Digital techniques for strain measurement using electro-optic holography

摘要

Some new approaches to the digital analysis of the fringes obtained j electro^optic holography are presented. The technique of phase stepping (supplemented by Fourier filtering, for the elimination of noise in wrapped-phase itiaps, is discussed first. The problem introduced by 'discontinuities at the object t^oundary and a fringe extrapolation technique to overcome this prpblem are discussed next. Finally, a technique to compute the phase derivatives directly from the wrapped-phase map is outlined.