摘要： 超声导波在高速公路护栏立柱检测中存在信噪比低、回波中特征信号不明显等问题,为此,提出一种改进 的子空间匹配追踪算法(ISMP),利用回波信号的先验信息在过完备Chirp 原子库上得到每次迭代的强相关原子 集,经过迭代得到待匹配信号的最佳时频原子,从而实现对立柱回波信号的特征提取。通过对中心频率为128 kHz的检测信号进行算法验证,结果表明,ISMP 可以有效提取出回波信号的特征原子,所得检测长度与实际测量误差小于1% ,满足工程检测要求。

关键词: 匹配追踪, Chirp 原子, 超声导波技术, 护栏立柱, 埋深检测, 无损检测

Abstract: For the low signal to noise ratio,unconspicuous echo characteristic signal and other issues encountered in ultrasonic guided waves inspection of highway guardrail posts,an Improved Subspace Matching Pursuit(ISMP) algorithm is presented,which obtains the correlated atomic sets for each iteration from over-complete chirp atom library by the priori information of echo signal and achieves echo signal feature extraction by iterating to get the best time-frequency atom of the signal to be matched. The algorithm is verified by the guided wave inspection signal whose center frequency is 128 kHz. The results show that ISMP can effectively extract the characteristic atoms from echo signal, and the actual measurement error is less than 1% . It can meet the requirements of project detection.

Key words: matching pursuit, Chirp atom, ultrasonic guided wave technology, guardrail post, buried depth detection, nondestructive detection

中图分类号: 

• O347. 4