Abstract

In recent studies, the advanced wide field of view architectures for image reconstruction and exploitation (AWARE) multiscale camera, which is composed of a monocentric objective lens and an array of microcameras, was developed for the realization of snapshot wide field of view and high resolution imaging. This paper describes accelerated autofocus (AF) methods for the AWARE system based on a hierarchical spatial algorithm and an iterative temporal algorithm. In the algorithms, sensor positions of each microcamera are hierarchically scanned with contrast detection to effectively search for a focusing distance. The positions are then updated iteratively for dynamic scenes using temporal information. The algorithms are theoretically analyzed and experimentally demonstrated. The developed AF methods can be used for the realization of the temporal gigapixel imaging by the AWARE system.

© 2013 Optical Society of America

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References

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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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2013 (3)

2012 (4)

2011 (5)

2010 (1)

O. Cossairt, C. Zhou, and S. K. Nayar, “Diffusion coding photography for extended depth of field,” ACM Trans. Graph. 29, 31 (2010).
[CrossRef]

2009 (1)

2007 (1)

L. Shih, “Autofocus survey: a comparison of algorithms,” Proc. Soc. Photo-Opt. Instrum. Eng. 6502, 65020B (2007).

2001 (1)

C. Raphael, “Coarse-to-fine dynamic programming,” IEEE Trans. Pattern Anal. Mach. Intell. 23, 1379–1390 (2001).
[CrossRef]

1995 (1)

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, 526–530 (1990).
[CrossRef]

1985 (1)

F. C. A. Groen, I. T. Young, and G. Ligthart, “A comparison of different autofocus algorithms,” Cytometry 6, 81–91 (1985).
[CrossRef]

1972 (1)

G. Häusler, “A method to increase the depth of focus by two step image processing,” Opt. Commun. 6, 38–42 (1972).
[CrossRef]

Brady, D. J.

H. S. Son, A. Johnson, R. A. Stack, J. M. Shaw, P. McLaughlin, D. L. Marks, D. J. Brady, and J. Kim, “Optomechanical design of multiscale gigapixel digital camera,” Appl. Opt. 52, 1541–1549 (2013).
[CrossRef]

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

D. R. Golish, E. M. Vera, K. J. Kelly, Q. Gong, P. A. Jansen, J. M. Hughes, D. S. Kittle, D. J. Brady, and M. E. Gehm, “Development of a scalable image formation pipeline for multiscale gigapixel photography,” Opt. Express 20, 22048–22062 (2012).
[CrossRef]

E. J. Tremblay, D. L. Marks, D. J. Brady, and J. E. Ford, “Design and scaling of monocentric multiscale imagers,” Appl. Opt. 51, 4691–4702 (2012).
[CrossRef]

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

D. L. Marks, E. J. Tremblay, J. E. Ford, and D. J. Brady, “Microcamera aperture scale in monocentric gigapixel cameras,” Appl. Opt. 50, 5824–5833 (2011).
[CrossRef]

H. S. Son, D. L. Marks, J. Hahn, J. Kim, and D. J. Brady, “Design of a spherical focal surface using close-packed relay optics,” Opt. Express 19, 16132–16138 (2011).
[CrossRef]

D. J. Brady and N. Hagen, “Multiscale lens design,” Opt. Express 17, 10659–10674 (2009).
[CrossRef]

D. L. Marks and D. J. Brady, “Gigagon: a monocentric lens design imaging 40 gigapixels,” in Imaging Systems, OSA Technical Digest (CD) (Optical Society of America, 2010), paper ITuC2.

D. J. Brady, “Focus in multiscale imaging systems,” in Imaging and Applied Optics Technical Papers, OSA Technical Digest (online) (Optical Society of America, 2012), paper CM2B.1.

Cathey, W. T.

Chen, H. H.

C. H. Shen and H. H. Chen, “Robust focus measure for low-contrast images,” in IEEE International Conference on Consumer Electronics (IEEE, 2006), pp. 7–11.

D. C. Tsai and H. H. Chen, “Smooth control of continuous autofocus,” in IEEE International Conference on Image Processing (IEEE, 2012).

Cossairt, O.

O. Cossairt, C. Zhou, and S. K. Nayar, “Diffusion coding photography for extended depth of field,” ACM Trans. Graph. 29, 31 (2010).
[CrossRef]

Davis, L. S.

H. Thanarat, D. Harwood, and L. S. Davis, “A statistical approach for real-time robust background subtraction and shadow detection,” in IEEE International Conference on Computer Vision (IEEE, 1999).

Dowski, E. R.

Feller, S. D.

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

Ford, J. E.

Gamadia, M.

