Iterative Fourier transform method for phase map recovery in electronic speckle-shearing pattern interferometry

Increasing phase values at the edges of objects under analysis in electronic speckle shearing interferometry (ESSPI) cause errors in the actual recovering methods to obtain the spatially integrated phase. An iterative least minimum squares method is proposed here to recover the phase map from the approximated ESSPI derivatives when the displacement phase is increasing near the object edges. It is based in an iterative Fourier transform method derived from a least-squares phase map recovery algorithm. Experimental results from a rotating cylindrical bar show the validity of our approach.