An investigation of the imaging of spheres can aid in understanding details
of the surface profiling method of confocal microscopy. The use of semicir
cular masks to eliminate artifacts in confocal profiling is investigated ex
perimentally. A theoretical treatment of image formation for a spherical ob
ject in reflection confocal microscopy is presented. For large spheres a si
mple approximate theory is described and is shown to be equivalent to appli
cation of the Kirchhoff theory for surface scattering; (C) 2000 Optical Soc
iety of America OCIS codes: 180.0180, 180.1790, 170.6900, 120.6660.