Urban Damage Level Mapping Based on Co-Polarization Coherence Pattern Using Multitemporal Polarimetric SAR Data

Accurate detection and identification of destructed urban areas are essentially important for rescue planning after a large-scale natural disaster (e.g., earthquake, tsunami). Spaceborne synthetic aperture radar (SAR) can provide quick response and huge area monitoring to mitigate the further loss. Due to the layover, speckle effect, multiple scattering, etc., accurate mapping of urban damage conditions with SAR is even challenging. Fully polarimetric SAR (PolSAR) has the better potential to understand urban damage conditions from the viewpoint of scattering mechanism investigation. Polarimetric coherence is an important source for PolSAR data investigation. This paper focuses on the hidden signature exploration of co-polarization coherence in the rotation domain along the radar line of sight for urban damage investigation. A damage index is proposed based on the interpretation tool of co-polarization coherence pattern. It can successfully discriminate urban patches with various damage levels. Then, a damage level inversion relationship and an urban damage level mapping approach are established. The study case is the great 3.11 East Japan earthquake and tsunami using multitemporal ALOS/PALSAR PolSAR data. Experimental studies validate the efficiency of the proposed co-polarization coherence pattern technique and the mapping approach.