基于新型水体指数(NWI)进行水体信息提取的实验研究

Study on information extraction of water body with a new water index(NWI)

基于遥感数据构建的水体指数模型可用于水体信息的提取。本文在对水体及其背景地物进行光谱特征分析的基础上,结合水体在近红外和中红外波段(相当于Landsat TM/ETM+影像的Band 4,Band 5和Band 7)同时具有强吸收这一典型特征,提出了一种新型的水体指数NW I(New W ater Index)。将该指数在含不同水体类型的遥感影像上进行实验,均获得了较好的提取效果。利用文献样本数据所作的实验表明,NW I具有很强的普适性,可用于水体信息的快速提取,且具有较高的精度。

Remotely sensed data can be used to extract water information. Based on the analysis of the spectral features of water bodies with different surroundings, this paper presents a new water index （NWI） , which fully utilize the unique characteristics of water bodies simultaneous strong absorption at near and middle infrared bands （ corresponding to the Band 4, Band 5 and Band 7 of Landsat TM/ETM ＋ imagery） . Using the Landsat ETM ＋ data acquired on May 4, 2000 （path 119, row 42, covering Fuzhou City）, the NWI has been tested in the reservoir, lake and river areas with various backgrounds. Besides, in order to test the universal applicability of NWI, sample data obtained from previously published studies at other sites were also collected and tested. The research results show that： NWI performs well at most test sites and it can be used to quickly and accurately extract water information with relatively high accuracy.