Robust method to improve the quality of shearographic phase maps obtained in harsh environments

This paper presents a new approach to improve the quality of shearographic phase maps acquired in a harsh environment. During in-field nondestructive inspections, the presence of higher disturbances, mainly vibrations, can introduce unknown phase deviations in the sequence of shearographic images. This paper presents a different approach that combines the N-dimensional Lissajous algorithm [Int. J. Optomechatron.8, 340 (2014)1559-961210.1080/15599612.2014.942933] and the concept of phase of differences [Proc. SPIE6345, 634510 (2006)PSISDG0277-786X10.1117/12.693149] to improve the quality of phase maps. The concept is compared with two other methods. Results, advantages, and difficulties of each method are also presented and discussed by using real fringe maps.