Full-field modal identification using reliability-guided frequency-domain-based digital image correlation method based on multi-camera system

Abstract

A multi-camera array system was established to address the limitations of traditional measurement methods in full-field modal measurement. According to the principle of binocular vision, two cameras are utilized to form a set of three-dimensional measurement subsystems, and the subsystems are calibrated to establish unity in coordinates. To improve computational efficiency, a reliability-guided frequency-domain-based digital image correlation method is proposed to optimize pixel matching and calculation path. This method incorporates the benefits of a reliability-guided strategy and an integer-pixel search method based on the frequency domain to ensure that the seed point with the optimal matching effect in the calculation area is selected. The zero-mean normalized cross-correlation coefficient is used as the criterion for determining reliability. This approach effectively avoids the problem of error transmission and reduces the need for complex operations and repeated searches in the spatial domain, thus improving computational efficiency. The matching time is reduced, the calculation efficiency of displacement signal extraction under large data volume is improved, and the obtained response signal is substituted into the modal identification algorithm to obtain the modal parameters of the structure. Ultimately, the modal test of a solar panel is performed by constructing a four-camera system, which verifies the correctness of the proposed method and has practical engineering significance.