A new single-frequency fringe projection profilometry for discontinuous shape measurement is proposed.Four-step sinusoidal fringe patterns with phase increment of π/2 generated by computer are projected onto the object surface by a digital video projector and the deformed fringe patterns are acquired by a CCD camera.The captured fringe patterns are firstly employed to extract phase information.Sum operation is then applied on four deformed fringe patterns to remove fringes and determine the shadow and dark background.The sum image of four fringe patterns is binarized and used for the phase correction.The experimental results demonstrate the validity of the proposed method for discontinuous shape measuring.