Abstract

A new method for real-time edge enhancement and image equalization using photochromic filters is presented. The reversible self-adaptive capacity of photochromic materials is used for creating an unsharp mask of the original image. This unsharp mask produces a kind of self filtering of the original image. Unlike the usual Fourier (coherent) image processing, the technique we propose can also be used with incoherent illumination. Validation experiments with Bacteriorhodopsin and photochromic glass are presented.

© 2009 Optical Society of America

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References

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  1. J. A. Sorenson and C. R. Mitchell, “Evaluation of optical unsharp masking and contrast enhancement of low-scatter chest radiographs,” Am. J. Roentgenol. 149, 275-281 (1987).
  2. P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
    [CrossRef] [PubMed]
  3. M. Schirmer, “Image processing: noise reduction/unsharp masking,” http://www.astro.uni-bonn.de/~mischa/ps/unsharpmask.html.
  4. S. Binnewies, “M81, M82 (wide field) in Ursa Major,” http://www.capella-observatory.com/ImageHTMLs/Galaxies/M81M82.htm.
  5. F. Specht, “Echte unscharfe Maskierung,” http://astronomy.rainbow-serpent.de/howto/unsharpmask.html.
  6. Carl Zeiss, MicroImaging GmbH, “Microscopy & Imaging,” http://www.zeiss.de/c12567be0045acf1/Contents-Frame/df26845c0814ac96c12573c9006e0a97.
  7. M. W. Davidson, “Unsharp Mask Filtering,” (2003), http://microscope.fsu.edu/primer/java/digitalimaging/processing/unsharpmask/.
  8. D. Romeuf, “Le masque flou en imaginerie numerique,” http://www.david-romeuf.fr/Publications/Amateur/MasqueFlou/mf.html.
  9. J. Phillips, “Unsharp Masking--A beginners primer,” http://www.largeformatphotography.info/unsharp/.
  10. S. McHugh, “Sharpening: unsharp mask,” http://www.cambridgeincolour.com/tutorials/unsharp-mask.htm.
  11. A. Polesel, G. Ramponi, and V. J. Mathews, “Image enhancement via adaptive unsharp masking,” IEEE Trans. Image Proc. 9, 505-510 (2000).
    [CrossRef]
  12. J. W. Goodman, Introduction to Fourier Optics, 2nd ed. (McGraw-Hill, 1996).
  13. G. O. Reynolds, J. B. De Velis, G. B. Parrent, and B. J. Thompson, The New Physical Optics Notebook: Tutorials in Fourier Optics (SPIE Optical Engineering Press, 1989).
    [CrossRef]
  14. E. U. Wagemann and H.-J. Tiziani, “Spatial self-filtering using photorefractive and liquid crystals,” J. Mod. Opt. 45, 1885-1897 (1998).
    [CrossRef]
  15. C. Uhrich and L. Hesselink, “Submicrometer defect detection in periodic structures by photorefractive holography: system design and performance,” Appl. Opt. 33, 744-757 (1994).
    [CrossRef] [PubMed]
  16. J. Feinberg, “Real-time edge enhancement using the photorefractive effect,” Opt. Lett. 5, 330-333 (1980).
    [CrossRef] [PubMed]
  17. E. Ochoa, J. W. Goodman, and L. Hesselink, “Real-time enhancement of defects in a periodic mask using photorefractive Bi12SiO20,” Opt. Lett. 10, 430-432 (1985).
    [CrossRef] [PubMed]
  18. J. Kato, I. Yamaguchi, and H. Tanaka, “Nonlinear spatial filtering with a dye-doped liquid-crystal cell,” Opt. Lett. 21, 767-769 (1996).
    [CrossRef] [PubMed]
  19. C. Egami, Y. Suzuki, T. Uemori, O. Sugihara, and N. Okamoto, “Self-adaptive spatial filtering by use of azo chromophores doped in low glass-transition-temperature polymers,” Opt. Lett. 22, 1424-1426 (1997).
    [CrossRef]
  20. T. Huang and K. H. Wagner, “Photoanisotropic incoherent-to-coherent optical conversion,” Appl. Opt. 32, 1888-1900 (1993).
    [CrossRef] [PubMed]
  21. T. Okamoto, I. Yamaguchi, and K. Yamagata, “Real-time enhancement of defects in periodic patterns by use of a bacteriorhodopsin film,” Opt. Lett. 22, 337-339 (1997).
    [CrossRef] [PubMed]
  22. R. Thoma, N. Hampp, and C. Brauchle, “Bacteriorhodopsin films as spatial light modulators for nonlinear-optical filtering,” Opt. Lett. 16, 651-653 (1991).
    [CrossRef] [PubMed]
  23. J. A. Ferrari, E. Garbusi, E. M. Frins, and G. Píriz, “Spatial self-filtering with polarizer sheets,” Appl. Opt. 44, 4510(2005).
    [CrossRef] [PubMed]
  24. T. E. Gureyev, Y. I. Nesterets, A. W. Stevenson, and S. W. Wilkins, “A method for local deconvolution,” Appl. Opt. 42, 6488-6494 (2003).
    [CrossRef] [PubMed]
  25. T. E. Gureyev, A. W. Stevenson, Y. I. Nesterets, and S. W. Wilkins, “Image debluring by means of defocus,” Opt. Commun. 240, 81-88 (2004).
    [CrossRef]
  26. W. H. Armistead and S. D. Stookey, “Photochromic silicate glasses sensitized by silver halides,” Science 144, 150-154(1964).
    [CrossRef] [PubMed]
  27. T. Kawamoto, R. Kikuschi, and Y. Kimura, “Photochromic glasses containing silver chloride. Part 1. Effects of glass composition on photosensitivity,” and “Photochromic glasses containing silver chloride. Part 2. Effects of the addition of small amounts of oxides on photosensitivity,” Phys. Chem. Glasses 17, 23-29 (1976).
  28. A. V. Dotsenko, L. B. Glebov, and V. A. Tsekhomsky, Physics and Chemistry of Photochromic Glasses (CRC, 1998).
  29. N. Hampp, “Bacteriorhodopsin as a photochromic retinal protein for optical memories,” Chem. Rev. 100, 1755-1776(2000).
    [CrossRef]
  30. J. A. Ferrari and C. D. Perciante, “Two-state model of light induced activation and thermal bleaching of photochromic glasses: theory and experiments,” Appl. Opt. 47, 3669-3673(2008).
    [CrossRef] [PubMed]
  31. J. A. Ferrari and C. D. Perciante, “Two-state model of light induced activation and thermal bleaching of photochromic glasses: erratum,” Appl. Opt. 47, 6879 (2008).
    [CrossRef]
  32. I. Núñez and J. A. Ferrari, “Differential operator approach for Fourier image processing,” J. Opt. Soc. Am. A 24, 2274-2279(2007).
    [CrossRef]
  33. J. Lodriguss, “Catching the light. Real digital unsharp masking,” http://www.astropix.com/HTML/J_DIGIT/USM.HTM.

