【作者】 王臻；

【导师】 胡敏；

【作者基本信息】 合肥工业大学 ， 计算机应用技术， 2008， 硕士

【摘要】 三维真实感地形是可视化系统及虚拟仿真的基本组成部分，随着未来可视化和仿真技术快速发展，具有真实自然视觉效果的三维地形生成和建模技术显得越来越重要。同时随着测绘技术的提高，获得大规模的地形数据已不是难题。然而，由于图形显示硬件及传输线路的限制又导致我们不能很好的实时显示和处理这些庞大的数据。因此，如何简化地形显示，加快绘制速度成为国内外研究的热点。目前在三维地形的建模和简化领域，使用最多的是利用LOD算法生成地形的连续多分辨率模型，进而完成地形的实时多分辨率显示。本文首先介绍了三维地形建模及简化技术的研究目的、内容及应用领域和发展前景，随后介绍多分辨率LOD地形及分形地形建模技术的相关理论和研究技术。在深入研究地形建模和简化的典型算法的基础上，提出基于层次细节简化和分形的真实感地形生成方法。该方法相对于用DEM数据构造地形，所用数据量减少，能实时生成满足一定需要的真实感场景。针对以往简化算法中单向裂缝消除算法效率低的问题，提出一种新的裂缝消除算法：双向裂缝消除算法，实验结果证明了该算法的正确性和有效性。更多还原

【Abstract】 Realistic 3D terrain is one of the important components of virtual reality system and real time emulation. With the quickly development of virtual reality and emulation, the generation and modeling of high realistic terrain becomes more and more important. At the same time, with the development of mapping technology, it is easy to get massive terrain data now. But because of the limitation of graphics hardware and transport circuitry, we can’t deal with these data in real-time. So how to simply the terrain efficiently and quicken the protract speed become the research hotspots broad and home. Recently the most often used way in this field is to generate multi-resolution terrains with level of detail (LOD) technology.Firstly, this dissertation presents the purpose, the background, the application and the prospect of terrain generation and simplification. Secondly, the dissertation gives an introduction of LOD and fractal theory. Thirdly, based on the study of classical modeling algorism, the dissertation puts forward a new method to simulate complex terrain using fractal and LOD. It uses much less data than DEM but gives a good result. Finally, thinking of the low efficiency of the old cracks elimination way, a new bi-directional method is given which can simplify the terrain efficiently and increase the rendering speed.更多还原