Application of 3d Tree Modeling Using Point Cloud Data by Terrestrial Laser Scanner

Abstract

Abstract. Constructing 3D models for trees such as those found in Japanese gardens, in which many species exist, requires the generation of tree shapes that combine the characteristics of the tree's species and natural diversity. Therefore, this study proposes a method for constructing a 3D tree model with highly-accurate tree shape reproducibility from tree point cloud data acquired by TLS. As a method, we attempted to construct a 3D tree model using the TreeQSM, which is open source for TLS-QSM method. However, in TreeQSM, since processing is based on the assumption that the tree point cloud consists of data related to trunks and branches, measuring trees in which leaves have fallen is recommended. To solve this problem, we proposed an efficient classification process that mainly uses thresholds for deviation and reflectance, which are the adjunct data of the object that can be acquired by laser measurement. Furthermore, to verify accuracy of the model, position coordinates from the constructed 3D tree model were extracted. The extracted coordinates were compared with the those of the tree point cloud data to clarify the extent to which the 3D tree model was constructed from the tree point cloud data. As a result, the 3D tree model was constructed within the standard deviation of 0.016 m from the tree point cloud data. Therefore, the reproducibility of the tree shape by the TLS-QSM method was also effective in terms of accuracy.

Assessment of Permeability Windbreak Forests with Different Porosities Based on Laser Scanning and Computational Fluid Dynamics

“…Currently, some scholars use the standard RNG k-epsilon model to calculate ambient air temperature and wind speed [32,33], Although the standard k − ε model has been widely used, the improved RNG k − ε model yields higher accuracy by modifying the turbulent viscosity, considering the rotating mean flow, and increasing the mainstream strain rate reflected in the epsilon equation. The momentum and mass conservation equations can be expressed as follows:…”

“…2022, 14, x FOR PEER REVIEW 18 of 22 cloud of the upper part of the canopy was missing because of partial shading between the trees at the top of the tree during modeling, resulting in a partially incomplete final model. In this study, based on the results of Kumazaki and Kunii [33], five single trees were randomly selected from the TLS-scanned experimental site, and the modeling results were compared with the real results using AdQSM. For these five random samples, the absolute errors of three factors (diameter at breast height, height, and crown width) were less than 5 mm, the relative errors of diameter at breast height and height were less than 2%, and the relative errors of crown width were larger (approximately 8%) because of the shading between trees.…”