Author Affiliations
1College of Mathmatics and Physics, Chengdu University of Technology, Chengdu 610000, China2The college of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610000, China3School of Geophysics, Chengdu University of Technology, Chengdu 610000, Chinashow less
Fig. 1. Multi-depth-of-field images of the object in the foreground and in the background
Fig. 2. Focus evaluation function curve in multi-depth-of-field scene
Fig. 3. The target objects are roughly distributed in the image
Fig. 4. Flow chart of target location using U-net
Fig. 5. Flowchart of focusing window algorithm
Fig. 6. Flow to locate the target and set the corresponding window
Fig. 7. Partial images of five sets of images
Fig. 8. For a group of images, the prediction map obtained by U-net and the images to be evaluated
Fig. 9. The first group of image focus evaluation function curves
Fig. 10. Focus evaluation function curves of the second group of images off and with windows
Fig. 11. Focus evaluation function curves of the third group of images off and with windows
Fig. 12. Focus evaluation function curves of the fourth group of images before and after adding windows
Fig. 13. Focus evaluation function curves of the fifth group of images before and after
Fig. 14. Image obtained by the central window method and obtained by the proposed method
Fig. 15. Focus evaluation function of central window method and window method proposed in this paper
| function | w/pix
| R/pix
| S/pix
| δSE/pix
| ɑ/pcs
| Τ/s
| ϛ/pcs
| | SMD | 24 | 6.8875 | 0.0411 | 7.2582 | 0 | 1.6137 | 1 | | Roberts | 24 | 7.3431 | 0.0410 | 6.8648 | 0 | 1.6456 | 1 | | Sobel | 24 | 1.4623 | 0.0389 | 1.2439 | 0 | 3.1041 | 1 | | Brenner | 23 | 8.1275 | 0.0420 | 5.8426 | 0 | 1.2990 | 1 | | SML | 22 | 1.3183 | 0.0409 | 0.9761 | 1 | 2.1598 | 1 | | SMD-Roberts | 23 | 1404.7 | 0.0434 | 121.69 | 0 | 2.2995 | 1 |
|
Table 1. Evaluation indexes of focus evaluation functions of group one
| function | w/pix
| R/pix
| S/pix
| δSE/pix
| ɑ/pcs
| Τ/s
| ϛ/pcs
| | SMD/SMD-W | 29/25 | 2.1698/2.5157 | 0.0325/0.0283 | 1.9085/0.839 | 3/0 | 2.0453/2.1611 | 1/1 | | Roberts/Roberts-W | 29/25 | 2.2958/2.5687 | 0.0324/0.0278 | 1.7515/0.7671 | 2/0 | 2.2270/2.0975 | 1/1 | | Sobel/Sobel-W | 29/28 | 1.5113/1.7246 | 0.0307/0.0315 | 1.8000/2.9075 | 0/0 | 3.6727/3.7181 | 1/1 | | Brenner/Brenner-W | 30/30 | 2.8219/3.7761 | 0.0311/0.0314 | 1.5077/4.0807 | 2/0 | 1.6520/1.5994 | 1/1 | | SML/SML-W | 28/27 | 1.1721/1.2726 | 0.0344/0.0335 | 1.7768/3.7476 | 2/2 | 2.5761/2.6616 | 1/1 |
|
Table 2. Evaluation indexes of focus evaluation functions of group two
| function | w/pix
| R/pix
| S/pix
