The application discloses a tunnel three-dimensional center line extraction method based on
octree occupancy map and distance transformation, which takes tunnel scene
point cloud sequences registered to the same
global coordinate system as input, incrementally constructs a global
octree occupancy map to obtain an occupancy leaf
voxel center
point set, extracts a candidate occupancy
voxel center
point set and performs three-dimensional
principal component analysis to obtain a stable axial direction, constructs a cross-
section plane along the stable axial direction, extracts a
point set within the
slice thickness range, projects the point set to a two-dimensional coordinate
system, rasterizes a cross-section obstacle grid, performs two-dimensional distance transformation, takes a point corresponding to a maximum value of a distance field as a maximum inscribed circle center, and back-projects the point to obtain a slice center point and a clear
radius, accumulates continuous effective center points, applies a maximum
turning angle constraint, and outputs a tunnel three-dimensional center line. The application does not require strict alignment of the input tunnel coordinate
system Z-axis with the gravity direction, and does not depend on an
odometer trajectory or a platform attitude
estimation axial direction, and is suitable for straight or curved tunnel structures with longitudinal slopes.