利用反射光谱信息提取叶片水分含量的方法比较

Comparison of the Methods of Obtaining Leaf Water Content by Using Reflectance Data

实验采集了21个样区10余种类型植被的叶片信息,其中包括52组反射光谱数据(350 nm^2 500 nm),对应的叶片含水量(相对含水量FMC和等效水厚度EWT)。分析了叶片反射率与含水量之间的相关关系。实验结果表明EWT与叶片反射率之间存在较好的线性相关关系,而FMC与叶片反射率相关关系较差。通过选取不同光谱波段构造多个光谱指数,研究光谱指数与叶片含水量的相关关系,发现构造指数方法优于普通的光谱回归分析,其中,Ratio975和Ratio1 200效果最好。同时在利用光谱指数反演叶片含水量时,对于EWT仍存在较高的反演精度。

In the experiment, ten kinds of plant leaves were collected from 21 different sample areas. With these leaves, data were collected as follows： leaf water content （ including Fuel Moisture Content and Equivalent Water Thickness）, the corresponding reflectance. Using the statistical model, the relationship between leaf water content and leaf reflectance was studied. The result showed that EWT （Equivalent Water Thickness） had a better linear.correlation with reflectance than FMC （Fuel Moisture Content）. Besides the statistics, constructing spectral index is another method. In this paper, seven spectral indexes are mentioned and they are obviously more effective than the statistical method mentioned above, especially the spectral indexes Ratio975 and Ratio1200. In the second part of the study, EWT can still be inverted with higher precision.