A rapid calibration method of underwater structured light 3D reconstruction system for hull bottom cleaning and inspection

Biofouling on ship hull reduces speed and increases energy consumption. An effective evaluation of fouling status is needed to optimize the cleaning schedule and quantify the cleaning performance. However, the specialized equipment for underwater 3D reconstruction is costly and difficult to calibrate quickly, which leads to time-consuming data collection and processing. For above problem, our study proposed a novel method of rapid calibration, which can improve the continuous operation capability of underwater 3D reconstruction system. Firstly, camera calibration parameters is obtained by a single-viewpoint model, and a fast correction of the pixel coordinates of feature points is utilized based on the radial distortion properties of the camera. Secondly, the fit of the light plane in the camera coordinate system is improved by extracting the feature points of the linear laser projection on the special stereo calibration target and establishing the constraint relationship of this points. Finally, the velocity vector in the specified world coordinate system is calibrated by calculating the translation vector from the camera coordinate system to the world coordinate system for different frame images, and generates 3D point clouds of the target object. The effectiveness of the proposed method is verified by underwater 3D reconstruction experiments.