作者：刘祚时^1,2, 周继雯¹, 俞跃³, 李伟², 叶超³, 唐大为⁴

作者单位：1. 江西理工大学电气工程与自动化学院, 江西 赣州 341000;
2. 江西理工大学机电工程学院, 江西 赣州 341000;
3. 中国特种设备检测研究院, 北京 100029;
4. 中国石油化工股份有限公司天然气榆济管道分公司, 山东 济南 250000

关键词：锁相红外热成像;主成分分析;粘接缺陷;聚乙烯材料;检测深度

摘要：

为降低油气管道聚乙烯层粘接处的脱粘、粘接缝隙等面积型缺陷造成的安全事故发生概率，通过主动式红外热成像技术以及对不同深度的聚乙烯材料缺陷进行检测，采用主成分分析法和锁相技术对获取的原始红外图像进行处理，实现深度在5 mm处的粘接缺陷定量检测，该深度为油气管道聚乙烯层的标准尺寸大小。通过实验确定锁相频率与图像信噪比的关系，可为提高锁相检测效果提供依据。研究表明：激励频率在0.005~0.006 Hz范围内，锁相检测可以满足在役油气管道5 mm深的粘接缺陷检测，主成分分析法可以有效解决激励导致的温度分布不均匀带来的噪声干扰，弥补锁相检测方法的不足，提升缺陷可检测深度，该方法可以将原始温度分布图像的信噪比均值由0.637 dB提升至8.033 dB。

Research on infrared thermal imaging detection method and signal enhancement technology for bonding defects of polyethylene layer in oil and gas pipeline
LIU Zuoshi^1,2, ZHOU Jiwen¹, YU Yue³, LI Wei², YE Chao³, TANG Dawei⁴
1. College of Electrical Engineering and Automation, Jiangxi University of Science and Technology, Ganzhou 341000, China;
2. School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China;
3. China Special Equipment Inspection and Research Institute, Beijing 100029, China;
4. China Petroleum and Chemical Corporation Natural Gas Yuji Pipeline Branch, Jinan 250000, China
Abstract: In order to reduce the probability of safety accidents caused by area defects such as debonding and bonding gaps in the polyethylene layer of oil and gas pipelines, active infrared thermal imaging technology and detection of polyethylene bonding defects at different depths are detected. The original infrared thermal images obtained are processed by the principal component analysis method and the phase-locking technique to realize the quantitative detection of the bonding defect at a depth of 5 mm, which is the standard size of the polyethylene layer of the oil and gas pipeline. The relationship between phase-locked frequency and image signal-to-noise ratio is determined by experiments, which provides a basis for improving the phase-locking detection effect.The research shows that if the excitation frequency was in the range of 0.005 Hz-0.006 Hz, the phase-locking detection can meet the 5 mm deep bonding defect detection of the in-service oil and gas pipeline. The principal component analysis method can effectively solve the noise interference caused by the uneven temperature distribution and make up for the deficiency of the phase-locked detection method, improving the detectable depth of the defect. The method can raise the signal-to-noise ratio of the original temperature distribution image from 0.637 dB to 8.033 dB.
Keywords: phase-locked infrared thermal imaging;principal component analysis;bonding defect;polyethylene material;detection depth
2019, 45(11):1-8  收稿日期: 2018-11-20;收到修改稿日期: 2019-01-19
基金项目: 国家重点研发计划项目（2017YFF0209704）
作者简介: 刘祚时(1963-),男,江西吉安市人,教授,主要从事无损检测、智能机器人方面的研究
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