面向包壳管应变测量的多相机3D-DIC标定方法OA

In practical applications of multi-camera three-dimensional digital image correlation(3D-DIC)systems for strain measurement of nuclear fuel cladding tubes,the multi-camera calibration process suffers from accumulated errors increase caused by coordinate systems transformation and insufficient global optimization capability.To address these issues,a multi-camera global calibration method based on a spatial calibration target was proposed.First,an approach was developed to provide initial values of the exterior orientation parameters for each camera at every pose of the calibration target,ensuring the correct convergence of space resection.Subsequently,a multi-camera multi-pose bundle adjustment(BA)method was introduced to ensure the global optimality of multi-comera calibration accuracy.Experimental results demonstrate that the proposed method improves calibration accuracy by 55.1％compared with the direct linear transformation(DLT)method,and reduces the standard deviation of the maximum displacement error by 16.3％.In addition,the proposed method eliminates the need for manual labeling of target points,enabling automation of the calibration process and significantly improving calibration efficiency.