改进的小波变换用于处理FBG信号

解调系统是光纤布拉格光栅（FBG）传感技术的核心。信号去噪和峰值搜索是影响FBG 传感系统精确解调的两个重要因素。为提高测量精度，文中针对传统方法存在的缺陷，提出了一种新的FBG 波长解调方法，此解调方法由一种改进的去噪方法与高斯拟合寻峰算法组成。采用平移不变量小波与文中提出的改进阈值和改进阈值函数相结合的方法来处理FBG 含噪信号；然后采用高斯拟合寻峰算法对去噪信号作进一步解调。实验结果表明，改进阈值的平移不变量小波能处理不同的FBG 含噪信号，该方法获得的信噪比和均方差性能优于传统小波阈值去噪法以及其他改进的小波去噪法；该改进小波的波长解调方法测量的峰值误差低于1pm，比常用的波长解调方法具有更高的测量精度。

Processing of FBG sensor signal by improved wavelet

Demodulation system is the core sensing technology of optical fiber Bragg grating (FBG). De-noising and seeking the peak wavelength are the two important factors that influence the demodulation accuracy. In order to obtain the precise wavelength drift, aiming at the defects of the traditional demodulation methods, a new wavelength detection scheme for optical fiber Bragg grating (FBG) was put forward, which was composed of an improved de-noising method and the Gaussian fitting peak searching algorithm. The translation invariant wavelet combined with the new threshold value and the proposed new threshold function method to deal with noisy FBG sensor signal; then the Gaussian fitting peak searching algorithm was adopted to find the peak wavelength of the de-noised signal for further analysis. The experiment result shows that the improved invariant wavelet can deal with noisy FBG sensor signal with different SNR and get a higher SNR value and a lower mean square error value than the other wavelet de-noising methods mentioned; this kind of wavelength detection technique can get the measurement maximum peak error of less than 1 pm, which means a much higher accuracy than general wavelength detection methods.