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针对分布式光纤管道安全预警系统检测信号的混沌特性,最大Lyapunov指数(λm ax)被定义为降噪指标用于评价各种小波及其阈值组合的降噪性能.基于小波阈值降噪法,采用不同的小波族系和阈值选取及重调方法对现场实测人工挖掘信号进行降噪处理.现场实验数据的分析结果表明检测信号存在混沌特征.在此基础上,λm ax被用于评价小波降噪性能.最后,通过对比实验结果,sym2小波、Sqtwolog阈值选取规则和M ln阈值重调方法,可以有效地消除现场实测信号中的噪声,达到最优的降噪效果.
According to the chaotic characteristics of distributed optical fiber pipeline pre-warning system, the maximum Lyapunov exponent (λm ax) is defined as the noise reduction index for evaluating the noise reduction performance of various wavelet and threshold combinations.Based on the wavelet threshold denoising method, Different wavelet family and threshold selection and re-adjustment method to field-measured artificial mining signal denoising processing.Experimental data analysis results show that the detection signal chaos characteristics.On this basis, λm ax is used to evaluate the wavelet denoising Performance.Finally, by contrasting the experimental results, sym2 wavelet, Sqtwolog threshold selection and M ln threshold adjustment method, the noise in field measurement signal can be effectively eliminated to achieve the optimal noise reduction effect.