Standards help manage software's contribution to CMM measurement uncertainty.
Measurements obtained with coordinate measuring machines (CMMs) are subject to several uncertainty components, much like any other measurement and test equipment. However, unlike most other such equipment, CMMs fit geometrical forms to the points gathered from various types of sensors. To calculate these geometrical forms, complex data fitting routines must analyze the data and fit the data to a particular geometry. Most CMMs are able to fit data to geometries such as lines, planes, circles, spheres, cylinders and cones using a least squares fit. In some instances, the least squares fit might not be sufficient; the software might be required to find minimum circumscribed, maximum inscribed and minimum zone data fits as well.