Proposal for a Simple Inspection Tool using HoloLens2

In Japan, the importance of maintenance is growing as civil engineering structures and buildings age. It is important to carry out regular inspections at high frequencies and accumulate the data for proper maintenance. In recent years, with the wide spread of 3D scanning technology, it has become an effective method to use 3D models obtained by 3D scanning of the target structure as a base, and to associate electronic inspection information such as photos and documents with the relevant locations and manage them. It is the advantage that subsequent searches can be made in intuitive and easy ways by providing location information on the 3D model to the inspection information. In this paper, we develop a simple inspection tool using the head-mounted device HoloLens2. The developed tool allows inspectors to perform 3D scans as they move around a structure based on SLAM. And when deterioration or damage is found, images can be captured with the device's camera. In addition, the corresponding location on the 3D scanned model can be specified by simply pointing to the relevant location in the real environment with a hand gesture, and inspection information such as captured images and documents can be registered here. Experiments on an actual bridge demonstrated that this tool allows a series of inspection processes, such as 3D scanning, taking photos, and registering the photos on a 3D model, to be carried out at the inspection site with very simple and intuitive operations. In addition, the accuracy of the constructed 3D model was evaluated by comparing it with the TLS point cloud.