Near Real-Time 3D Reconstruction and Quality 3D Point Cloud for Time-Critical Construction Monitoring

Improving the rapidity of 3D reconstruction is vital for time-critical construction tasks such as progress monitoring and hazard detection, but the majority of construction studies in this area have focused on improving its quality. We applied a Direct Sparse Odometry with Loop Closure (LDSO)-based 3D reconstruction method, improving the existing algorithm and tuning its hyper-parameter settings, to achieve both near real-time operation and quality 3D point cloud simultaneously. When validated using a benchmark dataset, the proposed method showed notable improvement in 3D point cloud density, as well as loop closure robustness, compared to the original LDSO. In addition, we conducted a real field test to validate the tuned LDSO's accuracy and speed at both object and site scales, where we demonstrated our method's near real-time operation and capability to produce a quality 3D point cloud comparable to that of the existing method. The proposed method improves the accessibility of the 3D reconstruction technique, which in turn helps construction professionals monitor their jobsite safety and progress in a more efficient manner.