3D concave defect measurement system of the cryogenic insulated cylinder based on linear structured light

Cryogenic insulated cylinders' features of the large size and reflecting make the geometric size measurement a challenge work. A new system for 3D visualization measurement of cryogenic insulated cylinders is designed in this paper. The system consists of three CCD cameras and three laser projectors. The measurement method is mainly based on monocular vision, linear structured light extraction and 3D reconstruction. Cylinder fitting and connected component labeling methods are adopted to process the point cloud data after 3D reconstruction. At the same time, approximate voxel grid filter based on Point Cloud Library (PCL) is applied to simplify the processing. Accordingly, the concave depth and position of the cylinder can be obtained. Through the experimental verification, the system can achieve the actual measurement demands of the measurement standard and the error of the depth measurement is lower than 1 mm.