Employing an optical configuration for full-surface 360° measurement in multi-view digital image correlation

Abstract

The mirror-assisted multi-view digital image correlation (MV-DIC) method employs a stereo vision system using two mirrors to achieve 360° panoramic measurement of objects. This approach utilizes the two mirror devices to divide the object into three images, reconstructed independently using the stereo vision system. A complete 360° panoramic measurement is achieved by image stitching. However, this method poses challenges in simultaneously capturing all three surfaces of the object within the different depth of field of the imaging system, resulting in unclear images of certain surfaces and measurement errors. To address this issue, this study introduced a novel optical configuration for MV-DIC system. In this system, a pair of right-angle prisms are incorporated, which play a crucial role in adjusting the position of the prisms to effectively resolve the issue of achieving high-precision imaging of different regions of the object across varying depth of field ranges. Furthermore, to facilitate high-precision 360° panoramic measurement, a panoramic stitching method for three-dimensional data from different viewpoints is proposed. Experimental results indicated that the proposed method not only compensates for errors induced by the depth of field discrepancies but also offers superior accuracy in 360° panoramic morphology, displacement and strain measurement compared to traditional mirror-assisted MV-DIC systems, providing reassurance in its performance.