A step towards length scale corrected and instrument independent surface roughness analysis

Surface roughness is a function of the length scale it is measured at and the frequency response function of the particular type of instrument used to acquire data. The goal of this paper is to provide a methodology for predicting surface roughness values for one particular instrument from measurements with another type of instrument, which may operate at different length scales. In particular we compared surface roughness results for four different polymers obtained with three different instruments: a stylus profilometer, an optical profilometer and an atomic force microscope. When length scale differences are eliminated through the use of image morphology and segmented analysis, the measured roughness is still a strong function of the type of instrument for some of the materials. To eliminate the instrumental dependence we determined the frequency response function for each instrument, using a reference sample, and calculated the surface roughness based on frequency response corrected power spectral densities for the polymers. The correction improves inter-instrument agreement significantly. (paper)