基于小波包域噪声能量分布的脉冲噪声消除  

Impulsive noise removal based on noise energy distribution in wavelet packet domain

作　　者：何志勇[1] 朱忠奎[2] 张茂青[1] 

机构地区：[1]苏州大学机电工程学院,苏州215021 [2]苏州大学城市轨道交通学院,苏州215021

出　　处：《仪器仪表学报》2011年第9期2071-2078,共8页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(No.50905121);江苏省高校自然科学基金(No.10KJD510008);苏州市国际科技合作计划(No.SWH0817)资助项目

摘　　要：针对信号被平稳脉冲噪声污染的场合,提出了一种从含噪信号中检测脉冲噪声并降噪的脉冲噪声消除方法。该方法选择脉冲噪声能量相比含噪信号能量最为显著的小波包树节点,并利用该节点小波包系数重构信号进而检测脉冲噪声的时域分布。在降噪中,该方法于小波包域内估计脉冲噪声的能量分布并依据估计结果计算每段脉冲噪声的滤波阀值。将该方法用语音增强实验验证,结果表明所提出的检测算法能获得较好的检测结果,而提出的降噪算法能显著地改善信噪比,获得较好的降噪效果。将文中的检测算法应用于轴承故障检测的信号预处理,进一步验证了方法的有效性。To remove noise when signal is polluted by stationary impulsive noise, this paper provides a new method to detect and denoise impulsive noise from a noisy signal. The method finds the wavelet packet tree node where the energy of impulsive noise is most evident. The signal is reconstructed using the wavelet packet coefficients of the node ; a detection algorithm is developed, the time domain distribution of the impulsive noise is detected and an algorithm for estimating the noise energy distribution in wavelet packet domain is also developed. According to the estimation result, the adaptive thresholds of the impulsive noises are also calculated and the thresholds can be used when the noisy signal is denoised in wavelet packet domain. The method was used in speech enhancement tests, and results show that the method can obtain good performance in the removal of impulsive noise. The method was also successfully applied in the signal pre-processing of bearing fault detection, and the effectiveness of the method is further verified.

关 键 词：脉冲噪声 小波包 噪声能量分布 降噪 

分 类 号：TN911.7[电子电信—通信与信息系统]