Seven-Component Decomposition Using Refined Volume Scattering Models and New Configurations of Mixed Dipoles

In this article, an extended seven-component decomposition method using refined volume scattering models and new configurations of mixed dipoles (M7SD) is proposed to interpret the scattering mechanisms of various terrain types. In the M7SD, refined volume scattering models are proposed to reasonably characterize the scattering mechanisms of various land covers with different orientation angles, and the redefined configurations of the mixed dipoles, which have better explanations for the scattering mechanisms, are introduced. Although the diameter of the dipole used in the experiment is very small, the superposition of two dipoles in the same plane will cause one of the dipoles to have a distance from the plane. According to the experimental results, since the distance between one of the dipoles and plane cannot be ignored, it will cause an error between the scattering matrix obtained by the experiment and the scattering matrix obtained under ideal conditions. In this case, in the M7SD, two dipoles are placed in two planes, respectively, with a distance of half wavelength. The performance of the proposed method is demonstrated and evaluated with the spaceborne C-band GaoFen-3, Radarsat-2, and airborne L-band ESAR fully polarimetric data over different study sites. The experimental results demonstrate that the use of the M7SD can reasonably interpret the scattering mechanisms of various terrain types (especially the building areas with large orientation angles), overcome the overestimation of the volume scattering and reduce the percentage of negative scattering power pixels.