Effect of the Speckle Size on the Quality of Speckle Pattern in DSPI System

Zhisong Li, Ping Zhong, Xin Tang, Jiayao Ling, Jiawei Chen, Guoxing He
2019 IEEE Access  
In order to detect the deformation and strain of materials accurately, the key is to obtain the phase information caused by dynamic loading in digital speckle pattern interferometry (DSPI). In this paper, the evaluation method of quality of the speckle pattern in DSPI system is proposed, and the influence of the size of speckle grain on the stability and contrast of speckle pattern is discussed. And then, the strain detection experiments of inactive and bioactive materials are provided with
more » ... erent aperture slit size under the same detection conditions. The size of speckle grain has an important influence on the quality of speckle pattern. For strain detection of inactive materials, using the small size of speckles can obtain higher quality speckle pattern under the condition of satisfying the Nyquist theorem and spectral separation. For active biomaterials, non-structural factors easily induce the instability of speckle pattern, which leads to the decorrelation of between pre-deformation and post-deformation speckle pattern. So the compromise between the stability and the information capacity of speckle images should be considered in the selection of speckle size. Experiments show that the optimum size of speckles used for strain detection active biomaterials is larger than that of inactive biomaterials under the same conditions in the same DSPI system. INDEX TERMS Speckle stability, image contrast, de-correlation, speckle size, strain distribution detection. 115010 This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see http://creativecommons.org/licenses/by/4.0/ VOLUME 7, 2019
doi:10.1109/access.2019.2935754 fatcat:x4m3mx7luveuzoz33ou74hfwcy