面向Sentinel-2影像的LBV和K-T变换水体信息提取模型

Water Body Extraction from Sentinel-2 Image Based on LBV and K-T Transformation

为实现在复杂水环境下水体的精确提取,以斯里兰卡中东部为研究区,推导了用于Sentinel-2影像的LBV变换方程,在分析了水体与植被、阴影、水田泥地等典型地物经LBV和K-T变换后特征的基础上,提出了基于LBV和K-T变换的水体提取模型,并从目视判读和定量分析2个角度与归一化水体指数、改进的归一化差异水体指数模型的提取结果进行对比。结果表明:归一化水体指数和改进的归一化差异水体指数模型的总体精度相对较低,低于90%,存在较为明显的误提现象,归一化水体指数模型将一部分云阴影、山体阴影和水田泥地误分为水体,改进的归一化差异水体指数模型将一部分云和水田泥地误分为水体,同时2个模型还存在一定的漏提现象;基于LBV和K-T变换的水体提取模型总体精度最高,达到98.13%,有效消除了云、云阴影、山体阴影和水田泥地的影响,实现了复杂水环境下水体的精确提取,模型可广泛应用与多云、多山、复杂水环境等区域,对水资源调查、监测与保护有重要的现实意义。

In order to extract water accurately in complex water environment,this paper takes the east-central Sri Lanka as the study area,and the LBV transformation equation of Sentinel-2 image is derived.Based on the analysis of the characteristics of water and other typical features after LBV and K-T transformation,a water extraction model based on LBV and K-T transformation is proposed.Finally,the extraction results of NDWI,MNDWI and the model presented in this paper are compared from visual interpretation and quantitative analysis.The results show that the overall accuracy of NDWI and NDWI models is lower than 90%,and the phenomenon of error extraction is serious.The NDWI model incorrectly extracts part of cloud shadow,mountain shadow and cement field into water,and the MNDWI model incorrectly extracts part of cloud and cement field into water.At the same time,there are some less extraction phenomena in the two models.The water extraction model based on LBV and K-T transformation has the highest overall accuracy,reaching 98.13%,which effectively eliminates the influence of cloud,cloud shadow,mountain shadow and cement field,and achieves the accurate extraction of water in complex water environment.The model can be widely applied to cloudy area,mountainous area and complex water environments area,which has important practical significance for water resources investigation,monitoring and protection.