摘要
现有地基激光雷达林下植被滤除研究精度不高且自动化程度较低,针对当前研究存在的不足,以两块地基激光雷达天然林样地点云数据为研究对象,提出了一种基于点云主方向的林下植被自动滤除方法。首先对数据进行裁剪、去噪、滤波和高度归一化等预处理后,根据样地林下植被的生长高度,将数据以一定高度分为上下两层,上层为乔木点云,下层为包含林下植被点云。然后,计算下层点云的空间邻域内特征以提取点云主方向,根据主方向与Z轴方向的法向量之间的夹角提取林下主干,滤除大量林下植被点云。最后,利用欧式距离聚类方法对林下主干提取结果进行聚类,精细提取林下主干,实现林下植被的完全滤除。根据以上方法,研究以两块天然林样地进行实验,结果表明,当样地1的邻域值k为100,夹角阈值t为30°,样地2的k邻域值为150,夹角阈值t为30°时,两块样地林下主干数量都实现了100%的完全提取,说明林下植被滤除结果较好。通过对邻域值k和夹角阈值t进行讨论,研究认为k值选择100~150为宜,t值选择30°为宜。该方法参数少,自动化程度高,可为以灌木或乔木为对象的研究提供一定的技术参考。
Existing Terrestrial Laser Scanning research on understory vegetation filtering has low precision and low degree of automation.In view of the shortcomings of the current research,the study takes the cloud data of two natural forest sample plots of Terrestrial Laser Scanning as the research object,an automatic filtering method of understory vegetation based on the main direction of the point cloud is proposed.First,after preprocessing the data such as cropping,denoising,filtering and height normalization,according to the growth height of understory vegetation in the sample plot,the data is divided into upper and lower layers at a certain height.Among them,the upper layer is a tree point cloud,and the lower layer is a point cloud containing understory vegetation.Then,the features in the spatial neighborhood of the lower layer point cloud are calculated to extract the main direction of the point cloud,and the understory main trunk is extracted according to the angle between the main direction and the normal vector of the Z-axis direction,so as to filter out a large number of understory vegetation point clouds.Finally,the Euclidean distance clustering method is used to cluster the extraction results of the understory main trunks,and the understory main trunks are finely extracted to achieve complete filtration of the understory vegetation.According to the above methods,two natural forest plots were tested.The results showed that when the neighborhood value k of plot 1 was 100 and the included angle threshold t was 30°,the neighborhood value k of plot 2 was 150 and the included angle threshold t was 30°.The number of understory trunk in the two plots achieved 100%complete extraction,indicating that the filter results of understory vegetation were good.Through the discussion of the neighborhood value k and the threshold of the included angle t,it is considered that 100~150 is appropriate for k value and 30°is appropriate for t value.This method has few parameters and high degree of automation,which can provide a certain technical reference for the study of shrubs or trees.
作者
张建鹏
王金亮
刘广杰
麻卫峰
刘钱威
邓云程
ZHANG Jianpeng;WANG Jinliang;LIU Guangjie;MA Weifeng;LIU Qianwei;DENG Yuncheng(Faculty of Geography,Yunnan Normal University,Kunming 650500,China;Key Laboratory of Resources and Environmental Remote Sensing for Universities in Yunnan,Kunming 650500,China;Center for Geospatial Information Engineering and Technology of Yunnan Province,Kunming 650500,China;College of Resources and Environment,Yunnan Agriculture University,Kunming 650201,China;Power China Kunming Engineering Corporation Limited,Kunming 650051,China)
出处
《遥感技术与应用》
CSCD
北大核心
2023年第2期405-412,共8页
Remote Sensing Technology and Application
基金
国家自然科学基金项目(41961060)
云南省高校科技创新团队项目(IRTSTYN)
云南省教育厅科学研究基金项目(2020J0256)
云南省教育厅科学研究基金项目(2021J0438)。
关键词
地基激光雷达
林下植被
主干
主方向
欧式距离聚类
Terrestrial Laser Scanning
Understory vegetation
Main trunk
Main direction
Euclidean distance clustering
