High-resolution polarimetric SAR image decomposition of urban areas based on a POA correction method

Abstract

ABSTRACTPolarimetric decomposition in urban areas is important for monitoring the speed of city expansion and studying its ecological environmental influence. Using fully Polarimetric Synthetic Aperture Radar (PolSAR) is a way to keep large range urban change under observation. PolSAR images allow us to detect the scattering mechanisms using polarimetric target decomposition methods. Much of the research on decomposition methods has stated that the polarization orientation angle (POA) would affect the result of decomposition. The available deorientation methods cannot rotate built-up areas with large POAs. As a result, some urban areas are still misjudged as volume scattering dominant. In this paper, an algorithm for decomposition of high-resolution urban area images based on a POA correction method is proposed. First, for high-resolution images of built-up areas, the POA changes radically pixel by pixel. An approximate assessment of urban areas can be done using POA randomness. Then, in order to search out the true POAs of large dominant POA areas (most built-up regions), the linear approximation method is used to locate POAs that can minimize the cross-polarized term. Thereby, the inaccurate decomposition that occurs by the deviation of POA can be fixed, and the accuracy of the results is improved.