Three-dimensional topometry with stereo microscopes

A stereo microscope arrangement used for visual quality inspection is extended to a fast 3-D topometer using the fringe projection technique. With specially designed binary gratings, an ideal sinusoidal intensity distribution can be achieved for an optimized illumination. Using a two-grating technique, the unambiguity range can be increased significantly. Thus, various applications can be solved with this method as is discussed. The resolution that can be achieved depends on the field of view, which at a large magnification is below 0.2 mu m. (C) 1997 Society of Photo-Optical Instrumentation Engineers.