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空间外差光谱技术是应用于天文测量以及大气遥感等方面的一种超光谱分析技术。为消除应用过程中的基线漂移,提出了改进的小波变换进行基线校正的方法。通过对不同小波函数以及分解层数对基线校正结果影响的分析,对原始光谱信号进行小波分解得到细节系数和逼近系数,将逼近系数置零以实现光谱信号的重构,从而实现干涉图的基线校正。最后将小波校正结果与阈值拟合校正结果进行对比。结果显示:两种方法校正光谱的相关系数为0.999 9,结果一致,但小波变换的程序运算耗时缩短10余倍。说明利用小波变换进行空间外差干涉图基线校正是一种行之有效、省时、简便的方法。
Spatial heterodyne spectroscopy is a hyperspectral technique used in astronomical measurements and atmospheric remote sensing. In order to eliminate the baseline drift during the application process, an improved method of baseline correction based on wavelet transform is proposed. Through the analysis of the influence of different wavelet functions and the decomposition level on the baseline correction, the original spectral signal is decomposed by wavelet to get the detail coefficient and the approximation coefficient. The approximation coefficient is set to zero in order to reconstruct the spectrum signal so as to achieve the baseline of the interferogram Correction. Finally, the results of wavelet correction and threshold fitting correction are compared. The result shows that the correlation coefficient between the two methods is 0.999 9, and the result is the same. However, the program of wavelet transform is shortened more than 10 times. It is proved that the baseline correction of the space heterodyne interferogram using wavelet transform is an effective, time-saving and convenient method.