Resaerch On Polarized BRDF And Polarized Active Imaging Of Atmosphere-Ocean System

Polarization plays a significant role in object identification.The incorporation of polarized parameters will improve the distinguishability and clarity of image considerably.Polarized ray tracing and Monte Carlo method are widely used in investigating the reflection properties of target surface and radiative properties in internal medium.However,hardly researches adopted these two methods to study active polarized imaging in multiple layered scattered medium with rough surfaces.Based on the coupled atmosphere-ocean system considering rough surface which was built in this paper,polarized ray tracing was used to calculate the polarized BRDF of sea surface under the influence of incident polarization state,wind speed and incoming angle.Results show that,with the increase of wind speed,the part of polarizer acted by sea surface to the non-polarized incident light become weaken.Furthermore,the richer the incoming information is,the richer of reflected signal and the higher of reflected intensity is.Due to rough surface,the greatest linear and the smallest circular polarization information of reflected light lies in pseudo-Brewster angle,of which the angle between incident and reflected orientation equals to doubled Brewster angle.Polarized Monte Carlo method was utilized to achieve unpolarized and polarized imaging under the above model after the code being verified.The influences of different types of scattering and reflecting,single or multiple layer and various air or ocean condition on detected intensity and image resolution were analyzed.It is found that in single air layered medium,addition of polarized information has really active effect on imaging results,from whatever intensity or distinguishability perspective.In atmosphere-ocean coupled system,due to apparent scattering and absorbing effect of water,the extinct coefficient of air will have no influence once it is below some value.In this way,whether incorporating polarization or not,there is no distinction in detected intensity.However,from images,it can be apparently seen that images with incoming polarization are much clear than those not.As a whole,active imaging is an effective way to consider the influence of polarization.