Synchronous measurement of three-dimensional deformations by multicamera digital speckle patterns interferometry

We present a spatial phase-shift digital speckle patterns interferometry (SPS-DSPI) system with the capability of measuring three-dimensional (3-D) deformations under a dynamic loading condition simultaneously using multiple cameras. The Fourier transform method is utilized to calculate the phase difference. The consistency of different cameras is achieved using digital image correlation (DIC) technology. Calibration and calculation programs are compiled to make sure each subset on the measuring surface is uniform. SPS-DSPI and DIC techniques are combined to provide a direct measurement of the 3-D deformation of the entire surface area simultaneously. The theory, application result, and validation experiment are presented.