Study on accuracy evaluation of deformation and strain distribution measurement using digital image correlation method

Sub-pixel digital image correlation (Sub-DIC) method is effective for health monitoring of structures, because the Sub-DIC method can measure full-field deformation and strain distribution. However, the effect of analysis parameters of Sub-DIC method on measurement accuracy is not clarified. In this paper, we discussed the relation between the analysis parameters and the measurement accuracy of the Sub-DIC method. We demonstrated the analysis parameters such as a sub-set size, scan-step interval, and averaged point size on the standard deviation of measured deform and strain error distributions. Moreover, we found measurement accuracy is correlation related to the half width of spatial FFT spectrum of measured object and strain distribution. Finally, it is basically confirmed the measurement accuracy of Sub-DIC method depends on the central limit theorem.