Boltzmann equation, Riemannian metric, Transport equation
Optical tomography is the use of near-infrared light to determine the optical absorption and scattering properties of a medium M ⊂ Rn. If the refractive index is constant throughout the medium, the steady-state case is modeled by the stationary linear transport equation in terms of the Euclidean metric and photons which do not get absorbed or scatter travel along straight lines. In this expository article we consider the case of variable refractive index where the dynamics are modeled by writing the transport equation in terms of a Riemannian metric; in the absence of interaction, photons follow the geodesics of this metric. The data one has is the measurement of the out-going flux of photons leaving the body at the boundary. This may be knowledge of both the locations and directions of the exiting photons (fully angularly resolved measurements) or some kind of average over direction (angularly averaged measurements). We discuss the results known for both types of measurements in all spatial dimensions.
Required Publisher's Statement
CUBO: A mathematical journal published by the Universidad de La Frontera Universidade Federal de Pernambuco Volume 11/No ¯ 05 – DECEMBER 2009
McDowall, Stephen R., "Optical Tomography for Media with Variable Index of Refraction" (2009). Mathematics. 33.
Subjects - Topical (LCSH)
Optical tomography; Transport theory; Integral geometry; Inverse scattering transform
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