High-accuracy profiler that uses depth from focus

A CCD-based confocal microscope system that is used to measure accurate three-dimensional surface profiles is reported. For a field of view of 500 µm, surface samples spaced at 12 µm on smooth specular test objects are simultaneously resolved in depth to   1 µm (depending on the surface being observed). A precision of 0.1 µm is obtained for a mirrored surface for a field of view 400 µm wide. Simple scaling and sampling results permit these results to be extended to other apparatus dimensions and range sampling intervals.