基于扫描成像的作物近地高光谱获取与特征分析

In-situ crop hyperspectral acquiring and spectral features analysis based on pushbroom imaging spectrometer

为了验证自主研制的扫描成像光谱仪(PIS)在近地应用的可行性,该文以小麦、玉米为研究对象,利用PIS近地获取作物冠层和叶片的高光谱图像,在对田间和室内获得的成像数据进行对比分析的同时,探讨了成像光谱采集过程中的影响因素。此外,将PIS获取的成像高光谱与地物光谱仪(ASD)测定的高光谱进行比对研究。结果表明:PIS能准确收集作物的光谱信息,且采集的高光谱数据与ASD具有很好的一致性;PIS在田间采集作物光谱信息时,受氧气吸收的影响,在760nm处有明显的干扰吸收;PIS除了能反映作物不同叶位叶片、不同器官光谱的差异,还可依据影像提取杂草、土壤对作物冠层光谱的影响程度。上述初步结果为进一步应用PIS进行农作物长势诊断提供了参考。

In order to validate the feasibility of self-developed pushbroom imaging spectrometer （PIS） for near ground application,PIS was used to acquire the hyperspectral information of wheat and corn at canopy and leaf scales. The hyperspectral data were collected from field and laboratory respectively and were compared with each other,and the affect factors that appeared in the collection of PIS imaging were also analyzed. In addition,the hyperspectral images were compared with the spectra that obtained from classical field spectroradiometers （ASD Fieldspec FR2500,ASD）. The results showed that PIS data had good consistency with ASD data,and PIS could accurately obtain spectral information of crops. Due to the influence of the absorption of oxygen,the spectra obtained by PIS had disturbance absorption at 760 nm. Meanwhile,PIS could not only analyze the effect degree of weed and soil background for crop canopy spectra,but also extract spectral differences among leaves from different layers and organs. These preliminary results provide a foundation for further application of PIS on monitoring crop growth status.