Boundary Exploration of Next Best View Policy in 3D Robotic Scanning

Abstract: The Next Best View (NBV) problem is a pivotal challenge in 3D robotic scanning, with the potential to greatly improve the efficiency of object capture and reconstruction. Current methods for determining the NBV often overlook view overlaps, assume a virtual origin point for the camera's focus, and rely on voxel representations of 3D data. To address these issues and improve the practicality of scanning unknown objects, we propose an NBV policy in which the next view explores the boundary of the scanned point cloud, and the overlap is intrinsically considered. The scanning distance or camera working distance is adjustable and flexible. To this end, a model-based approach is proposed where the next sensor positions are searched iteratively based on a reference model. A score is calculated by considering the overlaps between newly scanned and existing data, as well as the final convergence. Additionally, following the boundary exploration idea, a deep learning network, Boundary Exploration NBV network (BENBV-Net), is designed and proposed, which can be used to predict the NBV directly from the scanned data without requiring the reference model. It predicts the scores for given boundaries, and the boundary with the highest score is selected as the target point of the next best view. BENBV-Net improves the speed of NBV generation while maintaining the performance of the model-based approach. Our proposed methods are evaluated and compared with existing approaches on the ShapeNet, ModelNet, and 3D Repository datasets. Experimental results demonstrate that our approach outperforms others in terms of scanning efficiency and overlap, both of which are crucial for practical 3D scanning applications. The related code is released at \url{github.com/leihui6/BENBV}.