Evaluation of the continuous wavelet transform method for the phase measurement of electronic speckle pattern interferometry fringes

We present an evaluation of the continuous wavelet transform method when it is used to measure the phase distribution encoded by electronic speckle pattern interferometry (ESPI) fringes. The evaluation is performed using computer-simulated fringes, an approach that allows knowing precisely the phase map contained in the pattern. It is shown that only ESPI fringes that verify the stationary phase approximation and its analytic asymptotic limit can be analyzed with the continuous wavelet transform method. The influence of the filtering process to smooth the ESPI fringes and the method used to extend the fringe pattern edges is also analyzed. Finally, additional drawbacks that emerge when this phase evaluation method is applied are discussed. (C) 2002 Society of Photo-Optical Instrumentation Engineers.