Research On The Polarization Features And Ultraviolet Polarization Imaging Technology Of Oil Spill On Water Surface

Oil spill on water surface causes damage to both the ecosystem and economic production.Analysis of damaging range and pollution degree of oil spill pollution are the key to timely and accurate discovery of the location,amount and type of the oil spill.Ultraviolet(UV)polarization remote sensing is one of the new optical remote sensing technique.Domestic and international researches shows that there exists latent capacity of oil spill detection in UV band and polarization dimension.In order to improve the efficiency of oil spill detection and recognition in remote sensing,conducting a series of study on polarization features of oil spill on water surface and UV polarization imaging technology have both scientific and engineering significance.In view of the polarization characteristics of reflected light from oil spill targets on water surface in atmospheric environment,the factors influencing the polarization propagation of light in form of Stokes representation are introduced.The optical properties are analyzed and the physical model of oil spill is established based on the mechanism of oil film formation.Ellipsometric measurement of oil film at 270~900 nm shows the stability of the polarization characteristics of the oil film in UV.In addition,the polarized atmospheric radiation transmission process and mathematical model of the oil spill remote sensing in the atmosphere are analyzed.The UV polarized reflection of oil spill on water surface at different solar positions,atmospheric composition and observation angles is numerically simulated,which gives constraints to the polarimetric detection system.Furthermore,according to the system requirements,a design of large field of view,high resolution and real-time UV polarization imaging system is proposed,and the theoretical signal-to-noise ratio and polarization measurement error of the system are analyzed.The scheme of four-channel UV polarization imaging system is built,installed,optical calibrated and tested.A calibration method for polarization imaging system is proposed,which can reduce more than 90% system error caused by polarizer installation angle deviation to less than 10%.The experimental platform is built to perform imaging experiments on oil spill targets in atmospheric environment.Means of image preprocessing UV polarization data such as channel matching,multi-dimensional bilateral filtering,polarization calculation and polarization image fusion,are implemented.The results show that the polarization of UV reflection of thin oil film is 0.8,and the relative polarization difference between thin oil film and water is 0.05 under the condition of field experiment.The experimental and simulation results of oil spill have verified the important role of UV polarization in oil spill observation,which lays a solid foundation for further research on oil spill zoning and oil discrimination.