Three-Dimensional Instance Segmentation of Rooms in Indoor Building Point Clouds Using Mask3D

While most recent work in room instance segmentation relies on orthographic top-down projections of 3D point clouds to 2D density maps, leading to information loss of one dimension, 3D instance segmentation methods based on deep learning were rarely considered. We explore the potential of the general 3D instance segmentation deep learning model Mask3D for room instance segmentation in indoor building point clouds. We show that Mask3D generates meaningful predictions for multi-floor scenes. After hyperparameter optimization, Mask3D outperforms the current state-of-the-art method RoomFormer evaluated in 3D on the synthetic Structured3D dataset. We provide generalization results of Mask3D trained on Structured3D to the real-world S3DIS and Matterport3D datasets, showing a domain gap. Fine-tuning improves the results. In contrast to related work in room instance segmentation, we employ the more expressive mean average precision (mAP) metric, and we propose the more intuitive successfully detected rooms (SDR) metric, which is an absolute recall measure. Our results indicate potential for the digitization of the construction industry.