2008 (2)

2007 (1)

2005 (1)

2004 (1)

T. E. Gureyev, A. W. Stevenson, Y. I. Nesterets, and S. W. Wilkins, “Image debluring by means of defocus,” Opt. Commun. 240, 81-88 (2004).
[CrossRef]

2003 (1)

2000 (2)

A. Polesel, G. Ramponi, and V. J. Mathews, “Image enhancement via adaptive unsharp masking,” IEEE Trans. Image Proc. 9, 505-510 (2000).
[CrossRef]

N. Hampp, “Bacteriorhodopsin as a photochromic retinal protein for optical memories,” Chem. Rev. 100, 1755-1776(2000).
[CrossRef]

1998 (1)

E. U. Wagemann and H.-J. Tiziani, “Spatial self-filtering using photorefractive and liquid crystals,” J. Mod. Opt. 45, 1885-1897 (1998).
[CrossRef]

1997 (2)

1996 (1)

1994 (1)

1993 (1)

1991 (2)

R. Thoma, N. Hampp, and C. Brauchle, “Bacteriorhodopsin films as spatial light modulators for nonlinear-optical filtering,” Opt. Lett. 16, 651-653 (1991).
[CrossRef] [PubMed]

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

1987 (1)

J. A. Sorenson and C. R. Mitchell, “Evaluation of optical unsharp masking and contrast enhancement of low-scatter chest radiographs,” Am. J. Roentgenol. 149, 275-281 (1987).

1985 (1)

1980 (1)

1976 (1)

T. Kawamoto, R. Kikuschi, and Y. Kimura, “Photochromic glasses containing silver chloride. Part 1. Effects of glass composition on photosensitivity,” and “Photochromic glasses containing silver chloride. Part 2. Effects of the addition of small amounts of oxides on photosensitivity,” Phys. Chem. Glasses 17, 23-29 (1976).

