Noise-free determination of isochromatic fringe order by load stepping

The traditional ambiguity in the sign of fractional retardation in certain zones of the model by phase shifting technique has been overcome with the development of load stepping in digital photoelasticity. However, the existing methodology of load stepping introduces several points in the model domain that are subjected to excessive noise. A new methodology has been proposed that combines the merits of load stepping and phase shifting to obtain fractional retardation free of noise and ambiguity over the model domain.