Mathematical Modeling and Simulation of Light Propagation in Multi-Layers Earlobe for Non-Invasive Hemoglobin Measurements

Ahmad Al Nabulsi, Lutz Angermann, Omar Abdallah, and Armin Bolz


Light propagation in multilayers, diffusion equation and boundary condition, optical properties, finite element method, hemoglobin concentration


Many applications in the biomedical research regarding to the non-invasive hemoglobin measurements have been done depending on Lambert-Beers law, but unfortunately they suffer from the inaccuracy because of the poor modeling of the realistic behavior of light propagation in non-homogeneous translucent materials like human tissue. Our work in this paper is split into different steps, starting with building the simulation of earlobe sensor and then building the geometry of the simulated earlobe, after that the light propagation inside the multi-layers earlobe is modeled depending on diffusion equation with boundary conditions that are judiciously chosen. The optical properties of the different layers are experimentally determined. A set of more than fifty boundary value problems regarding to the individual layers in the systole and diastole cases and also the variety with respect to the different given wavelengths are solved numerically using finite element method, which is here briefly explained. After the numerical solution has been obtained a post-processor step starts in order to compute the absorbed, the scattered and the transmitted light intensities in the individual layers with respect to the different wavelengths.

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