A least squares line fit through the raw traced profile may be used as a reference line to remove the misalignment. This is because a least squares mean line is distorted by flaws or unusually shaped profiles. Filter Mean Line A filter mean line is the mean line implicit in a profile filter. For example, the waviness profile may be considered the mean line of the texture profile. The height of a profile at a particular point is the distance from the profile to its mean line.
Profile height is considered positive above the mean line and negative below the mean line.
A profile peak is a region of the profile that lies above the mean line and intersects the mean line at each end. In the figure below, each shaded region is a peak. The height of a peak is defined to be the point of maximum height within the region. Profile peaks are regions above the mean line. Local peaks are regions between two local minima.