基于计算机图形处理器的海底三维地形可视化

发布时间：2018-11-12 18:11

【摘要】：随着信息技术的发展，地形可视化技术被应用于多种领域当中，其中海底地形可视化更加是这项技术的热点问题。由于海底环境的复杂多变，海底的情况在现今阶段对于人们来说还是一个神秘的地方，所以研究海底地形是近几年来的研究重点也是一个难点。本文是以VC++6.0为平台，利用四叉树LOD视点相关技术进行插值构造格网，用OpenGL三维编程接口进行坐标变换，视景裁剪出合适的视口大小，再将Cg Shader嵌入到三维图形程序中对地形渲染，以达到调用计算机中图形处理器对图形的处理，，利用其强大的并行处理能力，实现解放CPU加快计算速度的目的。论文采用真实地形数据进行DEM建模，详尽的介绍了关于DEM文件的操作，包括数据结构的定义、生成及读取。在绘制地形的方法中采用四叉树LOD算法对地形进行建模，构造连续实时动态的格网，详细的讲述了四叉树数据结构的具体构建过程及如何消除裂缝，从而实现了地形根据不同的视点距离产生不同的细节层次效果。本文围绕基于GPU技术这一主题，渲染程序在图形处理器(GPU)上执行，利用Cg高级着色语言添加光照、纹理渲染及环境映射，增强了地形的真实感。并对运用GPU和CPU并行处理与只运用CPU进行处理的性能进行了比较，从而论证了GPU在图形渲染方面的强大优势。最终实现的地形可视化系统能逼真的显示海底实时地形并进行人机交互，可进行网格与渲染模式的切换及海底地形漫游。
[Abstract]:With the development of information technology, terrain visualization technology has been applied in many fields, among which submarine terrain visualization is a hot issue. Because of the complexity of the sea floor environment, the seabed situation is still a mysterious place for people at the present stage, so the study of submarine topography is also a difficult point in recent years. This paper takes VC 6.0 as the platform, uses quadtree LOD viewpoint correlation technology to interpolate to construct the grid, uses the OpenGL three-dimensional programming interface to carry on the coordinate transformation, the scene cuts out the suitable view port size. Then the Cg Shader is embedded in the 3D graphics program to render the terrain, so that the graphics processing in the computer can be called, and the powerful parallel processing ability can be used to realize the purpose of freeing CPU to speed up the calculation. In this paper, real terrain data is used to model DEM, and the operation of DEM file is introduced in detail, including the definition, generation and reading of data structure. In the method of terrain rendering, quadtree LOD algorithm is used to model terrain, and a continuous real-time dynamic grid is constructed. The concrete construction process of quadtree data structure and how to eliminate cracks are described in detail. Thus, the terrain can produce different level of detail effect according to different view distance. In this paper, based on the theme of GPU technology, the rendering program is executed on the graphics processor (GPU), and the illumination, texture rendering and environment mapping are added by using the Cg advanced coloring language, which enhances the reality of the terrain. The performance of parallel processing with GPU and CPU is compared with that of CPU only, and the powerful advantages of GPU in graphics rendering are demonstrated. The final terrain visualization system can realistically display the real-time terrain of the sea floor and carry out human-computer interaction. It can switch the grid and render mode and roam the seabed terrain.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP391.41;P229.1

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