微地形DEM的最佳点云密度选取  

Ascertainment of Optimum Point Cloud Density for Microtopography DEM

作　　者：魏舟[1,2] 李光录[1] 任磊[1] 

机构地区：[1]西北农林科技大学资源环境学院,陕西杨凌712100 [2]陕西省土地工程建设集团,陕西西安710000

出　　处：《水土保持通报》2015年第6期155-158,163,共5页Bulletin of Soil and Water Conservation

基　　金：陕西省水保局重点科技示范项目"PP织物袋梯田筑坎技术的试验与推广"(20101003);水利部科技推广计划项目(TG1308)

摘　　要：[目的]通过对微地形DEM的最佳点云密度进行分析研究,从中选取出最佳点云密度,以实现高效、快速获取地表微地形观测结果的目的,既可降低计算成本,又能够保证观测精度。[方法]通过对多个扫描测次的点云数据进行深入的研究,确定出针对该数据最佳DEM水平分辨率为4mm,对原数据进行7种等级的压缩生成对应的DEM。采用平均误差、中误差、标准差3种最常见的DEM精度指标对生成的DEM进行精度评价分析。[结果](1)在点云压缩程度>15%时,随着点云密度的减小,平均误差基本没有变化,维持在极低的数值上;点云压缩程度<15%时,平均误差随着点云密度的减小而迅速的增大。(2)在点云压缩程度>10%时,随着点云密度的减小,标准差基本没有变化;点云压缩程度<10%时,标准差随着点云密度的减小而迅速增大。(3)在点云压缩程度>20%时,随着点云密度的减小,中误差基本没有变化,维持在极低的数值上;点云压缩程度<20%时,中误差随着点云密度的减小而迅速的增大。[结论]对比验证分析结果表明,20%的点云压缩密度为生成微地形DEM最佳的点云密度。[Objective]Through the analysis and research for optimal point cloud density mico DEM,this paper aimed to select the best point cloud density from it to achieve efficient,rapid access to micro-surface topography observations purpose.Upon which the computational cost was expected to be reduced under the precondition of observation accuracy.[Methods]Previous research of point cloud data proved that the optimal level of resolution about the data was 4mm.The raw data were compressed by 7ratings：100%,75%,50%,25%,10%,5% and 1%to generate the corresponding DEM.Three most common DEM accuracy indicators：average error,root mean square error,standard deviation were used to evaluate the accuracy of the DEM above.[Results]（1）When the point cloud compression level was set above 15%,the average error unchanged and maintained at a low value with the decrease of point cloud density,when it was compressed15%,the average error increased rapidly with the decrease of point cloud density.（2）When the compression of the point cloud was 〉10%,standard deviation was in a flat status with the decrease of the point cloud density.When it was 〈10%,the standard deviation of point cloud density decreases rapidly with the increasing of point cloud density.（3）When point cloud was compressed over 20%,with the decrease of the point cloud density,root mean square error was in the flat segmentation;when it was20%,the root mean square error rapidly increased with the decrease of point cloud density.[Conclusion]The comparison of different compression ratings verified that the optimal compression level to generate micro-topography DEM should be 20%.

关 键 词：点云密度 DEM 微地形 数据压缩 

分 类 号：P225.2[天文地球—大地测量学与测量工程] P217[天文地球—测绘科学与技术]