A Study on Information Extraction of Water Body with the Modified Normalized Difference Water Index （MNDWI）
A Study on Information Extraction of Water Body with the Modified Normalized Difference Water Index （MNDWI）
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DOI：
10.11834/jrs.20050586
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Han-qiu Xu
中科院分区：
文献类型：
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作者：
Han-qiu Xu
本文在mcfeters（1966）的归一化差分水指数（NDWI）的基础上，提出了一种改进的归一化差分水指数（MNDWI），用MIR（TM5）代替NIR（TM4）来构建MNDWI。使用Landsat TM/ETM+图像，在海洋、湖泊和河流地区测试了MNDWI，背景是建筑用地和/或植被地，以及清洁和受污染的水体。这表明，在以建设用地为背景的地区，MNDWI可以显著增强水信息。MNDWI在突出水体信息的同时，有效地抑制了建成区信息，准确提取了研究区水体信息。而利用NDWI增强的水体信息总是与建筑用地噪音混合在一起，从而高估了基于该指数提取的水体面积。因此，NDWI不适合用于建成区的水信息增强和提取。此外，与NDWI或其他可见光波段相比，MNDWI可以更有效地揭示水的细微特征，这主要是由于其更宽的动态数据范围。MNDWI在厦门图像中的应用取得了很好的效果。MNDWI图像成功地揭示了由于农业活动导致的厦门岛周围水域的严重非点状污染。此外，利用比例计算的优势，MNDWI可以去除水信息中的阴影噪声，而无需使用复杂的程序，否则难以去除。
A modified normalized difference water index(MNDWI) has been proposed in this paper based on the normalized difference water index(NDWI) of Mcfeeters (1966), which uses MIR(TM5) instead of NIR(TM4) to construct the MNDWI. The MNDWI has been tested in the ocean, lake and river areas with the background of built-up lands and/or vegetated lands, and with both clean and polluted water bodies using Landsat TM/ETM+ imagery. This reveals that the MNDWI can significantly enhance the water information, especially in the area mainly with built-up land as background. The MNDWI can depress the built-up land information effectively while highlighting water information, and accurately extract the water body information from the study areas. While the enhanced water information using the NDWI always has been mixed with built-up land noise and the area of a water body extracted based on the index is thus overestimated. Therefore, the NDWI is not suitable for enhancing and extracting water information in built-up land-dominated areas. Furthermore, the MNDWI can reveal subtle features of water more efficiently than the NDWI or other visible spectral bands do due largely to its wider dynamic data range. The application of the MNDWI in the Xiamen image has achieved an excellent result. The MNDWI image successfully reveals significant non-point pollution of the water surrounding the Xiamen Island due to agricultural activities. In addition, taking the advantage of the ratio computation, the MNDWI can remove shadow noise from water information without using sophisticated procedures, which is otherwise difficult to be removed.