Investigating performance of Airborne LiDAR data filtering algorithms for DTM generation

• Five different algorithms are used to filter LiDAR point cloud.
• Removing non-terrain objects to get bare earth is called filtering.
• Filtering process is the basic step of DTM generation from raw LiDAR point cloud.

Digital Terrain Model (DTM) is an important topographic product and essential demand for many applications. Traditional methods for creating DTM are very costly and time consuming because of land surveying. In time, Photogrammetry has become one of the major methods to generate DTM. Recently, airborne Light Detection and Ranging (LiDAR) system has become a powerful way to produce a DTM due to advantage of collecting three-dimensional information very effectively over a large area by means of precision and time.Airborne LiDAR system collects information not only from land surface, but also from every object between plane and terrain that can reflect the laser beam. So filtering out non ground points from raw point clouds is the major step of DTM generation. There are many filtering algorithms due to several factors that affect the filtering procedures. The performances of these filters change based on the topographic features of the area.In this study the five different algorithm is used to filter LiDAR point cloud that is collected from two different sites. While one of these sites is a rural area, the other site is an urban area; therefore these sites have different topographic features. In addition, the reference DTMs are available for these sites. In order to test the performance of algorithms, the LiDAR point clouds are filtered and used to generate DTM for the sites. Finally, the generated DTM is compared with the reference DTM for each site.