1964 (1)

W. H. Armistead and S. D. Stookey, “Photochromic silicate glasses sensitized by silver halides,” Science 144, 150-154(1964).
[CrossRef] [PubMed]

Armistead, W. H.

W. H. Armistead and S. D. Stookey, “Photochromic silicate glasses sensitized by silver halides,” Science 144, 150-154(1964).
[CrossRef] [PubMed]

Binnewies, S.

S. Binnewies, “M81, M82 (wide field) in Ursa Major,” http://www.capella-observatory.com/ImageHTMLs/Galaxies/M81M82.htm.

Brauchle, C.

Correa, J.

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

Davidson, M. W.

M. W. Davidson, “Unsharp Mask Filtering,” (2003), http://microscope.fsu.edu/primer/java/digitalimaging/processing/unsharpmask/.

De Velis, J. B.

G. O. Reynolds, J. B. De Velis, G. B. Parrent, and B. J. Thompson, The New Physical Optics Notebook: Tutorials in Fourier Optics (SPIE Optical Engineering Press, 1989).
[CrossRef]

Dotsenko, A. V.

A. V. Dotsenko, L. B. Glebov, and V. A. Tsekhomsky, Physics and Chemistry of Photochromic Glasses (CRC, 1998).

Egami, C.

Feinberg, J.

Ferrari, J. A.

Frins, E. M.

Garbusi, E.

Glebov, L. B.

A. V. Dotsenko, L. B. Glebov, and V. A. Tsekhomsky, Physics and Chemistry of Photochromic Glasses (CRC, 1998).

Gomez, L.

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

Gonzalez, C.

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

Goodman, J. W.

Gureyev, T. E.

T. E. Gureyev, A. W. Stevenson, Y. I. Nesterets, and S. W. Wilkins, “Image debluring by means of defocus,” Opt. Commun. 240, 81-88 (2004).
[CrossRef]

T. E. Gureyev, Y. I. Nesterets, A. W. Stevenson, and S. W. Wilkins, “A method for local deconvolution,” Appl. Opt. 42, 6488-6494 (2003).
[CrossRef] [PubMed]

Hampp, N.

Hesselink, L.

Huang, T.

Kato, J.

Kawamoto, T.

T. Kawamoto, R. Kikuschi, and Y. Kimura, “Photochromic glasses containing silver chloride. Part 1. Effects of glass composition on photosensitivity,” and “Photochromic glasses containing silver chloride. Part 2. Effects of the addition of small amounts of oxides on photosensitivity,” Phys. Chem. Glasses 17, 23-29 (1976).

Kikuschi, R.

T. Kawamoto, R. Kikuschi, and Y. Kimura, “Photochromic glasses containing silver chloride. Part 1. Effects of glass composition on photosensitivity,” and “Photochromic glasses containing silver chloride. Part 2. Effects of the addition of small amounts of oxides on photosensitivity,” Phys. Chem. Glasses 17, 23-29 (1976).

Kimura, Y.

T. Kawamoto, R. Kikuschi, and Y. Kimura, “Photochromic glasses containing silver chloride. Part 1. Effects of glass composition on photosensitivity,” and “Photochromic glasses containing silver chloride. Part 2. Effects of the addition of small amounts of oxides on photosensitivity,” Phys. Chem. Glasses 17, 23-29 (1976).

Lodriguss, J.

J. Lodriguss, “Catching the light. Real digital unsharp masking,” http://www.astropix.com/HTML/J_DIGIT/USM.HTM.

Mathews, V. J.

A. Polesel, G. Ramponi, and V. J. Mathews, “Image enhancement via adaptive unsharp masking,” IEEE Trans. Image Proc. 9, 505-510 (2000).
[CrossRef]

McHugh, S.

S. McHugh, “Sharpening: unsharp mask,” http://www.cambridgeincolour.com/tutorials/unsharp-mask.htm.

Mitchell, C. R.

J. A. Sorenson and C. R. Mitchell, “Evaluation of optical unsharp masking and contrast enhancement of low-scatter chest radiographs,” Am. J. Roentgenol. 149, 275-281 (1987).

Nesterets, Y. I.

