Asymptotic Radiative Transfer

TL;DR

This paper introduces asymptotic radiative transfer (ART), an improved model over diffusion theory that accurately describes light propagation in scattering media, especially at low albedoes, by using asymptotic intensity profiles and attenuation coefficients.

Contribution

The paper extends ART to low albedo scattering media and compares its accuracy with diffusion theory and radiative transfer data, highlighting improvements.

Findings

ART provides more accurate results than diffusion theory at low albedoes.

Comparison shows ART closely matches radiative transfer data.

Boundary transients can further improve accuracy.

Abstract

Asymptotic radiative transfer (ART), like diffusion theory, assumes the angular intensity distribution incident at a boundary is identical with that in the depth of the scattering medium. However, the asymptotic intensity profile and accurate attenuation coefficient corresponding to the scattering phase function are used in preference to the P1 approximations of diffusion theory, thereby extending the range of asymptotic radiative transfer to the lowest particle scattering albedoes. Asymptotic calculations for scattering media with refracting boundaries are compared with diffusion theory and accurate radiative transfer data to illustrate this. The error involved can be further reduced by the addition of a suitable boundary transient