A Novel 3d Profile Measurement Method Based On Digital Photoelastic Technology

A three-dimensional profile measurement method based on digital photoelastic fringe analysis technology is proposed in this paper. According to the actual stress field of a disc under appropriate load, the photoelastic fringe patterns are generated. These patterns are illuminated on the reference plane and objects through a projector, which are regarded as the structured-light pattern sequence. Then a series of images including normal images and deformed fringe images are captured. These images contain two significant photoelastic parameters, isoclinic parameter and isochromatic parameter, which could be evaluated by the phase shifting method. Therefore, phase differences can be calculated by photoelastic isochromatic parameter after phase unwrapping. Depth information is carried in the phase differences and virtual 3D profile equal to real objects could be reconstructed. Experiments demonstrate that this method is robust and suitable for measuring objects with regular and general shape.