Abstract:With the development of the field of marine engineering, how to obtain high-precision three-dimensional point clouds of underwater objects has significant academic and practical value. However,the propagation of light in different media causes change in the optical path,which may lead to refraction distortion in the point clouds obtained through underwater structured light vision measurement and reduce accuracy. To address these issues, this article proposes an tunderwater rotational scanning measurement system based on structured light. An algorithm for axial calibration is proposed to register multi-view underwater point clouds into a unified coordinate system. In addition, an underwater camera imaging model is introduced, whichincorporates refraction compensation. This model accurately describes the optical path of laser propagation between different media. By applying the constraints of the underwater laser plane equation,refraction correction is performed on the underwater point clouds. Thereby, the reconstruction accuracy is improved. Experimental results of underwater measurements demonstrate that the proposed high-precision measurement method can obtain three-dimensional point cloud information of underwater objects. The measurement accuracy reaches 0.2mm when the distance to the target is between 30~80 cm,which could meet the requirements of high-precision three-dimensional measurement of underwater targets.