"A novel Electronic Speckle Pattern Interferometry, ESPI, technique is presented in this work. The technique consist of an out-of-plane interferometer which incorporates a specially fabricated computer-generated hologram. This hologram allows us to achieve spatial phase stepping and therefore analysis of transient phenomena becomes feasible. The advantage of this technique is the calculation of deformation by means of a double exposure method where no changes of any kind are necessary to be introduced between consecutive recordings".