Abstract

An auto-focus method for digital imaging systems is proposed that combines depth from focus (DFF) and improved depth from defocus (DFD). The traditional DFD method is improved to become more rapid, which achieves a fast initial focus. The defocus distance is first calculated by the improved DFD method. The result is then used as a search step in the searching stage of the DFF method. A dynamic focusing scheme is designed for the control software, which is able to eliminate environmental disturbances and other noises so that a fast and accurate focus can be achieved. An experiment is designed to verify the proposed focusing method and the results show that the method's efficiency is at least 3-5 times higher than that of the traditional DFF method.

© 2014 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Nanoscale depth reconstruction from defocus: within an optical diffraction model

Yangjie Wei, Chengdong Wu, and Zaili Dong
Opt. Express 22(21) 25481-25493 (2014)

Fast auto-focusing search algorithm for a high-speed and high-resolution camera based on the image histogram feature function

Chenzi Guo, Zelong Ma, Xu Guo, Wenxian Li, Xinda Qi, and Qinglei Zhao
Appl. Opt. 57(34) F44-F49 (2018)

Depth from defocus measurement method based on liquid crystal lens

Mao Ye, Xiaoxi Chen, Qichang Li, Jun Zeng, and Shuda Yu
Opt. Express 26(22) 28413-28420 (2018)

References

  • View by:
  • |
  • |
  • |

  1. S. Yazdanfar, K. B. Kenny, K. Tasimi, A. D. Corwin, E. L. Dixon, and R. J. Filkins, “Simple and robust image-based autofocusing for digital microscopy,” Opt. Express 16(12), 8670–8677 (2008).
    [Crossref] [PubMed]
  2. J. W. Han, J. H. Kim, H. T. Lee, and S. J. Ko, “A novel training based auto-focus for mobile-phone cameras,” IEEE Trans. Consum. Electron. 57(1), 232–238 (2011).
    [Crossref]
  3. B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
    [Crossref]
  4. C. S. Liu, P. H. Hu, and Y. C. Lin, “Design and experimental validation of novel optics-based autofocusing microscope,” Appl. Phys. B 109(2), 259–268 (2012).
    [Crossref]
  5. C. S. Liu, Y. C. Lin, and P. H. Hu, “Design and characterization of precise laser-based autofocusing microscope with reduced geometrical fluctuations,” Microsyst. Technol. 19(11), 1717–1724 (2013).
    [Crossref]
  6. W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
    [Crossref]
  7. D. K. Cohen, W. H. Gee, M. Ludeke, and J. Lewkowicz, “Automatic focus control: the astigmatic lens approach,” Appl. Opt. 23(4), 565–570 (1984).
    [Crossref] [PubMed]
  8. C. Mo and B. Liu, “An auto-focus algorithm based on maximum gradient and threshold,” 5th International Congress on Image and Signal Processing (CISP) (IEEE, 2012), pp.1191–1194.
    [Crossref]
  9. M. Subbarao, T. Choi, and A. Nikzad, “Focusing techniques,” J. Opt. Eng. 32(11), 2824–2836 (1993).
    [Crossref]
  10. M. Subbarao and J. K. Tyan, “The optimal focus measure for passive autofocusing and depth-from-focus,” Proc. SPIE 2598, 89–99 (1995).
    [Crossref]
  11. M. Subbarao and J. K. Tyan, “Selecting the optimal focus measure for autofocusing and depth-from-focus,” IEEE Trans. Pattern Anal. Mach. Intell. 20(8), 864–870 (1998).
    [Crossref]
  12. S. K. Nayar and Y. Nakagawa, “Shape from focus,” IEEE Trans. Pattern Anal. Mach. Intell. 16(8), 824–831 (1994).
    [Crossref]
  13. J. Kautsky, J. Flusser, B. Zitova, and S. Simberova, “A new wavelet-based measure of image focus,” Pattern Recognit. Lett. 23(14), 1785–1794 (2002).
    [Crossref]
  14. C. H. Lee and T. P. Huang, “Comparison of Two Auto Focus Measurements DCT-STD and DWT-STD,” in Proceedings of the international MultiConference of Engineers and Computer Scientists (Academic, 2012), pp.746–750.
  15. G. Yang and B. J. Nelson, “Wavelet-based autofocusing and unsupervised segmentation of microscopic images,” in Proceedings of IEEE Conference on Intelligence Robots and Systems (IEEE, 2003), pp. 2143–2148.
  16. K. Ooi, K. Izumi, M. Nozaki, and I. Takeda, “An advanced autofocus system for video camera using quasi condition reasoning,” IEEE Trans. Consum. Electron. 36(3), 526–530 (1990).
    [Crossref]
  17. K. S. Choi, J. S. Lee, and S. J. Ko, “New autofocus technique using the frequency selective weighted median filter for video cameras,” IEEE Trans. Consum. Electron. 45(3), 820–827 (1999).
    [Crossref]
  18. J. He, R. Zhou, and Z. Hong, “Modified fast climbing search autofocus algorithm with adaptive step size searching technique for digital camera,” IEEE Trans. Consum. Electron. 49(2), 257–262 (2003).
    [Crossref]
  19. M. Subbarao, “Parallel Depth Recovery by Changing Camera Aperture,” in Proceedings of International Conference on Computer Vision, (Academic, 1988), pp. 149–155.
  20. M. Subbarao and G. Surya, “Depth from Defocus: a Spatial Domain Approach,” Int. J. Comput. Vis. 13(3), 271–294 (1994).
    [Crossref]
  21. P. Favaro and S. Soatto, “A Geometric Approach to Shape from Defocus,” IEEE Trans. Pattern Anal. Mach. Intell. 27(3), 406–417 (2005).
    [Crossref] [PubMed]
  22. A. Levin, R. Fergus, and F. Durand, “Image and depth from a conventional camera with a coded aperture,” ACM Trans. Graph.26(70), 70 (2007) (TOG).
  23. C. Zhou, S. Lin, and S. Nayar, “Coded aperture pairs for depth from defocus and defocus deblurring,” Int. J. Comput. Vis. 93(1), 53–72 (2011).
    [Crossref]
  24. L. Hong, J. Yu, and C. Hong, “Depth estimation from defocus images based on oriented heat-flows,” in Proceedings of IEEE 2nd International Conference on Machine Vision (IEEE, 2009), pp. 212–215.
    [Crossref]
  25. D. T. Huang, Z. Y. Wu, X. C. Liu, and H. S. Zhang, “A depth from defocus fast auto-focusing technology for any target,” Journal of Optoelectronics laser. 24(4), 799–804 (2013).(in Chinese)