| δSE/pix
| ɑ/pcs
| Τ/s
| ϛ/pcs
| | SMD/SMD-W | 6/11 | 18.6244/10.0582 | 0.1372/0.0891 | 3.1678/21.556 | 1/0 | 1.6038/1.6348 | 1/1 | | Roberts/Roberts-W | 6/11 | 14.2448/7.6339 | 0.1328/0.0886 | 2.2774/15.969 | 1/0 | 1.8546/1.6742 | 1/1 | | Sobel/Sobel-W | 8/11 | 3.0674/3.7650 | 0.1005/0.0871 | 1.9598/9.0097 | 1/0 | 3.2885/3.3039 | 1/1 | | Brenner/Brenner-W | 6/10 | 10.2044/11.6104 | 0.1269/0.0942 | 2.0341/10.880 | 1/0 | 1.2648/1.2660 | 1/1 | | SML/SML-W | 7/11 | 1.43591/9.3751 | 0.0734/0.0890 | 0.3356/19.314 | 1/0 | 2.4652/1.9295 | 0.86/1 |
|
Table 3. Evaluation indexes of focus evaluation functions of group three
| function | w/pix
| R/pix
| S/pix
| δSE/pix
| ɑ/pcs
| Τ/s
| ϛ/pcs
| | SMD/SMD-W | 22/21 | 12.374/3.5626 | 0.0448/0.0459 | 3.8276/5.0336 | 1/0 | 1.5648/1.5551 | 0.90/1 | | Roberts/Roberts-W | 22/21 | 13.184/3.4488 | 0.0449/0.0458 | 3.6610/4.7100 | 1/0 | 1.5518/1.6737 | 0.90/1 | | Sobel/Sobel-W | 22/21 | 1.9829/1.6798 | 0.0421/0.0440 | 1.0151/1.7624 | 2/1 | 2.9408/2.9797 | 0.90/1 | | Brenner/Brenner-W | 22/22 | 12.778/10.217 | 0.0448/0.0450 | 4.4590/6.5856 | 2/1 | 1.2274/1.2255 | 0.90/1 | | SML/SML-W | 22/21 | 1.4090/1.2870 | 0.0409/0.0397 | 0.7853/0.8094 | 1/1 | 2.5329/1.9305 | 0.90/1 |
|
Table 4. Evaluation indexes of focus evaluation functions of group four
| function | w/pix
| R/pix
| S/pix
| δSE/pix
| ɑ/pcs
| Τ/s
| ϛ/pcs
| | SMD/SMD-W | 29/26 | 3.5789/2.3022 | 0.0335/0.0377 | 0.0334/2.9570 | 1/0 | 2.1879/2.1025 | 0.94/1 | | Roberts/Roberts-W | 29/26 | 3.8800/2.3054 | 0.0334/0.0376 | 1.9252/2.7358 | 1/1 | 2.2622/2.0914 | 0.94/1 | | Sobel/Sobel-W | 27/28 | 1.5170/1.4799 | 0.0324/0.0347 | 0.8593/0.8298 | 1/1 | 4.4030/3.9267 | 1/1 | | Brenner/Brenner-W | 27/28 | 4.3384/4.4870 | 0.0352/0.0353 | 2.1226/1.8485 | 1/1 | 1.7418/1.6939 | 1/1 | | SML/SML-W | 28/28 | 1.3850/1.3531 | 0.0345/0.0353 | 1.2580/0.8797 | 2/1 | 2.7556/2.6546 | 1/1 |
|
Table 5. Evaluation indexes of focus evaluation functions of group five
| function | w/pix
| R/pix
| S/pix
| δSE/pix
| ɑ/pcs
| Τ/s
| ϛ/pcs
| | SMD-C/SMD-W | 10/11 | 3.5506/10.0582 | 0.0861/0.0891 | 0.0861/21.556 | 3/0 | 1.6262/1.5907 | 1/1 | | Roberts-C/Roberts-W | 10/11 | 2.8268/7.6339 | 0.08214/0.0886 | 1.9627/15.969 | 3/0 | 1.6108/1.6742 | 1/1 | | Sobel-C/Sobel-W | 8/11 | 3.0189/3.7650 | 0.1045/0.0871 | 2.3171/9.0097 | 1/0 | 2.9433/3.3039 | 1/1 | | Brenner-C/Brenner-W | 10/10 | 3.0372/11.610 | 0.0804/0.0942 | 1.9952/10.880 | 4/0 | 1.2488/1.2660 | 1/1 | | SML-C/SML-W | 11/11 | 6.4727/1.6053 | 0.0827/0.0746 | 4.3409/1.8873 | 0/0 | 1.8998/2.1836 | 1/1 |
|
Table 6. Evaluation indexes of focus evaluation functions of center window method and proposed method
