3D Shape Measurement Based On Digital Speckle Shearing Interferometry

Digital speckle shearing interferometry is the interference detection method which is originated from speckle interferometry. The measure method that combined Digital image processing and speckle shearing interferometry, the precision can reach up to dozens of nanometer, so it can be used to measuring the3D shape of an object.3D Shape Measurement based on Digital Speckle Shearing Interferometry is studied in this paper. The experiment device uses Twyman-Green system. The speckle field of object light beam is deflected by inclining mirror and the speckle fields before and after mirror inclining are recorded by CCD. We input the interferograms to the computer for digital image processing, and we can get the speckle pattern of object shape by two speckle pattern subtractions.Editing program using MATLAB software, we conduct digital image processing of interferogram to improve the contrast of speckle interference frings. The4interferograms are obtained by precise controlling the speckle shearing interference fringes shifting parallel and directionally,4steps digital phase shifting was realized.3D shape measurement is realized and3D map of object shape is got.