The demand for non-powered facility towing is increasing with the development of large-scale offshore projects. It is of great interest for its safe operation to measure the state of the towing process in real time. This paper proposed a computer vision algorithm designed to measure the tug yawing during the towing operation by estimating the towing line angle. The geometrical projection of the towing line from 3D to 2D is described in detail. By fixing the camera at specific locations and simplifying the calculation procedure, the towing line angle in the 3D world can be estimated by the line angle in the image. Firstly, the sea–sky line is detected to estimate the rolling angle of the tug in the captured image. Then, the towing line angle is calculated by an image processing method. At the same time, the estimation of the towing angle is achieved through the captured video data analysis. Finally, field experiments were carried out and the results demonstrated that this method is suitable for real-time calculation of the towing angle during the towing operation.

中文翻译：

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一种新颖的基于视觉的海上拖曳作业牵引角估计

随着大型海上项目的发展，对无动力设施牵引的需求正在增加。实时测量拖曳过程的状态对其安全操作引起了极大的兴趣。本文提出了一种计算机视觉算法，该算法旨在通过估计拖曳线角度来测量拖曳过程中的拖船偏航。详细描述了从3D到2D的拖曳线的几何投影。通过将摄像机固定在特定位置并简化计算过程，可以通过图像中的线角来估算3D世界中的拖线角。首先，检测到海天线以估计拖船在捕获图像中的滚动角度。然后，通过图像处理方法计算牵引线角度。同时，牵引角的估计是通过捕获的视频数据分析实现的。最后，进行了野外实验，结果表明该方法适用于拖曳过程中拖曳角的实时计算。