Application of the least-squares method in processing profilograms

Conclusions

The orthogonal-regression-line factors have a nonlinear relationship to the recording scale, and therefore, the median plotted on the profilogram does not correspond to that of the profile. The error in determining the surface-roughness parameters is eliminated by using the formulas (7), (8), and (9). The median of a stationary normal process plotted by means of the least-squares method differs but little from the orthogonal regression line even if the amplitude of waviness is three times greater than that of surface roughness. Moreover, this median's factors have a linear relationship to the scale factors and require a smaller number of mathematical operations for their evaluation. Such a median plotted on the profilogram strictly corresponds to the profile's median.