About The Reproducibility Of Texture Profiles And The Problem Of Spikes

The ISO working group ISO/TC43/SC1/WG39 has recently been worrying about the quality of texture profiles, measured with laser profilometers. It appears that the quality has not improved in recent years, rather on the contrary: in spite of the technological progress it appears to decrease! The WG is especially concerned of the presence of invalid positive spikes in some profiles which might dramatically affect the Mean Profile Depths (MPD) [1] and to some extent the texture spectra calculated with those spectra, if one does not properly deal with these erroneous measurement points prior to calculating the MPD or spectrum. In this paper the results of an international round robin test with static laser profilometer devices on two epoxy moulds of dense asphalt concrete road surfaces are shown, indicating the reproducibility of this kind of devices for the wavelength range from 2,5 mm up to 125 mm. A new procedure to deal with the spike problem is presented. The aim is to remove the spikes without affecting significantly the valid part of the spectra. The effect on MPD and spectra will be shown for some typical cases. The method, based on the detection of steep jumps in the profile, appears to work.