Research Of Temporal Speckle Pattern Interferometry For In-plane Measurement

Speckle pattern interferometry is a non-contact, high sensitivity and full-field measurement method to be applied in surface deformation, roughness, stress and strain analysis, which has a widely application in engineering and materials. The research for out-plane displacement measurement is very popular in speckle pattern interfernometry already. In this paper, the major purpose is to research the in-plane displacement measurement. The main works as follows:1) The program based on Wavelet transform technique to recovery and unwrap phase are made. The object displacement measurement is simulated by the program based on Wavelet transform technique and Fourier transform technique.2) A non-heterodyne temporal speckle pattern interferometry (TSPI) system to measure the in-place displacement is built, which is different from conventional speckle pattern interferometry. Meanwhile a heterodyne temporal speckle pattern interferometry (HTSPI) system is built, which can improve the precision when the displacement is micro and nonlinear, while TSPI system can not.3) The displacement information is extracted by a Fourier transform technique and Wavelet transform technique from the speckle pattern that is recorded over a period of time as the object is displaced. The results of two techniques are compared, and the differences between two systems are discussed.