为了去除声发射信号中的随机噪声与脉冲干扰,提高有用信号质量,提出一种中值滤波与奇异值分解相结合的降噪方法.该方法首先对原始声发射信号进行中值滤波,去除幅值较大的异常值,其次对去除异常值的信号序列进行相空间重构和奇异值分解,最后针对确定重构阶数这一难点,提出奇异值能量差分谱概念,并利用能量差分谱的较大峰值位置来确定奇异值的重构阶数,以实现降噪.数值仿真和五层胶合板强度测试的实测数据分析表明,该方法能够有效地保留原有信号的特征,并能最大限度地消除噪声,提高信噪比.%In order to reduce random noise and pulse disturbance in acoustic emission ( AE) signals and to raise the quality of useful signals, A new method combining median filtering and singular value decomposition was proposed. Firstly, the outliers in the original AE signals were suppressed with median filtering. Secondly, signal sequences with outliers removed were reconstructed in phase space, and the attractor track matrix was decomposed with singular value decomposition ( SVD). Finally, aiming at determine reconstruction order number of singular values, the concept of energy difference spectrum of singular values was put forward, and denoising was through determing reconstruction order number according to the peak position of the energy difference spectrum. The numerical simulation results and the measured data of the bonding strength of a five-plywood showed that the proposed method can retain the original signal characteristic efficiently, eliminate noise and enhance the signal-to-noise ratio as much as possible.
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