Profilometer is a measuring instrument used to measure a surface's profile, in order to quantify its roughness.
There are two types of profilometer: contact and non-contact profilometer.
Non contact profilometer is a frequently-used term for an optical profilometer. An optical profilometer is a non-contact method for providing much of the same information as a stylus based profilometer where the tip of the cantilever does not contact the sample surface.