Development of three-dimensional speckle deformation measurement method with same sensitivities in three directions

Abstract

The speckle interferometry is a useful optical deformation measurement method in the object with rough surfaces. The deformation measurement method by using only two speckle pattern has also been proposed in ESPI by using Fourier transform. Then, the method can measure the deformation in high resolution. Furthermore, the method can measure not only the out-of-plane but also the in-plane deformation measurement of the objects with rough surfaces in high resolution. Then, the methods can also measure three-dimensional deformation. Many kinds of the three-dimensional measurement methods based on the speckle interferometry have been proposed. However, the parameters in sensitivity matrices of these conventional methods are not generally same concerning the three directions. The method of which sensitivity in three directions is not same cannot be employed as the exact three-dimensional measurement method. In this paper, the method of which sensitivity in three directions is same is proposed. The optical system is set up under the concept of the proposed method. The multi-recording technology of the signals of the deformations for speckle interferometry using one camera is discussed. From the experimental results, the validity of the novel method is confirmed.