2013 (2)

C. S. Liu, Y. C. Lin, and P. H. Hu, “Design and characterization of precise laser-based autofocusing microscope with reduced geometrical fluctuations,” Microsyst. Technol. 19(11), 1717–1724 (2013).
[Crossref]

D. T. Huang, Z. Y. Wu, X. C. Liu, and H. S. Zhang, “A depth from defocus fast auto-focusing technology for any target,” Journal of Optoelectronics laser. 24(4), 799–804 (2013).(in Chinese)

2012 (1)

C. S. Liu, P. H. Hu, and Y. C. Lin, “Design and experimental validation of novel optics-based autofocusing microscope,” Appl. Phys. B 109(2), 259–268 (2012).
[Crossref]

2011 (2)

J. W. Han, J. H. Kim, H. T. Lee, and S. J. Ko, “A novel training based auto-focus for mobile-phone cameras,” IEEE Trans. Consum. Electron. 57(1), 232–238 (2011).
[Crossref]

C. Zhou, S. Lin, and S. Nayar, “Coded aperture pairs for depth from defocus and defocus deblurring,” Int. J. Comput. Vis. 93(1), 53–72 (2011).
[Crossref]

2009 (1)

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

2008 (2)

B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
[Crossref]

S. Yazdanfar, K. B. Kenny, K. Tasimi, A. D. Corwin, E. L. Dixon, and R. J. Filkins, “Simple and robust image-based autofocusing for digital microscopy,” Opt. Express 16(12), 8670–8677 (2008).
[Crossref] [PubMed]

2005 (1)

P. Favaro and S. Soatto, “A Geometric Approach to Shape from Defocus,” IEEE Trans. Pattern Anal. Mach. Intell. 27(3), 406–417 (2005).
[Crossref] [PubMed]

2003 (1)

