海量低空机载LiDAR点云的地形断面快速生成算法
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摘要
针对现有算法二次插值造成的精度损失问题,结合新兴的低空机载LiDAR技术,提出了一套高精度地形断面快速、自动生成算法。该算法通过内存映射和断面线缓冲区分析,从海量点云数据中快速提取构TIN点集;优化了逐点插入法,实现局部Delaunay三角网的快速构建;根据三角网拓扑关系,实现断面线与TIN的快速求交,生成并优化地形断面图。实验结果表明,算法克服了海量数据处理时计算机内存不足的瓶颈问题,并有效避免了二次插值造成的精度损失,且运行高效。
In view of the accuracy loss problem caused by twice interpolation of the existing methods,a fast and automatic high-precision terrain profile generation algorithm based on newly-emerging low-altitude airborne LiDAR technique is proposed,which consists of the following steps. Firstly,TIN point set is extracted from the massive point cloud data quickly by memory mapping and section line buffer analysis. Then,the incremental insertion algorithm is optimized to realize the fast construction of the local Delaunay triangulation. Lastly,the terrain profile is generated and optimized by section line and TIN quick intersection according to topological relations between the triangles. The experimental results show that the algorithm not only overcomes the bottleneck problem of insufficient computer memory in massive data processing,but also effectively avoids the precision loss caused by twice interpolation and runs efficiently.
In view of the accuracy loss problem caused by twice interpolation of the existing methods,a fast and automatic high-precision terrain profile generation algorithm based on newly-emerging low-altitude airborne LiDAR technique is proposed,which consists of the following steps. Firstly,TIN point set is extracted from the massive point cloud data quickly by memory mapping and section line buffer analysis. Then,the incremental insertion algorithm is optimized to realize the fast construction of the local Delaunay triangulation. Lastly,the terrain profile is generated and optimized by section line and TIN quick intersection according to topological relations between the triangles. The experimental results show that the algorithm not only overcomes the bottleneck problem of insufficient computer memory in massive data processing,but also effectively avoids the precision loss caused by twice interpolation and runs efficiently.
引文
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[4]董保根,张良,张钢,等.利用Li DAR点云提取有地形约束的光滑海岸线[J].测绘科学技术学报,2012,29(2):113-117.DONG B G,ZHANG L,ZHANG G,et al.Smooth shoreline extraction with topographic constraints using Li DAR point clouds[J].Journal of Geomatics Science and Technology,2012,29(2):113-117.
[5]石德斌.轻型Lidar设备在铁路工程勘测中的应用分析[J].铁道工程学报,2016(8):30-33.SHI D B.Application analysis of light-Lidar in the railway engineering survey[J].Journal of Railway Engineering Society,2016(8):30-33.
[6]余杰,吕品,郑昌文.Delaunay三角网构建方法比较研究[J].中国图象图形学报,2010,15(8):1158-1164.YU J,LYU P,ZHENG C W.A comparative research on methods of Delaunay triangulation[J].Journal of Image and Graphics,2010,15(8):1158-1164.
[7]李晶晶,范大昭,耿弘毅,等.城市点云的区域生长三角网构建方法[J].测绘科学技术学报,2016,33(1):65-70.LI J J,FAN D Z,GENG H Y,et al.Triangular mesh construction for city points based on region growing[J].Journal of Geomatics Science and Technology,2016,33(1):65-70.
[8]GREEN P J,SIBSON R.Computing dirichlet tesselations in the plane[J].The Computer Journal,1978,21(2):168-173.
[9]SHAMOS M I,HOEY D.Closest-point problems[C]∥Proceedings of the 16th Annual Symposium on the Foundations of Computer Science.Washington DC,USA,1975:151-162.
[10]LAWSON C L.Software for C1 surface interpolation[M].New York:Academic Press,1977:161-194.
[11]刘学军,符锌砂,赵建三.三角网数字地面模型快速构建算法研究[J].中国公路学报,2000,13(2):31-36.LIU X J,FU X S,ZHAO J S.A study of algorithm for fast constructing triangulation irregular net(TIN)[J].China Journal of Highway and Transport,2000,13(2):31-36.
[12]LEE D T,SCHACHTER B J.Two algorithms for constructing a delaunay triangulation[J].International Journal of Computer and Information Science,1980,9(3):219-242.