Polarization-Guided unsupervised convection networks for marine velocity field recovery

Accurate flow field measurement in the marine environment is crucial for promoting innovative development of ocean engineering. However, the limited concentration of deployable tracer particles and the complexities of marine environments often lead to unreliable flow field measurements. To address these challenges, we propose a marine environment flow field measurement system under a polarization optical framework. The proposed system utilizes the locally smooth characteristics of flow fields by designing an unsupervised convection network architecture to optimize the velocity field from sparse point clouds. Additionally, a tracer particle polarization feature discriminator is introduced to mitigate the interference from ghost particles. To support the system, a polarized light field sensor is developed to simultaneously capture three-dimensional and polarization information. The system is validated on both simulated and real-world datasets. Compared to existing studies confined to controlled laboratory conditions, the proposed system significantly enhances the applicability of particle tracking velocimetry technology in uncontrolled, complex marine environments. Quantitative evaluations demonstrate that our system achieves an EPE3D/m of 0.027, outperforming the state-of-the-art GotFlow3D method with 0.067. The paper resources can be viewed at https://github.com/polwork.