用LabVIEW的小波工具处理超声信号中的噪声

Noise Treatment in Ultrasonic Signal by Wavelet Analysis of LabVIEW

为了抑制噪声,提高信造比,实现精确的探伤,本文采用了系统的LabVIEW软件中小波分析工具———降噪函数Denoise.vi对检测系统中超声信号的噪声进行处理,在综合比较降噪效果和执行速度后,确定小波分解尺度为6,并将所有尺度的阈值均设为0.1。经对CS 1 5试块的Ф2平底孔超声反射回波和某型直升机旋翼大梁疲劳裂纹超声反射回波的降噪试验,试验结果表明,处理后的超声信号信噪比显著增强。满足我军航空维修无损检测的需要,实现了探伤工作的快速、机动和高效,提高了检测的可靠性。

In this paper noise-reduction function Denoise. vi-the wavelet analysis tool in LabVIEW software is adopted to deal with noise in ultrasonic signal. After synthetically comparing noise-reduction effect and the running speed, this paper ascertains the scale of wavelet transform 6 and all scales＇ threshold 0. 1. By ultrasonic echo noise-reduction testing on CS- 1 - 5 test block＇s flat bottom hole and certain helicopter totor＇ fatigue flaw, it is shown that ultrasonic signal SNR is increased remarkably. Therefore the needs in aircraft maintenance NDT are met; speeding, maneuvering and high efficiency are realized in NDT;and testing reliability is improved.