Fig. 1. Original point cloud

Fig. 2. Spatial distribution of noise. (a) Plane point cloud map; (b) distance map of neighbor points

Fig. 3. Flow chart of proposed algorithm

Fig. 4. Characteristic density distributions of 10 points in neighborhood

Fig. 5. Characteristic density distributions of 20 points in neighborhood

Fig. 6. Characteristic density distributions of 30 points in neighborhood

Fig. 7. Characteristic density distributions of 40 points in neighborhood

Fig. 8. Extracted results. (a) Original point cloud; (b) 10 neighbor points; (c) 20 neighbor points; (d) 30 neighbor points; (e) 40 neighbor points

Fig. 9. Experimental results and accuracy. (a) Trend of slope difference; (b) trend of accuracy difference; (c) number of ground point clouds; (d) error curves

Fig. 10. Extraction results of radius filter, voxel filter, and statistical filter

Fig. 11. Extraction results based on Method-Library. (a) After denoising in front view; (b) after denoising in side view

Fig. 12. Extraction results of large-area point cloud. (a) Before denoising in front view; (b) after denoising in front view; (c) before denoising in side view; (d) after denoising in side view