeling techniques, such as LOD, texture mapping, instance, external references are used to lessen the cost of system resources, improve system performance, and get perfect vision results. The thesis introduces 3D sound modeling thchnology, includes locatin principle of 3D sound, model of sound rolloff model according to distance, Doppler effect. The audio API used in the vehicle simulation system is discusses too. The design and implementation of audio module of the system are discussed in detail in the thesis.The VR modeling techniques discussed had been used successfully in system development, which fulfilled the "immersion", "real time" and "interactivity" requirement of system, and got effective simulation results. At the same time, 3D sound added into the graphic scene increase the immersion feel as it supplies the driver hearing sense.更多还原