4. Surface condition parameters

4.1 Separation of geometric deviations

The separation of geometric deviations is necessary to quantify each deviation independently of the others. There are two standardized methods for separating geometric deviations:

• Average line method: this involves filtering the primary profile with a bandpass filter. The differentiation between one deviation and another is performed by considering the distances between two peaks (wavelength). The boundary between two geometric deviations is therefore expressed as a length (cut-off wavelength). The filter generates a mean line, hence the name "mean line method."

• pattern method: this involves breaking down the primary profile into patterns by applying a "pattern...