The analytical expression for total integrated scatter (defined as diffuse reflectance divided by total reflectance) has been around for almost six decades TIS = 1 - exp[-(4π cosθ_i σ/λ)²]. Most surface scatter analysts now realize that the expression is ambiguous unless spatial frequency band-limits are specified for the rms roughness, σ, in the expression. However, there still exists uncertainty about the domain of validity of the expression with regard to both surface characteristics and incident angle. In this paper we will quantitatively illustrate this domain of validity for both Gaussian and fractal one-dimensional surfaces as determined by the rigorous integral equation method (method of moments) of electromagnetic theory. Two dimensional error maps will be used to illustrate the domain of validity as a function of surface characteristics and incident angle. Graphical illustrations comparing the TIS predictions of several approximate surface scatter theories will also be presented.

Date Published: 15 October 2012
PDF: 11 pages
Proc. SPIE 8495, Reflection, Scattering, and Diffraction from Surfaces III, 849502 (15 October 2012); doi: 10.1117/12.930566

Published in SPIE Proceedings Vol. 8495:
Reflection, Scattering, and Diffraction from Surfaces III
Leonard M. Hanssen, Editor(s)