Simultaneous three-dimensional dynamic deformation measurements with pulsed digital holography

The three deformation components x, y, z of a vibrating object are measured simultaneously by use of digital holography with a double-pulse ruby laser source. The object is illuminated from three different directions, each op tically path matched with three reference beams such that three independent digital holograms are formed and added incoherently in one single CCD imag e. The optical phase difference between the two recordings taken for each h ologram is quantitatively evaluated by the Fourier-transform method so that a set of three phase maps is obtained, representing the deformation along three sensitivity vectors. The total object deformation is obtained as a ve ctor resultant from the data of the three phase maps. To give the full thre e-dimensional (3-D) description, the shape of the object is measured by the two-wavelength contouring method. Experiments are performed with a cylinde r as the test object, transiently and harmonically excited. The 3-D deforma tion and shape measurement results are presented graphically. (C) 1999 Opti cal Society of America OCIS codes: 040.1520, 120.7280, 140.3540.