A New Method of Information Extraction of Eutrophic Water Body

The improved normalized difference water body index（MNDWI）proposed by Xu Hanqiu is further studied,and the improved eutrophic water body index（MEWI）is proposed. The experimental results show that the MEWI index has not only excellent extraction effect on the boundary of ultra green algae eutrophic water body but also an overall extraction accuracy of 89.5%,which is better than NDWI（85.5%）,ESWI（87.5%）and NEWI（87%）the overall accuracy of the water body index,and the MEWI index for the shadow distinction between water body and non water body is 0.38,which is better than NDWI（0.14）,ESWI（0.16）and NEWI（0.10）Discrimination of water body index. NDWI,ESWI,NEWI and other water body indexes cannot eliminate the interference of algae containing eutrophic water body,and their extraction accuracy is reduced due to the mixing of building and other information. The experiment shows that MEWI index is less affected by sediment factors than other indexes,which is very helpful to water body monitoring in the flood season. At present,most of the research on the information extraction of this kind of ultra green eutrophic water body is only aimed at extracting the water body itself,ignoring its impact on the extraction of the overall water area. The proposal of MEWI index can effectively solve this problem.