光滑叶片的偏振高光谱特性及与叶绿素含量的关系

Polarized hyperspectral characteristics of smooth leaves and its relationship with chlorophyll content

为探讨偏振光遥感快速估算植物叶绿素含量并用于农业气象自动化观测,根据植物叶绿素颗粒可产生偏振光响应的物理特性,应用SPAD-502叶绿素仪和加偏振镜的FieldSpec3■Hi-Res便携式高光谱仪,在多角度观测平台上测量和研究了表面光滑的桑树、红叶石楠、茶花3种代表性叶片的偏振高光谱特性与叶绿素含量的关系。结果表明:对于光滑叶片而言,550nm附近的绿峰强度随着叶绿素含量的增加缓慢降低,即偏振高光谱与叶绿素含量呈非线性关系;绿峰波段的偏振度(DOP)与叶绿素含量的关系最好,其次为偏振反射,再次为最高反射和总反射,最低反射的关系最不明显。该研究对进一步开展偏振光遥感评价作物生长状况、灾害及估产具有重要意义。

The study aims to rapidly estimate chlorophyll content in plants by polarized light remote sensing and apply the method in agrometeorological automatic observation.According to the physical characteristic that the polarized response is produced by chlorophyll particles,SPAD-502 chlorophyll meter and FieldSpec■3 Hi-Res portable hyper-spectrometer with polarizer were used on the multi-angle observation platform to measure and study the relationship between polarized hyperspectral characteristics and the chlorophyll content of three representative plant leaves with smooth surface,including mulberry,photinia frase and camellia.The results indicate that the intensity of green peak of smooth leaves near 550nm decreases gradually with the increase of chlorophyll content.In other words,the polarization hyperspectrum has a non-linear relationship with chlorophyll content.The Degree of Polarization(DOP)of green peak band has the best relationship with chlorophyll content,followed by polarization reflection,with the highest reflection and total reflection behind,and the relationship with the lowest reflection is the least.This study has great significance for further study on evaluation of crop growth status,disaster and yield estimation with polarized remote sensing.