炭疽病胁迫下的茶树叶片高光谱特征分析

Analysis of the hyperspectral characteristics of tea leaves under anthracnose disease stress

试验以茶树不同炭疽病受害程度的叶片及健康叶片为材料，室内测定其光谱反射率。结果表明，炭疽病危害后，茶树叶片的光谱值随发病程度的增加表现出有规律的变化，740～1000 nm波段的光谱反射率随病情加重呈现下降趋势；而1370～2500 nm波段却表现出相反趋势。在742～974 nm和1374～2500 nm，炭疽病受害程度与光谱反射率呈极显著相关。对光谱一阶微分特征分析表明，在680～780 nm范围内处理间变幅最大，有2个波段的一阶微分值与受害程度表现出极显著相关性，分别为715～763 nm和776～778 nm波段。建立的炭疽病严重度诊断模型，均达到极显著水平，其中利用植被指数（Rg－Rr）／（Rg＋Rr）建立的模型精确度最高。

The spectrum reflectance of single tea leaves infected by anthracnose was measured by ASD handy spec-troradiometer. The results indicated that the spectrum characteristics of tea leaves infected by anthracnose had regular change with the increase of disease severity. Spectrum reflectance decreased significantly in 740-1 000 nm with the increase of the disease severity,whereas it increased in range 1 370-2 500 nm . There were significant correlations between disease severity and the spectrum reflectance in 742-974 nm and 1 374-2 500 nm. The characteristics of first derivative spectra in the diseased leaves and healthy leaves were changed,especially in 680-780 nm. There were significant correlations between the disease severity and first derivative spectral reflectance in 715-763 nm and 776-778 nm. The models for estimating tea leaf disease severity of anthracnose all reached significant level. The model constructed using vegetation index（Rg-Rr ）/（Rg＋Rr ）could accurately invert the tea leaf damage degree.