Research on the imaging of concrete defect based on the pulse compression technique  

基于脉冲压缩技术的混凝土缺陷检测方法研究(英文)

作　　者：李长征[1,2] 张碧星[1] 师芳芳[1] 谢馥励[1] 

机构地区：[1]中国科学院声学研究所声场声信息国家重点实验室,北京100190 [2]黄河水利科学研究院,郑州450003

出　　处：《Applied Geophysics》2013年第3期337-348,359,共13页应用地球物理（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.11074273);the ministry of water resources'special funds for scientific research on public causes(No.201301061)

摘　　要：When the synthetic aperture focusing technology （SAFT） is used for the detection of the concrete, the signal-to-noise ratio （SNR） and detection depth are not satisfactory. Therefore, the application of SAFT is usually limited. In this paper, we propose an improved SAFT technique for the detection of concrete based on the pulse compression technique used in the Radar domain. The proposed method first transmits a linear frequency modulation （LFM） signal, and then compresses the echo signal using the matched filtering method, after which a compressed signal with a narrower main lobe and higher SNR is obtained. With our improved SAFT, the compressed signals are manipulated in the imaging process and the image contrast is improved. Results show that the SNR is improved and the imaging resolution is guaranteed compared with the conventional short-pulse method. From theoretical and experimental results, we show that the proposed method can suppress noise and improve imaging contrast, and can also be used to detect multiple defects in concrete.利时用合成孔径聚焦技术(SAFT)检测混凝土缺陷,常规的短脉冲检测方法信噪比较低,导致检测距离较浅,使应用范围受到限制。本文引入雷达探测中使用的脉冲压缩技术,并提出了改进的基于脉冲压缩技术的合成孔径聚焦榆测方法(ISAFT)。该方法通过发射线性调频信号(LFM),将缺陷回波信号经匹配滤波进行脉冲压缩处理,得到的压缩信号具有主瓣宽度较窄、峰值较高的特点。然后利用该压缩信号进行SAFT成像处理,提高了图像对比度。与常规的短脉冲检测方法相比,该方法既提高了信噪比,又保证了缺陷检测的分辨率。理论和实验结果表明,该方法不仅能抑制噪声提高成像对比度,而且还适用于混凝土内部多个缺陷的检测。

关 键 词：Concrete defect LFM pulse compression SAFT SNR 

分 类 号：TU712.3[建筑科学—建筑技术科学] TU755TU528