焊接缺陷的超声衍射信号分析与图像处理
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摘要
随着现代工业技术的高速发展,厚壁钢结构越来越广泛地应用于机械工业、核工业及航天航空等领域。由于低合金结构钢具有较高的强度和较好的塑性与韧性,其成为厚壁焊接结构中常用的材料。超声TOFD检测技术以其原理简单,操作方便,检测速度快,对焊缝中裂纹类缺陷检出率高,特别适合于大厚件焊缝检测等特点越来越受到人们的青睐。因此,对中厚板低合金结构钢焊缝的TOFD检测就具有重要的理论和实际意义。
本文研制了TOFD检测系统的手动扫查装置,开发了基于USB接口的便携式超声TOFD采集系统,该系统具有结构简单,操作方便等特点,适合于工程现场检测与分析。由于工件表面不平整等原因使得探头移动不够平稳,从而造成检测图像发生畸变现象。本文提出了采用互相关分析法和灰度差法对检测图像进行矫正。研究结果表明:该方法能够很好地矫正图像,使侧向波保持在相同的水平位置,为缺陷的准确定量定性和目标提取做准备。
为分析TOFD法检测图像特征,本文选用24mm厚度的低合金钢板,采用手工电弧焊制备出大量的缺陷样本,共计129个,包括气孔、夹渣、裂纹及未焊透等。利用开发的系统采集了上述缺陷的超声信号,分析总结了典型缺陷检测图像特征。与射线照相底片相对比,TOFD检测对缺陷性质的判断大致与射线检测相符合。
在图像矫正基础上,提取了检测图像中焊缝区域,并自动将检测图像进行线性化处理。这种处理有利于识别缺陷的深度及高度,简化了检测过程,减少了人为因素的干扰,提高了缺陷定位的精度。为了提高工作效率、减低误判率,利于后续缺陷特征提取与分类识别,本文采用基于背景差法进行缺陷目标提取。结果表明:该方法能够很好地模拟并去除TOFD法检测图像的背景并提取出缺陷。
Recently thick-walled steel structures are widely used in machinery industry, nuclear industry, aerospace and other fields. Low-alloy structural steel with high strength as well as good ductility and toughness, are commonly used in thick-walled structures. As an accurate and rapid testing method, TOFD has advantages on weld defects testing for thick plate, especially on crack defects. It has been widely concerned. Therefore, the TOFD testing for thick plate weld of low-alloy structural steel is significant of theory and practice.
A USB-based portable type ultrasonic TOFD acquisition system was developed in this paper, and the manual scanning device of the system was also designed. The developed system is easy to operate, simple for structure, and suitable for work-site detection and analysis.
Because of the unsmooth sample surface, the probes motion is not easily stable, which result in testing image distortion. Therefore, the cross-correlation analysis and the gray-level difference method were used to calibrate these images. The results show that the methods are able to correct the images, which maintain the lateral wave in the same level that prepares for accurately quantitative, qualitative analysis and object extraction for defects.
For TOFD testing image feature analysis, samples of a large number of defects were prepared using low-alloy steel of 24mm thickness plate by arc welding, which haves a total of 129, including the pores, slag, cracks, lack of penetration and so on. The ultrasonic signals of the above-mentioned defects were collected by the developed system, and the characteristics of typical defects in the testing images were analyzed and summarized. The identification of defects properties by TOFD technology approximately agree with radiographic film.
In this paper, weld zone was extracted from the calibration image, and linear algorithm was used for automatic processing the image, so as to help for identification the defect depth and height, simplifying the testing process, and increasing the accuracy of defect location and quantity. For increasing of efficiency, decreasing the misjudge rate and defect features extracting and classification, differential analysis between background and defect target was applied to extract the target of defects and image segmentation. The result shows that this method not only can well simulate and remove the background of TOFD D scan image, but also extract the defect effectively.
