Automated fringe pattern analysis in experimental mechanics: a review

The paper reviews the main numerical techniques that have been developed to carry out fully automated analysis of fringe patterns resulting from solid mechanics experiments. These include temporal and spatial phase shifting interferometry, temporal and spatial phase unwrapping, and calculation of strain fields from the phase maps. Systematic and random errors associated with the various procedures are also analysed. A unified treatment for both speckle and smooth-wavefront interferograms is presented, and the common features underlying many of the algorithms are emphasized. The paper is illustrated with applications that include ball impact (moire photography), bending waves in orthotropic plates (double-pulsed dual-reference wave holography) and finite strains in propellant grains (fine grid technique).