This paper presents some preliminary success in the computerizing of data reduction in shearography. Computerization is made possible by the introduction of a fringe carrier technique that removes the ambiguities in fringe interpretation. The technique is based on superposing a set of carrier fringes upon the deformation fringes. The resulting fringe pattern has monotonically increasing fringe orders, thereby allowing the fringe orders to be determined in a straightforward manner and without ambiguity. It is shown that the data deduction process can be computerized. The deformed carrier fringe pattern is digitized, and the displacement derivatives are then automatically deduced by means of digital image processing.
Douglas W. Templeton,
Yau Y. Hung,
"Shearographic Fringe Carrier Method For Data Reduction Computerization," Optical Engineering 28(1), 280130 (1 January 1989). https://doi.org/10.1117/12.7976897