Out of plane displacement measurement based on electronic speckle pattern interferometry

A method was described to measure out-of-plane displacement based on electronic speckle pattern interferometry (ESPI). The beam path of Twyman-Green was set up to collect speckle interference patterns. And then, the speckle correlation fringes were generated by subtracting the speckle interference patterns fore-displacement and back-displacement. Finally, we got the displacement by analysing the speckle correlation fringes which were processed by homomorphic filter. It is shown that this proposed method is characterized by full field, non-contact, high accuracy, high sensitivity and non-special shock resistance. Therefore, in the hologram of speckle metrology, electronic speckle pattern interferometry has the highest application value.