针对应急灾情态势显示系统数据量庞大与数据更新迅速而造成模型数据量大、计算时间久的问题,提出了一种多分辨率三维地形建模方法。目的是使地形模型本身既满足视觉逼真度,又可以降低调用模型所耗的计算时间。为此,采用构建三维模型的分层递阶模型(hierarchicalmodel,HM)的方法进行多分辨率建模。将用于遥感地物识别的基于尺度空间的层次聚类算法(scale-spacebasedhierarchicalclusteringalgorithm,SSHC)引入HM的构造过程,依据HM设置三维模型的各组节点,并与基于多边形优化的多细节层次(1evelsofdetail,LOD)建模技术相结合构建大场景的三维地形模型.实验证明该方法可以实现符合视觉原理的由宏观到微观显示的同时降低地形模型的计算量,满足应急灾情态势显示的需要.
Aimed at emergency disaster situation display system (EDSDS), an approach to create 3D terrain models of multi-resolution with the purpose of rapid switching between different levels of information granules was presented. According to the characteristics and requirements of EDSDS, the multi-resolution approach was proposed to solve the time-consuming problem caused by transferring 3D terrain models into virtual scenes during switching different levels of information granules. Firstly, the hierarchical model (HM) is constructed through the scale- space based hierarchical clustering algorithm (SSHC) on the basis of remote sensing images. Secondly, accordance with the HM 3D terrain models were established following the OpenFlight data structure. Lastly, the 3D terrain models were optimized by levels of detail (LOD) techniques. Experimental results demonstrate that this proposed optimization algorithm accelerates the tempo of transferring 3D terrain models, especially the process from far and near. And this rapidity provides strong support for emergencies.