Flight Planning for Survey-Grade 3D Reconstruction of Truss Bridges

Abstract

Autonomous UAV 3D reconstruction has been widely used for infrastructure inspections and asset management. However, its applications on truss structures remain a challenging task due to geometric complexity and the severe self-occlusion problem of the truss structures when constrained by camera FOV, safety clearance, and flight duration. This paper proposes a new flight planning method to effectively address the self-occlusion problem to enable autonomous and efficient data acquisition for survey-grade 3D truss reconstruction. The proposed method contains two steps: First, identifying a minimal set of viewpoints achieves the maximal reconstruction quality at every observed surface of the truss geometry through an iterative optimization schema. Second, converting the optimal viewpoints into the shortest, collision-free flight trajectories while considering the UAV constraints. The computed flight path can also be implemented in a multi-UAV fashion. Evaluations of the proposed method include a synthetic truss bridge and a real-world truss bridge. The evaluation results suggested that the proposed approach outperforms the existing works in terms of 3D reconstruction quality while taking less time in both the inflight image acquisition and the post-flight 3D reconstruction.