Traditional nondestructive evaluation (NDE) of bonding flaws has generally used either ultrasound or x-rays as a directed energy source to image or otherwise detect the discontinuity of an improper bond. While this approach has broad applicability, it is inadequate where the material is highly attenuating or anisotropic, or when it is impossible to achieve an adequate interrogation due to geometrical constraints. These difficulties are seen in materials such as the silica fiber composites used for the thermal protection tiles on the Space Shuttle Orbiter, insulating rubber liners used for solid rocket motors, and rubber or foam coating materials.