3D deformation measurement by digital speckle correlation method and stereo vision - art. no. 67231N

An advanced 3D deformation measurement method based on 2D digital speckle correlation method and stereo vision is proposed in the paper. The intrinsic parameters and extrinsic parameters of two digital CCD cameras have been calibrated. The speckle images of the specimen from different directions are recorded by two cameras before and after deformation. The deformation displacement and strain of the specimen are calculated from these speckle images by digital speckle correlation method and geometrical relation of stereography. The whole field deformation can be obtained by tracking the gray character of each surface point in a subset. A new correlation search method based on genetic algorithm is proposed, which gets rid of great computational complexity and bad quality of conventional correlation search methods. The performance of the method is demonstrated by real test.