M. Gamadia and N. Kehtarnavaz, “A real-time continuous automatic focus algorithm for digital cameras,” in IEEE Southwest Symposium on Image Analysis and Interpretation (IEEE, 2006).

Gehm, M. E.

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

D. R. Golish, E. M. Vera, K. J. Kelly, Q. Gong, P. A. Jansen, J. M. Hughes, D. S. Kittle, D. J. Brady, and M. E. Gehm, “Development of a scalable image formation pipeline for multiscale gigapixel photography,” Opt. Express 20, 22048–22062 (2012).
[CrossRef]

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

Golish, D. R.

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

D. R. Golish, E. M. Vera, K. J. Kelly, Q. Gong, P. A. Jansen, J. M. Hughes, D. S. Kittle, D. J. Brady, and M. E. Gehm, “Development of a scalable image formation pipeline for multiscale gigapixel photography,” Opt. Express 20, 22048–22062 (2012).
[CrossRef]

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

Gong, Q.

Goodman, J. W.

J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, 1996).

Groen, F. C. A.

F. C. A. Groen, I. T. Young, and G. Ligthart, “A comparison of different autofocus algorithms,” Cytometry 6, 81–91 (1985).
[CrossRef]

Hagen, N.

Hahn, J.

Harwood, D.

H. Thanarat, D. Harwood, and L. S. Davis, “A statistical approach for real-time robust background subtraction and shadow detection,” in IEEE International Conference on Computer Vision (IEEE, 1999).

Häusler, G.

G. Häusler, “A method to increase the depth of focus by two step image processing,” Opt. Commun. 6, 38–42 (1972).
[CrossRef]

Horisaki, R.

Hua, H.

Hughes, J. M.

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, 526–530 (1990).
[CrossRef]

Jansen, P. A.

Johnson, A.

Kehtarnavaz, N.

M. Gamadia and N. Kehtarnavaz, “A real-time continuous automatic focus algorithm for digital cameras,” in IEEE Southwest Symposium on Image Analysis and Interpretation (IEEE, 2006).

Kelly, K. J.

Kim, J.

Kittle, D. S.

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

D. R. Golish, E. M. Vera, K. J. Kelly, Q. Gong, P. A. Jansen, J. M. Hughes, D. S. Kittle, D. J. Brady, and M. E. Gehm, “Development of a scalable image formation pipeline for multiscale gigapixel photography,” Opt. Express 20, 22048–22062 (2012).
[CrossRef]

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

Ligthart, G.

F. C. A. Groen, I. T. Young, and G. Ligthart, “A comparison of different autofocus algorithms,” Cytometry 6, 81–91 (1985).
[CrossRef]

Liu, S.

Liu, X.

X. Xu, Y. Wang, J. Tang, X. Zhang, and X. Liu, “Robust automatic focus algorithm for low contrast images using a new contrast measure,” Sensors 11, 8281–8294 (2011).
[CrossRef]

Lowe, D. G.

D. G. Lowe, “Object recognition from local scale-invariant features,” in IEEE International Conference on Computer Vision (IEEE, 1999).

Marks, D. L.

H. S. Son, A. Johnson, R. A. Stack, J. M. Shaw, P. McLaughlin, D. L. Marks, D. J. Brady, and J. Kim, “Optomechanical design of multiscale gigapixel digital camera,” Appl. Opt. 52, 1541–1549 (2013).
[CrossRef]

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

E. J. Tremblay, D. L. Marks, D. J. Brady, and J. E. Ford, “Design and scaling of monocentric multiscale imagers,” Appl. Opt. 51, 4691–4702 (2012).
[CrossRef]

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

D. L. Marks, E. J. Tremblay, J. E. Ford, and D. J. Brady, “Microcamera aperture scale in monocentric gigapixel cameras,” Appl. Opt. 50, 5824–5833 (2011).
[CrossRef]

H. S. Son, D. L. Marks, J. Hahn, J. Kim, and D. J. Brady, “Design of a spherical focal surface using close-packed relay optics,” Opt. Express 19, 16132–16138 (2011).
[CrossRef]

D. L. Marks and D. J. Brady, “Gigagon: a monocentric lens design imaging 40 gigapixels,” in Imaging Systems, OSA Technical Digest (CD) (Optical Society of America, 2010), paper ITuC2.

McLaughlin, P.

Nakamura, T.

Nayar, S. K.

O. Cossairt, C. Zhou, and S. K. Nayar, “Diffusion coding photography for extended depth of field,” ACM Trans. Graph. 29, 31 (2010).
[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, 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, 526–530 (1990).
[CrossRef]

Raphael, C.

C. Raphael, “Coarse-to-fine dynamic programming,” IEEE Trans. Pattern Anal. Mach. Intell. 23, 1379–1390 (2001).
[CrossRef]

Shaw, J. M.

