Research On Salient Characteristic Analysis And Modeling Method Of Polarized Skylight Pattern

As one of the important natural properties of the earth,the distribution of the global polarized skylight pattern contains rich target information.We can get the information of solar orientation,environmental parameters and target characteristics by analyzing,calculating and modeling the significant characteristics of polarized skylight pattern,and have a wide application prospect in many fields such as bionic polarized light navigation,polarization remote sensing,polarization imaging and atmospheric optical characteristics analysis.Based on the atmospheric Rayleigh scattering theory,the variation characteristics of angle of polarization and degree of polarization of polarized skylight pattern were modeled and analyzed.In this thesis,a neutral point detection method based on angle of polarization of polarized skylight pattern was proposed,which can detect the neutral points position in sunny day and occlusion.In addition,the model of equal degree of polarization was established to verify the distribution characteristics of the polarized skylight pattern in this thesis,and the analytical characterization of the degree of polarization of the measured polarized skylight pattern was realized.The main contents include:(1)In view of the problem that the distribution of degree of polarization of polarized skylight pattern is easily affected by environmental factors,a neutral point detection method based on the characteristics of angle of polarization of polarized skylight pattern was proposed in this thesis.The distribution characteristics of neutral point are compared in degree of polarization images and angle of polarization images of polarized skylight pattern by the experimental data.Based on Rayleigh scattering theory,the neutral point was defined from the angle of polarization characteristics of polarized skylight pattern,and a neutral point model was established for the distribution of angle of polarization.The experimental results verified the effectiveness of the method.(2)In order to establish an analytical characteristic model about degree of polarization of polarized skylight pattern in ideal weather environment,based on Rayleigh scattering theory,the distribution of degree of polarization of polarized skylight pattern was extracted.The polarization characteristic model of degree of polarization of polarized skylight pattern was established by using the transformation relationship of three-dimensional space coordinate.The symmetry,position and shape of the polarized skylight polarization in the ideal weather were analyzed and verified.(3)The angle of polarization and degree of polarization characteristic model were measured and the results were analyzed in this thesis.Firstly,the neutral points positions were detected and compared by the angle of polarization distribution method and the ellipsoid fitting method respectively in sunny day and occlusions.The experimental results of different time in continuous time show that the detection accuracy of the proposed method is basically the same as that of the ellipsoid fitting method,but the robustness is better.Then,the distribution of the measured polarized skylight polarization was characterized by the degree of polarization characteristic model established in this thesis.The accuracy and superiority of the model were verified by comparing with the Rayleigh model.