Fig. 1. Connections between adjacent points. (a) Simplest connection layout; (b) extension of distance between connected points

Fig. 2. Principle diagram of threshold t2

Fig. 3. Expansion of connections. (a) Point cloud; (b) untypical connections; (c) connections after expansion

Fig. 4. Parameters of neighborhood characteristic. (a) θV; (b) θL; (c) θP

Fig. 5. Parameter distribution characteristics. (a) θV; (b) θL; (c) θP; (d) θF

Fig. 6. Flow chart of algorithm

Fig. 7. Ground unmanned experimental platform

Fig. 8. Experimental scene for parameter selection

Fig. 9. Results of different values of δ. (a) δ=0.4; (b) δ=0.6; (c) δ=0.8; (d) δ=1.0

Fig. 10. Experimental scenes. (a) Scene 1; (b) scene 2

Fig. 11. Detection results in artificial scene. (a) Manual marking; (b) proposed algorithm; (c) model matching algorithm; (d) covariance algorithm

Fig. 12. Detection results in field scene. (a) Manual marking; (b) proposed algorithm; (c) model matching algorithm; (d) covariance algorithm

Fig. 13. Comparison of running time of different algorithms. (a) Artificial scene; (b) field scene