J. He, R. Zhou, and Z. Hong, “Modified fast climbing search autofocus algorithm with adaptive step size searching technique for digital camera,” IEEE Trans. Consum. Electron. 49(2), 257–262 (2003).
[Crossref]

2002 (1)

J. Kautsky, J. Flusser, B. Zitova, and S. Simberova, “A new wavelet-based measure of image focus,” Pattern Recognit. Lett. 23(14), 1785–1794 (2002).
[Crossref]

1999 (1)

K. S. Choi, J. S. Lee, and S. J. Ko, “New autofocus technique using the frequency selective weighted median filter for video cameras,” IEEE Trans. Consum. Electron. 45(3), 820–827 (1999).
[Crossref]

1998 (1)

M. Subbarao and J. K. Tyan, “Selecting the optimal focus measure for autofocusing and depth-from-focus,” IEEE Trans. Pattern Anal. Mach. Intell. 20(8), 864–870 (1998).
[Crossref]

1995 (1)

M. Subbarao and J. K. Tyan, “The optimal focus measure for passive autofocusing and depth-from-focus,” Proc. SPIE 2598, 89–99 (1995).
[Crossref]

1994 (2)

S. K. Nayar and Y. Nakagawa, “Shape from focus,” IEEE Trans. Pattern Anal. Mach. Intell. 16(8), 824–831 (1994).
[Crossref]

M. Subbarao and G. Surya, “Depth from Defocus: a Spatial Domain Approach,” Int. J. Comput. Vis. 13(3), 271–294 (1994).
[Crossref]

1993 (1)

M. Subbarao, T. Choi, and A. Nikzad, “Focusing techniques,” J. Opt. Eng. 32(11), 2824–2836 (1993).
[Crossref]

1990 (1)

K. Ooi, K. Izumi, M. Nozaki, and I. Takeda, “An advanced autofocus system for video camera using quasi condition reasoning,” IEEE Trans. Consum. Electron. 36(3), 526–530 (1990).
[Crossref]

1984 (1)

Chen, F. Z.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Chen, N. T.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Chen, P. J.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Choi, K. S.

K. S. Choi, J. S. Lee, and S. J. Ko, “New autofocus technique using the frequency selective weighted median filter for video cameras,” IEEE Trans. Consum. Electron. 45(3), 820–827 (1999).
[Crossref]

Choi, T.

M. Subbarao, T. Choi, and A. Nikzad, “Focusing techniques,” J. Opt. Eng. 32(11), 2824–2836 (1993).
[Crossref]

Chung, D. S.

B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
[Crossref]

Cohen, D. K.

Corwin, A. D.

Dixon, E. L.

Durand, F.

A. Levin, R. Fergus, and F. Durand, “Image and depth from a conventional camera with a coded aperture,” ACM Trans. Graph.26(70), 70 (2007) (TOG).

Favaro, P.

P. Favaro and S. Soatto, “A Geometric Approach to Shape from Defocus,” IEEE Trans. Pattern Anal. Mach. Intell. 27(3), 406–417 (2005).
[Crossref] [PubMed]

Fergus, R.

A. Levin, R. Fergus, and F. Durand, “Image and depth from a conventional camera with a coded aperture,” ACM Trans. Graph.26(70), 70 (2007) (TOG).

Filkins, R. J.

Flusser, J.

J. Kautsky, J. Flusser, B. Zitova, and S. Simberova, “A new wavelet-based measure of image focus,” Pattern Recognit. Lett. 23(14), 1785–1794 (2002).
[Crossref]

Gee, W. H.

Han, J. W.

J. W. Han, J. H. Kim, H. T. Lee, and S. J. Ko, “A novel training based auto-focus for mobile-phone cameras,” IEEE Trans. Consum. Electron. 57(1), 232–238 (2011).
[Crossref]

He, J.

J. He, R. Zhou, and Z. Hong, “Modified fast climbing search autofocus algorithm with adaptive step size searching technique for digital camera,” IEEE Trans. Consum. Electron. 49(2), 257–262 (2003).
[Crossref]

Hong, Z.

J. He, R. Zhou, and Z. Hong, “Modified fast climbing search autofocus algorithm with adaptive step size searching technique for digital camera,” IEEE Trans. Consum. Electron. 49(2), 257–262 (2003).
[Crossref]

Hsu, W. Y.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Hu, P. H.

