基于多光谱影像的水体自动提取方法比较研究

以鄱阳湖湿地及附近水域为研究区,基于Landsat OLI影像从水体错提率和面积精度两方面比较了单波段阈值法、归一化差异水体指数法(NDWI)、改进的归一化差异水体指数法(MNDWI)、新型水体指数法(NWI)提取湿地水体的效果。并针对传统提取方法中阈值难以确定的问题,引入直方图波谷法、大津法、迭代法计算阈值。结果表明:单波段阈值法的提取效果较差,3种水体指数法均能对水体进行有效提取;直方图波谷法的计算效果不稳定,不适合计算此次水体提取方法的阈值;大津法和迭代法均能较准确地计算阈值,其中大津法结合新型水体指数法(NWI)精度最高。

Comparison on water-body information extraction methods based on multi-spectral remote sensing image

In this paper, Poyang Lake wetland and nearby water zone were taken as the study area, single band threshold method, Normalized Difference Water Index method (NDWI), Modified Normalized Difference Water Index method (MNDWI) and New Water Index method (NWI) were applied respectively to extract water body information based on Landsat OLI images. Then the results of water body extraction were compared according to two aspects of water error-extraction rate and area accuracy. By considering the deficiency in determining the threshold value in previous extraction method, histogram trough method, Otsu method and iterative method were used to calculate the threshold value. The results indicate that single band threshold method has poor extraction effect but other three water indexes methods can extract various water bodies. The histogram trough method is not satisfactory due to its poor performance in determination of threshold value, the threshold value calculated by iteration method and Otsu method is more accurately. Among all these methods, the combination of New Water Index method and Otsu method get the highest precision.