Characterisation of individual areal features

Along with the characterisation of areal surface topography through texture parameters, surface metrology is increasingly facing challenges related to the dimensional and geometric characterisation of individual surface features. Typical scenarios range from the inspection of individual elements of micro-parts and devices, to the characterisation of pattern units in structured surfaces, and to the analysis of scratches, pores, bumps and other singularities either generated by the manufacturing process, or originated during the operational life of the surface. The characterisation of individual surface features opens up a wide array of new application scenarios and creates novel challenges for surface metrology. Early approaches are not as consolidated as what is available for the characterisation of surface texture and see the convergence of mathematical models, methods and algorithmic solutions coming from heterogeneous disciplines such as image processing, computer vision, coordinate metrology, reverse engineering, and computer-aided design. In this chapter an overview of the tools available in current surface metrology software is provided first. Then, the main challenges and open issues of achieving full metrological characterisation of individual surface features are introduced and discussed, as well as the current research approaches addressing them.