空间外差光谱仪光谱降噪方法研究

空间外差光谱仪是一种新式的超高分辨率光谱仪，可用于大气监测、卫星遥感等领域。为了减少空间外差光谱信号中的噪声，提出基于提升小波变换结合中值滤波方法来实现信号的降噪。改进的提升小波变换融合了一种双因子的阈值函数、分层阈值选取。与小波变换的软、硬阈值对比发现，它能提取空间外差光谱，减小峰宽和保留重要的细节特征，降噪效果优于小波变换的软、硬阈值法。最后用信噪比和均方误差两项定量指标来衡量算法的效果。实验结果表明:该算法比软阈值法在处理氙灯和积分球时信噪比提高了24.6%和31%，均方误差减少了43.2%和51.5%；与硬阈值法相比信噪比提高了21.5%和30.6%，均方误差减少了40.2%和51.2%。因此，算法在空间外差光谱降噪方面具有可行性。

Denoising method for spectrum of spatial heterodyne spectrometer

The spatial heterodyne spectrometer is a new ultra-high resolution spectrometer, which can be used for the atmospheric monitoring, satellite remote sensing and other fields. In order to reduce the noise in the spatial heterodyne spectral signal, a denoising method based on lifting wavelet transform combined with median filter was proposed. The two-factor threshold function and hierarchical threshold selection were incorporated by the improved lifting wavelet transform. Compared with the soft and hard thresholds of the wavelet transform, the spatial heterodyne spectrum could be extracted, the peak width could be reduced, and the important detail features could be preserved by the proposed algorithm, which had superior denoising effect than the wavelet transform. Finally, the two quantitative indexes of SNR and mean square error were used to measure the effect of the proposed algorithm. The experimental results show that, compared with the soft threshold method, the signal-to-noise ratio of the algorithm for the xenon lamp and the integrating sphere is increased by 24.6% and 31%, respectively, and the mean square error is reduced by 43.2% and 51.5%, respectively. Compared with the hard threshold method, the signal-to-noise ratio is increased by 21.5% and 30.6%, respectively, and the mean square error is reduced by 40.2% and 51.2% respectively. Therefore, the algorithm is feasible in the spatial heterodyne spectral noise reduction.