基于四叉树孤立分割和屏幕误差的地形LOD算法  

LOD Algorithm of Terrain Based on Conservative Screen Error and Isolated Division of Quad-tree

作　　者：张俊峰[1] 姚志宏[1] 

机构地区：[1]华北水利水电学院资源与环境学院,河南郑州450011

出　　处：《西南交通大学学报》2013年第4期666-671,677,共7页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金资助项目(40971244);华北水利水电学院高层次人才科研启动项目(201206)的资助

摘　　要：为解决静态和动态细节层次模型存在的数据冗余度大、精度判断标准单一和层次切换跳跃感强的问题,提出了基于四叉树孤立分割和屏幕误差的地形LOD(level of detail)算法.采用该算法,针对于规则格网,通过地形瓦片分割和数据预处理减少实时阶段计算量,利用四叉树孤立分割消除结点间依赖关系,并构建保守性屏幕误差评价标准以弱化视觉跳跃感,最后采用添加拆分点和高程平均值法消除相邻瓦片和结点间裂隙.实验结果表明:该算法能较好解决常规方法中存在的问题;可满足大规模地形实时三维显示的要求;实时显示计算量小,帧速可保持在0.03 s以内.In order to deal with the problems of enormous data redundancy, single evaluation standard of precision and strong scene of jumping at level switch in static and dynamic level of detail models, an algorithm for regular real-time expression square grid was proposed. This algorithm reduces the complex computation in through terrain tile partition and data pre-progressing, and eliminates dependencies between nodes using isolated division of quad-tree. By building up an evaluation standard based on conservative screen error, jumping feeling is weakened greatly. Finally, cracks between adjacent tiles and nodes are eliminated easily by adding split points and averaging elevation value. Experiment results show that this algorithm has abilities to overcome the shortcoming of the conventional methods and meets the requirements of 3D real-time expression of Furthermore, amount of calculation for real-time display is small and frame speed large-scale terrain. is within O. 03 s.

关 键 词：虚拟现实 四叉树 屏幕误差 裂隙 细节层次模型 

分 类 号：P208[天文地球—地图制图学与地理信息工程]