Study on Water Information Extraction Method Based on Tiangong-2 Interferometric Imaging Radar Altimeter Data

Abstract— Tiangong-2 Interferometric Imaging Radar Altimeter (InIRA) has obtained a large amount of interferometric imaging results of ocean, island, land (mountain, lake, river, sand dune and farmland) by applying a new mechanism of interferometry with short baseline and small incident angle. Because water area in InIRA images has high signal-to-noise ratio(SNR) and high coherence, InIRA images are very suitable for water area identification. In this paper, we propose an algorithm combining Otsu image segmentation method and coherence coefficient of interference image based on the characteristic of InIRA images. Otsu method is selected to divide all pixels of InIRA image into two groups, one belongs to water areas and the other belongs to background. Coherence coefficient of interference image is used to identify water areas that have been misjudged due to system noise. The algorithm is applied to the An Feng Tang in China’s Anhui province and Tiangang Lake in China’s Jiangsu province, the experiment result shows water areas in InIRA images can be well resolved.