基于光谱特征的城市水体提取

Urban water extraction based on spectral features

现有水体提取方法大多基于多光谱遥感数据,将其应用于高光谱数据时,会出现光谱信息未被充分利用且难以选取合适波段的问题,且未考虑城市中建筑物阴影的影响。因此,本文基于高光谱遥感影像数据,采用近红外波段阈值及固定波段范围内的积分差异,构建了改进的高光谱差异水体指数(MHDWI),并选取4种常用的水体指数在不同传感器下的嘉兴、长沙和舟山地区进行试验和精度对比分析。试验结果表明,该方法的总体精度和Kappa系数分别为98.50%、98.76%、97.35%及0.88、0.85、0.86,均高于其他4种方法,错分误差对比其他方法有明显降低。表明该方法可以有效抑制建筑物阴影,且适用于不同传感器不同地区的水体提取。

Most of the existing water extraction methods are based on multi-spectral remote sensing data,and when they are applied to hyperspectral data,the spectral information is not fully utilized and it is difficult to select appropriate bands,and the shadow effect of buildings in the city is not considered.Therefore,in this study,the modified hyperspectral difference water index(MHDWI)is constructed based on hyperspectral remote sensing image data,using the near-infrared band thresholds and the integral difference in the fixed band range.Four commonly used water indices are selected for experiments and accuracy comparison analysis in Jiaxing,Changsha and Zhoushan areas under different sensors,and the experimental results show that the overall accuracy and Kappa coefficient of the method are 98.50%,98.76%,97.35%,and 0.88,0.85,0.86,respectively,which are higher than the other four methods.And the misclassification error is significantly reduced compared with the other methods,which shows that the method can effectively suppress building shadows and is applicable to water extraction in different areas with different sensors.