This paper presents two decomposition schemes for polarimetric synthetic aperture radar data. The proposed schemes intend to overcome the problem of scattering ambiguity and reduce the volume scattering power in oriented urban areas. The first proposed scheme uses an empirical volume model based on the correlation coefficients of the Pauli component in the horizontal–vertical basis, whereas the second one employs a volume model defined on correlation coefficients of the Pauli components expressed in the circular basis. The correlation coefficients are calculated from polarimetric interferometric synthetic aperture radar (PolInSAR) data. The characteristics adopted from these volume models are used to enhance the results of the decomposition schemes. The scattering powers estimated from the proposed methods give promising results compared to existing methods in the literature, particularly in urban areas since all the oriented built-up areas are well discriminated as double or odd bounce scattering. The methods are evaluated using the experimental airborne SAR sensor (E-SAR) PolInSAR L band data acquired on the Oberpfaffenhofen test site in Germany.
Polarimetric image decomposition is nowadays among the most important applications of multi-polarization, multifrequency SAR radar images. With the growth of new satellite missions equipped with fully polarimetric modes there is a strong need for accurate methods and for new approaches to handle the huge data coming from different airborne and space borne missions and to understand better the several and different mechanisms that occur in a resolution cell. We are interested in this paper in polarimetric SAR image decomposition that makes a comparison between Yamaguchi decomposition called also the four component decomposition before and after image compensation from the orientation angle. This latter affects directly the scattering mechanisms and induces errors in the decomposition results especially in urban area where there are complex structures. We demonstrate with power profiles and with RGB color composite images that the volume scattering type decreases drastically after deorientation, whereas the helix scattering type is not sensitive to orientation. The test site is situated in the north of Algiers city and the satellite data is a fully polarimetric acquisition in C band. Results are in a high agreement with Google earth optical image.