基于小波包变换方法的超声回波信号去噪研究

The research on the de-nosing of ultrasonic echo signal based on Wavelet Packet Transform

超声回波信号中含有大量有关缺陷性质的信息,但同时也掺杂着大量噪声干扰。为了很好的从回波信号中提取反映缺陷本质特征的信号,文章中使用了一种改进的小波包去噪方法-平均能量阈值法,讨论了小波包变换的多分辨率分析及平均能量阈值法消噪的原理,仿真结果表明,基于平均能量阈值的小波包去噪是一种有效的去噪方法,其效果优于小波去噪。

The ultrasonic echo signals contain much many information,which reflect defect, and there are various disturbance and noises in them. In order to distill effective signal from echo signals, A modified method called average energy threshold using wavelet packet transform is put forward for signal de-noising. The muti-resloving analysis of wavelet packet transform and the principle of the mean energy threshold to reduce the noise is introduced. It has been proved that the wavelet packet de-noising is an effective method and prior to wavelet de-noising.