3D data generation of manholes from single panoramic inspection images

Infrastructure facilities require proper maintenance, including diagnosing structural durability and determining appropriate repair methods. Structural analysis is widely used to assess structural conditions, necessitating three-dimensional (3D) data that accurately reflect the locations of deterioration. Therefore, we investigate a method to generate 3D data of manholes from single-shot panoramic inspection images, focusing on accurately mapping the condition of wall surfaces, the primary targets of manhole inspections, including their deterioration such as rebar corrosion. However, some areas of the wall are occasionally occluded by internal objects such as cables or adjacent walls, making accurate layout estimation and 3D reconstruction difficult. To address this issue, we propose a model that incorporates 3D data generated from design drawings as additional input, along with a post-processing method to adjust the estimated layout based on geometry in the drawings. The evaluation results show that our method improves 3D IoU accuracy, especially under occluded conditions. Moreover, with a mapping error of 14.3 cm in the reconstructed 3D data, our approach demonstrates its practical potential for use in the structural analysis of most manholes.