基于内插频谱校正方法的超声共振测厚

The Thickness Measurement by Ultrasonic Resonance Based on Interpolated Spectrum Correction

超声共振测厚法是一种常用的测厚方法,具有可测下限小、精度高等优点。超声共振频率的估计精度,是采用超声共振法测厚的关键。提出采用基于汉宁窗的内插频谱校正方法估计超声共振频率。相比通过传统傅里叶变换直接获得频率的方法,该方法在不增加计算量级的前提下,可提高共振频率的估计精度,达到提高薄壁管壁厚测量精度的目的;并且,通过试验验证了该方法的有效性。

Thickness measurement by ultrasonic resonance is a commonly used method,which has the advantage of small measurement limit and high precision.The estimation accuracy of resonance frequency is critical for thickness measurement.In this paper,an estimation method of resonance frequency is proposed which is using the spectrum correction based on the Hanning window interpolation.Compared with the method of calculating the frequency by the traditional Fourier transform directly,the precision of resonance frequency can be improved by the proposed method without increasing the computing magnitude,thus improving the thickness measurement accuracy.The experiment proves the availability of the proposed method.