REAL-TIME MONITORING OF UAV PHOTO SHOOTING FOR 3D RECONSTRUCTION

Abstract

 Since the aging of a large amount of infrastructure built during the high growth period has become a problem, the maintenance, and management of ICT (Information and Communication Technology)-utilized infrastructure is an urgent matter in Japan. Although UAV is an up-and-coming tool in 3D data generation for existing structures, the operation method for complex-shaped structures is ad hoc. SfM (Structure from Motion) of the photogrammetry process is a compelling 3D digitization method. However, the processing cost is very high, primarily when aerial photography with UAV handles many photographs. Also, the rework caused by imperfections in aerial photography is a substantial loss. This paper proposes a method to monitor whether aerial photos are suitable for SfM by visual SLAM (simultaneous location and mapping) process in real-time to prevent such rework. Visual SLAM, which also uses the photogrammetry principle, can track the camera's egomotion from the captured image sequences. By taking aerial photographs at various speeds in advance and investigating the causal relationship with the quality of SfM, the appropriate limit of moving speed is determined. Using this speed limit as an index, SLAM monitors the moving speed in real-time to evaluate aerial photography's appropriateness. We also validated the derived index by experiments based on the implemented proposed method on an actual UAV.