C. S. Liu, Y. C. Lin, and P. H. Hu, “Design and characterization of precise laser-based autofocusing microscope with reduced geometrical fluctuations,” Microsyst. Technol. 19(11), 1717–1724 (2013).
[Crossref]

C. S. Liu, P. H. Hu, and Y. C. Lin, “Design and experimental validation of novel optics-based autofocusing microscope,” Appl. Phys. B 109(2), 259–268 (2012).
[Crossref]

Huang, D. T.

D. T. Huang, Z. Y. Wu, X. C. Liu, and H. S. Zhang, “A depth from defocus fast auto-focusing technology for any target,” Journal of Optoelectronics laser. 24(4), 799–804 (2013).(in Chinese)

Hwang, C. H.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Izumi, K.

K. Ooi, K. Izumi, M. Nozaki, and I. Takeda, “An advanced autofocus system for video camera using quasi condition reasoning,” IEEE Trans. Consum. Electron. 36(3), 526–530 (1990).
[Crossref]

Kautsky, J.

J. Kautsky, J. Flusser, B. Zitova, and S. Simberova, “A new wavelet-based measure of image focus,” Pattern Recognit. Lett. 23(14), 1785–1794 (2002).
[Crossref]

Kenny, K. B.

Kim, C. Y.

B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
[Crossref]

Kim, J. H.

J. W. Han, J. H. Kim, H. T. Lee, and S. J. Ko, “A novel training based auto-focus for mobile-phone cameras,” IEEE Trans. Consum. Electron. 57(1), 232–238 (2011).
[Crossref]

Kim, S. S.

B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
[Crossref]

Ko, S. J.

J. W. Han, J. H. Kim, H. T. Lee, and S. J. Ko, “A novel training based auto-focus for mobile-phone cameras,” IEEE Trans. Consum. Electron. 57(1), 232–238 (2011).
[Crossref]

K. S. Choi, J. S. Lee, and S. J. Ko, “New autofocus technique using the frequency selective weighted median filter for video cameras,” IEEE Trans. Consum. Electron. 45(3), 820–827 (1999).
[Crossref]

Kuo, C. H.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Lee, C. S.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Lee, H. T.

J. W. Han, J. H. Kim, H. T. Lee, and S. J. Ko, “A novel training based auto-focus for mobile-phone cameras,” IEEE Trans. Consum. Electron. 57(1), 232–238 (2011).
[Crossref]

Lee, J. S.

K. S. Choi, J. S. Lee, and S. J. Ko, “New autofocus technique using the frequency selective weighted median filter for video cameras,” IEEE Trans. Consum. Electron. 45(3), 820–827 (1999).
[Crossref]

Lee, S. D.

B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
[Crossref]

Levin, A.

A. Levin, R. Fergus, and F. Durand, “Image and depth from a conventional camera with a coded aperture,” ACM Trans. Graph.26(70), 70 (2007) (TOG).

Lewkowicz, J.

Lin, S.

C. Zhou, S. Lin, and S. Nayar, “Coded aperture pairs for depth from defocus and defocus deblurring,” Int. J. Comput. Vis. 93(1), 53–72 (2011).
[Crossref]

Lin, Y. C.

C. S. Liu, Y. C. Lin, and P. H. Hu, “Design and characterization of precise laser-based autofocusing microscope with reduced geometrical fluctuations,” Microsyst. Technol. 19(11), 1717–1724 (2013).
[Crossref]

C. S. Liu, P. H. Hu, and Y. C. Lin, “Design and experimental validation of novel optics-based autofocusing microscope,” Appl. Phys. B 109(2), 259–268 (2012).
[Crossref]

Liu, C. S.

C. S. Liu, Y. C. Lin, and P. H. Hu, “Design and characterization of precise laser-based autofocusing microscope with reduced geometrical fluctuations,” Microsyst. Technol. 19(11), 1717–1724 (2013).
[Crossref]

C. S. Liu, P. H. Hu, and Y. C. Lin, “Design and experimental validation of novel optics-based autofocusing microscope,” Appl. Phys. B 109(2), 259–268 (2012).
[Crossref]

Liu, X. C.

D. T. Huang, Z. Y. Wu, X. C. Liu, and H. S. Zhang, “A depth from defocus fast auto-focusing technology for any target,” Journal of Optoelectronics laser. 24(4), 799–804 (2013).(in Chinese)

Ludeke, M.

