Abstract

In this paper we present a simple approach to obtain extended depth of field for any optical imaging system just by adding a birefringent plate between the lens and the detector. The width of the plate is properly designed such that one polarization state contains in-focus near field information while the other polarization state contains in-focus far field details. Both images are superimposed one on top of the other and thus an all-optical spatially sharp imaging is obtained containing both fields. The width of the plate is also designed such that there is a longitudinal overlapping of the two regions (the near and the far) such that continuously well focused imaging is generated. The presented approach for extending the depth of focus is significantly simple compared to the use of birefringent and bi-focal lenses published recently. Preliminary numerical as well as experimental results verify the proposed approach.

© 2007 Optical Society of America

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  1. J. Ojeda-Castaneda, J. C. Escalera and M. J. Yzuel, " Super-Gaussian rings: focusing properties," Opt. Commun. 114, 189-193 (1995).
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    [CrossRef] [PubMed]
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    [CrossRef]
  7. E. Ben-Eliezer, E. Marom, N. Konforti, and Z. Zalevsky, "Experimental realization of an imaging system with an extended depth of field," Appl. Opt. 44, 2792-2798 (2005).
    [CrossRef] [PubMed]
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    [CrossRef]
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    [CrossRef] [PubMed]
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    [CrossRef]
  11. S. Sanyal and A. Ghosh, "High tolerance to spherical aberrations and defects of focus with a birefringent lens," Appl. Opt. 41, 4611-4619 (2002).
    [CrossRef] [PubMed]
  12. S. Sanyal, P. Bandyopadhyay, and A. Ghosh, "Vector wave imagery using a birefringent lens," Opt. Eng. 37, 592-599 (1998).
    [CrossRef]
  13. S. Sanyal and A. Ghosh, "Simulation of complex masks on the lens aperture using a birefringent lens," Opt. Optoelectron. 1, 656-661 (1998).
  14. S. Sanyal and A. Ghosh, "Imaging characteristics of birefringent lenses under focused and defocused conditions," Optik 110, 513-520 (1999).
  15. S. Sanyal and A. Ghosh, "High focal depth with a quasi-bifocus birefringent lens," Appl. Opt. 39, 2321-2325 (2000).
    [CrossRef]
  16. X. Liu, X. Cai, S. Chang and C. Grover, "Cemented doublet lens with an extended focal depth," Opt. Express 13, 552-557 (2005).
    [CrossRef] [PubMed]
  17. Z. Zalevsky and S. Ben-Yaish, "All optical longitudinal super resolved imaging with birefringent plate," US Provisional Patent Application #  60/793,227 (2006).

2006 (2)

Z. Zalevsky and S. Ben-Yaish, "All optical longitudinal super resolved imaging with birefringent plate," US Provisional Patent Application #  60/793,227 (2006).

Z. Zalevsky, A. Shemer, A. Zlotnik, E. Ben-Eliezer, and E. Marom, "All-optical axial super resolving imaging using low-frequency binary-phase mask," Opt. Express 14, 2631-2643 (2006).
[CrossRef] [PubMed]

2005 (2)

2003 (1)

E. Ben-Eliezer, Z. Zalevsky, E. Marom, and N. Konforti, "All-optical extended depth of field imaging system," J. Opt. A: Pure Appl. Opt. 5, S164-S169 (2003).
[CrossRef]

2002 (1)

2001 (1)

2000 (1)

1999 (1)

S. Sanyal and A. Ghosh, "Imaging characteristics of birefringent lenses under focused and defocused conditions," Optik 110, 513-520 (1999).

1998 (2)

S. Sanyal, P. Bandyopadhyay, and A. Ghosh, "Vector wave imagery using a birefringent lens," Opt. Eng. 37, 592-599 (1998).
[CrossRef]

S. Sanyal and A. Ghosh, "Simulation of complex masks on the lens aperture using a birefringent lens," Opt. Optoelectron. 1, 656-661 (1998).

1996 (1)

1995 (2)

E. R. Dowski and W. T. Cathey, "Extended depth of field through wave-front coding," Appl. Opt. 34, 1859-1866 (1995).
[CrossRef] [PubMed]

J. Ojeda-Castaneda, J. C. Escalera and M. J. Yzuel, " Super-Gaussian rings: focusing properties," Opt. Commun. 114, 189-193 (1995).

