Measurement of Three-Dimensional Deformations by Phase-Shifting Digital Holographic Interferometry

Out-of-plane deformations of a cantilever were measured using phase-shifting digital holographicinterferometry (PSDHI) and the Fourier transform method (FTM). The cantilever was recorded in twodifferent states, and holograms were stored electronically with a charge-coupled device (CCD) camera.When the holograms are superimposed and reconstructed jointly, a holographic interferogram results.The three-dimensional (3D) surface deformations were successfully visualized by applying FTM toholographic interferogram analysis. The minimum surface displacement measured was 0.317 µm. Theprocessing time for the digital reconstruction and visualization of 3D deformation took about 1 minute.The technique was calibrated using Michelson interferometry setup.