Calculation of structural information of bridges using 3D point clouds

Abstract

In this study, we examined a method to automatically calculate the structural information of bridges using point cloud data measured with the Matterport Pro3. We calculated the dimensions of railings, decks, and main girders and evaluated their accuracy. The point clouds were pre-annotated, and this information was utilized during processing. The length of the railings was estimated by projecting the point cloud onto a 2D image from a top-down view and using image processing techniques. The RMSE was 0.289 m, suggesting a possible error of about 5cm. The length and width of the deck were compared using principal component analysis and ellipse fitting, with RMSEs of 0.10 m and 0.50 m, respectively. Additionally, we attempted to detect the intersections of the main girders, but estimating the position of intersections was difficult in areas with missing data. Future work should aim for more accurate estimation by combining the method with automatic point cloud classification using deep learning.