The study of the index models used in extraction of water body based on HJ-1 CCD imagery

A new index mode for extraction of water body with HJ-1 satellite CCD imagery Normalized Difference of RVI and NDWI(NDRW) which combined both RVI and NDWI values is purposed in this paper based on analyzing the spectral characteristics of water in HJ-1 satellite CCD imagery and the advantages and disadvantages of three the most frequently used indexes, which are Ratio Vegetation Index(RVI), Normalized Difference Vegetation Index(NDVI) and Normalized Difference Water Index(NDWI). Not only are the extraction results of water body based on NDR W and other 3 index compared qualitatively, but also the accuracy of extraction of water body is analyzed quantitatively with the contrast value, the overall accuracy and the Kappa coefficient. The extraction result of water body of ETM+ image by using Modified Normalized Difference Water Index (MNDWI) is used as the reference image. The test results show that the NDRW index mode can be used to distinguish water and artificial construction land which are difficult to do so for other indexes. The water information is highlighted effectively and accuracy of extraction of water body is improved compared to the other 3 indexes.