Abstract: Recognition and calculation of echo time difference based on signal correlation method in ultrasonic thickness measurement are studied in this paper. By computer simulation, least square fitting method is used to extract the peak of correlation coefficients. Then validation and comparison of the calculation precision, anti-noise ability, stability of the algorithm are carried out. The ideal order of polynomial fitting model is given and verified by experiments.

Key words: ultrasonic thickness measurement, signal correlation method, time difference measurement, peak extraction, least square method

摘要： 研究了信号相关法在超声法厚度测量中回波时间差的识别计算。通过计算机模拟的方法，采用相关系数最小二乘拟合的方法进行峰值提取，对相关运算算法的精度、抗噪声能力进行了验证和比较，给出了较理想多项式拟合模型的阶数，并通过实验进行了验证。

关键词: 超声波测厚, 信号相关法, 时差测量, 峰值提取, 最小二乘法