Fig. 1. Included angle between laser beam vector and normal vector of the surface of the object

Fig. 2. Projection of semi-major axis and semi-minor axis of a laser spot on x, y, z coordinate

Fig. 3. Deformation simulator

Fig. 4. Deformation of different distances and incidence angles

Fig. 5. Histogram of point cloud error entropy. (a) Different distances; (b) different incidence angles

Fig. 6. Histogram of deformation monitoring indicators. (a) Different distances; (b) different incidence angles

Fig. 7. Ratio histogram of the number of extracted deformation points to the number of the total cloud points for all trials at different distances

Fig. 8. Ratio histogram of the number of extracted deformation points to the number of the total cloud points for all trials at different incidence angles. (a) 5°, 15°, 25° and 35°; (b) 45°, 55°, 65° and 75°

Fig. 9. Bridge site and schematic diagrams of the original point cloud data obtained by scanning

Fig. 10. Point cloud change of top part

Fig. 11. Point cloud change of upside part

Fig. 12. Point cloud change of middle part

Fig. 13. Point cloud change of right bottom part

Fig. 14. Point cloud change of left bottom part

Fig. 15. Point cloud change of stay-cables part