Phase-shifted interferometry without phase unwrapping: reconstruction of a decentered wave front

We apply the method of the line integration of the phase gradient to determine unambiguously the phase from several phase-shifted interferograms (intensity fringe patterns) without phase unwrapping. The ambiguities introduced owing to the multiple values of the arctangent function and to the necessity to invoke a priori knowledge in the regions of high-intensity gradients are avoided. A decentered wave front with circular boundaries is reconstructed from high-fringe-density interferograms with an error of less than 0.1 percent, thus demonstrating the feasibility of testing the off-axis optical elements with approximate reference components.