基于分离谱技术的激光超声信号处理

摘要

In laser ultrasonic inspection of the material surface breaking defects, The signal to noise ratio ( SNR) of ultrasonic pulse-echo was low because of the disturbance from structural noises. In order to improve the signal to noise ratio of laser ultrasonic detection signal, the surface acoustic wave signal is processed by the separation spectrum technique.Based on the experimental signal, the same signal was simulated.Processing the simulated signal with noise by using separation spectrum technique and comparing the signal to noise ratio of the processed signal.Experimental data of laser ultrasonic are processed with the most effective separation technique. The results show that the use of this technology can improve the signal to noise ratio, and on the characteristics containing different depth from the surface of the defect signal can be clearly extracted, and the results are consistent with the theoretical derivation.%在材料表面缺陷激光超声检测中，超声脉冲反射回波信号往往受到结构噪声的干扰，信噪比较低。为了提高激光超声检测信号的信噪比，提出了用分离谱技术处理检测到的声表面波信号。仿真实验信号，模拟了同等的信号，用分离谱技术处理含噪声的模拟信号，比较处理后信号的信噪比，选择最有效的分离谱技术处理激光超声实验数据。结果表明：使用该技术可以提高信噪比，且对含有不同深度表面缺陷信号的特征可以清晰提取，与理论公式推导的结果相符合。