7. Non Metallic NDE, Acoustic Microscopy
Acoustic holography is an elegant and accurate technique for characterizing defects by forming visual images of them. Traditionally, optical reconstruction methods have been used to display the images but due to constraints of the optical systems, digital reconstruction techniques are now being employed.
Brophy, J. W.; Holt, A. E.; and Flora, J. H., "Digital Dislpay of Acoustic Holographic Images" (1980). Proceedings of the DARPA/AFML Review of Progress in Quantitative NDE, July 1978–September 1979. 39.