Domain of validity of the equation for total integrated scatter (TIS)

摘要

The analytical expression for total integrated scatter (defined as diffuse reflectance divided by total reflectance) has been around for almost six decadesiTIS/i = 1 - expstrong[/strong-(4π cosθisubi/sub/i σ/λ)sup2/supstrong]/strong.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.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.