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Etude du speckle de milieux diffusants liquides. Application à la détermination de paramètres biophysiques

Abstract : Development of the optical medical diagnostic interests a lot of researchers around the world. By this way, biological media illuminated by a coherent light source can be study by the analysis of the produced speckle field. This optical phenomena contains many information. Indeed, when any imaging system is not used, the speckle characteristics as the speckle size, the contrast, the polarization and the dynamic depend on the scattering and dynamical properties of the media. Firstly, statistical aspect of the speckle and experimental background are presented. Then, we studied the scattering effect on the speckle size and on the speckle contrast. For measurement in transmittance, this study permit us to characterize the media according to the particle dimensions. The calculation of the transmitted light by Monte Carlo simulation may permit to provide the speckle size evolution versus the scattering and particle size. Actually, many research works are made on the applications of the optical monitoring for non-invasive and in-vivo assessment of glucose. Within this framework, we measured the speckle size evolution induced by a glucose addition in a scattering media. This experience has been made for measurement in diffuse reflectance. Analysis of speckle dynamics is frequently used to study the motion of scattering objects or liquids. By assessing the contrast on the speckle field produced by a blood plasma sample, illuminated by a laser during a coagulation test, as well as the slowing down of speckle fluctuations, we measured the time required for blood plasma coagulation in vitro and evidenced the process dynamics.
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Contributor : Yann Piederrière <>
Submitted on : Thursday, March 11, 2004 - 7:06:59 PM
Last modification on : Wednesday, October 14, 2020 - 3:52:15 AM
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Yann Piederriere. Etude du speckle de milieux diffusants liquides. Application à la détermination de paramètres biophysiques. Autre. Université de Bretagne occidentale - Brest, 2003. Français. ⟨tel-00005314⟩

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