Deformation analysis with temporal speckle pattern interferometry

The continual deformation of an object will lead to a temporal speckle patt ern. By analyzing this time-dependent speckle pattern the temporal deformat ions of the object can be obtained. We propose a method for measuring the d isplacement components caused by deformations using the temporal speckle pa ttern interferometry (TSPI). By capturing a series of speckle interference patterns related to the object deformations, we can get the fluctuations in the intensity of the interference patterns. Further, the phase maps for wh ole-field object displacements are calculated with the inversion of the tem poral interference intensities by estimating both the average intensity and the modulation. In this way, one can quantitatively measure temporal displ acements simply using a conventional electronic speckle pattern interferome try (ESPI) system without phase shifting or a carrier. An elaboration of th e TSPI is presented and out-of-plane displacements caused by pressure and t hermal deformations are measured. (C) 2001 Society of Photo-Optical Instrum entation Engineers.