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MICROTOPOGRAPHY - THE PHOTOGRAMMETRIC DETERMINATION OF FRICTION SURFACES

The understanding of friction processes assumes numerous methods for analysing the features and changes of surfaces in micro- and nanoscale. One of these features is the three-dimensional characterisation of the topography of friction surfaces. The combination of digital photogrammetric methods with image acquisition through Scanning Electron Microscopes (SEM) offers the possibility to derive topographic information over a wide scale, the integration of different data sets and the detection of changes. This paper discusses the photogrammetric methods, which are necessary to measure the three-dimensional shape of friction surfaces in microscale and its changes. This includes a bundle adjustment with different imaging geometries, image correlation by least-squares-matching, three-dimensional point determination and the generation of Digital Surface Models. The processing software, developed for this special task, is presented together with some results, which were processed in relation with the Special Research Project „Elementary Friction Processes“ at the Technical University of Berlin.