Light source distribution and scattering phase function influence light transport in diffuse multi-layered media
TypeArticles dans des revues avec comité de lecture
Red and near-Infrared light is often used as a useful diagnostic and imaging probe for highly scattering media such as biological tissues, fruits and vegetables. Part of diﬀusively reﬂected light gives interesting information related to the tissue subsurface, whereas light recorded at further distances may probe deeper into the interrogated turbid tissues. However, modelling diﬀusive events occurring at short source-detector distances requires to consider both the distribution of the light sources and the scattering phase functions. In this report, a modiﬁed Monte Carlo model is used to compute light transport in curved and multi-layered tissue samples which are covered with a thin and highly diﬀusing tissue layer. Diﬀerent light source distributions (ballistic, diﬀuse or Lambertian) are tested with speciﬁc scattering phase functions (modiﬁed or not modiﬁed Henyey-Greenstein, Gegenbauer and Mie) to compute the amount of backscattered and transmitted light in apple and human skin structures. Comparisons between simulation results and experiments carried out with a multi-spectral imaging setup conﬁrm the soundness of the theoretical strategy and may explain the role of the skin on light transport in whole and half-cut apples. Other computational results show that a Lambertian source distribution combined with a Henyey-Greenstein phase function provides a higher photon density in the stratum corneum than in the upper dermis layer. Furthermore, it is also shown that the scattering phase function may aﬀect the shape and the magnitude of the Bidirectional Reﬂectance Distribution (BRDF) exhibited at the skin surface.
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Assessment of tissue optical parameters in a spherical geometry using three different optical spectroscopy methods: comparison based on a theoretical approach VAUDELLE, Fabrice; ASKOURA, Mohamed-Lamine; L'HUILLIER, Jean-Pierre (The Society of Photo-Optical Instrumentation Engineers (SPIE), 2015)The non-invasive research of information inside the biological tissues can be made by means of continuous, time dependent or frequency modulated light source, emitting in the visible or infrared range. Moreover, the ...
Use of steady-state imaging setup for assessing the internal optical properties of non-spherical apple samples ASKOURA, Mohamed Lamine; VAUDELLE, Fabrice; L'HUILLIER, Jean-Pierre (Elsevier BV, 2019)The aim of this paper was to retrieve the absorption (µa) and reduced scattering (µ's) coefficients of whole apples which exhibit a complex shape. The effect of the local boundary curvature on the retrieved optical properties ...
Multispectral measurement of scattering-angular light distribution in apple skin and flesh samples ASKOURA, Mohamed Lamine; VAUDELLE, Fabrice; L’HUILLIER, Jean-Pierre (The Optical Society of America, 2016)Knowledge of the optical properties of apple tissues such as skin and flesh is essential to better understand the light–tissue interaction process and to apply optical methods for apple quality inspection. This work aimed ...
ASKOURA, Mohamed; VAUDELLE, Fabrice; L’HUILLIER, Jean-Pierre (MDPI AG, 2016)This work aimed at high lighting the role played by the skin in the light propagation through the apple ﬂesh. A multispectral Visible-Near Infrared (Vis-NIR) steady-state imaging setup based on the use of four continuous ...
ASKOURA, Mohamed; VAUDELLE, Fabrice; L’HUILLIER, Jean-Pierre (MDPI AG, 2015)This paper reports on the quantiﬁcation of light transport in apple models using Monte Carlo simulations. To this end, apple was modeled as a two-layer spherical model including skin and ﬂesh bulk tissues. The optical ...