Earth Observation Using SAR and Social Media Images

Earth Observation (EO) is mostly carried out through centralized optical and synthetic aperture radar (SAR) missions. Despite the controlled quality of their products, such observation is restricted by the characteristics of the sensor platform, e.g. the revisit time. Over the last decade, the rapid development of social media has accumulated vast amount of online images. Despite their uncontrolled quality, the sheer volume may contain useful information that can complement the EO missions, especially the SAR missions. This paper presents a preliminary work of fusing social media and SAR images. They have distinct imaging geometries, which are nearly impossible to even coregister without a precise 3-D model. We describe a general approach to coregister them without using external 3-D model. We demonstrate that, one can obtain a new kind of 3-D city model that includes the optical texture for better scene understanding and the precise deformation retrieved from SAR interferometry.