EVALUATION OF A METHOD TO DETERMINE INTERFEROMETRIC PHASE DERIVATIVES

A recently published method for the determination of phase derivatives maps by direct manipulation of three or more phase-shifted interferog rams is tested for accuracy. The method is evaluated on computer-simul ated holographic and electronic speckle pattern interferometry fringes and the results are assesed through the calculation of two comparativ e parameters: the relative image difference and the linear correlation coefficient. It is shown that errors in the phase derivative strongly depend on the filtering method used for smoothing the fringe patterns . An experimentally recorded ESPI fringe pattern is used to confirm th e predictions of the numerical simulations. (C) 1997 Elsevier Science Ltd.