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在分布式光纤温度传感器(DTS)的系统分析中,所探测到的含有温度信息的后向拉曼散射信号的强度十分微弱,并且所携带的噪声很大,严重影响了测温精度。针对该系统存在的噪声,提出了将小波变换和经验模态分解(EMD)相结合的方法对拉曼信号进行信号处理。实验结果表明:该方法能够有效地去除系统中的噪声,很好地保留了信号的有用部分,系统的信噪比由原来的5.7dB提高到15dB,系统的平均测温误差也由原来的2.8℃降到0.5℃,从而得到更加精确的温度值。
In the system analysis of distributed optical fiber temperature sensor (DTS), the detected intensity of backscattered Raman scattering signal with temperature information is very weak and the noise carried is very serious, which seriously affects the temperature measurement accuracy. In view of the noise existing in the system, a method of combining wavelet transform and empirical mode decomposition (EMD) is proposed to process Raman signals. The experimental results show that this method can effectively remove the noise in the system and keep the useful part of the signal well. The signal-to-noise ratio of the system is increased from 5.7dB to 15dB. The average temperature error of the system is also 2.8 ℃ down to 0.5 ℃, resulting in more accurate temperature value.