Fig. 1. Flow of proposed algorithm

Fig. 2. Experimental data. (a) Original image; (b) objectives; (c) synthesis of data

Fig. 3. Detection effects of different algorithms at different thresholds. (a)--(c) SAM algorithm; (d) proposed algorithm

Fig. 4. Time complexity of proposed algorithm under different initial number of points

Fig. 5. Target growth process. (a) 1^st layer; (b) 2^nd layer; (c) 3^rd layer; (d) 4^th layer; (e) dentification result

Fig. 6. Root node optimization process. (a) Short chain growth result; (b) adjacent frequency

Fig. 7. Background growth process. (a) 1^st layer; (b) 2^nd layer; (c) 3^rd layer; (d) 4^th layer; (e) against result

Fig. 8. Position of missing and overlapping pixels and final recognition effect. (a) Comprehensive display effect; (b) missing pixels; (c) overlapping pixels; (d) determination effect

Fig. 9. Detection effects of different algorithms. (a) Original images; (b) truth ground; (c) CEM algorithm; (d) ACE algorithm; (e) WCM-OSP algorithm; (f) DERSG algorithm; (g) AG algorithm

Fig. 10. ROCs of different algorithms under different datasets. (a) Data 1; (b) data 2; (c) data 3; (d) data 4