Abstract
The overestimation of volume scattering is an essential shortcoming of the model-based polarimetric synthetic aperture radar (PolSAR) target decomposition method. It is likely to affect the measurement accuracy and result in mixed ambiguity of the scattering mechanism. In this article, an extended adaptive four-component decomposition method with multiple thresholds is proposed. First, the orientation angle compensation is applied to the coherency matrix, and artificial areas are extracted as the basis for selecting the decomposition method. Second, for the decomposition of artificial areas, one of the two complex unitary transformation matrices of the coherency matrix is selected according to the wave anisotropy (A <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">w</sub> ). In addition, the branch condition that is used as a criterion for the hierarchical implementation decomposition is the ratio of the correlation coefficient (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cc</sub> ). Finally, the selected unitary transformation matrix and the discriminative threshold are used to determine the structure of the selected volume scattering models, which are more effective to adapt to various scattering mechanisms. In this article, the performance of the proposed method is evaluated on GaoFen-3 full PolSAR datasets for various time periods and regions. The experimental results demonstrate that the proposed method can effectively represent the scattering characteristics of the ambiguous regions, and the oriented building areas can be well discriminated as dihedral or odd-bounce structures.
Highlights
W ITH the development of synthetic aperture radar (SAR) imaging and polarization measurement techniques, polarimetric SAR (PolSAR), which led to a fruitful period in the past two decades, has been applied in many fields [1]–[4].Manuscript received September 3, 2019; revised April 23, 2020; accepted May 16, 2020
[T]vveg, [T]ovd, Thi Thi where [T]vveg, and [T]ovd are the models that correspond to general volume scattering and oriented-dihedral scattering, respectively, which are compensated by the orientation angle compensation (OAC) and phase angle compensation (PAC)/helix angle compensation (HAC)
Oriented dihedral scattering generated by oriented buildings facing the radar line of sight is misinterpreted as volume scattering, and similar polarization echoes render it difficult to distinguish building areas and vegetated areas
Summary
W ITH the development of synthetic aperture radar (SAR) imaging and polarization measurement techniques, polarimetric SAR (PolSAR), which led to a fruitful period in the past two decades, has been applied in many fields [1]–[4].Manuscript received September 3, 2019; revised April 23, 2020; accepted May 16, 2020. Volume scattering can be used to characterize the high cross-pol terms that are generated by forest areas [13]. From this point of view, the cross-pol power can be considered to be generated by volume scattering, which is completely consistent with the principles of the traditional three-component and four-component decomposition methods. In the oriented building areas, substantial cross-pol power is induced by rotated dihedral scattering, thereby causing building areas to be misdecomposed as vegetation areas [14]. In this case, if the original scattering model is used, the decomposition result may cause an overestimation of volume scattering (OVS)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
