嫦娥一号干涉成像光谱仪(IIM)2C级数据信息提取

Information Extraction of the Chang'E-1 Interference Imaging Spectrometer(IIM) 2C Data

通过分析Chang’E-1卫星所获取的高光谱数据的太阳高度角因素,选取了太阳高度角较高的IIM2C数据进行光谱定标。采用邻域平均法及邻域加权均值法对原始数据进行了杂点、条带修复。由于干涉成像光谱仪CCD阵列增益畸变以及它的自身问题使得干涉影像存在横向响应不均一性,提出采用基于子空间最大特征值法进行校正,结果影像亮度统计其强度表现均一,符合自然图像特征,并采用自编程序进行几何校正。运用国际上较为成熟的经验线性法对Chang’E-1IIM 2C数据进行绝对定标;与此同时,为了修正线性定标的偏置系数及降低数据噪声,首次采用自适应小波变换法对辐射定标后数据进行后处理,确定了IIM2C数据可用波段。通过对比国际标准定标点数据,制订了嫦娥IIM2C数据分析方案,完成了第一幅完整的Chang’E-1IIM 2C月球正面反射率影像。

Through analysis of solar azimuth of Chang＇E1 IIM data, the data of highangle were chosen to do radiometric cali bration. The method of neighbourhood averaging and neighbourhood weighted averaging were adopted to repaire original data which contains bad points and hands. Because of interference imaging spectrometer＇s inherent problem and CCD array gain dis tortion, the image displays discontinuity of transverse response. By using the method of subspaee maximum eigenvalue to cabli brate image, the statistical result of processed images shows homogeneity on intensity of radiance. The empirical linear method was adopted to calibrate IIM data absolutely. Meanwhile, in order to correct bias coefficient of data which has been calibrated and denoised , the method of wavelet transform was adopted to modificate data of radiometric calibration for the first time, the final available IIM 2C data were confirmed. Compared with the data which has been accredited, the analysis proposal of IIM 2C data was established. Then the first reflectivity image of the lunar nearside based on Chang＇E1 IIM 2C was accomplished.