Angular smoothing and spatial diffusion from the Feynman path integral representation of radiative transfer

作     者：Tessendorf, Jerry 

作者机构：Rhythm & Hues Studios Los Angeles CA USA 

出 版 物：《JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER》 (定量光谱学与辐射传递杂志)

年 卷 期：2011年第112卷第4期

页      面：751-760页

核心收录：

学科分类：070207[理学-光学] 07[理学] 08[工学] 0703[理学-化学] 0803[工学-光学工程] 0702[理学-物理学] 

主　　题：Feynman path integral Diffusion Stationary phase Steepest descents Propagation kernel Computer graphics 

摘      要：The propagation kernel for time dependent radiative transfer is represented by a Feynman path integral (FPI). The FPI is approximately evaluated in the spatial-Fourier domain. Spatial diffusion is exhibited in the kernel when the approximations lead to a Gaussian dependence on the Fourier domain wave vector. The approximations provide an explicit expression for the diffusion matrix. They also provide an asymptotic criterion for the self-consistency of the diffusion approximation. The criterion is weakly violated in the limit of large numbers of scattering lengths. Additional expansion of higher-order terms may resolve whether this weak violation is significant. (C) 2010 Elsevier Ltd. All rights reserved.