A direct solution for radiative intensity with high directional resolution in isotropically scattering media

Radiative intensity with high directional resolution can provide fruitful information inside radiative systems, which is very useful for inverse analysis. In this work, a direct solution for radiative intensity with high directional resolution in isotropically scattering media enclosed by diffuse boundaries is developed. First, linear equations about radiative intensity at the boundaries (outgoing directions) and source terms in the media are established based on the integral form of the Radiative Transfer equation (RTE). Then, after directly solving the established equations and with the obtained radiative intensity and source terms, radiative intensity at any position with high directional resolution is readily calculated by summation operation. The proposed method is validated by comparing the calculated directional radiative intensity with that of the iterative Distributions of Ratios of Energy Scattered Or Reflected (iterative-DRESOR) method as well as the reverse Monte Carlo (RMC) method, both in one-dimensional and three-dimensional cases. The computing time comparison shows that the proposed method has a distinct advantage for calculating radiative intensity with high directional resolution compared with the reverse Monte Carlo method.