中文摘要：

光纤布拉格光栅（FBG）传感系统的关键是精确解调中心波长，噪声是影响解调中心波长的主要因素。为了消除噪声，获取真实的传感信号，本文研究了非线性去噪法。非线性去噪通常的方法采用小波阈值去噪。小波阈值去噪的核心是阈值函数及其阈值的选取。首先，分析了传统的阈值函数和阈值选取存在的问题，改进了自寻优阈值选取策略；其次，提出了折中法阈值函数中系数a（调节因子）的最优值选取方法。仿真和实验结果表明：随着n的取值不同，会获得不同的信噪比（SNR），但a在0．40～O．45范围内分别平均变化的去噪效果较好；与传统软硬阈值去噪法相比，SNR提高了2～4dB，均方差（MSE）分别平均降低了0．2～0．5；与参考的改进阈值去噪法相比，SNR提升了1dB，MSE降低了0．1。本文方法优于文献中提到的阈值函数的去噪效果，处理含噪信号能获得较好的SNR和MSE性能，而且方法简单。

英文摘要：

To demodulate the central wavelength precisely is the key of FBG sensor system. How to denoising is a challenging problem. In order to gain the drift of wavelength and achieve the measurement of ambient environment parameters precisely, nonlinear de-noising methods are investigated in this paper. Wavelet threshold de-noising is usually a method of nonlinear de-noising. The selection of threshold function and threshold value is important in wavelet threshold de-noising. Firstly, this paper analyzes the problem of choosing the threshold function and threshold in traditional soft and hard threshold de-noising, and then improves the self-optimizing threshold. Secondly, the paper proposes a method of gaining the optimal value of a （regulatory factor） in the compromising threshold function. Simulation and experiment results show that the signal-to-noise ratio （SNR） changes with a. When the value of a changes between 0. 40 and 0. 45, the effect of de-noising will become better. Compared with the traditional soft threshold and hard threshold methods,the SNR is increased by 2-4 dB,and the mean square root error （MSE） is reduced by 0. 2-0. 5. While compared with the reference improved threshold method, the SNR is improved by t dB and the MSE is reduced by 0. 1. The overall de-noising effect is better than the others.