利用Hyperion数据进行环境星HSI红边参数真实性检验

针对我国新发射运行的HJ-1A星HSI数据,利用高光谱分辨率的Hyperion数据进行了HJ-1A星HSI的光谱模拟,提取了红谷位置、红边位置、红边斜率和红边振幅等4个主要的红边参数,对真实与模拟环境星HSI数据的红边参数进行了对比分析,从而以Hyperion数据为参照检验了环境星HSI红边参数的真实性。研究结果显示,环境星HSI与模拟HSI的红边范围光谱反射率平均相关系数为0.946,标准差为0.011,为极显著相关,两种数据在红边范围内的光谱反射率变化高度一致;4个红边参数的相关系数分别为0.414,0.543,0.808和0.802,并且随植被覆盖度的变化呈现出明显的规律性,模拟与真实红边参数差值标准差分别为5.75,1.86,5.7e-4和0.024,认为环境星HSI的红边参数可以较好反映该区域植被变化所造成的红边光谱特征差异。

Validation of HJ-1 HSI red edge parameters based on spectral reflectance of Hyperion

To validate the HJ-1A HSI red edge indices, spectral reflectance data from EO-1 Hyperion of close date were used to simulate the band reflectance of HJ-1A HSI. Four red edge indices (red vale position, red edge position, red edge slop and red edge swing) were extracted from both simulated and actual HJ-1A HSI band reflectance. Comparisons of the 4 red edge indices between simulated and actual HJ-1A HSI were made to validate the red edge indices product of HJ-1A HSI. The average correlation coefficient of red edge reflectance between actual and simulated HJ-1A HSI is 0.946 and its standard deviation is 0.011, thus a high consistency could be found. The correlation coefficients of red edge indices between simulated and actual HJ-1A HSI were 0.414, 0.543, 0.808 and 0.802 for red edge position, red vale position, the red edge swing and red edge slop respectively. An obvious regular varying trend was found for these 4 red edge indices along different vegetation cover fraction. The standard deviations of differential images between real and simulated HJ-1A HSI red edge indices are 5.75, 1.86, 5.7 e(-4) and 0.024. The result showed that the red edge indices from HJ-1A HSI is consistent with that from simulated indices from Hyperion; the vegetation variation could be effectively reflected in HJ-1A HSI red edge indices.