Automatic structures detection and spatial registration using multisensor satellite imagery
Mesoscale processes such as upwellings, eddies, or thermal fronts are very energetic and their knowledge is very important not only to study oceanic circulation but also areas of applications that include acoustic propagation anomalies, fisheries management and exploitation, coastal monitoring and offshore or ocean oil detection and exploitation. A variety of techniques and algorithms have been developed to detect such structures. The foremost difficulties encountered in the preceding approaches are the presence of noise, mainly due to clouds and other atmospheric phenomena. In this context, the proposed methodology, due to its region-based nature, overcomes the edge detection inconveniences and obtains the proper structure identification. Moreover and in order to perform an exhaustive analysis of the structure dynamics, it is necessary to compare image sequences. In this context, the use of spatial registration techniques is necessary to achieve that pixels in different images correspond to the same geographic region. An automatic contour based approach for high accuracy registration of multisensor and multitemporal remote sensing images is presented. It avoids the use of ground control points, while exploiting the maximum reliable information in both images. These automatic tools, that combine structures detection techniques and multitemporal and multisensoral registration, have been applied to AVHRR, SeaWiFS and MODIS images of the Canary Island and Alboran Sea areas and have demonstrated that it can be a fundamental tool to validate marine and coastal dynamic studies using remote sensing data.