Everybody has the ability to describe a surface using adjectives such as “smooth” or “rough”, “even” or “circular”. Beyond this, a trained observer is able to give a description of a surface, e.g., in the form “reflecting even” or “rough with sharp-edged grooves”. Precision gauges were invented to quantify surface structures in manufacturing technology, particularly in the areas of quality control and quality security. In practice, the different types of form deviations are calculated from a one-dimensional profile. The evaluation of surfaces is limited to some exceptional cases. Peak-to-valley roughness parameters require a mean line in order to perform a roughness measurement; often this line is manually positioned by following the general trends of the profile. Profiles, especially of technical surfaces, can be understood as a superposition of waves of different frequencies and amplitudes. The high-frequency parts describe the roughness, against which the lower-frequency parts contain information about the ripple and the form deviation.