中文摘要：

超声散斑相关法能对物体的变形进行非接触式测量，但在相关运算时，由于相关系数是一个多峰函数，在搜索相关系数最大值时经常会将次峰误判为主峰，从而造成很大的测量误差。本文提出的超声散斑多谱值相关法，对位移前和位移后的散斑场中各散斑信号进行离散谱分析时，取多个振幅谱值分别组成数据矩阵并各自进行相关运算，比较运算得到的各个位移值来确定真实位移，它能避免因相关系数主峰误判所引起的误差。本文应用超声散斑多谱值相关法对水下物体的位移进行了实测，实验结果表明该方法不仅能有效地避免相关系数主峰的误判，而且提高了位移测量精度。

英文摘要：

Ultrasonic speckle correlation method can be used in non-contact measurement of object deformation. Since the correlation parameter is a multi-peak function, so the secondary peak is often misjudged as the main peak when searching the maximum correlation coefficient in performing correlation process, which results in a great measurement error. To avoid this kind of error, ultrasonic speckle multiple spectrum correlation method is proposed in this paper. When discrete spectral analysis of speckle signals from speckle fields before displacement and after displacement respectively carried out, several amplitude spectrum values were selected to form data array respectively. Then correlation operations between the data array of before and after displacement were conducted respectively. Real displacement is finally determined by comparing the displacement obtained by each of the correlation operation. In order to verify the feasibility of this method, an experimental measurement system was set up. With this system, underwater displacement of an object was detected. Experimental results show that above-mentioned multiple spectrum correlation method not only avoids misjudgment the main peak of correlation coefficient effectively, but also improves the displacement measurement accuracy.