Abnormal phase removing method in phase measuring profilometry

An abnormal phase removing method in phase measuring profilometry is proposed. In the five equal shifting phase steps algorithm, the shifting phase might be extracted from the deformed patterns captured by CCD camera. But there may be some errors introduced by a digital fringe projector and CCD camera in these deformed patterns. The impurity of the deformed patterns may lead to four classes of abnormalities when extracting the shifting phase. These abnormalities may cause the wrong shifting phase extraction by which the reconstructed object might be misshapen or anamorphic, or even in failure. By this proposed method, the above abnormalities can be removed, and the shifting phase can be auto-extracted precisely from the impure deformed patterns without knowing its value. Experimental results verify the feasibility and effectiveness of the proposed method