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介绍了一种测量归一化差异植被指数(NDVI)的方法及仪器,利用日光作光源,通过四个具有特殊光谱响应特性的光电探测器,在植被近红外反射率平台和红光叶绿素吸收谷两个特征波段,分别对入射光和植被的反射光进行探测,经模拟—数字转换后,求出NDVI值。通过与ASDFieldSpec型便携式光谱仪测得的NDVI数据进行对比、标定,表明NDVI仪测定数据十分可靠。利用NDVI仪的数据,成功反演了小麦植株的叶面积、叶绿素密度,展示了NDVI仪在作物长势、营养诊断方面的应用前景。
A method and apparatus for measuring normalized difference vegetation index (NDVI) are introduced. By using daylight as light source and four photodetectors with special spectral response characteristics, the near-infrared reflectance platform and the red-light chlorophyll absorption valley Two characteristic bands, respectively, the incident light and vegetation reflected light detection, after the analog - digital conversion, find the NDVI value. Compared with NDVI data measured by ASDFieldSpec portable spectrometer, calibration shows that the data of NDVI instrument is reliable. Using the data of NDVI, the leaf area and chlorophyll density of wheat plants were successfully inverted, and the application prospect of NDVI instrument in crop growth and nutrition diagnosis was demonstrated.