Space remote sensing for urban damage detection, mapping and mitigation

Abstract

In the last years the remote sensing techniques have been demonstrated a suitable monitoring tool for providing data useful for disaster mitigation. In particular, in case of strong earthquake, the rapid detection of damaged buildings and infrastructures has assumed an important role for the civil protection rescue activities. Moreover, the damage assessment can help the redevelopment process of the hit area. The Synthetic Aperture Radar (SAR) is widely used in environmental studies thanks to its peculiarities which allow a fairly synoptic view in almost completely weather and time independent conditions. SAR has been revealed a powerful instrument for change detection and damage evaluation purpose. In particular, interferometric features like the InSAR phase coherence and the intensity correlation of multi-look images collected before and after an earthquake have been used in previous works to detect and quantify changes in built-up area. On the other side, optical sensors have also been successfully used for damage estimation. Thanks to the strong increase of their spatial resolution, reaching to less than 1 meter per pixel, the new optical sensors have become reliable systems for detecting changes of single buildings. However, the presence of clouds, shadows, variation in Sun illumination and geometric distortions are critical for this type of sensors and prevent a fully automatic change detection approach. When both optical and SAR are available, a damage classification can also be obtained by combining the two data types, leading to a more reliable result. This work proposes an effective procedure oriented to the damage mapping. From data requirements (satellite images and auxiliary data) to product delivery the chain for damage mapping is described. This latter in order to provide new instruments useful to Civil Protection Departments and Administrations for disaster management.