λf
The F-Operator is used to remove the base form comprising the surface. As displayed in the figure below, a spherical surface is rendered “flat” after an F-Operator for spherical shape is applied. A number of F-Operators are available such as Tilt, Curvature (i.e. parabolic fit), Spherical (i.e. true spherical fit), Cylinder and various combinations. The F-Operator may be set to find the best fitting form based on a least squares fit or user-defined values for the radius of curvatures may be selected.
Spherical surface as measured.
After F-Operator of spherical form applied.