A Study On Data Filtering And DEM Extraction Of LiDAR Point Cloud

As a new technology for obtaining three-dimensional geographic information,LiDAR measurement technology has many advantages,and it has represented a new direction for the development of ground detection.The data of the measured objects obtained by LiDAR are called point cloud data.The processing and application of point cloud data is a research subject of scholars at home and abroad in recent years.This paper focuses on two key steps of the digital elevation model(DEM)of LiDAR data generation,point cloud filtering and point cloud generation DEM.The quality of the DEM is determined by the quality of the point cloud filtering,so it is of great significance to improve the filtering effect of the LiDAR point cloud.In this paper,the cloth simulation point cloud filtering algorithm is applied to generate DEM generation.Based on a large number of experimental data analysis,this paper proposes the best parameters based on cloth simulation algorithm under different terrain,making cloth simulation algorithm best in different terrain.15 groups of different terrain data by ISPRS provided as the reference data,the cross tabulation method and Kappa coefficient method of point cloud filtering cloth simulation results of quantitative evaluation,comparison is made at the same time filtering algorithm with the international top level,results show that the cloth simulation algorithm is close to the international top algorithm,at the same time cloth simulation algorithm has fewer parameters and good filtering effect and wide applicable terrain features.Comprehensive comparison of three commonly used three kinds of DEM,irregular triangle to the sampling density and sampling point position by changing the expression change complexity of terrain,and irregular triangle net can reduce the data redundancy,while maintaining the topography,and to render the terrain surface with different resolution.In this paper,the Irregular Triangulation Network is used to represent the establishment of DEM.There are many algorithms to realize triangulation,but Delaunay triangulation shows the best terrain fitting.In this paper,the point by point insertion method is used to generate the Delaunay triangulation network,and the point by point insertion method is optimized to improve the performance of the algorithm.The filter is based on the cloth simulation algorithm,and then the digital elevation model is generated by the optimized point by point insertion method.