A New Approach to Collapsed Building Extraction Using RADARSAT-2 Polarimetric SAR Imagery

Large-scale earthquakes severely damage people's lives and properties. Airborne and spaceborne remote sensing can be used accurately and effectively to monitor and assess earthquake disasters in near real time, providing an important scientific basis and decision-making support for government emergency command and postdisaster reconstruction. This letter proposes a new H-alpha-rho method (H is the entropy, a is the average scattering mechanism, and rho is the circular polarization correlation coefficient) for extracting the spatial distribution of collapsed buildings using RADARSAT-2 fine-mode polarimetric synthetic aperture radar (SAR) data. The method was tested on imagery from the Yushu earthquake in the Qinghai Province of China which occurred in 2010. When compared with high-resolution optical imagery, the result indicates that the proposed method can be effectively used to identify collapsed buildings and also demonstrates that polarimetric SAR data have potential for application in urban disaster monitoring and assessment.