Beijiang water body information extraction based on ENVISAT-ASAR

SAR has the advantage of all-time all-whether for the earth observation, the water and land boundary is obvious in the SAR images, and it is not affected by night and fog and which has the penetrating ability for the cloud interference during the flood period. So SAR has broad application prospects in the flood disaster assessment. Comparing with the world´s leading space-borne radar system, ENVISAT/ASAR has a new breakthrough on the polarization, incident angle and width. ENVISAT/ASAR has become the most powerful space-borne radar system. Due to the low backscattering coefficient of water body in the SAR images, image segmentation-the threshold methods are often used in water body extraction from SAR images. So in this paper, ENVISAT/ASAR APP-1P is selected as the test data. And the improved Otsu is applied to the water body extraction from ENVISAT/AAR images, which comprehensively considers both variances of inter/ inner classes. The method is simple, is easy to implement. It improves the automatic identification level of computer water body identification to a large extent, promoting the progress of flood disaster research.