Nakagawa, Y.

S. K. Nayar and Y. Nakagawa, “Shape from focus,” IEEE Trans. Pattern Anal. Mach. Intell. 16(8), 824–831 (1994).
[Crossref]

Nayar, S.

C. Zhou, S. Lin, and S. Nayar, “Coded aperture pairs for depth from defocus and defocus deblurring,” Int. J. Comput. Vis. 93(1), 53–72 (2011).
[Crossref]

Nayar, S. K.

S. K. Nayar and Y. Nakagawa, “Shape from focus,” IEEE Trans. Pattern Anal. Mach. Intell. 16(8), 824–831 (1994).
[Crossref]

Nikzad, A.

M. Subbarao, T. Choi, and A. Nikzad, “Focusing techniques,” J. Opt. Eng. 32(11), 2824–2836 (1993).
[Crossref]

Nozaki, M.

K. Ooi, K. Izumi, M. Nozaki, and I. Takeda, “An advanced autofocus system for video camera using quasi condition reasoning,” IEEE Trans. Consum. Electron. 36(3), 526–530 (1990).
[Crossref]

Ooi, K.

K. Ooi, K. Izumi, M. Nozaki, and I. Takeda, “An advanced autofocus system for video camera using quasi condition reasoning,” IEEE Trans. Consum. Electron. 36(3), 526–530 (1990).
[Crossref]

Park, B. K.

B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
[Crossref]

Simberova, S.

J. Kautsky, J. Flusser, B. Zitova, and S. Simberova, “A new wavelet-based measure of image focus,” Pattern Recognit. Lett. 23(14), 1785–1794 (2002).
[Crossref]

Soatto, S.

P. Favaro and S. Soatto, “A Geometric Approach to Shape from Defocus,” IEEE Trans. Pattern Anal. Mach. Intell. 27(3), 406–417 (2005).
[Crossref] [PubMed]

Subbarao, M.

M. Subbarao and J. K. Tyan, “Selecting the optimal focus measure for autofocusing and depth-from-focus,” IEEE Trans. Pattern Anal. Mach. Intell. 20(8), 864–870 (1998).
[Crossref]

M. Subbarao and J. K. Tyan, “The optimal focus measure for passive autofocusing and depth-from-focus,” Proc. SPIE 2598, 89–99 (1995).
[Crossref]

M. Subbarao and G. Surya, “Depth from Defocus: a Spatial Domain Approach,” Int. J. Comput. Vis. 13(3), 271–294 (1994).
[Crossref]

M. Subbarao, T. Choi, and A. Nikzad, “Focusing techniques,” J. Opt. Eng. 32(11), 2824–2836 (1993).
[Crossref]

Surya, G.

M. Subbarao and G. Surya, “Depth from Defocus: a Spatial Domain Approach,” Int. J. Comput. Vis. 13(3), 271–294 (1994).
[Crossref]

Takeda, I.

K. Ooi, K. Izumi, M. Nozaki, and I. Takeda, “An advanced autofocus system for video camera using quasi condition reasoning,” IEEE Trans. Consum. Electron. 36(3), 526–530 (1990).
[Crossref]

Tasimi, K.

Tyan, J. K.

M. Subbarao and J. K. Tyan, “Selecting the optimal focus measure for autofocusing and depth-from-focus,” IEEE Trans. Pattern Anal. Mach. Intell. 20(8), 864–870 (1998).
[Crossref]

M. Subbarao and J. K. Tyan, “The optimal focus measure for passive autofocusing and depth-from-focus,” Proc. SPIE 2598, 89–99 (1995).
[Crossref]

Wu, Z. Y.

D. T. Huang, Z. Y. Wu, X. C. Liu, and H. S. Zhang, “A depth from defocus fast auto-focusing technology for any target,” Journal of Optoelectronics laser. 24(4), 799–804 (2013).(in Chinese)

Yazdanfar, S.

Yu, Z. R.

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Zhang, H. S.

D. T. Huang, Z. Y. Wu, X. C. Liu, and H. S. Zhang, “A depth from defocus fast auto-focusing technology for any target,” Journal of Optoelectronics laser. 24(4), 799–804 (2013).(in Chinese)

Zhou, C.

