A fast digital image correlation algorithm based on Hartley transform and global sum-table scheme

摘要

Digital image correlation method (DICM) as a flexible tool for deformation measurements has found widespread use in a variety of fields. One major challenge in practical applications, however, lies in that this technique founded on zero-normalized cross-correlation (ZNCC) criterion is extremely time-consuming in correlation calculation. This paper introduces the Hartley transform and a so-called global sum-table strategy to evaluate the cross-correlation term and all double sums in the ZNCC expression, which can dramatically reduce computational complexity of correlation searching and therefore lead to significant computational savings. Both simulation tests and an actual example of displacement acquisition are employed to validate the feasibility and effectiveness of the fast algorithm, which indicates that it can improve the efficiency of the DICM calculation by ~4-14 times in comparison with the conventional algorithm. This is crucial for realizing a high-efficiency DICM to satisfy speed requirements for time-critical applications and large-scale data processing.