基于维纳滤波的超声增强实现方法

Implementation of Ultrasonic Enhancement Based on Wiener Filtering

超声在传播时,由于受到材质不均匀、材料内部杂质等的影响而使接收信号受到噪声的干扰,这种干扰有时会淹没所检测的裂纹信号,因此必须要经过增强处理。声学增强处理常用的方法是维纳滤波。本文提出维纳滤波用于超声增强的具体实现方法,即首先统计平均无脉冲段的初始噪声功率谱,然后自适应计算带干扰超声段功率谱,最后进行维纳滤波。超声数据在不同信噪比下的维纳滤波实验表明了所提方法的有效性,超声维纳去噪方法与谱减法一样能够降低超声回波中的噪声,且更加有效。

The propagating ultrasound is disturbed by the clutter,which is resulted from interior discontinuities,material impurities,etc.. And the clutter may submerge the detected flaw reflection. Therefore,ultrasonic echo needs to be enhanced.Wiener filter is the common method of acoustic enhancement,and here is utilized in the ultrasonic noise reduction.We give the procedure of the Wiener filter to process the ultrasound.Firstly,initial noise power spectra of no pulse phases are statistically averaged.Then the power spectra of the ultrasound phase with clutter are adaptively calculated. Finally,the Wiener filter is performed to each ultrasonic phase. The experiments of the ultrasonic data filtering under different signal-noise-ratios are demonstrated that the proposed method is valid.Wiener filter has the same ability with spectral subtraction to reduce the noise superposed on the ultrasonic echo,and is more effective.