MODULATION ANALYSIS OF PHASE-SHIFTED HOLOGRAPHIC INTERFEROGRAMS

A new evaluation technique for phase-shifted holographic interferogram s is developed and verified by experiments. In evaluating the interfer ograms, both the discrete phase distribution and the intensity modulat ion of interference fringes are calculated and a binary control mask i s generated by analysing histograms and tracing local minima of the in tensity modulation distribution. The control mask is used to identify valid and invalid areas of the discrete phase distribution in subseque nt phase unwrapping and phase interpolation, and to control the path o f phase unwrapping. The evaluation of experimentally obtained phase-sh ifted holographic interferograms shows that this method can be success fully applied for the processing of complex interference patterns, eve n if the interferograms have fringe discontinuities and shaded areas.