干涉型成像光谱仪是嫦娥1号(CE-1)卫星的重要设备, 用于分析月球表面物质成分含量及其分布, 目前所得到的2B级科学数据的光谱分辨率为325 cm-1, 转化为波长分辨率表示后各谱段不一样, 第一个波段为7.6 nm, 最后一个波段为29 nm, 这引入两个问题: (1）与地面波谱库中用于标定和比对的光谱分辨率描述方式不一致; (2）由于波段窄而进入的信号少, 造成短波光谱信噪比差。 基于CE-1干涉成像光谱仪光谱重建模型, 讨论了波长分辨率与截止函数的关系, 提出了一种随波长及波长分辨率变化的可调截止函数, 并选取相应Sinc函数进行切趾, 实现了波段覆盖范围内任意指定波长分辨率的光谱数据重建。 利用该方法对CE-1号在轨0B数据进行处理, 得到了29 nm等波长高光谱图像, 采用光谱信噪、 主成分分析和无监督分类等方法对重建结果与同区域2级科学数据进行比对, 结果表明: 短波波段光谱信噪比提高了4倍, 平均提高了2.4倍, 基于光谱特征的分类结果一致, 数据质量大大改善。 EWSR方法的优点有: (1）在保持光谱信息量的情况下, 虽然牺牲部分光谱分辨率, 但提高短波波段的光谱信噪比; (2）实现了在波段覆盖范围内任意指定波长位置或任意设定波长分辨率的光谱数据重建。

Interference imaging spectrometer is one of the most important equipments of Chang’E 1 satellite, which is applied to analysis the material composition and its distribution of the surface on the moon. At present, the spectral resolution of level 2B scientific data obtained by existing methods is 325 cm-1. If we use the description way of wavelength resolution, various spectrum is different: the first band is 7.6 nm, the last band is 29 nm, which introduces two questions: (1) the spectral resolution description way mismatch with the way of ground spectral library used for calibration and comparison; (2) The signal-to-noise ratio of the spectra in the shortwave band is low due to the signal entering narrow band is little. This paper discussed the relationship between wavelength resolution and cut-off function based on the reconstruction model of CE-1 interference imaging spectrometer. It proposed an adjustable cut-off function changing with wavelength or wavelength resolution, while selected the appropriate Sinc function as apodization to realize the reconstruction of arbitrary specified wavelength resolution in the band coverage. Then we used this method to CE-1 on orbit 0B data to get a spectral image of 29 nm wavelength resolution. Finally, by usingthe signal-to-noise ratio, principal component analysis and unsupervised classification method on the reconstruction results with 2 grade science data from ground application system for comparison, the results showed that: signal-to-noise ratio of the shortwave band increased about 4 times, and the average increased about 2.4 times, the classification based on the spectrum was consistent, and the quality of the data was greatly improved. So, EWSR method has the advantages that: (1) in the case of keeping spectral information steadiness, it can improve the signal-to-noise ratio of shortwave band spectrum though sacrificed part of spectral resolution; (2) it can achieve the spectral data reconstruction which can set arbitrary band position or specify any wavelength resolution within the band range.