Abstract

Laser speckle contrast analysis (LASCA) is limited to being a qualitative method for the measurement of blood flow and tissue perfusion as it is sensitive to the measurement configuration. The signal intensity is one of the parameters that can affect the contrast values due to the quantization of the signals by the camera and analog-to-digital converter (ADC). In this paper we deduce the theoretical relationship between signal intensity and contrast values based on the probability density function (PDF) of the speckle pattern and simplify it to a rational function. A simple method to correct this contrast error is suggested. The experimental results demonstrate that this relationship can effectively compensate the bias in contrast values induced by the quantized signal intensity and correct for bias induced by signal intensity variations across the field of view.

© 2012 OSA

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  1. Z. Luo, Z. Yuan, M. Tully, Y. Pan, and C. Du, “Quantification of cocaine-induced cortical blood flow changes using laser speckle contrast imaging and Doppler optical coherence tomography,” Appl. Opt.48(10), D247–D255 (2009).
    [CrossRef] [PubMed]
  2. N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
    [CrossRef] [PubMed]
  3. Z. C. Luo, Z. J. Yuan, Y. T. Pan, and C. W. Du, “Simultaneous imaging of cortical hemodynamics and blood oxygenation change during cerebral ischemia using dual-wavelength laser speckle contrast imaging,” Opt. Lett.34(9), 1480–1482 (2009).
    [CrossRef] [PubMed]
  4. R. Bezemer, M. Legrand, E. Klijn, M. Heger, I. C. J. H. Post, T. M. van Gulik, D. Payen, and C. Ince, “Real-time assessment of renal cortical microvascular perfusion heterogeneities using near-infrared laser speckle imaging,” Opt. Express18(14), 15054–15061 (2010).
    [CrossRef] [PubMed]
  5. A. B. Parthasarathy, S. M. S. Kazmi, and A. K. Dunn, “Quantitative imaging of ischemic stroke through thinned skull in mice with Multi Exposure Speckle Imaging,” Biomed. Opt. Express1(1), 246–259 (2010).
    [CrossRef] [PubMed]
  6. R. C. Bray, K. R. Forrester, J. Reed, C. Leonard, and J. Tulip, “Endoscopic laser speckle imaging of tissue blood flow: applications in the human knee,” J. Orthop. Res.24(8), 1650–1659 (2006).
    [CrossRef] [PubMed]
  7. C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
    [CrossRef] [PubMed]
  8. D. D. Duncan and S. J. Kirkpatrick, “Can laser speckle flowmetry be made a quantitative tool?” J. Opt. Soc. Am. A25(8), 2088–2094 (2008).
    [CrossRef] [PubMed]
  9. P. Zakharov, A. Völker, A. Buck, B. Weber, and F. Scheffold, “Quantitative modeling of laser speckle imaging,” Opt. Lett.31(23), 3465–3467 (2006).
    [CrossRef] [PubMed]
  10. J. W. Goodman, Speckle Phenomena in Optics: Theory and Applications (Ben Roberts & Company, 2007).
  11. S. J. Kirkpatrick, D. D. Duncan, and E. M. Wells-Gray, “Detrimental effects of speckle-pixel size matching in laser speckle contrast imaging,” Opt. Lett.33(24), 2886–2888 (2008).
    [CrossRef] [PubMed]
  12. S. Yuan, A. Devor, D. A. Boas, and A. K. Dunn, “Determination of optimal exposure time for imaging of blood flow changes with laser speckle contrast imaging,” Appl. Opt.44(10), 1823–1830 (2005).
    [CrossRef] [PubMed]
  13. J. A. Zadnik and J. W. Beletic, “Effect of CCD Readout Noise in Astronomical Speckle Imaging,” Appl. Opt.37(2), 361–368 (1998).
    [CrossRef] [PubMed]
  14. T. L. Alexander, J. E. Harvey, and A. R. Weeks, “Average speckle size as a function of intensity threshold level: comparisonof experimental measurements with theory,” Appl. Opt.33(35), 8240–8250 (1994).
    [CrossRef] [PubMed]
  15. J. C. Dainty, Laser Speckle and Related Phenomena (Springer-Verlag, 1975).
  16. R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
    [CrossRef]
  17. T. Smausz, D. Zölei, and B. Hopp, “Real correlation time measurement in laser speckle contrast analysis using wide exposure time range images,” Appl. Opt.48(8), 1425–1429 (2009).
    [CrossRef] [PubMed]
  18. A. B. Parthasarathy, W. J. Tom, A. Gopal, X. J. Zhang, and A. K. Dunn, “Robust flow measurement with multi-exposure speckle imaging,” Opt. Express16(3), 1975–1989 (2008).
    [CrossRef] [PubMed]
  19. H. Zhang, P. Li, N. Feng, J. Qiu, B. Li, W. Luo, and Q. Luo, “Correcting the detrimental effects of nonuniform intensity distribution on fiber-transmitting laser speckle imaging of blood flow,” Opt. Express20(1), 508–517 (2012).
    [CrossRef] [PubMed]
  20. P. Li, S. Ni, L. Zhang, S. Zeng, and Q. Luo, “Imaging cerebral blood flow through the intact rat skull with temporal laser speckle imaging,” Opt. Lett.31(12), 1824–1826 (2006).
    [CrossRef] [PubMed]
  21. H. Zhang, P. Li, N. Feng, J. Qiu, B. Li, W. Luo, and Q. Luo, “Correcting the detrimental effects of nonuniform intensity distribution on fiber-transmitting laser speckle imaging of blood flow,” Opt. Express20(1), 508–517 (2012).
    [CrossRef] [PubMed]
  22. J. W. Goodman, Statistical Optics (Wiley, 1985).
  23. A. M. S. Maallo, P. F. Almoro, and S. G. Hanson, “Quantization analysis of speckle intensity measurements for phase retrieval,” Appl. Opt.49(27), 5087–5094 (2010).
    [CrossRef] [PubMed]
  24. D. D. Duncan, S. J. Kirkpatrick, and R. K. Wang, “Statistics of local speckle contrast,” J. Opt. Soc. Am. A25(1), 9–15 (2008).
    [CrossRef] [PubMed]

