This new approach is based on optimization algorithms. In contrast to common techniques like fringe analysis or phase stepping methods the wave aberration can be evaluated from a single interferogram -- apart from the sign. Describing the wave aberration by a polynomial expansion, the coefficients of that polynomial are used as variables which are adjusted by iterative variations so that the corresponding computed interferogram is approximating the real interferogram. We discuss the special problems and demonstrate the practical meaning of the new approach.
"New approach for quantitative interferogram analysis", Proc. SPIE 1781, Specification and Measurement of Optical Systems, (1 January 1993); doi: 10.1117/12.140977; http://dx.doi.org/10.1117/12.140977