One-grating projection for absolute three-dimensional profiling

A new method for absolute 3-D profiling, based on the fringe projection tec hnique using a vertical scan mode, is described. With a combined measuremen t of the modulation and the phase it is possible to acquire the topography without any ambiguity problems by using one grating period only. Consequent ly, the vertical measurement range is limited only by the free working dist ance and the resolution is comparable to standard fringe projection techniq ues. We present a microscopic solution, based on a zoom stereo microscope, which enables interesting applications in an extended microscopic range, su ch as the measurement of microcomponents and microshapes, for example. (C) 2001 society of Photo-Optical Instrumentation Engineers.