2012 (2)

2010 (3)

2009 (4)

2008 (4)

2006 (3)

2005 (3)

S. Yuan, A. Devor, D. A. Boas, and A. K. Dunn, “Determination of optimal exposure time for imaging of blood flow changes with laser speckle contrast imaging,” Appl. Opt.44(10), 1823–1830 (2005).
[CrossRef] [PubMed]

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

1998 (1)

1994 (1)

Alexander, T. L.

Almoro, P. F.

Bandyopadhyay, R.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Beletic, J. W.

Bezemer, R.

Boas, D. A.

Bray, R. C.

R. C. Bray, K. R. Forrester, J. Reed, C. Leonard, and J. Tulip, “Endoscopic laser speckle imaging of tissue blood flow: applications in the human knee,” J. Orthop. Res.24(8), 1650–1659 (2006).
[CrossRef] [PubMed]

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

Buck, A.

Devor, A.

Dixon, P. K.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Du, C.

Du, C. W.

Duncan, D. D.

Dunn, A. K.

Durian, D. J.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Feng, N.

Forrester, K. R.

R. C. Bray, K. R. Forrester, J. Reed, C. Leonard, and J. Tulip, “Endoscopic laser speckle imaging of tissue blood flow: applications in the human knee,” J. Orthop. Res.24(8), 1650–1659 (2006).
[CrossRef] [PubMed]

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

Frank, R.

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

Gittings, A. S.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Gopal, A.

Hanson, S. G.

Harvey, J. E.

Heger, M.

Hopp, B.

Ince, C.

Jia, X. F.

N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
[CrossRef] [PubMed]

Kazmi, S. M. S.

Kirkpatrick, S. J.

Klijn, E.

Legrand, M.

Leonard, C.

R. C. Bray, K. R. Forrester, J. Reed, C. Leonard, and J. Tulip, “Endoscopic laser speckle imaging of tissue blood flow: applications in the human knee,” J. Orthop. Res.24(8), 1650–1659 (2006).
[CrossRef] [PubMed]

Li, B.

Li, N.

N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
[CrossRef] [PubMed]

Li, P.

Lindsay, R.

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

Luo, Q.

Luo, W.

Luo, Z.

Luo, Z. C.

Maallo, A. M. S.

Murari, K.

N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
[CrossRef] [PubMed]

Ni, S.

Pan, Y.

Pan, Y. T.

Parlapalli, R.

N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
[CrossRef] [PubMed]

Parthasarathy, A. B.

Payen, D.

