Optimized digital speckle patterns for digital image correlation by consideration of both accuracy and efficiency

2018 ◽  
Vol 57 (4) ◽  
pp. 884 ◽  
Author(s):  
Zhenning Chen ◽  
Xinxing Shao ◽  
Xiangyang Xu ◽  
Xiaoyuan He
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Speckle Patterns ◽  
Digital Speckle

scholarly journals Gradient Correlation Functions in Digital Image Correlation

2019 ◽  
Vol 9 (10) ◽  
pp. 2127 ◽  
Author(s):  
Mikael Sjödahl
Keyword(s):  
Correlation Function ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Functions ◽  
Laser Speckle ◽  
Image Correlation ◽  
Intensity Correlation ◽  
Intensity Correlation Function ◽  
Speckle Patterns ◽  
The Difference

The performance of seven different correlation functions applied in Digital Image Correlation has been investigated using simulated and experimentally acquired laser speckle patterns. The correlation functions were constructed as combinations of the pure intensity correlation function, the gradient correlation function and the Hessian correlation function, respectively. It was found that the correlation function that was constructed as the product of all three pure correlation functions performed best for the small speckle sizes and large correlation values, respectively. The difference between the different functions disappeared as the speckle size increased and the correlation value dropped. On average, the random error of the combined correlation function was half that of the traditional intensity correlation function within the optimum region.

Digital Speckle Projection for Vibration Measurement by Applying Digital Image Correlation Method

2006 ◽  
Vol 326-328 ◽  
pp. 99-102 ◽  
Author(s):  
Fu Jun Yang ◽  
Xiao Yuan He
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Speckle Pattern ◽  
Plane Deformation ◽  
Correlation Method ◽  
Image Correlation ◽  
Vibration Measurement ◽  
Digital Image Correlation Method ◽  
Digital Speckle

Digital image correlation method (DICM) is described as a robust in-plane deformation measuring method due to its simple optical setup and the insensitivity against ambient noise. Based on DICM, digital speckle projection has been developed for shape measurement. This paper explores the possibilities for vibration analysis using digital speckle projection together with DICM. A digital speckle pattern, generated by computer, is projected on an object surface using an LCD projector. Then the dynamic deformation modulated speckle images are captured by a high-speed CCD camera and saved in the computer. By using the self-developed temporal sequence digital images correlation algorithm, the deformation and vibration mode can be analyzed quantitatively. The proposed method avoids using stroboscopic or laser illumination and simplifies the experimental setup for vibration measurement, while it is time-consuming thanks to calculating a large amount of correlation coefficients. The experimental performance on a harmonic-vibrating cantilever beam well demonstrates the validity of the new method.

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