2. Holographic interferometry methods

Holographic interferometry, whether based on photographic plates, photo-refractive crystals or digital image sensors, is capable of providing a highly accurate representation of the real, global behavior of a mechanical assembly or a physical phenomenon in general, without disturbing it, as the method requires no contact. This assembly or phenomenon may be small and possibly inaccessible (in which case microscopy and/or endoscopy are used), or very extensive (e.g. the vibration of a section of engineering structure or a car in operation). It is not only a method of global visualization, but also of quantitative measurement of static or dynamic three-dimensional phenomena. This makes it a highly effective method for vibration analysis.