Shen, C. H.

C. H. Shen and H. H. Chen, “Robust focus measure for low-contrast images,” in IEEE International Conference on Consumer Electronics (IEEE, 2006), pp. 7–11.

Shih, L.

L. Shih, “Autofocus survey: a comparison of algorithms,” Proc. Soc. Photo-Opt. Instrum. Eng. 6502, 65020B (2007).

Son, H. S.

Stack, R. A.

H. S. Son, A. Johnson, R. A. Stack, J. M. Shaw, P. McLaughlin, D. L. Marks, D. J. Brady, and J. Kim, “Optomechanical design of multiscale gigapixel digital camera,” Appl. Opt. 52, 1541–1549 (2013).
[CrossRef]

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[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, 526–530 (1990).
[CrossRef]

Tang, J.

X. Xu, Y. Wang, J. Tang, X. Zhang, and X. Liu, “Robust automatic focus algorithm for low contrast images using a new contrast measure,” Sensors 11, 8281–8294 (2011).
[CrossRef]

Tanida, J.

Thanarat, H.

H. Thanarat, D. Harwood, and L. S. Davis, “A statistical approach for real-time robust background subtraction and shadow detection,” in IEEE International Conference on Computer Vision (IEEE, 1999).

Tremblay, E. J.

Tsai, D. C.

D. C. Tsai and H. H. Chen, “Smooth control of continuous autofocus,” in IEEE International Conference on Image Processing (IEEE, 2012).

Vera, E. M.

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

D. R. Golish, E. M. Vera, K. J. Kelly, Q. Gong, P. A. Jansen, J. M. Hughes, D. S. Kittle, D. J. Brady, and M. E. Gehm, “Development of a scalable image formation pipeline for multiscale gigapixel photography,” Opt. Express 20, 22048–22062 (2012).
[CrossRef]

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

Wang, Y.

X. Xu, Y. Wang, J. Tang, X. Zhang, and X. Liu, “Robust automatic focus algorithm for low contrast images using a new contrast measure,” Sensors 11, 8281–8294 (2011).
[CrossRef]

Xu, X.

X. Xu, Y. Wang, J. Tang, X. Zhang, and X. Liu, “Robust automatic focus algorithm for low contrast images using a new contrast measure,” Sensors 11, 8281–8294 (2011).
[CrossRef]

Young, I. T.

F. C. A. Groen, I. T. Young, and G. Ligthart, “A comparison of different autofocus algorithms,” Cytometry 6, 81–91 (1985).
[CrossRef]

Zhang, X.

X. Xu, Y. Wang, J. Tang, X. Zhang, and X. Liu, “Robust automatic focus algorithm for low contrast images using a new contrast measure,” Sensors 11, 8281–8294 (2011).
[CrossRef]

Zhou, C.

O. Cossairt, C. Zhou, and S. K. Nayar, “Diffusion coding photography for extended depth of field,” ACM Trans. Graph. 29, 31 (2010).
[CrossRef]

ACM Trans. Graph. (1)

O. Cossairt, C. Zhou, and S. K. Nayar, “Diffusion coding photography for extended depth of field,” ACM Trans. Graph. 29, 31 (2010).
[CrossRef]

Appl. Opt. (4)

Appl. Phys. Express (1)

R. Horisaki, T. Nakamura, and J. Tanida, “Superposition imaging for three-dimensionally space-invariant point spread functions,” Appl. Phys. Express 4, 112501 (2011).
[CrossRef]

Cytometry (1)

F. C. A. Groen, I. T. Young, and G. Ligthart, “A comparison of different autofocus algorithms,” Cytometry 6, 81–91 (1985).
[CrossRef]

IEEE Trans. Consum. Electron. (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, 526–530 (1990).
[CrossRef]

IEEE Trans. Pattern Anal. Mach. Intell. (1)

C. Raphael, “Coarse-to-fine dynamic programming,” IEEE Trans. Pattern Anal. Mach. Intell. 23, 1379–1390 (2001).
[CrossRef]

Nature (1)

D. J. Brady, M. E. Gehm, R. A. Stack, D. L. Marks, D. S. Kittle, D. R. Golish, E. M. Vera, and S. D. Feller, “Multiscale gigapixel photography,” Nature 486, 386–389 (2012).
[CrossRef]

Opt. Commun. (1)

G. Häusler, “A method to increase the depth of focus by two step image processing,” Opt. Commun. 6, 38–42 (1972).
[CrossRef]

Opt. Express (5)

Opt. Lett. (1)

Proc. Soc. Photo-Opt. Instrum. Eng. (2)

D. J. Brady, D. L. Marks, S. D. Feller, M. E. Gehm, D. R. Golish, E. M. Vera, and D. S. Kittle, “Petapixel photography and the limits of camera information capacity,” Proc. Soc. Photo-Opt. Instrum. Eng. 8657, 86570B (2013).