C. Zhou, S. Lin, and S. Nayar, “Coded aperture pairs for depth from defocus and defocus deblurring,” Int. J. Comput. Vis. 93(1), 53–72 (2011).
[Crossref]

Zhou, R.

J. He, R. Zhou, and Z. Hong, “Modified fast climbing search autofocus algorithm with adaptive step size searching technique for digital camera,” IEEE Trans. Consum. Electron. 49(2), 257–262 (2003).
[Crossref]

Zitova, B.

J. Kautsky, J. Flusser, B. Zitova, and S. Simberova, “A new wavelet-based measure of image focus,” Pattern Recognit. Lett. 23(14), 1785–1794 (2002).
[Crossref]

Appl. Opt. (1)

Appl. Phys. B (1)

C. S. Liu, P. H. Hu, and Y. C. Lin, “Design and experimental validation of novel optics-based autofocusing microscope,” Appl. Phys. B 109(2), 259–268 (2012).
[Crossref]

IEEE Trans. Consum. Electron. (4)

J. W. Han, J. H. Kim, H. T. Lee, and S. J. Ko, “A novel training based auto-focus for mobile-phone cameras,” IEEE Trans. Consum. Electron. 57(1), 232–238 (2011).
[Crossref]

K. Ooi, K. Izumi, M. Nozaki, and I. Takeda, “An advanced autofocus system for video camera using quasi condition reasoning,” IEEE Trans. Consum. Electron. 36(3), 526–530 (1990).
[Crossref]

K. S. Choi, J. S. Lee, and S. J. Ko, “New autofocus technique using the frequency selective weighted median filter for video cameras,” IEEE Trans. Consum. Electron. 45(3), 820–827 (1999).
[Crossref]

J. He, R. Zhou, and Z. Hong, “Modified fast climbing search autofocus algorithm with adaptive step size searching technique for digital camera,” IEEE Trans. Consum. Electron. 49(2), 257–262 (2003).
[Crossref]

IEEE Trans. Pattern Anal. Mach. Intell. (3)

M. Subbarao and J. K. Tyan, “Selecting the optimal focus measure for autofocusing and depth-from-focus,” IEEE Trans. Pattern Anal. Mach. Intell. 20(8), 864–870 (1998).
[Crossref]

S. K. Nayar and Y. Nakagawa, “Shape from focus,” IEEE Trans. Pattern Anal. Mach. Intell. 16(8), 824–831 (1994).
[Crossref]

P. Favaro and S. Soatto, “A Geometric Approach to Shape from Defocus,” IEEE Trans. Pattern Anal. Mach. Intell. 27(3), 406–417 (2005).
[Crossref] [PubMed]

Int. J. Comput. Vis. (2)

C. Zhou, S. Lin, and S. Nayar, “Coded aperture pairs for depth from defocus and defocus deblurring,” Int. J. Comput. Vis. 93(1), 53–72 (2011).
[Crossref]

M. Subbarao and G. Surya, “Depth from Defocus: a Spatial Domain Approach,” Int. J. Comput. Vis. 13(3), 271–294 (1994).
[Crossref]

J. Opt. Eng. (1)

M. Subbarao, T. Choi, and A. Nikzad, “Focusing techniques,” J. Opt. Eng. 32(11), 2824–2836 (1993).
[Crossref]

Journal of Optoelectronics laser. (1)

D. T. Huang, Z. Y. Wu, X. C. Liu, and H. S. Zhang, “A depth from defocus fast auto-focusing technology for any target,” Journal of Optoelectronics laser. 24(4), 799–804 (2013).(in Chinese)

Meas. Sci. Technol. (1)

W. Y. Hsu, C. S. Lee, P. J. Chen, N. T. Chen, F. Z. Chen, Z. R. Yu, C. H. Kuo, and C. H. Hwang, “Development of the fast astigmatic auto-focus microscope system,” Meas. Sci. Technol. 20(4), 045902 (2009).
[Crossref]

Microsyst. Technol. (1)

C. S. Liu, Y. C. Lin, and P. H. Hu, “Design and characterization of precise laser-based autofocusing microscope with reduced geometrical fluctuations,” Microsyst. Technol. 19(11), 1717–1724 (2013).
[Crossref]

Opt. Express (1)

