OMHT method for weak signal processing of GPR and its application in identification of concrete micro-crack  

地质雷达弱信号处理OMHT法及其在混凝土微裂缝识别中的应用（英文）

作　　者：LING Tong-hua ZHANG Liang HUANG Fu GU Dan-ping YU Bin ZHANG Sheng 凌同华;张亮;黄阜;谷淡平;余彬;张胜(School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,China;Hunan Province Engineering Laboratory of Bridge Structure,Changsha University of Science and Technology,Changsha 410114,China;College of Civil Engineering,Hunan City University,Yiyang 413000,China)

机构地区：[1]School of Civil Engineering,Changsha University of Science and Technology,Changsha 410114,China [2]Hunan Province Engineering Laboratory of Bridge Structure,Changsha University of Science and Technology,Changsha 410114,China [3]College of Civil Engineering,Hunan City University,Yiyang 413000,China

出　　处：《Journal of Central South University》2019年第11期3057-3065,共9页中南大学学报（英文版）

基　　金：Projects(51678071,51608183)supported by the National Natural Science Foundation of China;Projects(CX2018B530,CX2018B531)supported by the Postgraduate Research and Innovation-funded Project of Hunan Province,China;Projects(16BCX13,16BCX09)supported by Changsha University of Science and Technology,China

摘　　要：In the light of the problem of weak reflection signals shielded by strong reflections from the concrete surface,the detection and the recognition of hidden micro-cracks in the shield tunnel lining were studied using the orthogonal matching pursuit and the Hilbert transform(OMHT method).First,according to the matching pursuit algorithm and the strong reflection-forming mechanism,and based on the sparse representation theory,a sparse dictionary,adapted to the characteristics of the strong reflection signal,was selected,and a matching decomposition of each signal was performed so that the weak target signal submerged in the strong reflection was displayed more strongly.Second,the Hilbert transform was used to extract multiple parameters,such as the instantaneous amplitude,the instantaneous frequency,and the instantaneous phase,from the processed signal,and the ground penetrating radar(GPR)image was comprehensively analyzed and determined from multiple angles.The results show that the OMHT method can accurately weaken the effect of the strong impedance interface and effectively enhance the weak reflected signal energy of hidden micro-crack in the shield tunnel segment.The resolution of the processed GPR image is greatly improved,and the reflected signal of the hidden micro-crack is easily visible,which proves the validity and accuracy of the analysis method.针对混凝土表面强反射等原因造成的异常强反射信号屏蔽下部微弱目的信号的问题,采用正交贪婪匹配追踪与希尔伯特变换相结合的方法(OMHT法)进行了盾构隧道衬砌隐伏微裂缝的检测与识别.首先,依据匹配追踪算法和强反射形成机理,基于稀疏表示理论,选取了与强反射信号特征相适应的稀疏字典,对每道信号进行匹配分解处理,使淹没于强反射中的微弱目标体信号得到较好的展示.其次,对处理后的信号进行希尔伯特变换提取雷达剖面瞬时振幅、瞬时频率和瞬时相位等多个参数信息,从多个角度对地质雷达图像进行综合分析和判断.结果表明,OMHT法可精准弱化强阻抗界面的影响,并有效增强管片隐伏微裂缝弱反射信号能量.处理后的地质雷达图像分辨率明显提高,隐伏微裂缝反射信号清晰可见,证明了该分析技术对隐伏微裂缝识别的有效性和准确性.

关 键 词：orthogonal matching pursuit Hilbert transform shield tunnel lining structure hidden micro-crack 

分 类 号：TN9[电子电信—信息与通信工程]