基于小波变换的超声波检测信号的消噪处理

Denoising of ultrasonic testing signal based on wavelet transform

基于超声回波信号的特点,提出了利用小波变换法对管材中沟槽的超声反射信号进行消噪的方法。选择db12小波基对含噪的超声信号进行4层分解,然后分别采用强制消噪法、固定阈值法、自适应阈值法进行消噪处理。并对三种方法的滤波结果进行了对比分析,结果表明:自适应阈值法具有很好的去噪效果,并且很好地保留了反映超声信号的特征尖峰点。利用小波变化理论,对管材沟槽的超声波检测信号进行了消噪处理,取得了较好的滤波效果。

Based on the characteristics of ultrasonic signal,a new denoising method of ultrasonic testing signalfor pipe groove by using wavelet transformis presented in this paper.First,the ultrasonic signal is decomposed in four layers by db12wavelet.And then the force ideas,fi xed threshold method and adaptive threshold method are used to denoise the signal.And the results were analyzed and compared.Experiment result indicates the adaptive threshold method can lead to satisfying result and has more adaptability.Using the adaptive threshold method,the characteristic peak point of the ultrasonic signal is well preserved.