Real-time Holographic Phase-Shifting Interferometry

Holographic interferometry enables the measurement of object deformations due to stress induced by pressure, heat, or applied force. Real-time double-exposure holographic interferometry and phase-measurement interferometry have been combined to measure both static and dynamic changes in objects.1-2 However, quantitative measurements are still not used much in the field of holographic nondestructive testing. Quantities such as fringe density, fringe contrast, speed of data taking, and being able to relate the phase to specific areas of the object have slowed down the spread of this technique. In this paper, we will discuss the state of the art in quantitative holographic nondestructive testing, and show results which we have obtained using our techniques.