A Pose Measurement Method for Vision Sensor in Slender Structures

The 3-D multiview internal reconstruction of the slender pipeline is crucial for the internal surface inspection in industrial fields, where the pose of the reconstruction sensor directly affects the global stitching accuracy of the multiple views. However, conventional methods suffer from cumulative errors over a long distance. This article proposes a pose measurement method via multisensor fusion for the vision reconstruction system in a slender structure. The process integrates a laser rangefinder for displacement measurement and an inclinometer for attitude determination, with spatial correlation achieved through a monocular camera tracking the laser spot projected onto a flat plate. Accordingly, we propose a combined calibration algorithm for the pose measurement system, using an auxiliary camera and a double-sided target. The experimental validation on a 200-mm-wide and 6-m-long platform shows that the proposed multisensor fusion method achieves an root mean square error (RMSE)of 1.34 mm for 3-D marker point reconstruction at a moving distance of 5 m.