L. Shih, “Autofocus survey: a comparison of algorithms,” Proc. Soc. Photo-Opt. Instrum. Eng. 6502, 65020B (2007).

Sensors (1)

X. Xu, Y. Wang, J. Tang, X. Zhang, and X. Liu, “Robust automatic focus algorithm for low contrast images using a new contrast measure,” Sensors 11, 8281–8294 (2011).
[CrossRef]

Other (9)

M. Gamadia and N. Kehtarnavaz, “A real-time continuous automatic focus algorithm for digital cameras,” in IEEE Southwest Symposium on Image Analysis and Interpretation (IEEE, 2006).

D. C. Tsai and H. H. Chen, “Smooth control of continuous autofocus,” in IEEE International Conference on Image Processing (IEEE, 2012).

H. Thanarat, D. Harwood, and L. S. Davis, “A statistical approach for real-time robust background subtraction and shadow detection,” in IEEE International Conference on Computer Vision (IEEE, 1999).

D. G. Lowe, “Object recognition from local scale-invariant features,” in IEEE International Conference on Computer Vision (IEEE, 1999).

J. W. Goodman, Introduction to Fourier Optics (McGraw-Hill, 1996).

D. L. Marks and D. J. Brady, “Gigagon: a monocentric lens design imaging 40 gigapixels,” in Imaging Systems, OSA Technical Digest (CD) (Optical Society of America, 2010), paper ITuC2.

C. H. Shen and H. H. Chen, “Robust focus measure for low-contrast images,” in IEEE International Conference on Consumer Electronics (IEEE, 2006), pp. 7–11.

“AWARE2 Multiscale Gigapixel Camera,” http://www.disp.duke.edu/projects/AWARE/ .

D. J. Brady, “Focus in multiscale imaging systems,” in Imaging and Applied Optics Technical Papers, OSA Technical Digest (online) (Optical Society of America, 2012), paper CM2B.1.

Supplementary Material (1)

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Figures (12)

Fig. 1.
Fig. 1.

Optical design and focusing mechanism of the AWARE multiscale gigapixel camera.

Fig. 2.
Fig. 2.

Gigapixel-class photograph of the Duke University Chapel taken by the AWARE-10 camera.

Fig. 3.
Fig. 3.

Schematic diagram of AF based on linear scanning of the focusing carriage of the micro-optic.

Fig. 4.
Fig. 4.

Schematic diagrams of the AF based on a hierarchical search. The focusing sensor position search range and the scan interval hierarchically decreased with increasing layer number.

Fig. 5.
Fig. 5.

Comparison of the performance of the AF based on linear scanning and hierarchical scanning.

Fig. 6.
Fig. 6.

Flow chart of an iterative AF for the time-sequential AWARE system.

Fig. 7.
Fig. 7.

Experimental setup for testing the AWARE camera system with the proposed AF algorithm.

Fig. 8.
Fig. 8.

(Media 1) Demonstration of the iterative AF for the time-continuous AWARE system. Captured images when (a) a microcamera is focused on a color chart, (b) when a poster is inserted in front of the color chart, (c) after focusing on the poster, (d) after removing the poster, and (e) after focusing on the color chart again. Green rectangles in the images are the ROIs for the contrast calculation.

Fig. 9.
Fig. 9.

(a) A captured image of two objects and (b) an EDOF image obtained by computational superposition imaging.

Fig. 10.
Fig. 10.

Schematic diagram of cooperative AF in the AWARE system.

Fig. 11.
Fig. 11.

Algorithm of a robust AF based on the cooperative AF.

Fig. 12.
Fig. 12.

Quick AF for a moving object based on the cooperative AF. (a) When t=t1, an object is moving within the FOV of the microcamera k toward the FOV of the microcamera k+1. (b) When t=t1+δt, the object is within the FOV of the camera k+1 as expected by a global model, and the focusing distances of both microcameras have already been adjusted in advance.

Equations (9)

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zAF=argmaxzf(gz)=argminzGz(0,0)jNyiNxGz(i,j)Gz(0,0),Gz=|F[gz]|,
zn+1=zn+r,
O(R,r)=Rr.
zn+1m=znm+rm,rm=RmD,Rm+1=αRmD,
r=rM,R=R1,
O(R,r,D)=DlogD(Rr).
f(gcur)<f(gref)d,
zn+1=znβf(gzn),
f(gzn)=0.

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