Light Propagation In Turbid Media Research Articles

Radiative transfer in turbid media with specular reflection at boundaries

A two-flux model for light propagation in turbid media is proposed based on the differential and integral forms of Pomraning-Eddington approximation. The accuracy of the differential form depends on the choice of the weighting function and the boundary conditions, the thickness of the medium, and the scattering properties of the medium. In the integral form, the boundary conditions are imbedded, the range of validity of the approach is extended, and it is also able to deal with anisotropically scattering inhomogeneous media. Numerical results for partial fluxes and the albedos are calculated and compared with published calculations.

Photon migration in turbid media using path integrals.

We describe the application of path integrals to the problem of light propagation in turbid media. The photon propagation process is separated into an absorption dependent part and a part that depends only on scattering. We determine the nonabsorption photon path and nonabsorption probability distribution function, from which other measurable optical parameters can be obtained. As an example, we calculate the diffuse reflectance for a semi-infinite medium and obtain a new result which reduces to a previously derived expression in the approximate limiting case.

Estimation of optical parameters in a living tissue by solving the inverse problem of the multiflux radiative transfer

Calculations of radiative transfer require knowledge of the absorption and scattering coefficients and the asymmetry factor of scattering in the medium. A method is presented for estimating these coefficients in living plant leaves from fiber-optic measurements. We consider the plant leaf as consisting of two layers of different refractive indices and with reflecting surfaces. Light intensities at the boundaries of these layers in several irradiated plant leaves have been measured using a thin (70-microm) glass fiber connected to a photomultiplier. The diffuse reflection and transmission were measured with an integrating sphere. From these values we derive an estimation of the scattering and absorption coefficients and the asymmetry factor of scattering applying an inversion of the multiflux theory of light propagation in turbid media. In addition, we compare these coefficients with those obtained by using the Kubelka-Munk theory.