A Modified Incoherent Compact Polarimetric Decomposition Algorithm

For circular polarization transmitting linear polarization receiving (CTLR) compact polarimetric (CP) synthetic aperture radar (SAR) data, the volume scattering power proportion derived through CP decomposition, such as the $m\text {-}\alpha $ decomposition algorithm, is typically overestimated. To address this issue, this study initially presents a theoretical analysis of the reason behind the overestimation of the volume scattering power proportion. The theoretical analysis reveals that the assumption “the volume scattering power proportion is $1\text {-}m$ ” employed by the $m-\alpha $ decomposition indeed leads to an overestimation, where m represents the degree of polarization. Subsequently, a novel and smaller form of the volume scattering power proportion has been discovered, namely ( $1\text {-}m)^{2}$ . Based on this finding, a modified $m\text {-}\alpha $ decomposition algorithm has been proposed. Experiments were conducted using two fully polarimetric SAR images and a CP SAR image acquired by E-SAR, GF-3, and RISAT. The experimental results demonstrate that: 1) ( $1\text {-}m)^{2}$ is statistically closer to the actual volume scattering power proportion than $1\text {-}m$ ; 2) the decomposition performance of the modified $m\text {-}\alpha $ decomposition algorithm surpasses that of the other six compact decomposition algorithms; and 3) employing the new volume scattering power proportion ( $1\text {-}m)^{2}$ effectively mitigates the issue of volume scattering power overestimation in CP decomposition.