Use of the δ-P_(1) approximation for recovery of optical absorption, scattering, and asymmetry coefficients in turbid media

摘要

We introduce a robust method to recover optical absorption, reduced scattering, and single-scattering asymmetry coefficients (μ_(a), μ_(s)~(′), g_(1)) of infinite turbid media over a range of (μ_(s)~(′)/μ_(a)) spanning 3 orders of magnitude. This is accomplished through the spatially resolved measurement of irradiance at sourcedetector separations spanning 0.25-8 transport mean free paths (l~(*)). These measurements are rapidly processed by a multistaged nonlinear optimization algorithm in which the measured irradiances are compared with predictions given by the δ-P_(1) variant of the diffusion approximation to the Boltzmann transport equation. The ability of the δ-P_(1) model to accurately describe radiative transport within media of arbitrary albedo and on spatial scales comparable to l~(*) is the key element enabling the separation of g_(1) from μ_(s)~(′).