Speckle interferometry when used for NDT suffers from overcrowding of fringes even for small making defect detection impossible. A fringe compensation technique is presented in this paper. The technique employs two objects, identical expect for the defect in one, that are loaded in the same way resulting in full compensation expect in the neighborhood of the defect. Theory and experimental results are presented.
© 1986 Optical Society of America
C. Joenathan, A. R. Ganesan, and Rajpal S. Sirohi, "Fringe compensation in speckle interferometry: application to nondestructive testing," Appl. Opt. 25, 3781-3784 (1986)