Post, I. C. J. H.

Qiu, J.

Reed, J.

R. C. Bray, K. R. Forrester, J. Reed, C. Leonard, and J. Tulip, “Endoscopic laser speckle imaging of tissue blood flow: applications in the human knee,” J. Orthop. Res.24(8), 1650–1659 (2006).
[CrossRef] [PubMed]

Rege, A.

N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
[CrossRef] [PubMed]

Scheffold, F.

Smausz, T.

Stewart, C. J.

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

Suh, S. S.

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Thakor, N. V.

N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
[CrossRef] [PubMed]

Tom, W. J.

Tulip, J.

R. C. Bray, K. R. Forrester, J. Reed, C. Leonard, and J. Tulip, “Endoscopic laser speckle imaging of tissue blood flow: applications in the human knee,” J. Orthop. Res.24(8), 1650–1659 (2006).
[CrossRef] [PubMed]

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

Tully, M.

van Gulik, T. M.

Völker, A.

Wang, R. K.

Weber, B.

Weeks, A. R.

Wells-Gray, E. M.

Yuan, S.

Yuan, Z.

Yuan, Z. J.

Zadnik, J. A.

Zakharov, P.

Zeng, S.

Zhang, H.

Zhang, L.

Zhang, X. J.

Zölei, D.

Appl. Opt. (6)

Biomed. Opt. Express (1)

Burns (1)

C. J. Stewart, R. Frank, K. R. Forrester, J. Tulip, R. Lindsay, and R. C. Bray, “A comparison of two laser-based methods for determination of burn scar perfusion: laser Doppler versus laser speckle imaging,” Burns31(6), 744–752 (2005).
[CrossRef] [PubMed]

J. Neurosci. Methods (1)

N. Li, X. F. Jia, K. Murari, R. Parlapalli, A. Rege, and N. V. Thakor, “High spatiotemporal resolution imaging of the neurovascular response to electrical stimulation of rat peripheral trigeminal nerve as revealed by in vivo temporal laser speckle contrast,” J. Neurosci. Methods176(2), 230–236 (2009).
[CrossRef] [PubMed]

J. Opt. Soc. Am. A (2)

J. Orthop. Res. (1)

R. C. Bray, K. R. Forrester, J. Reed, C. Leonard, and J. Tulip, “Endoscopic laser speckle imaging of tissue blood flow: applications in the human knee,” J. Orthop. Res.24(8), 1650–1659 (2006).
[CrossRef] [PubMed]

Opt. Express (4)

Opt. Lett. (4)

Rev. Sci. Instrum. (1)

R. Bandyopadhyay, A. S. Gittings, S. S. Suh, P. K. Dixon, and D. J. Durian, “Speckle-visibility spectroscopy: A tool to study time-varying dynamics,” Rev. Sci. Instrum.76(9), 093110 (2005).
[CrossRef]

Other (3)

J. W. Goodman, Statistical Optics (Wiley, 1985).

J. W. Goodman, Speckle Phenomena in Optics: Theory and Applications (Ben Roberts & Company, 2007).

J. C. Dainty, Laser Speckle and Related Phenomena (Springer-Verlag, 1975).

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Figures (9)

Fig. 1
Fig. 1

(a) Flow chart for contrast correction in experiments. (b) Experimental setup. (LD: Laser diode; SPMF: Single mode polarization maintaining fiber; NDF: Neutral density filter; BPF: Band pass filter)

Fig. 2
Fig. 2

Simulated contrast as a function of mean intensity for cameras with different bit depths. The intensity of the unquantized speckle pattern was multiplied by a factor from 0.1 to 1.

Fig. 3
Fig. 3

Error map of the contrast: (a) before contrast correction (using a logarithmic pseudo color scale to show the large range of errors); (b) after contrast correction (using a linear pseudo color scale).

Fig. 4
Fig. 4

Contrast as the function of bit depth. The square of the contrast from the simulation was fitted according to Eq. (23).

