Semantic segmentation of large-scale segmental lining point clouds using 3D deep learning

Abstract

It is highly challenging to comprehensively measure the deformations of large-scale tunnel structures because of the numerous individual segments of tunnel linings. Laser scanning and 3D deep learning (DL) can provide abundant geometric data and the ability to interpret such data automatically. To fill the gap in applying 3D DL to the segment-wise segmentation of large-scale tunnel point clouds, a new 3D dataset and an optimized DL network are presented in this paper. The point cloud dataset was manually annotated by labeling every individual segment and element. Subsequently, a 3D DL network capable of handling large-scale point clouds (approximately 106 points) was developed to perform the data experiments. The influences of network parameters, namely, the number of neighbor points, layer number, down-sampling ratio, and channel number, were investigated in the data experiments. The results indicate that the number of neighboring points and channel number have a notable influence on the segmentation performance, with the best mean interaction over union reaching 85.5%. This study provides preliminary insights into the 3D DL network design for large-scale tunnel point clouds.