Three-Dimensional Reconstruction of Large Multilayer Interchange Bridge Using Airborne LiDAR Data

Accurate and timely updated three-dimensional (3-D) model data of interchange bridges are significant for traffic navigation, landscape design, and many other applications. In this study, we explore the potential of using airborne light detection and ranging (LiDAR) data for 3-D reconstruction of large multilayer interchange bridges. To reduce the technical difficulty in this 3-D reconstruction process, we propose a concept of “structure unit.” We propose a new technical framework based on the structure units for 3-D reconstruction of large multilayer interchange bridge, including point cloud extraction, connectivity-based segmentation, determination of structure units, occlusion detection and restoration, and 3-D modeling. The general idea of this framework is to divide an entire interchange bridge into many simple “structure units,” and then derive a complete 3-D model by reconstructing each “structure unit.” The technical novelties in this framework include: 1) a hierarchal segmentation strategy including connectivity-based segmentation and determination of structure units; and 2) an automatic technique for detection and restoration of occluded structures. The experiments provide specific analysis and evaluation from three aspects: 1) correctness and completeness; 2) horizontal accuracy; and 3) elevation accuracy. The experimental results indicate that the proposed framework can provide satisfactory 3-D models of large complex bridges.