摘要
多发于采空区的弱振幅微震信号具有强度弱、不平稳、噪源强的特点,基于同步挤压小波变换(SS-CWT)及Yoon-V自适应阈值提出分频降噪方法.首先,SS-CWT重构含噪信号,位于高能噪声的频段使用软阈值降噪;其次,为保留高低频逆转换的有效信息,选用合适的参数进行Yoon-V自适应阈值降噪.该方法相比传统小波变换具有分辨率高的优势,相较经验模态分析(EMD)而言更能提取信号中的弱振幅分量.最后用SS-CWT时频谱对比分析降噪前后信号特征,并用复合变异系数定权T值法对本次降噪效果进行评价,本文方法很好的保留有效信息,降噪效果显著.
Weak amplitude micro-seismic received around mined out area has characterized by weak of intensity,non-stationary and strong noise of source,we provide the method of de-noising by divided frequency for wake amplitude based on SS-CWT and customed threshold Yoon-V. Above all,noise-contained original signal is reconstructed by Synchro-Squeezed Continuous Wavelet Transform(SS-CWT),of the high-energy noise de-noising by hard threshold. Then, useful information is remained during reverse conversion from high-low frequency,reasonable parameter selected to de-noise by costumed threshold Yoon-V. Compared with the traditional wavelet transform,this method has the advantage of high resolution,and it can extract the weak amplitude component of the signal more effectively than the Empirical Mode Decomposition(EMD). In the end,the characteristics of the signal before and after noise reduction are analyzed by SS-CWT time spectrum comparison,and the noise reduction effect is evaluated by the composite variable coefficient weighting T-value method. Keep effective information method in this paper is valid,obvious effect.
引文
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