Digital speckle correlation method with compensation technique for strain field measurements

Guan-chang Jin; Zhen Wu; Nai-Keng Bao; Xuefeng Yao

doi:10.1117/12.429568

13 June 2001 Digital speckle correlation method with compensation technique for strain field measurements

Guan-chang Jin, Zhen Wu, Nai-Keng Bao, Xuefeng Yao

Proceedings Volume 4317, Second International Conference on Experimental Mechanics; (2001) https://doi.org/10.1117/12.429568
Event: Second International Conference on Experimental Mechanics, 2000, Singapore, Singapore

Abstract

In the strain field measurements especially in large strain field measurements, usually the correlation coefficient values obtained by the digital speckle correlation method are very low due to the relative pixel movement of the subset. Thus the measuring error will be increased. A primary method, that is called compensation algorithm, is introduced for improving the correlation coefficient. A flow scheme with the compensation algorithm of our software is developed and some improving techniques for reducing the calculation error are discussed in the paper. After getting a set of displacement data with high correlation, a de-noise wavelet processing is adopted. It is obviously that the measuring accuracy of the strain field is much better than before. The error is 0.1 to 0.3 pixels less than before. A strain field of testing experiment is performed with this compensation technique. The correlation coefficients can increase from 0.70 to 0.99 and that will be of much benefit for the improvements of the measuring accuracy.

Citation Download Citation

Guan-chang Jin, Zhen Wu, Nai-Keng Bao, and Xuefeng Yao "Digital speckle correlation method with compensation technique for strain field measurements", Proc. SPIE 4317, Second International Conference on Experimental Mechanics, (13 June 2001); https://doi.org/10.1117/12.429568

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