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以塔里木河典型植被为研究对象,分析胡杨、芦苇叶片及柽柳冠层的可分性,并计算背景的影响。首先用ASD光谱仪测新鲜叶片光谱,找出光谱特征点;然后模拟EO-1高光谱数据和TM多光谱数据;最后植被与土壤光谱按比例混合,分析背景的影响。以上三步分别计算植被指数(VI)。结果显示:叶片光谱特征位置430 nm、670nm、750 nm附近,黄边斜率和红外平台平均高度,1 080~1 280 nm、1 430~1 650 nm能够区分塔里木河流域3个主要植被类型。模拟的EO-1波谱保持了控制波形的10个特征,TM只有绿反射峰和红吸收谷、近红外1个反射峰3个特征,大部分特征都消失了。植被指数显示(R680-R500)/R750、(R680-R550)/R705、R1430+…+R1650、D712/D688能够区分3类,且指数值差异较大,为绿峰、红谷和近红外波峰的组合;模拟的EO-1数据(R680-R500)/R750、(R680-R550)/R705、R1430+…+R1650能分别区分植被,TM多波谱数据不能有效区分植被。
Taking the typical vegetation of the Tarim River as the research object, the separability of Populus euphratica, Phragmites australis leaves and canopy canopy were analyzed, and the influence of background was calculated. Firstly, the spectrum of fresh leaves was measured by ASD spectrometer to find out the characteristic points of the spectrum. Then the EO-1 hyperspectral data and TM multi-spectral data were simulated. Finally, the vegetation and soil spectra were mixed in proportion to analyze the influence of the background. The above three steps were used to calculate the vegetation index (VI). The results showed that the spectral characteristic positions of leaves at 430 nm, 670 nm and 750 nm, the slope of the yellow edge and the average height of the infrared platform, ranging from 1 080 to 1 280 nm and 1 430 to 1 650 nm, could distinguish the three main vegetation types in the Tarim River Basin. The simulated EO-1 spectrum maintains 10 characteristics of the control waveform. TM has only three features, green reflectance peak and red absorption valley, and one near-IR reflection peak, most of which disappear. The vegetation index showed that there were three types of differentiation between (R680-R500) / R750, (R680-R550) / R705, R1430 + ... + R1650, and D712 / D688 The simulated EO-1 data (R680-R500) / R750, (R680-R550) / R705, R1430 + ... + R1650 can distinguish vegetation respectively. TM multi-spectral data can not effectively distinguish vegetation.