Fig. 1. Flowchart of green belt extraction and objects classification

Fig. 2. Improved mathematical morphological filtering algorithms

Fig. 3. Ground points and low ground objects extraction results

Fig. 4. Elevation extraction and echo strength histogram

Fig. 5. Points cloud clustering and green belt extraction result

Fig. 6. Typical low ground objects' points clouds

Fig. 7. Classification of low ground objects in the green belt

Fig. 8. Raw points cloud data of the experiment area

Fig. 9. Overall and partial extraction results of green belts

Fig. 10. Overall and partial classification results of green belts

Fig. 11. Map of local landform change in the green belts