基于小波包变换方法的超声回波信号去噪研究

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一平均能量阈值法，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 research on the de-nosing of ultrasonic echo signal based on Wavelet Packet Transform

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.