Fig. 1. Sharp and blurred images and their DWHT results. (a) Sharp image; (b) blurred image; (c) DWHT of Fig.1(a); (d) DWHT of Fig.1(b)

Fig. 2. Block diagram of proposed algorithm

Fig. 3. Focus region detection based on DWHT

Fig. 4. Generation process of final decision map. (a) Initial decision map IDM (x,y); (b) small patch removing operation MD₁ (x,y); (c) morphology operation MD₂ (x,y); (d) final decision map FDM (x,y)

Fig. 5. Three groups of multi-focus source images. (a) Clock; (b) book; (c) golf

Fig. 6. Clock’s fusion images and corresponding residual images of different methods. (a)(f) GFF; (b)(g) MWGF; (c)(h) CNN; (d)(i) DCT; (e)(j) proposed method

Fig. 7. Enlarged images of labeled regions in Fig. 6

Fig. 8. Multi-sequence focused images. (a) Multi-sequence gravure pattern appearance images; (b) multi-sequence lithium battery pole piece images

Fig. 9. Multi-focus fusion results of multi-sequence gravure pattern appearance image. (a) GFF; (b) CNN; (c) DCT; (d) proposed method

Fig. 10. Multi-focus fusion results of multi-sequence lithium battery pole piece image. (a) GFF; (b) CNN; (c) DCT; (d) proposed method

Fig. 11. Enlarged images of labeled regions in Fig. 10. (a) GFF; (b) CNN; (c) DCT; (d) proposed method

Fig. 12. Quality evaluation of multi-focus sequence image fusion