优化EMD的卫星激光测高数据地面点直接提取算法  

A Ground Point Extraction Algorithm Based on Optimized EMD with Satellite Laser Altimetry Data

作　　者：邢帅[1] 张国平 徐青[1] 张鑫磊 李鹏程[1] 陈坤 吴立亭 XING Shuai;ZHANG Guoping;XU Qing;ZHANG Xinlei;LI Pengcheng;CHEN Kun;WU Liting(Information Engineering University,Zhengzhou 450001,China)

机构地区：[1]信息工程大学,河南郑州450001

出　　处：《测绘科学技术学报》2020年第3期294-300,共7页Journal of Geomatics Science and Technology

基　　金：国家自然科学基金项目(41876105;41371436)。

摘　　要：ICESat-2卫星是全球首颗光子计数激光雷达卫星,其探测性能达到了一个全新的高度。探测数据的处理是决定其最终产品质量的关键因素,而地面点提取是其中的一项重要工作。目前ATLAS激光测高光子数据普遍采用先滤波再分类的方法进行地面点提取,存在着受全局阈值影响大、提取地面点数量少的问题,提出一种基于优化EMD的地面点直接提取算法。该算法通过最大类间方差法对EMD算法进行了优化,并结合潜在地面点缓冲区和百分位数法从原始光子数据中直接提取出精确的初始地面点,在此基础上利用渐进加密法实现了其它地面点的准确提取。针对登封地区4轨ATLAS数据的实验结果得出,本文算法较改进的椭圆邻域密度法显著提高了正确地面点的提取数量,减小了信号点损失,并得到了与实际地面更加吻合的地表曲线,可为后续地形和植被分析提供更加准确的分类数据。ICESat-2 is the first satellite with photon counting LiDAR in the world,its detection performance is more better than that of ICESat-1.The processing of photon data is important to the application of ICESat-2 and ground point extraction is one step of the processing.Now ground point extraction algorithms of ICESat-2 ATLAS data are mainly focused on filtering and classifying,which are remarkably influenced by global threshold value and extract few correct ground points.A new ground point direct extraction algorithm based on optimized empirical mode decomposition(EMD)is proposed in this paper.The EMD is optimized by Ostu method,and the construction of potential ground point buffer and percentile method are combined to directly extract the accurate initial ground points from original photon point.Then the left ground points in the track are extracted with a gradual densified method based on the accurate initial ground points.Experiment results with 4 tracks of ATLAS data in Dengfeng city shows that,the proposed algorithm extracts more ground points than those of the improved elliptic neighborhood density algorithm,and significantly reduced the loss of signal points.The ground surface curve constructed by the proposed algorithm is more approximate to real ground surface,which will benefit subsequent terrain and vegetation analysis.

关 键 词：星载激光雷达 光子计数 冰、云及陆地高程卫星2号 地面点提取 经验模态分解 渐进加密 

分 类 号：P237[天文地球—摄影测量与遥感]