1994 (1)

K. Bhattacharya, A. K. Chakraborty and A. Ghosh, "Simulation of effects of phase and amplitude coatings on the lens aperture with polarization masks," J. Opt. Soc. Am.  A 11, 586 (1994).
[CrossRef]

1990 (1)

1989 (1)

Bandyopadhyay, P.

S. Sanyal, P. Bandyopadhyay, and A. Ghosh, "Vector wave imagery using a birefringent lens," Opt. Eng. 37, 592-599 (1998).
[CrossRef]

Ben-Eliezer, E.

Ben-Yaish, S.

Z. Zalevsky and S. Ben-Yaish, "All optical longitudinal super resolved imaging with birefringent plate," US Provisional Patent Application #  60/793,227 (2006).

Berriel-Valdos, L. R.

Bhattacharya, K.

K. Bhattacharya, A. K. Chakraborty and A. Ghosh, "Simulation of effects of phase and amplitude coatings on the lens aperture with polarization masks," J. Opt. Soc. Am.  A 11, 586 (1994).
[CrossRef]

Cai, X.

Castaneda, J. O.

Cathey, W. T.

Chakraborty, A. K.

K. Bhattacharya, A. K. Chakraborty and A. Ghosh, "Simulation of effects of phase and amplitude coatings on the lens aperture with polarization masks," J. Opt. Soc. Am.  A 11, 586 (1994).
[CrossRef]

Chang, S.

Chi, W.

Deaver, D.

Diaz, A.

Dowski, E.

Dowski, E. R.

Escalera, J. C.

J. Ojeda-Castaneda, J. C. Escalera and M. J. Yzuel, " Super-Gaussian rings: focusing properties," Opt. Commun. 114, 189-193 (1995).

George, N.

Ghosh, A.

S. Sanyal and A. Ghosh, "High tolerance to spherical aberrations and defects of focus with a birefringent lens," Appl. Opt. 41, 4611-4619 (2002).
[CrossRef] [PubMed]

S. Sanyal and A. Ghosh, "High focal depth with a quasi-bifocus birefringent lens," Appl. Opt. 39, 2321-2325 (2000).
[CrossRef]

S. Sanyal and A. Ghosh, "Imaging characteristics of birefringent lenses under focused and defocused conditions," Optik 110, 513-520 (1999).

S. Sanyal, P. Bandyopadhyay, and A. Ghosh, "Vector wave imagery using a birefringent lens," Opt. Eng. 37, 592-599 (1998).
[CrossRef]

S. Sanyal and A. Ghosh, "Simulation of complex masks on the lens aperture using a birefringent lens," Opt. Optoelectron. 1, 656-661 (1998).

K. Bhattacharya, A. K. Chakraborty and A. Ghosh, "Simulation of effects of phase and amplitude coatings on the lens aperture with polarization masks," J. Opt. Soc. Am.  A 11, 586 (1994).
[CrossRef]

Grover, C.

Konforti, N.

E. Ben-Eliezer, E. Marom, N. Konforti, and Z. Zalevsky, "Experimental realization of an imaging system with an extended depth of field," Appl. Opt. 44, 2792-2798 (2005).
[CrossRef] [PubMed]

E. Ben-Eliezer, Z. Zalevsky, E. Marom, and N. Konforti, "All-optical extended depth of field imaging system," J. Opt. A: Pure Appl. Opt. 5, S164-S169 (2003).
[CrossRef]

Liu, X.

Marom, E.

Ojeda-Castaneda, J.

J. Ojeda-Castaneda, J. C. Escalera and M. J. Yzuel, " Super-Gaussian rings: focusing properties," Opt. Commun. 114, 189-193 (1995).

Sanyal, S.

S. Sanyal and A. Ghosh, "High tolerance to spherical aberrations and defects of focus with a birefringent lens," Appl. Opt. 41, 4611-4619 (2002).
[CrossRef] [PubMed]

S. Sanyal and A. Ghosh, "High focal depth with a quasi-bifocus birefringent lens," Appl. Opt. 39, 2321-2325 (2000).
[CrossRef]

S. Sanyal and A. Ghosh, "Imaging characteristics of birefringent lenses under focused and defocused conditions," Optik 110, 513-520 (1999).

S. Sanyal, P. Bandyopadhyay, and A. Ghosh, "Vector wave imagery using a birefringent lens," Opt. Eng. 37, 592-599 (1998).
[CrossRef]

S. Sanyal and A. Ghosh, "Simulation of complex masks on the lens aperture using a birefringent lens," Opt. Optoelectron. 1, 656-661 (1998).

