Fig. 1. Framework of proposed algorithm

Fig. 2. Target-feature visualization. (a) Original image; (b) HOG feature; (c) conv3-4 feature; (d) conv4-4 feature; (e) conv5-4 feature

Fig. 3. Schematic of feature fusion

Fig. 4. Update mechanism of temporal model

Fig. 5. Flow chart of algorithm

Fig. 6. Qualitative results of 10 tracking algorithms for some video sequences

Fig. 7. Tracking results of different feature experts

Fig. 8. Tracking accuracy and success rate of algorithm on OTB-2013 and OTB-2015 databases. (a) Tracking accuracy on OTB-2013 database; (b) tracking success rate on OTB-2013 database; (c) tracking accuracy on OTB-2015 database; (d) tracking success rate on OTB-2015 database

Fig. 9. Tracking precision of 11 different attribute video sequences on OTB-2013 database. (a) Background clutter; (b) deformation; (c) fast motion; (d) in-plane rotation; (e) illumination variation; (f) low resolution; (g) motion blur; (h) occlusion; (i) out-of-plane rotation; (j) out of view; (k) scale variation

Fig. 10. Tracking success rates of 11 different attribute video sequences on OTB-2013 database. (a) Background clutter; (b) deformation; (c) fast motion; (d) in-plane rotation; (e) illumination variation; (f) low resolution; (g) motion blur; (h) occlusion; (i) out-of-plane rotation; (j) out of view; (k) scale variation

Fig. 11. Tracking precision of 11 different attribute video sequences on OTB-2015 database. (a) Background clutter; (b) deformation; (c) fast motion; (d) in-plane rotation; (e) illumination variation; (f) low resolution; (g) motion blur; (h) occlusion; (i) out-of-plane rotation; (j) out of view; (k) scale variation

Fig. 12. Tracking success rates of 11 different attribute video sequences on OTB-2015 database. (a) Background clutter; (b) deformation; (c) fast motion; (d) in-plane rotation; (e) illumination variation; (f) low resolution; (g) motion blur; (h) occlusion; (i) out-of-plane rotation; (j) out of view; (k) scale variation

Fig. 13. Tracking precision and success rate of algorithm under long-term tracking. (a) Tracking precision;(b) tracking success rate

Table 1. Frequency statistics of feature experts

Table 2. Tracking accuracy, success rate, and speed of algorithm on OTB-2013 and OTB2015 databases