Imaging of spheres and surface profiling by confocal microscopy.

An investigation of the imaging of spheres can aid in understanding details of the surface profiling method of confocal microscopy. The use of semicircular masks to eliminate artifacts in confocal profiling is investigated experimentally. A theoretical treatment of image formation for a spherical object in reflection confocal microscopy is presented. For large spheres a simple approximate theory is described and is shown to be equivalent to application of the Kirchhoff theory for surface scattering.