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Water extraction of SAR image based on region merging algorithm

SAR (Synthetic aperture radar) has the advantages that it can be observed all day long and all weather. Space borne SAR is able to observe the target area periodically, therefore the extraction of lakes using SAR image is more and more widely used. The detection and update of lake plays an important role in water resources managing, water environment monitoring and watershed management. The traditional image segmentation method can hardly extract the lake quickly and accurately due to the impact of the wind, the differences of backscattering characteristic and the influence of noise on SAR images. Taking Hulun Lake as an example, this paper presents a combination of coarse and fine based region merging algorithm for SAR image to extract lakes automatically. The results show that the improved algorithm increases the accuracy of lake surface extraction and reduces the time complexity of region merging.