Robust fringe pattern analysis method for transient phenomena

We propose a method for analysing a sequence of noisy interferograms with closed fringes acquired at a high-speed frame rate. Our method is appropriate for analysing ESPI sequences of transient phenomena such as deformations caused by vibrations. Firstly, we compute a differential phase between frames using a procedure based on a Gabor filter bank. We then refine this initial phase with a regularised quadratic cost function that keeps the consistency of the restored phase with the fringe patterns. In addition, we also present the robust version of our phase refining method. This prevents the introduction of phase deformations by the smoothing process. We demonstrate by means of numerical and real-data experiments that our method is appropriate for analysing ESPI sequences of transient phenomena.