截止频率法提取粗晶材料超声检测的目标反射信号

Extraction of target echo signals for the ultrasonic testing of coarse grained materials by cutoff frequency technique

对于粗晶材料的超声检测，当组织噪声很强而目标反射信号又很弱时，分离谱技术及其常规的恢复算法不能起到有效的降噪作用。本文在分离频谱法的基础上，提出一种改进的信号处理技术——截止频率法。实验结果表明，该方法能从很强的组织噪声中将微弱的目标反射信号提取出来，从而有效地消除了材料组织噪声的影响。

For the ultrasonic testing of coarse grained materials, splitspectrum processing(SSP) technique with conventional algorithms could not work for the reduction of material noise when the structural noise is strong while the target echoes are weak. In this paper, a new signal processing technique, cutoff frequency technique, is developed on the base of SSP. It is shown by the experimental results that the technique presented here can extract weak target echoes from strong structural noise, and hence eliminate the influences of structural noise of the material efficiently.