T. E. Gureyev, A. W. Stevenson, Y. I. Nesterets, and S. W. Wilkins, “Image debluring by means of defocus,” Opt. Commun. 240, 81-88 (2004).
[CrossRef]

T. E. Gureyev, Y. I. Nesterets, A. W. Stevenson, and S. W. Wilkins, “A method for local deconvolution,” Appl. Opt. 42, 6488-6494 (2003).
[CrossRef] [PubMed]

Núñez, I.

Ochoa, E.

Okamoto, N.

Okamoto, T.

Parrent, G. B.

G. O. Reynolds, J. B. De Velis, G. B. Parrent, and B. J. Thompson, The New Physical Optics Notebook: Tutorials in Fourier Optics (SPIE Optical Engineering Press, 1989).
[CrossRef]

Perciante, C. D.

Phillips, J.

J. Phillips, “Unsharp Masking--A beginners primer,” http://www.largeformatphotography.info/unsharp/.

Píriz, G.

Polesel, A.

A. Polesel, G. Ramponi, and V. J. Mathews, “Image enhancement via adaptive unsharp masking,” IEEE Trans. Image Proc. 9, 505-510 (2000).
[CrossRef]

Ramponi, G.

A. Polesel, G. Ramponi, and V. J. Mathews, “Image enhancement via adaptive unsharp masking,” IEEE Trans. Image Proc. 9, 505-510 (2000).
[CrossRef]

Reynolds, G. O.

G. O. Reynolds, J. B. De Velis, G. B. Parrent, and B. J. Thompson, The New Physical Optics Notebook: Tutorials in Fourier Optics (SPIE Optical Engineering Press, 1989).
[CrossRef]

Romeuf, D.

D. Romeuf, “Le masque flou en imaginerie numerique,” http://www.david-romeuf.fr/Publications/Amateur/MasqueFlou/mf.html.

Schirmer, M.

M. Schirmer, “Image processing: noise reduction/unsharp masking,” http://www.astro.uni-bonn.de/~mischa/ps/unsharpmask.html.

Sorenson, J. A.

J. A. Sorenson and C. R. Mitchell, “Evaluation of optical unsharp masking and contrast enhancement of low-scatter chest radiographs,” Am. J. Roentgenol. 149, 275-281 (1987).

Souto, M.

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

Specht, F.

F. Specht, “Echte unscharfe Maskierung,” http://astronomy.rainbow-serpent.de/howto/unsharpmask.html.

Stevenson, A. W.

T. E. Gureyev, A. W. Stevenson, Y. I. Nesterets, and S. W. Wilkins, “Image debluring by means of defocus,” Opt. Commun. 240, 81-88 (2004).
[CrossRef]

T. E. Gureyev, Y. I. Nesterets, A. W. Stevenson, and S. W. Wilkins, “A method for local deconvolution,” Appl. Opt. 42, 6488-6494 (2003).
[CrossRef] [PubMed]

Stookey, S. D.

W. H. Armistead and S. D. Stookey, “Photochromic silicate glasses sensitized by silver halides,” Science 144, 150-154(1964).
[CrossRef] [PubMed]

Sugihara, O.

Suzuki, Y.

Tahoces, P. G.

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

Tanaka, H.

Thoma, R.

Thompson, B. J.

G. O. Reynolds, J. B. De Velis, G. B. Parrent, and B. J. Thompson, The New Physical Optics Notebook: Tutorials in Fourier Optics (SPIE Optical Engineering Press, 1989).
[CrossRef]

Tiziani, H.-J.

E. U. Wagemann and H.-J. Tiziani, “Spatial self-filtering using photorefractive and liquid crystals,” J. Mod. Opt. 45, 1885-1897 (1998).
[CrossRef]

Tsekhomsky, V. A.

A. V. Dotsenko, L. B. Glebov, and V. A. Tsekhomsky, Physics and Chemistry of Photochromic Glasses (CRC, 1998).

Uemori, T.

Uhrich, C.

Vidal, J. J.

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

Wagemann, E. U.

E. U. Wagemann and H.-J. Tiziani, “Spatial self-filtering using photorefractive and liquid crystals,” J. Mod. Opt. 45, 1885-1897 (1998).
[CrossRef]

Wagner, K. H.

Wilkins, S. W.

