Application of Passive 3D Reconstruction in Establishing Digital Model of Bridge Cable

Abstract

Cables are widely used in the construction of long-span bridges such as cable-stayed bridges, arch bridges and suspension bridges. The detection of the cables is a critical task, since the effective bearing area of the bridge cables will affect the stability and service life of the bridge. Establishing the digital model of the cable can facilitate the subsequent damage detection work. This led to many applications with 3D reconstruction technology in cable detection. Passive 3D reconstruction is a method to restore the geometric structure of a scene from one or more pictures, and finally obtain the 3D model of the scene. With the passive 3D reconstruction technology, the 3D digital model of the cable can be reconstructed only using the image data of bridge cables. In this work, the image data taken by the cable detection robot while moving is used for experiment, and data processing such as distortion correction is performed on the acquired image data. The information of camera position can be obtained based on the geometric structure of bridge cable. Combining this information with multiple images from different viewpoints, the three-dimensional information can be recovered for the final 3D model. For the final reconstructed model, 4 points were selected for geometric accuracy evaluation and compared with the ground truth. The relative errors of these chosen points reach 0.913%, 1.196%, 0.947% and 0.568% respectively, and the MAE is 1.0053 mm. The experimental results show that the method proposed can generate a model with clear texture and high accuracy, and also reduce the cost of data acquisition.