Texture direction analysis of micro-topographies using fractal geometry

In recent years fractal geometry has been repeatedly shown to help describe and characterize micro-topographies. Important properties of micro-topographies include roughness or texture direction. Consequently, in this work, fractal geometry is investigated to determine texture direction. For this purpose, synthetic data and real height maps of different micro-topographies are evaluated using the fractal power spectrum density method. The results are compared with a manual determination of the texture direction and determining the texture direction according to ISO 25 178 using the S td parameter. The results show that the fractal method is more accurate than the currently standardized method. Another advantage is that secondary texture directions can be detected. Thus, the fractal method is well suited for characterizing micro-topographies and can complement existing parameters from ISO 25 178.