T. E. Gureyev, A. W. Stevenson, Y. I. Nesterets, and S. W. Wilkins, “Image debluring by means of defocus,” Opt. Commun. 240, 81-88 (2004).
[CrossRef]

T. E. Gureyev, Y. I. Nesterets, A. W. Stevenson, and S. W. Wilkins, “A method for local deconvolution,” Appl. Opt. 42, 6488-6494 (2003).
[CrossRef] [PubMed]

Yamagata, K.

Yamaguchi, I.

Zeiss, Carl

Carl Zeiss, MicroImaging GmbH, “Microscopy & Imaging,” http://www.zeiss.de/c12567be0045acf1/Contents-Frame/df26845c0814ac96c12573c9006e0a97.

Am. J. Roentgenol. (1)

J. A. Sorenson and C. R. Mitchell, “Evaluation of optical unsharp masking and contrast enhancement of low-scatter chest radiographs,” Am. J. Roentgenol. 149, 275-281 (1987).

Appl. Opt. (6)

Chem. Rev. (1)

N. Hampp, “Bacteriorhodopsin as a photochromic retinal protein for optical memories,” Chem. Rev. 100, 1755-1776(2000).
[CrossRef]

IEEE Trans. Image Proc. (1)

A. Polesel, G. Ramponi, and V. J. Mathews, “Image enhancement via adaptive unsharp masking,” IEEE Trans. Image Proc. 9, 505-510 (2000).
[CrossRef]

IEEE Trans. Med. Imaging (1)

P. G. Tahoces, J. Correa, M. Souto, C. Gonzalez, L. Gomez, and J. J. Vidal, “Enhancement of chest and breast radiographs by automatic spatial filtering,” IEEE Trans. Med. Imaging 10, 330-335 (1991).
[CrossRef] [PubMed]

J. Mod. Opt. (1)

E. U. Wagemann and H.-J. Tiziani, “Spatial self-filtering using photorefractive and liquid crystals,” J. Mod. Opt. 45, 1885-1897 (1998).
[CrossRef]

J. Opt. Soc. Am. A (1)

Opt. Commun. (1)

T. E. Gureyev, A. W. Stevenson, Y. I. Nesterets, and S. W. Wilkins, “Image debluring by means of defocus,” Opt. Commun. 240, 81-88 (2004).
[CrossRef]

Opt. Lett. (6)

Phys. Chem. Glasses (1)

T. Kawamoto, R. Kikuschi, and Y. Kimura, “Photochromic glasses containing silver chloride. Part 1. Effects of glass composition on photosensitivity,” and “Photochromic glasses containing silver chloride. Part 2. Effects of the addition of small amounts of oxides on photosensitivity,” Phys. Chem. Glasses 17, 23-29 (1976).

Science (1)

W. H. Armistead and S. D. Stookey, “Photochromic silicate glasses sensitized by silver halides,” Science 144, 150-154(1964).
[CrossRef] [PubMed]

Other (12)

A. V. Dotsenko, L. B. Glebov, and V. A. Tsekhomsky, Physics and Chemistry of Photochromic Glasses (CRC, 1998).

J. Lodriguss, “Catching the light. Real digital unsharp masking,” http://www.astropix.com/HTML/J_DIGIT/USM.HTM.

J. W. Goodman, Introduction to Fourier Optics, 2nd ed. (McGraw-Hill, 1996).

G. O. Reynolds, J. B. De Velis, G. B. Parrent, and B. J. Thompson, The New Physical Optics Notebook: Tutorials in Fourier Optics (SPIE Optical Engineering Press, 1989).
[CrossRef]

M. Schirmer, “Image processing: noise reduction/unsharp masking,” http://www.astro.uni-bonn.de/~mischa/ps/unsharpmask.html.

S. Binnewies, “M81, M82 (wide field) in Ursa Major,” http://www.capella-observatory.com/ImageHTMLs/Galaxies/M81M82.htm.

F. Specht, “Echte unscharfe Maskierung,” http://astronomy.rainbow-serpent.de/howto/unsharpmask.html.

Carl Zeiss, MicroImaging GmbH, “Microscopy & Imaging,” http://www.zeiss.de/c12567be0045acf1/Contents-Frame/df26845c0814ac96c12573c9006e0a97.

M. W. Davidson, “Unsharp Mask Filtering,” (2003), http://microscope.fsu.edu/primer/java/digitalimaging/processing/unsharpmask/.