Fig. 5
Fig. 5

Simulated contrast as a function of the mean gray levels (12 bit camera), together with the analytically calculated contrast values and the corrected values. (a) Fully developed speckle pattern without noise; (b) Sum of three speckle patterns without noise; (c) Fully developed speckle pattern with noise; (d) Sum of three speckle patterns with Poisson noise. Blue asterisks: Contrast calculated from quantized simulation; Red circles: (a)-(d) Contrast calculated from Eqs. (9), (12), (14), (19). Green squares: (a)-(d) Contrast corrected to the mean gray level of the brightest intensity using Eqs. (10), (10), (15), (20). Blue diamonds: (a)-(d) Contrast corrected to the mean intensity (before quantization) using Eqs. (10), (10), (15), (20). Red crosses: (a)-(d) Contrast calculated from unquantized speckle patterns.

Fig. 6
Fig. 6

The blue circles show the experimentally measured contrast of the stationary reflectance standard as a function of the mean intensity, and the blue line is the fit to this data using Eq. (19). The red squares are the corrected contrast values and the red line is a linear fit through these corrected values.

Fig. 7
Fig. 7

Experimental contrast values calculated from the speckle pattern of the moving reflectance standard at a range of different speeds for a high intensity speckle image (blue asterisks), a low intensity speckle image (red circles) and corrected contrast values from the low intensity speckle image (green diamonds).

Fig. 8
Fig. 8

Illustration of the correction speckle contrast in imaging domain: (a) the grayscale speckle image at two different intensities; (b) From the top to the bottom: the contrast maps at high intensity, low intensity and the corrected contrast at low intensity. The color was applied to the negative natural logarithm value of the contrast. (c) The contrast profile along the red line marked in (a) from the three contrast images in (b); (d) The original and corrected contrast from the low intensity speckle pattern along the yellow line marked in (a).

Fig. 9
Fig. 9

Contrast as a function of the mean gray level of the quantized speckle patterns when M = 100.

Equations (24)

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C= σ μ .
C 2 = σ 2 μ 2 = 0 ( Iμ ) 2 P(I)dI [ 0 IP(I)dI ] 2 = 0 I 2 P(I)dI [ 0 IP(I)dI ] 2 1,
I =INT( I ΔI )=INT( I I max 2 K 1 ),
C 2 = σ 2 μ 2 = I'=0 2 K 1 I 2 P( I ) ( I'=0 2 K 1 I P( I ) ) 2 1,
P(I')= I ΔI ( I +1)ΔI P(I)dI =exp( I ΔI μ )exp( ( I +1 )ΔI μ ) =exp( I μ )exp( ( I +1 ) μ ),
C 2 = [ 1exp( 1 μ ) ] I'=0 2 K 1 I 2 [ exp( 1 μ' ) ] I [ 1exp( 1 μ ) ] 2 { I'=0 2 K 1 I [ exp( 1 μ' ) ] I } 2 1.
C 2 =exp( 1 μ ).
C 2 =exp( 1 μ )1+ 1 μ .
C 2 = C 0 2 ( 1+ 1 μ ).
C c 2 = C 0 2 ( 1 I c 1 I m )+ C m 2 ,
P( I ) exp( M μ I ) ( M μ I ) M1 ( 1exp( M μ ) ) Γ(M) ,
C 2 1 M ( 1+ 1 μ )  C 0 2 ( 1+ 1 μ ).
P( I )= L=0 N exp( L μ )exp( 1 1 μ ) L I I ! exp( L )             ( 1exp( 1 1 μ ) ) ( μ μ +1 ) I'+1 .
C 2 C 0 2 ( 1+ 2 μ ).
C c 2 = C 0 2 ( 2 I c 2 I m )+ C m 2 .
P( I )= L=0 N exp( M μ L ) ( M μ L ) M1 ( 1exp( M μ ) ) Γ(M) L I I ! exp(L) .        
P( I ) ( M μ ) M1 ( 1exp( M μ ) ) Γ(M) ( I +M1)! ( M μ +1 ) I M I ! .
C 2 1 M ( 1+ M+1 μ ).
C 2 C 0 2 ( 1+ M+1 μ ).
C c 2 = C 0 2 ( M+1 I c M+1 I m )+ C m 2 .
{ M= ( C 1 2 C 2 2 ) μ 1 μ 2 C 2 2 μ 2 C 1 2 μ 1 1 C 0 = C 1 2 ( 1+ ( 1+M ) μ 1 ) ,
C c =sqrt ( C 0 2 ( M+1 )( 1 I c 1 I m )+ C m 2 ),
C 2 C 0 2 ( 1+ 1 μ ) C 0 2 ( 1+ I max μ( 2 K 1) ).
Error=( C Q C U )/ C U *100%.

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