快速傅里叶变换在喇曼光谱信号噪声平滑中的应用

The application of fast Fourier transform in the noise smoothing of weak Raman spectrum

摘要: 通过快速傅里叶变换(FFT)处理水的普通喇曼散射光谱信号,实现对其干扰噪声的抑制,获得信噪比较高的喇曼光谱.结果表明,通过快速傅里叶变换,获得弱信号源的目标信号和噪声信号的频谱,针对实验获得的弱信号喇曼光谱进行低通滤波和门限滤波,可以分别将具有高频和较低振幅的噪声信号去除,从而实现噪声平滑并获得高信噪比的喇曼光谱.

Abstract: By using the method of fast Fourier transform(FFT),spontaneous Raman signal of water is handled,and the Raman spectra with high signal to noise ratio(SNR) has been obtained by reducing noises.Low pass and threshold filters have been used to handle the numerical data of Raman signal.The former wipes off the noise component if its frequency is higher than frequency of cut-off(FC),and the latter wipes off the noise component if its amplitude is lower than that of noise with maximal amplitude,the noise is reduced and the Raman spectrum with high SNR can be obtained.