Fig. 1. Ideal focus evaluation curve

Fig. 2. RGB pixel mapping grayscale pixels

Fig. 3. RGB color space

Fig. 4. Simulated image sequence

Fig. 5. Normalized focused evaluation curve for simulation images. (a) Table pixel focusing evaluation curve; (b) Boxes pixel focus evaluation curve; (c) Sideboard pixel focus evaluation curve

Fig. 6. Simulated image with noise

Fig. 7. Normalized focusing evaluation curve of noisy simulation images. (a) Table pixel focusing evaluation curve; (b) Boxes pixel focus evaluation curve; (c) Sideboard pixel focus evaluation curve

Fig. 8. Comparison between all-in-focus reference image and stacked focal fusion image. (a) Reference image; (b) Proposed fusion image; (c) SML fusion image; (d) Tenengrad fusion image; (e) GLV fusion image; (f) DCT fusion image; (g) SWAV fusion image; (h) Bre4d_var fusion image; (i) FMC fusion image

Fig. 9. Microscopic image acquisition. (a) Digital microscopy system; (b) Wafer samples; (c) Chip samples

Fig. 10. Multi focus image sequence captured by microscope

Fig. 11. Normalized focusing evaluation curve of microscopic images. (a) Pixel focusing evaluation curve of wafer surface; (b) Chip bonding wire pixel focusing evaluation curve

Fig. 12. Chip bonding wire overlay fusion image. (a) Proposed; (b) SML; (c) Tenengrad;(d) GLV; (e) DCT; (f) SWAV; (g) Bre4d_var; (h) FMC

Fig. 13. Wafer surface overlay fusion image. (a) Proposed; (b) SML; (c) Tenengrad; (d) GLV; (e) DCT; (f) SWAV; (g) Bre4d_var; (h) FMC

Table 1. Performance comparison of focusing evaluation algorithms in simulated images

Table 2. Performance comparison of focused evaluation algorithms for noisy simulated images

Table 3. Objective evaluation indicators for image fusion quality with reference

Table 4. Performance comparison of focusing evaluation algorithms in microscopic images

Table 5. Objective evaluation indicators for image fusion quality without reference