D. Romeuf, “Le masque flou en imaginerie numerique,” http://www.david-romeuf.fr/Publications/Amateur/MasqueFlou/mf.html.

J. Phillips, “Unsharp Masking--A beginners primer,” http://www.largeformatphotography.info/unsharp/.

S. McHugh, “Sharpening: unsharp mask,” http://www.cambridgeincolour.com/tutorials/unsharp-mask.htm.

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Figures (12)

Fig. 1
Fig. 1

Setup for unsharp masking using a photochromic filter. M is the photochromic filter (mask) placed at the defocused plane ∑, L is an imaging lens, I 0 is the image to be processed, and I out is the processed image.

Fig. 2
Fig. 2

Edge enhancement by unsharp masking. T ( I ) is the filter transmittance, I 0 ( x ) is a one-dimensional intensity step, and I out ( x ) is the resultant image.

Fig. 3
Fig. 3

Absorption spectra of BR. The arrows with continuous line describe the B M transition, while the arrows with dashed line describe the M B transition.

Fig. 4
Fig. 4

Steady-state transmittance of BR for light of wavelength λ V = 405 nm , when light of wavelength λ G = 532 nm is incident. I th is a threshold intensity and T s a saturation transmittance. The circles are the experimental data, and the continuous curve is the fitting using Eq. (5).

Fig. 5
Fig. 5

Steady-state transmittance of a photochromic glass slab for light of wavelength 405 nm , when light of wavelength 388 nm is incident. I th is a threshold intensity and a saturation transmittance. The circles are the experimental data, and the continuous curve is the fitting using Eq. (5).

Fig. 6
Fig. 6

Experimental setup for image processing experiments with BR. SF 1 , 2 are spatial filters, D is a random-phase rotating diffuser, WF is a wavelength filter blocking λ G = 532 nm , and CCD is a digital camera.

Fig. 7
Fig. 7

(a) Original image I 0 ; (b) processed images obtained with the BR is placed at a distance Δ z 6 mm from the plane 0 ; (c) image obtained for Δ z 10 mm ; (d) image obtained for Δ z 30 mm .

Fig. 8
Fig. 8

(a) Square illuminated with UV light, (b) one-dimensional intensity cut (parallel to one of the square sides) across the center of the image shown in (a).

Fig. 9
Fig. 9

(a) Output intensity distribution I out obtained experimentally using photochromic glass filter; (b) the continuous curve shows a one-dimensional intensity cut parallel to one of the square sides of the output image shown in (a). The dotted curve is a numerical simulation using Eq. (6), for which the original pattern shown in 8b was considered as input.

Fig. 10
Fig. 10

(a) Original image that presents inhomogeneous intensity distribution; (b) processed image with balanced illumination and fine details; (c) histograms of the original and processed images.

Fig. 11
Fig. 11

Image processed using BR as the filter overexposed with green laser light.

Fig. 12
Fig. 12

Numerical simulation of Fourier processing obtained using Eq. (10) with m 02 / m 00 = 3 × 10 - 2 (in the arbitrary units of the figure). E 0 ( x ) = I 0 ( x ) is the input field, and I out ( x ) is the resultant image.

Equations (11)

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

I out ( x , y ) = T ( I ( x , y ) ) · I 0 ( x , y ) ,
I ( x , y ) I 0 ( x , y ) + a 22 2 I 0 ( x , y ) ,
E ( x , y ) E 0 ( x , y ) + h 22 2 E 0 ( x , y ) ,
I ( x , y ) I 0 ( x , y ) + 2 Re { h 22 E 0 * ( x , y ) · 2 E 0 ( x , y ) } ,
T ( I ) T s + α · exp ( I / I s ) ,
T ( I ( x , y ) ) T s + α · exp ( I 0 ( x , y ) / I s ) exp ( a 22 2 I 0 ( x , y ) / I s ) .
T ( I ( x , y ) ) T s + α · exp ( I 0 ( x , y ) / I s ) exp ( 2 Re { h 22 E 0 * ( x , y ) · 2 E 0 ( x , y ) } / I s ) .
I out ( x , y , λ V ) = T ( I ( x , y , λ G ) ) · I 0 ( x , y , λ V ) .
E out ( x , y ) m 00 E 0 ( x , y ) + m 02 2 E 0 ( x , y ) ,
I out | E out | 2 | m 00 E 0 ( x , y ) + m 02 2 E 0 ( x , y ) | 2 .
I out T s I 0 + α I 0 exp ( I 0 / I s ) exp ( - a 22 2 I 0 / I s ) ,

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