Comparison of Robust Filtration Techniques in Geometrical Metrology

Filtration is one of core elements of analysis tools in geometrical metrology. Filtration techniques are progressing along with the advancement of manufacturing technology. The modern filtration techniques are requested to be robust against outliers, applicable to surfaces with complex form and reliable in whole range of measurement data. A comparison study is conducted to evaluate the commonly used robust filtration techniques in geometrical metrology, including the two-stage Gaussian filter, the robust Gaussian regression filter, the robust spline filter and morphological filters. They are compared in terms of four aspects: functionality, mathematical computation, capability and characterization parameters. As a result, it offers metrologists an instruction to choose the appropriate filter for various applications.