基于自适应滤波的超声杂波抑制方法

在超声衍射时差(time of flight diffraction,TOFD)法检测获取的回波中,作为固定存在的侧向直通波信号会导致近表面缺陷信号不易于识别.针对这一问题,提出一种基于自适应滤波技术的杂波信号抑制方法.该方法通过迭代滤波器自身参数,调节参考信号以满足待处理回波中杂波的时基抖动变化要求,并予以去除,从而分离出与其混叠的近表面缺陷信号.阐明了基于自适应滤波技术的杂波信号抑制原理,并利用所提方法对计算机仿真信号及人工缺陷检测回波进行了杂波抑制处理.结果表明,所提方法可有效滤除超声TOFD法检测回波中具有时基抖动特性的杂波信号,并提取近表面缺陷信号.

An ultrasonic clutter suppression method using adaptive filter

In ultrasonic TOFD (time of flight diffraction) collected waves, the lateral wave brings about difficulty in identification of near surface defect signal. To solve this problem, a clutter suppression method using an adaptive filter is presented. Through iterative the parameters, the filter can adjust the reference signal to meet the changes of the clutter wave to be suppressed. Then the clutter wave can be removed and the near surface defect signal can be separated. The principle of clutter suppression method based on adaptive technology is described. The proposed method is studied by using computer simulation technique. Artificial defect collected waves are clutter suppression processed. The results show that the proposed method can effectively suppress clutter and extract near surface defect signal.