Fig. 1. Framework of autofocus algorithm

Fig. 2. (a) Schematic diagram of global autofocus module structure, (b) DBL structure and (c) ResBlock structure

Fig. 3. The structure of defocus distance regression network

Fig. 4. (a) Structure diagram of local autofocus module. (b) Upsample structure. (c) Concat structure

Fig. 5. Determination of focus direction

Fig. 6. Image acquisition platform

Fig. 7. Laplacian sharpness curves of an image sequence

Fig. 8. Autofocus process

Fig. 9. Focus results for different input images

Fig. 10. Focusing results of 4 groups of image sequences

Fig. 11. Autofocus results of proposed method on the test set

Fig. 12. Focusing results of four ablation experiments