Optical methods for the measurement of the shape of objects and their measurement uncertainty

There are various optical methods for the measurement of the geometrical shape of objects. We calculate the measurement uncertainty for several "paradigm" methods, by means of the Cramer - Rao lower bound. Thus the parameters, on which the measurement uncertainty depends, can be found. Substantial features of individual optical measurement methods (geometrical arrangement, optically smooth or rough surface, used light, dominant source of noise) of various measurement methods are compared and their influence on the measurement uncertainty is discussed.