Ambiguity Elimination in Confocal Microscopy
Original Publication Date: 1987-Dec-01
Included in the Prior Art Database: 2005-Feb-02
Incorrect surface height measurements on tortuous or textured surfaces under confocal microscope inspection can be eliminated by comparing a measurement where the illumination and detection points are coincident with a measurement where the illumination and detection points are separated. A problem in confocal inspection of metal and ceramic parts is that there is a family of equivalent surfaces of an object under inspection which produces identical confocal signals. This is unacceptable where the measurement is being used to indicate the height of the surface. For example, a surface with a radius of curvature matching that of the incoming spherical wave will create a return signal corresponding to a planar surface located at the center of the radius of curvature.