TUC-Net: A Point Cloud Segmentation Network Based on Neighborhood Feature Perception Aggregation for Tunnels Under Construction

The high risks in tunnel construction underscore the critical necessity for intelligent tunnel construction. Unmanned tunnel data collection is vital for intelligent construction; additionally, semantic segmentation aids in understanding the environment. However, complex tunnel terrains are challenging for three-dimensional (3D) laser scanning, and diverse interior structures and nontunnel elements complicate accurate segmentation by subsequent networks. Therefore, this paper proposed a tunnel mobile 3D mapping system (TMMS) for complex terrain in construction tunnels using a quadruped robot and simultaneous localization and mapping (SLAM). Additionally, a deep learning-based semantic segmentation network (TUC-Net) is proposed for analysing 3D point clouds in tunnels under construction. The research presented the neighbourhood feature perception enhancement (NFPE) module to enhance the representation of local features, introduce a self-attention (SA) module and improve the loss function to improve network accuracy. The NFPE module enhances feature aggregation for unstructured objects, and the SA module improves the learning of global features, critical for tunnel point cloud segmentation. The TMMS is used to collect point cloud data from tunnels under construction, leading to the creation of the tunnels under construction point clouds (TUCPC) dataset for training and evaluating the TUC-Net network. Compared to other 3D point cloud semantic segmentation methods, the proposed method demonstrated superior performance, achieving an overall accuracy (OA) of 99.45% and a mean intersection over union (mIoU) of 94.06%, surpassing that of other methods by at least 4.41%. In addition, ablation studies were also performed on the NFPE and SA modules to validate their efficacy.