Laser & Optoelectronics Progress, Volume. 51, Issue 11, 111201(2014)
Research on New Shearing Speckle Interferometry System
Shearing speckle interferometry is a well known optical tool for qualitative as well as quantitative measurements of displacement components′ derivatives of engineering structures subjected either static or dynamic load. Shearing speckle interferometry, based on Mach-Zehnder interferometer, suffers from the disadvantage of low light efficiency due to the structure. A novel digital shearography set-up with two fold which can improve light efficiency for the measurement of first order derivative of out-of-plane displacement (slope) is demonstrated. There is a double aperture mask in front of the imaging lens for spatial phase shifting. Independent control of the shear and the frequency of the spatial carrier can be attained with this set-up. A shear is introduced between the two scattered fields. The double aperture which can introduce spatial carrier fringes within the speckle for spatial phase shifting is employed in this system. Phase extraction is obtained through advanced sinusoidal-fitting method, which is applied to interference patterns with a spatial carrier in the primary fringes. The experimental implementation of the set-up and the results obtained with it are presented and discussed.
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Cai Changqing, Zhang Yongshan, Wang Dayang, Han Qihao, Tang Chengzhi. Research on New Shearing Speckle Interferometry System[J]. Laser & Optoelectronics Progress, 2014, 51(11): 111201
Category: Instrumentation, Measurement and Metrology
Received: Apr. 10, 2014
Accepted: --
Published Online: Nov. 7, 2014
The Author Email: Changqing Cai (409414771@qq.com)