超光谱空间外差干涉仪探测器响应误差校正

Correction of Detector Response Error for Hyperspectral Spatial Heterodyne Interferometer

应用于大气CO2高精度探测的超光谱分辨率空间外差光谱仪,采用面阵探测器同时采集二维干涉数据。针对面阵探测器响应同时存在的非均匀性和非线性,分别分析了其对干涉数据及复原光谱的影响,指出在相同的探测器非均匀性噪声下,光谱分辨率越高复原光谱噪声越大;而非线性不但对有效光谱范围内光谱复原精度有影响,还会产生光谱截止频率外的非零值。阐述了一种多能量等级均匀辐射源的非线性及单一均匀辐射源非均匀性同时校正算法。开展了探测器响应校正实验。探测器数据校正后非均匀性从4.04%降至0.14%;干涉数据校正后复原的光谱平滑,大大降低了非均匀噪声,校正后光谱截止频率之外数据基本为零,去除了非线性影响。

The spatial heterodyne spectrometer used for high precision atmospheric CO2 remote sensing adopts arraydetector to collect the two-dimensional interferogram at the same time. According to the response nonlinearity andnon-uniformity existing in array detector simultaneously, the influence on the interferogram and the recoveredspectrum is analyzed respectively. It is pointed out that, at the same detector non-uniform noise, the higher thespectral resolution, the higher noise in recovered spectrum is. The nonlinearity not only impacts the effectivespectral range, but also brings nonzero value below the spectral cutoff frequency. A method of correction nonlinearityby several uniform radiances and non-uniformity by a single uniform radiance is reported. The experiments arefulfilled, and the response non-uniformity improves from 4. 04% to 0. 14%. The recovered spectrum from thecorrected interferogram is smooth due to the non-uniformity noise reduction greatly, and the data out of the spectrumcutoff frequency have zero values for correction the response nonlinearity.