Shemer, A.

Taylor, M.

Tepichin, E.

Van Der Gracht, J.

Yzuel, M. J.

J. Ojeda-Castaneda, J. C. Escalera and M. J. Yzuel, " Super-Gaussian rings: focusing properties," Opt. Commun. 114, 189-193 (1995).

Zalevsky, Z.

Z. Zalevsky, A. Shemer, A. Zlotnik, E. Ben-Eliezer, and E. Marom, "All-optical axial super resolving imaging using low-frequency binary-phase mask," Opt. Express 14, 2631-2643 (2006).
[CrossRef] [PubMed]

Z. Zalevsky and S. Ben-Yaish, "All optical longitudinal super resolved imaging with birefringent plate," US Provisional Patent Application #  60/793,227 (2006).

E. Ben-Eliezer, E. Marom, N. Konforti, and Z. Zalevsky, "Experimental realization of an imaging system with an extended depth of field," Appl. Opt. 44, 2792-2798 (2005).
[CrossRef] [PubMed]

E. Ben-Eliezer, Z. Zalevsky, E. Marom, and N. Konforti, "All-optical extended depth of field imaging system," J. Opt. A: Pure Appl. Opt. 5, S164-S169 (2003).
[CrossRef]

Zlotnik, A.

Appl. Opt. (6)

J. Opt. A: Pure Appl. Opt. (1)

E. Ben-Eliezer, Z. Zalevsky, E. Marom, and N. Konforti, "All-optical extended depth of field imaging system," J. Opt. A: Pure Appl. Opt. 5, S164-S169 (2003).
[CrossRef]

J. Opt. Soc. Am. (1)

K. Bhattacharya, A. K. Chakraborty and A. Ghosh, "Simulation of effects of phase and amplitude coatings on the lens aperture with polarization masks," J. Opt. Soc. Am.  A 11, 586 (1994).
[CrossRef]

Opt. Commun. (1)

J. Ojeda-Castaneda, J. C. Escalera and M. J. Yzuel, " Super-Gaussian rings: focusing properties," Opt. Commun. 114, 189-193 (1995).

Opt. Eng. (1)

S. Sanyal, P. Bandyopadhyay, and A. Ghosh, "Vector wave imagery using a birefringent lens," Opt. Eng. 37, 592-599 (1998).
[CrossRef]

Opt. Express (2)

Opt. Lett. (2)

Opt. Optoelectron. (1)

S. Sanyal and A. Ghosh, "Simulation of complex masks on the lens aperture using a birefringent lens," Opt. Optoelectron. 1, 656-661 (1998).

Optik (1)

S. Sanyal and A. Ghosh, "Imaging characteristics of birefringent lenses under focused and defocused conditions," Optik 110, 513-520 (1999).

US Provisional Patent Application (1)

Z. Zalevsky and S. Ben-Yaish, "All optical longitudinal super resolved imaging with birefringent plate," US Provisional Patent Application #  60/793,227 (2006).

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Figures (5)

Fig. 1.
Fig. 1.

(a). The through focus MTF chart for ordinary and extraordinary polarization states at 60 cycles per mm for object at infinity and at 25cm with birefringent plate added between the lens and the detector. (b). The overall point spread function of both polarizations obtained at infinity (left) and at 25cm (right). (c). The point spread function of the ordinary polarization when the extraordinary is in focus and vice versa.

Fig. 2.
Fig. 2.

The through focus MTF chart at 60 cycles per mm for object at infinity and at 15cm with birefringent plate added between the lens and the detector.

Fig. 3.
Fig. 3.

Numerical testing applied on real images. (a). Image captured when far filed objects are in focus. (b). Image captured when a near field object which was a business card positioned 10cm away from the camera was in focus. (c). Image captured when the birefringent plate approach was applied.

Fig. 4.
Fig. 4.

Experimental testing of the proposed approach. In both figures of (a) and (b) imaging of close as well as far objects was performed while the suggested birefringent element was inserted in the imaging module for the left side of the images of (a) and (b) and no element was used, for comparison purposes, in the right side of the images of (a) and (b).

Fig. 5.
Fig. 5.

Numerical deblurring algorithm to reduce the double image effects. In the left part of the image the algorithm was applied. For comparison reasons we present the right image obtained without the numerical processing.

Equations (3)

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1 U + 1 V = 1 F
Δ B = Δ ( 1 n o n e )
Δ B = 0.13 ( 1 1.99 2.22 ) = 1.25 mm

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