Transcript Analysis of statistical properties of laser speckles

Title: Analysis of statistical
properties of laser speckles, forming
in mucose of colon: Application in
laser surgery.
Authors: Vladimir Rubtsov, Sergey
Kapralov, Yuri Chalyk, Sergey Ulyanov
Statement of the problem
• Scattering of laser light from biological sample
leads to formation of speckles. In the case of
laser surgery, the localization of intensity may
cause the essential inhomogeneity thermal
effects of laser on processed area of human
organ under the surgery treatment.
• Non-Gaussian statistics of scattered light may
enhance the localization of light, which might
be the critical factor for laser surgery.
Purpose of researches
• Analyze the statistics of speckle, forming in
the mucose of colon.
• Suggest the way of speckle suppression to
provide inhomogeneous illumination of
processing organ under the surgery.
Scheme of experimental set-up
CMOS camera
Phoenix MuTech PC 1240
microobjective
Histological sample
Collimated laser beam
Device has been performed on the base of conventional microscope.
CMOS camera is placed instead of ocular.
Speckles observed from a cut of skin.
Compare with mucose scattering, slides # 8 - #39
Because of highly scattering, intensity fluctuations usually obey to negative exponent
distribution (in the case of polarized speckles)
Algorithm of speckle processing
• Select central line from 2D speckle pattern
• Chi-Square Test is performed
• Hypothesis about negative-exponent statistics
of intensity fluctuations is performed
Scattering from the histological
sample of mucose of colon.
Sample thickness is 50 um.
Realization #1
Realization #2
Realization #3
Realization #4
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #5
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #6
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #7
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #8
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #9
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #10
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Scattering from the histological
sample of mucose of colon.
Sample thickness is 100 um.
Realization #1
Realization #2
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #3
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #4
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #5
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #6
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #7
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #8
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #9
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #10
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Scattering from the histological
sample of mucose of colon.
Sample thickness is 150 um.
Realization #1
Realization #2
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #3
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #4
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #5
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #6
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #7
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #8
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #9
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Realization #10
Hypothesis about negative-exponent statistics of intensity fluctuations is rejected
Resume
• As it shown, statistics of speckle, forming in
the mucose of colon, is non-gaussian one.
• It is expedient to use additional scattering gel
(for example, mixture of Vaseline oil with TiO
particles) to reduce speckle size and to make
statics of speckle is gaussian one.
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