Very-high-resolution spaceborne synthetic aperture radar and urban areas: looking into details of a complex environment

The late years of the last decade marked a turnover from typical ground resolutions around ten meters to one meter for images acquired from space-borne radar sensors. When complex environments such as urban areas are concerned, this big step forward means more than just more visibility of details: it implies a change of approach to the problem of information extraction, both in terms of goals and of techniques. With this level of very-high-resolution it makes sense to turn one's attention from general, extensive inspection of urban areas (e.g., land cover & urban sprawl, density of buildings) to more intensive extraction of specific features such as individual building characteristics. Meanwhile, new problems are encountered. For example, geometric distortions inherent to SAR images become evident and need to be specifically addressed if building feature extraction is to be carried out; for some land cover classes, some previously developed speckle models may not be valid any more. This chapter deals with the new possibilities because of the increased resolution and the challenges when using such new satellite data in some urban applications, including building extraction and disaster management.