With shearography defect locations e.g. in composite materials are detected and measured credible. The somponents are insignificantly loded and their deformations and strains are measured full field. Through the high sensitivity of the interferometric measurement technique only very small amounts of loads are required to make defects (leading to inhomogenous strain distributions) visible.

The dynamic excitation through shaker is developped as the most credible technique for the online-defect detection. Stresses can be applied also through heat, pressure, vacuum or mechanically.