【作者】 黄全品；

【导师】 王绪本；

【作者基本信息】 成都理工大学 ， 信号与信息处理， 2005， 硕士

【摘要】 地形信息的可视化在实时仿真和地理信息可视化系统中占有十分重要的地位。随着应用领域的不断深入和扩大,特别是“数字地球”提出后,对三维地形实时可视化提出了更高的要求,人们希望以更自然的方式来观察效果更逼真、范围更广的地形。 从理论上讲,场景的复杂性是无限的,而任何硬件的单位时间内的处理能力总是有限的。所以,通过研究场景复杂性和人类视觉感知规律等相关因素的内部联系,设计出与场景规模基本不相关或弱相关的快速绘制算法是必要的,也是必然的趋势。 本文在研究现有各种算法的基础上,采用四叉树分割作为LOD算法的技术流派。并对其进行了较大改进,克服了传统四叉树LOD算法的一些不足,使其能够适应地形尺寸任意大小的需要,而不必受传统四叉树算法的必须满足(2~n+1)*(2~n+1)大小的限制,同时还引入了特征值技术,使简化效率得到了较大的提升。另外还采用了地形数据分块存储和动态调度的技术,采用多线程和有预测的数据预读策略,使系统的效率基本不受地形范围大小的影响,能满足地形范围无限大的需要。最后基于这些技术,实现了一个实用的地形漫游系统。更多还原

【Abstract】 Terrain information visualization plays a very important role in real-time emulation and the visual geographical information system. With the constant deepening and the expansion of its application, especially after putting forward "digital earth", more requirements are brought forward about the real-time visualization of 3D terrain. People hope to observe more vivid and widely-ranged terrain in a more natural way.Theoretically speaking, the complexity of the scene is limitless, and the treatment capability of any hardware in time of unit is always limited. Therefore, by investigating the internal relationship between the scene complexity and the relevant factors, such as laws of human visual perception, it is necessary to work out the fast drawing algorithms generally irrelevant or weakly relevant to the scale of the scene, which is the inevitable trend as well.This thesis adopts Quadtree segmentation as technological school of LOD algorithm on the basis of studying various kinds of existing algorithms, and the thesis has greatly improved it and has overcome the insufficiency of traditional LOD algorithms and can make it meet the need of random terrain size without being restricted by the traditional Quadtree algorithms which must meet the size of (2~n+1)*(2~n+1), and at the same time introduces eigenvalue technology and greatly increases simplification efficiency. Additionally, the thesis has also introduced the technology of block storage and dynamic scheduling of the terrain data, and adopts multithreading and predictive pre-reading data strategy so as to make the systematic efficiency basically free of the size of terrain range and meet the infinitely great need of terrain range. Finally, on the basis of the technology, a practical system of roaming is realized.更多还原