Water Body Change Detection Based On Ascending And Descending SAR Wavelet Fusion Imagery

Based on HH, HV PALSAR ascending images and RADARSAT-1descending image acquired on September15,2007and May15,2008respectively, water body of Quake Lake in Sichuan Province, China, was detected in this paper. Because of serious SAR image speckle noise, seven filtering methods were used to suppress speckle noise. Taking into account the impact of the filter window size for filtering results, four sizes of filter window were selected and analyzed based on assessment of the effect of filtering, and finally7×7window size Gamma filtering was selected to continue the following study. According to characteristics of SAR images, wavelet transform method was creatively used for ascending and descending SAR data fusion in two phases respectively. Finally, object-oriented method was used to extract water body information after earthquake based on the ascending and descending SAR data fusion image. And water body information before earthquake was extracted using PALSAR image. Then water body change information was obtained. This method can extract water body information effectively according to accuracy assessment.