Measurement and 3D reconstruction method for pipeline's joints based on shape feature

To resolve the problem of joint's synchronous measurement and reconstruction in complex pipeline system, a measurement and 3D reconstruction method for pipeline's joints based on shape feature was proposed. A shape feature matching between contours of joint's CAD model and those of joint's material object was adopted to realize the measurement of joint's spatial pose. Projected images of joint's CAD model were acquired through setting up "sphere of viewpoints" of virtual cameras. These projected images were layered in the pyramidal structure to compose a gallery of matching images, and the joint's edges images acquired from material object were matched with its matching images. The joint's spatial pose was calculated iteratively by the least square method, and the joint's 3D model in the pipeline system was reconstructed. A pipeline multi-camera measurement system was proposed, and the experiments on a pipeline's joint pose measurement and 3D reconstruction were carried out. The result showed that the measurement and reconstruction time could be controlled within 1 minute, the position and rotation error were respectively 0.654 mm and 0.73°. The efficiency and accuracy of the proposed measurement and reconstruction method could meet the engineering requirements.