HJ-1A星高光谱数据与地面实测柑橘光谱的差异比较

The Comparison of Citrus Spectral Characteristics Obtained by the HJ-1A/HSI and ASD Field Spec Pro

以柑橘树冠层光谱为例,通过对HJ-1A星HSI传感器所采集的柑橘高光谱遥感数据与ASD便携式手持光谱仪所采集的地面实测柑橘冠层光谱进行比较,旨在探究HJ-1A星高光谱数据反演柑橘光谱的可靠性与适用性。结果表明:ASD与HSI数据的柑橘光谱反射率存在差异,尤其在红光波段和近红外波段有显著差异;ASD数据的光谱反射和吸收特征都较HSI数据明显;ASD与HSI数据的柑橘光谱变量特征也存在差异,尤其是黄光波段微分值造成的光谱变量差异最明显。因此,在进行小区域尺度柑橘光谱研究时不宜采用HSI测得的柑橘冠层反射光谱数据,但通过适当地改进HSI数据预处理方法,在大区域尺度上HSI数据能较为准确地表现柑橘光谱吸收、反射、红边等特征,可以应用于柑橘植被指数的反演研究。

The purpose of this paper is to explore the reliability and applicability of the HJ-1A star hyperspectral data and provide scientific reference for the futher research of scale transformation problembetween the in-situ measured and the remote sensing image. The HSI image is treated with the processof Absolute Value Conversion, Strip Removal, Flaash Correction and Geometric Correction. Then thecitrus spectral reflectance is inversed by the treated HSI image. The in-situ citrus spectral are measuredby ASD FieldSpec HandHeld spectrometer. The comparison results show that：First, the ASD and the HSIdata of citrus spectral reflectance are different, especially in the red band and near-infrared band hassignificant difference; Second,spectral reflection and absorption characteristics of ASD data are moreclearly than HSI data;Third, the spectral variables of two data are also different,which is caused by theSDy. Therefore, it should not be using HSI spectral reflectance data in the study of small regional scale,but if the quality of HSI is improved, the HSI data is able to used for inversion vegetation index in largescale.