ERROR ANALYSIS AND PRACTICAL CONSIDERATIONS OF INCREMENTAL DIGITAL IMAGE CORRELATION

Incremental digital image correlation (DIC) method is commonly used in scenarios prone to image decorrelation, such as when the measured object undergoes large deformations, strong illumination changes exist or laser speckle is used for deformation tracking. Incremental method utilized the correlation within the image sequence and update the reference image to calculate the incremental deformation, which is accumulated to obtain the total deformation, thus overcoming the failure of traditional methods that use a fixed reference image when decorrelation occurs. However, the systematic error exists when computing deformation using DIC, accumulating incremental displacements leads to error accumulation in incremental calculation. To perform efficient and accurate measurement incremental DIC analysis, it is necessary to clarify the accumulation law and propose the suppression methods of the cumulative error. In this work, through simulations and experiments, we investigate the cumulative error of incremental method with different incremental strategies in different application scenarios. Results show that to minimize the cumulative error caused by reference image updating, conditional updating strategy should be adopted to reduce reference image updating frequency. Additionally, the adaptive reference subset shifting strategy and the classic Gaussian low-pass pre-filtering can significantly reduce the systematic error caused by interpolation and should be used in conjunction with the incremental method.