论文部分内容阅读
利用声压反射系数良好的自相关特性和与噪声无相关性等特点,提出了基于声压反射系数自相关函数测量薄层厚度的方法。与传统的声压反射系数幅度谱测量方法相比,本方法能够适用于窄频带超声探头和低信噪比信号下的薄层厚度测量。对于声压反射系数幅度谱中只有一个谐振频率以及低信噪比情况,传统的频谱分析方法难以获取谐振频率导致无法进行厚度测量时,本方法仍能准确测得薄层厚度。实验结果验证了该方法的正确性和可行性。
Based on the good autocorrelation characteristic of sound pressure reflection coefficient and no correlation with noise, a method of measuring the thickness of thin layer based on the autocorrelation function of sound pressure reflection coefficient was proposed. Compared with the traditional method of amplitude-spectrum reflection of sound pressure reflection coefficient, this method can be applied to the measurement of thin-layer thickness under narrow-band ultrasonic probe and low signal-to-noise ratio. For the case where there is only one resonance frequency and low signal-to-noise ratio in the amplitude spectrum of the sound pressure reflection coefficient, the method can still accurately measure the thickness of the thin film when the traditional frequency spectrum analysis method can not obtain the resonance frequency and can not measure the thickness. The experimental results verify the correctness and feasibility of the method.