红外干涉信号采样误差分析及修正方法研究

Error analysis and correction method of infrared interference signal sampling

傅立叶变换红外(FTIR)光谱系统用He-Ne激光干涉信号作为参考信号,存在过零点采样误差。基于光的干涉原理,通过傅里叶变换建立了FTIR光谱仪采样误差与光谱鬼线位置和强度之间的理论仿真模型。为降低采样误差,采用三次样条插值法修正过零点误差,线性插值法重建红外光干涉信号强度。结果表明该模型可以作为由采样误差引起光谱误差修正算法的理论依据,三次样条插值法用于He-Ne信号过零点重建能减小采样误差,误差范围降低了93%,线性插值法用于红外光信号强度重建能提高光谱信噪比,平均提高5.7%。

Fourier transform infrared（FTIR） spectroscopy system uses He-Ne laser interference signal as a reference signal, but there is zero crossing sampling error. Based on the principle of light interference,a theoretical simulation model between FTIR spectroscopy sampling error and spectral ghost line position and intensity is established by Fourier transform. In order to reduce the sampling error, the cubic spline interpolation method is used to correct zero crossing error, and intensity of infrared optical interference signal is reconstructed by linear interpolation method. Results show that the model can be used as a theoretical basis for spectral error correction algorithm caused by sampling error. The cubic spline interpolation method can reduce the sampling error on reconstruction of He-Ne signal zero-crossing, and the error range is reduced by 93%. The linear interpolation method is applied to reconstruction of the infrared light, intensity signal,which can improve the spectral signal-to-noise ratio, with an average increase of 5.7%.