A grating projection method using a stereo microscope is developed to provide a surface profile measurement. The phase shifting technique is applied to attain high accuracy detection of the projected fringe. Then, to overcome 2π phase jump caused by large height, contrast detection of the projected pattern is used. The contrast variation depends on the distance between sample and objective lens. This distribution is almost as same as an optical sectioning that is usually used in confocal microscopy. The fast reconstruction procedure is proposed to analyze the focused point from a few images. Moreover, this information is also available for the phase unwrapping of the phase detection. This method is experimentally verified by measuring a stepper specimen.
