Fig. 1. Calibration model of lidar and camera

Fig. 2. Calibration scene

Fig. 3. Schematic diagram of the distance error between the corresponding skew lines in point cloud and image

Fig. 4. Schematic diagram of the distance between skew lines

Fig. 5. Schematic diagram of the angle between the projected line and the line in image

Fig. 6. Plane extraction effect of point cloud data

Fig. 7. Comparison of straight line detection effects between Hough transform and LSD algorithm

Fig. 8. Extracting line features from images using LSD algorithm

Fig. 9. Experimental data

Fig. 10. Colored point cloud

Fig. 11. Definition of projection error

Fig. 12. Ten edges for testing

Fig. 13. Edges projection error boxplot

Fig. 14. Schematic diagram of the boundaries used by proposed method

Fig. 15. Overall projection rendering

Fig. 16. Comparison of local differences in projection effects

Fig. 17. Comparison of projection errors. The solid green lines represent the boundaries in the image， the red points represent the point cloud projection points of the proposed method， and the blue points represent the projection points using Ref. ［27］ method

Fig. 18. Error box diagram

Fig. 19. Error analysis diagram of edge-2. The red and blue dots represent the point cloud projection points of the proposed method and Ref. ［27］ method， respectively