Quantitative Relationship Between Multi-Angle Polarized Reflectance And BRDF

When using remote sensing data to increase the discernment capability of the Earthsurface, angle information was found to have influence and contribution to the identity andclassification of object in remote sensing images. In fact, the full angle information of anobject is its three-dimensional spectrum characteristics in 2π space. Two approaches havebeen used to characterize the angle spectrum. The first one emphasizes on applications only.It assumes that a ground target is a Lambert object and ignores the angle differences. Theother approach emphasizes the verity and difference of angle information. The BidirectionalReflection Distributing Function (BRDF) has been used in information extraction. In theprocess of reflecting, scattering and transmitting electromagnetic wave, earth targets canrepresent polarized characteristics, which relate to their nature. Polarization includes morecontents in describing dark targets (or low irradiance) and man-made targets, and can beanother dimension of information source in remote sensing. The traditional remote sensingmainly detects the earth surface vertically to obtain its planar information, but it is difficultto get enough parameters for the quantitative remote sensing to invert earth targets. Themulti-angle observation can get more detailed and reliable three-dimensional space structureparameters of targets, so that it is possible to realize the quantitative remote sensing.Therefore, the multi-angle polarized information detection of object has become a newmethod of quantitative remote sensing.For polarized reflectance always goes with bidirectional reflectance, we can attain thepolarized three-dimensional spatial distribution of the targets by a polarimeter whendetecting its bidirectional reflectance. In this paper, we have proved the reflected lightappears polarization when light irradiate the object surface slantwise, and have furtherinferred the function of solar zenith angles and degree of polarization. From the point ofview of multi-angle polarized remote sensing mechanism, the quantitative relation betweenpolarized BRDF and BRDF has studied in this paper, and from the experimentationstestified their equality of the reflectance of bidirectional reflect, polarized reflect of 45degree and polarized reflect of mean value in the corresponding azimuth angle, zenith angle,detection angle and detection channels in 2π space. Studying the relationship betweenmulti-angle polarized reflectance and Bidirectional reflectance may provide more importantparameters for polarized remote sensing interpretation and help to object precise recognitionand inversion. According to the relationship, we developed a new method to solve the sunglitter problem in remote sensing, and then we developed a new polarized BRDF model ofsoil as the Bidirectional Polarization Distribution Function (BPDF) model. The BPDFmodel helps to improve classification and quantitative analysis of soil.