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研究了一种应用恢复函数和低频超声波对超薄层弹性材料的声学特性（厚度、声速和密度）进行无损测量的新方法。这里所说的“超薄”是指材料的厚度远小于检测所用的声波波长。文中对应用透射恢复函数的幅度谱、相位谱和复谱在最小二乘意义下估计材料的定征参数的性能进行了详细的研究和比较，分析了影响估计准确性的典型因素，推导和讨论了灵敏度函数及其在误差传递中的意义．实验使用中心频率为2MHz的超声波测量厚度为25．4～152．4μm的铜箔，得到的估计值与真实值符合的非常好．
A new method for nondestructive measurement of the acoustic properties (thickness, sound speed and density) of ultrathin layer elastic materials by using the restoration function and low frequency ultrasonic was studied. As used herein, “ultra-thin” means that the thickness of the material is much less than the wavelength of the acoustic wave used for the test. In this paper, the amplitude, phase spectrum and complex spectrum of the transmission recovery function are studied and compared in detail in the estimation of the material’s characterization parameters in the least square sense. The typical factors that influence the accuracy of the estimation are analyzed, and the derivations and discussions are made Sensitivity Function and Its Significance in Error Transmission. Experiments using the center frequency of 2MHz ultrasonic measurement of the thickness of 25.4 ~ 152.4μm copper foil, the estimated value obtained in line with the true value is very good.