Pattern Recognit. Lett. (1)

J. Kautsky, J. Flusser, B. Zitova, and S. Simberova, “A new wavelet-based measure of image focus,” Pattern Recognit. Lett. 23(14), 1785–1794 (2002).
[Crossref]

Proc. SPIE (2)

B. K. Park, S. S. Kim, D. S. Chung, S. D. Lee, and C. Y. Kim, “Fast and accurate auto focusing algorithm based on two defocused images using discrete cosine transform,” Proc. SPIE 6817, 68170D (2008).
[Crossref]

M. Subbarao and J. K. Tyan, “The optimal focus measure for passive autofocusing and depth-from-focus,” Proc. SPIE 2598, 89–99 (1995).
[Crossref]

Other (6)

C. Mo and B. Liu, “An auto-focus algorithm based on maximum gradient and threshold,” 5th International Congress on Image and Signal Processing (CISP) (IEEE, 2012), pp.1191–1194.
[Crossref]

C. H. Lee and T. P. Huang, “Comparison of Two Auto Focus Measurements DCT-STD and DWT-STD,” in Proceedings of the international MultiConference of Engineers and Computer Scientists (Academic, 2012), pp.746–750.

G. Yang and B. J. Nelson, “Wavelet-based autofocusing and unsupervised segmentation of microscopic images,” in Proceedings of IEEE Conference on Intelligence Robots and Systems (IEEE, 2003), pp. 2143–2148.

M. Subbarao, “Parallel Depth Recovery by Changing Camera Aperture,” in Proceedings of International Conference on Computer Vision, (Academic, 1988), pp. 149–155.

L. Hong, J. Yu, and C. Hong, “Depth estimation from defocus images based on oriented heat-flows,” in Proceedings of IEEE 2nd International Conference on Machine Vision (IEEE, 2009), pp. 212–215.
[Crossref]

A. Levin, R. Fergus, and F. Durand, “Image and depth from a conventional camera with a coded aperture,” ACM Trans. Graph.26(70), 70 (2007) (TOG).

Cited By

OSA participates in Crossref's Cited-By Linking service. Citing articles from OSA journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (8)

Fig. 1
Fig. 1 Spreading process of the image points.
Fig. 2
Fig. 2 The optical imaging model.
Fig. 3
Fig. 3 Blurred image of P on different planes.
Fig. 4
Fig. 4 (a). The relevant parameters in the modeling change. ∆u denotes the variation of the object distance u, corresponding to two images taken at two positions in the focusing process, ∆v is the variation of the image distance v caused by ∆u, dmax is the defocus distance in image space, and uref denotes the defocus distance in the object space. (b) The process of the modeling change.
Fig. 5
Fig. 5 The combined focusing method.
Fig. 6
Fig. 6 The schematic of the experimental setup.
Fig. 7
Fig. 7 Curve of the estimated defocus distance. The horizontal axis corresponds to the 18 sampling positions from small to large distances from the focal position, and the value is the real corresponding defocused distance. The vertical axis denotes the corresponding estimated defocus distance.
Fig. 8
Fig. 8 Curve of the relative error.

Tables (2)

Tables Icon

Table 1 Estimated defocus distance for the three objects.

Tables Icon

Table 2 Comparison between the proposed combination method and the DFF method.

Equations (15)

Equations on this page are rendered with MathJax. Learn more.

R 1 =d D 2 ( 1 f 1 u ).
R 1 =kd.
R 2 =k(d+Δd).
V 1 S 1 < V 2 S 2 .
R 1 R 2 < V 2 V 1 .
d<Δd V 2 / V 1 1 V 2 / V 1 .
d max =Δd V 2 / V 1 1 V 2 / V 1 .
1 f = 1 u+Δu + 1 v+Δv .
d max =Δv V 2 / V 1 1 V 2 / V 1 .
Δv Δu = β 1 β 2 = f u 1 f f u 2 f .
d max u ref = β 1 β 0 = f u 1 f f u 0 f .
u ref (K)=KCΔu.
C= V 2 / V 1 1 V 2 / V 1 ,K= u 0 f u 2 f .
u ref =Δu V 2 / V 1 1 V 2 / V 1 .
u real(max) = u ref =Δu V 2 / V 1 1 V 2 / V 1 .

Metrics