一种新的ROAM算法及其在地形建模中的应用  

A New ROAM Algorithm and Its Application in Terrain Modeling

作　　者：李朝奎 王宁[1,2] 吴柏燕 方军[1,2] 杨文涛 褚楠[1,2] LI Chaokui;WANG Ning;WU Baiyan;FANG Jun;YANG Wentao;CHU Nan(National-Local Joint Engineering Laboratory of Geo-Spatial Information Technology,Hunan University of Science and Technology,Xiangtan 411201,China;Hunan Province Engineering Laboratory of Geospatial Information,Hunan University of Science and technology,Xiangtan 411201,China)

机构地区：[1]湖南科技大学地理空间信息技术国家地方联合工程实验室,湘潭411201 [2]湖南科技大学地理空间信息湖南省工程实验室,湘潭411201

出　　处：《地球信息科学学报》2018年第9期1209-1215,共7页Journal of Geo-information Science

基　　金：国家自然科学基金项目(41571374);国家重点研发计划项目(2017YFB0503802);湖南省教育厅重点项目(16A070);湖南省自然科学基金湘潭联合基金(2017JJ4037);特殊环境道路工程湖南省重点实验室开放基金项目(kfj150502)~~

摘　　要：地形建模是数字地形分析的重要基础工作。实时优化适应性网格算法(ROAM算法)是目前常用的地形建模方法。但ROAM算法应用于地形可视化实时渲染时要求原始数据为正方形,且渲染后常有裂缝产生,因而该法在地形建模实践中受到较大的限制。针对ROAM算法存在的上述不足,本文提出了基于内接正方形插值方法的改进ROAM算法。通过将多边形分割为一个内接正方形和多个边缘多边形,用多边形的一个顶点依次与其他顶点相连,使边缘多边形分割为多个三角形,并根据边缘三角形面积大小,确定是否对边缘多边形进行继续分割,由此解决数据源限定为正方形的问题,利用添加拆分点的方法消除地形渲染产生的裂缝。采用不规则地形的灰度图作为高程数据源进行地形模拟实验,结果表明:改进后的ROAM算法能够消除裂缝,且对数据源无约束性要求,降低了算法复杂度,提高了整体可视化性能,能够满足地形实时动态显示的要求。Terrain modeling is important in the digital terrain analysis. Real-time adaptive mesh algorithm （ROAM algorithm） is a commonly used terrain modeling method. However, applying ROAM algorithm to real- time rendering of terrain visualization requires the original data to be square and cracks often occur after rendering, so this method is greatly restricted in the practice of terrain modeling. Aiming at the above disadvantages of the ROAM algorithm, an improved ROAM algorithm based on the interpolation of inner square is proposed in this paper. The polygon is divided into an inner square and multiple edge polygons, then the vertexes of these polygons are connected sequentially to divide the polygons into multiple triangles, and according to the size of the edge triangles, whether to continue segmentation of the edge polygon is determined. Thus, the problem of limiting the data source to a square is solved, and the crack generated by the terrain rendering is eliminated by adding split points. Using the irregular terrain gray image as the elevation data for terrain simulation experiment, the results show that the improved levenshtein distance algorithm can eliminate the crack with no binding requirements for data source, reduce the algorithm complexity and improve the overall visual performance. It can meet the requirements of terrain real-time dynamic display.

关 键 词：地形建模 ROAM算法 内接正方形插值 算法改进 裂隙 

分 类 号：TP301.6[自动化与计算机技术—计算机系统结构]