The application provides a 3D reconstruction
system for mountain
pine forest environment, and relates to the technical field of unmanned aerial vehicle (UAV)
simultaneous localization and mapping (SLAM). The
system comprises a hardware platform and a
software system, which are composed of a UAV, a
laser radar, an
inertial measurement unit (IMU) and a global navigation
satellite system (GNSS). In view of the problems of sparse features in forest areas, easy drift and high redundancy caused by repetition during mapping, the
software system adopts three modules to build a
closed loop: 1) a data alignment and system initialization module, which realizes optimal robust alignment of
laser and GNSS trajectories by embedding weighted Procrustes analysis into a RANSAC framework; 2) a key
point cloud frame selection module, which scores the current frame by comprehensively considering geometric, density and structural characteristics, and dynamically adjusts the space-time threshold to select key frames in combination with historical feedback; and 3) a
graph optimization module with multi-dimensional factor constraints, which fuses
odometry, GNSS and loop factors to build a
factor graph, and globally optimizes the
mapping algorithm by using incremental
smoothing. The application effectively suppresses cumulative errors and improves the accuracy and efficiency of forest reconstruction.