Fig. 1. Structure of residual block

Fig. 2. Diagram of angle in three-dimensional space

Fig. 3. Part of the face detection results

Fig. 4. Clustering results

Fig. 5. Face image of folder 6

Fig. 6. Face images of folder 7

Fig. 7. Face image of folder 3

Fig. 8. Preferred results of the edge statistical feature method

Fig. 9. Preferred results of the variance method

Fig. 10. Preferred results of the mean method

Fig. 11. Unobstructed face with deflection. (a) Original image; (b) center line; (c) vertical projection; (d) deflection distance

Fig. 12. Undeflected face with occlusion. (a) Original image; (b) center line; (c) vertical projection; (d) deflection distance