High-resolution mapping of river and estuary areas by using unmanned aerial and surface platforms

The accurate and precise mapping of Land Use / Land Cover (LU/LC) plays a key role in the management of a region. In particular the knowledge of areas close to rivers and / or estuaries is fundamental to prevent flooding preserving the integrity of artificial structures and natural flora and fauna. Actually the mapping is performed by processing remote sensed data with a typical GSD of 0.5m. The survey is expensive and the presence of clouds could invalidate an entire survey. This kind of survey is perfect for a monitoring over a long period while is not appropriate for a quasi real time imagery. The adoption of unmanned aerial vehicles (UAVs) is a proper solution owing to the low cost and the reduced time for the setup, but it lacks of a complete view of the area. The reason is the presence of canopy that occludes the view. We integrate the images acquired by an UAV characterized by a GSD of 0.03m with an Unmanned Surface Vehicle (USV) that collects images of the river from different point of view enhanced by an RGB-D sensor. The change detection algorithm applied to the collected data is based on a innovative hybrid classifier that fuses the benefit of pixel and object based approaches mapping the changes over a well defined temporal horizon.