Mapping of drainage culverts using SLAM-based mobile laser scanning technology

In traditional drainage culvert measurement, manual surveying faces bottlenecks of low efficiency and poor accuracy, making it difficult to meet the mapping requirements of complex underground spaces. To break through these limitations, we introduced a handheld mobile 3D laser scanning solution based on SLAM technology, establishing a highly efficient and precise measurement system. This technology takes critical nodes such as culvert entrances/exits and maintenance manholes as entry points, performing full-coverage scanning of the internal spaces of the culvert and ground ancillary structures through portable devices. The operation innovatively integrates ground control point calibration technology, achieving seamless stitching of underground and ground point cloud data through data computation to form a high-precision integrated 3D model. This data acquisition mode overcomes the isolation of traditional single-point measurements, constructing a comprehensive database containing spatial coordinates, structural dimensions, and texture features, providing multidimensional data support for subsequent feature extraction. The results show that this technology significantly improves operational efficiency, achieves high measurement accuracy, and ensures complete data attributes. Its flexible mobile operation characteristics are particularly suitable for narrow and curved underground spaces, effectively solving the challenges of traditional equipment's inability to penetrate deeply. With the increasing demand for refined management of urban underground pipelines, this technology demonstrates broad prospects in drainage system planning, hidden hazard identification, and operation-maintenance decision-making.