Application of the morphological alpha shape method to the extraction of topographical features from engineering surfaces

In contrast to the mean-line based filters, morphological filters are function oriented and more suitable for the functional prediction of component performance. This paper presents a novel morphological method based on the alpha shape for the extraction of topographical features from engineering surfaces. Compared to the traditional implementation of morphological filters, the alpha shape method is more efficient in performance for large structuring elements. The resulting envelope follows the form of the surface all over such that the distortions caused the end effects are avoided. A series of measured surfaces from the automotive cylinder liner and the bioengineering artificial femoral heads are analyzed using the morphological alpha shape method. The topographical features are successfully extracted, enabling further physical and tribological analysis to the components.

► Morphological filters are suitable for the extraction of topographical features.
► The alpha shape method is efficient in performance for large structuring elements.
► The alpha shape method has no distortions caused by the end effects.
► The alpha shape method successfully extracts topographical features from surfaces.