Influence of tree density and terrain slope on ground point density in LiDAR point clouds: a simulation-based study with Helios++

Abstract. There is still no reliable solution for obtaining Digital Terrain Models (DTM) under the canopy in areas with difficult access on foot. The difficulty lies in the configuration of the environment. This configuration does not allow access on foot to all areas of the terrain. In addition, the dense leaf litter complicates any photogrammetry technique. Currently, LiDAR is a technique that could help solve this problem. The best solution to this problem requires many samples over hostile environment and LiDAR flight simulation can be a good option to approximate the problem. For this reason, this research carries out a series of LiDAR flight simulations, using Helios++, in different types of scenes under the canopy with the aim of analysing the influence of the density of trees and the mean terrain slope over the number of points that bounce off the terrain. Additionally, this research enables the scientific community to approach the problem and guide future research based on the obtained results.