The angular distribution of the light scattered by a rough surface contains information on the texture of the surface. Profiles of nine specimens were measured with a stylus instrument and angular distributions of the scattered light were measured with a detector. The rms roughness of a surface that has an identifiable specular beam can be determined from the relative intensity of that beam. The autocorrelation length and the parameters that define the autocorrelation function, as well as the roughness of rougher surfaces that produce no specular beam, can in principle be determined by fitting the distribution computed from a model of a random rough surface to the measured distribution. In practice, measurement errors and computation errors preclude the determination of these parameters by a leastÃ¢â‚¬â€?squares fit. Angular distributions were also computed from the surface profiles using a simplified model of the electromagnetic scattering.
T. V. Vorburger,
"Light Scattered By Random Rough Surfaces And Roughness Determination", Proc. SPIE 1165, Scatter from Optical Components, (2 January 1990); doi: 10.1117/12.962838; https://doi.org/10.1117/12.962838