本文研制了TOFD检测系统的手动扫查装置,开发了基于USB接口的便携式超声TOFD采集系统,该系统具有结构简单,操作方便等特点,适合于工程现场检测与分析。由于工件表面不平整等原因使得探头移动不够平稳,从而造成检测图像发生畸变现象。本文提出了采用互相关分析法和灰度差法对检测图像进行矫正。研究结果表明:该方法能够很好地矫正图像,使侧向波保持在相同的水平位置,为缺陷的准确定量定性和目标提取做准备。
为分析TOFD法检测图像特征,本文选用24mm厚度的低合金钢板,采用手工电弧焊制备出大量的缺陷样本,共计129个,包括气孔、夹渣、裂纹及未焊透等。利用开发的系统采集了上述缺陷的超声信号,分析总结了典型缺陷检测图像特征。与射线照相底片相对比,TOFD检测对缺陷性质的判断大致与射线检测相符合。
在图像矫正基础上,提取了检测图像中焊缝区域,并自动将检测图像进行线性化处理。这种处理有利于识别缺陷的深度及高度,简化了检测过程,减少了人为因素的干扰,提高了缺陷定位的精度。为了提高工作效率、减低误判率,利于后续缺陷特征提取与分类识别,本文采用基于背景差法进行缺陷目标提取。结果表明:该方法能够很好地模拟并去除TOFD法检测图像的背景并提取出缺陷。
Recently thick-walled steel structures are widely used in machinery industry, nuclear industry, aerospace and other fields. Low-alloy structural steel with high strength as well as good ductility and toughness, are commonly used in thick-walled structures. As an accurate and rapid testing method, TOFD has advantages on weld defects testing for thick plate, especially on crack defects. It has been widely concerned. Therefore, the TOFD testing for thick plate weld of low-alloy structural steel is significant of theory and practice.
A USB-based portable type ultrasonic TOFD acquisition system was developed in this paper, and the manual scanning device of the system was also designed. The developed system is easy to operate, simple for structure, and suitable for work-site detection and analysis.
Because of the unsmooth sample surface, the probes motion is not easily stable, which result in testing image distortion. Therefore, the cross-correlation analysis and the gray-level difference method were used to calibrate these images. The results show that the methods are able to correct the images, which maintain the lateral wave in the same level that prepares for accurately quantitative, qualitative analysis and object extraction for defects.
For TOFD testing image feature analysis, samples of a large number of defects were prepared using low-alloy steel of 24mm thickness plate by arc welding, which haves a total of 129, including the pores, slag, cracks, lack of penetration and so on. The ultrasonic signals of the above-mentioned defects were collected by the developed system, and the characteristics of typical defects in the testing images were analyzed and summarized. The identification of defects properties by TOFD technology approximately agree with radiographic film.
In this paper, weld zone was extracted from the calibration image, and linear algorithm was used for automatic processing the image, so as to help for identification the defect depth and height, simplifying the testing process, and increasing the accuracy of defect location and quantity. For increasing of efficiency, decreasing the misjudge rate and defect features extracting and classification, differential analysis between background and defect target was applied to extract the target of defects and image segmentation. The result shows that this method not only can well simulate and remove the background of TOFD D scan image, but also extract the defect effectively.
引文
1沈功田,张万岭.特种设备无损检测技术综述.无损检测. 2006, 28(1):34~39
2李光海,沈功田,李鹤年.工业管道无损检测技术.无损检测. 2006, 28(2):89~93
3王晓雷.承压类特种设备无损检测相关知识.中国劳动社会保障出版社. 2007:24~34, 124~132
4迟大钊.基于超声TOFD法的焊缝缺陷表征研究.哈尔滨工业大学博士论文. 2007:1~16
5 Ines Dukic and Predrag Dukic. Advantages and limitations of TOFD technique in casting inspection Brezice. Slovenia, 1998
6 M. Goto, Y. Yokote, H. Tanaka, et al. Ultrasonic time-of flight diffraction (TOFD) procedure for welds according to ASME Code Case 2235 in lieu of radiographic examination. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP. 1998, 375:141~149
7香勇,彭波,金宇飞,等.超声衍射时差技术的标准化.无损检测. 2009, 31(3):236~238
8 G. Zappavigna, C. Pedrenzani. Evaluation of indication detected in high-thickness welds: comparison between traditional methods. Insight, NDT & Condition Monitorning. 2006, 48(1):30~34
9伊新. TOFD检测技术基本原理及其应用.自动化工程. 2008, 12:53~55
10 British TOFD Standard BS 7706. Guide to Calibration and Setting-up of the Ultrasonic Time of Flight Diffraction (TOFD) Technique for Defect Detection, Location and Sizing of Flaws. 1993:1~37
11 F. Betti, G. Zappavigna and C. Pedrinzani. Accuracy capability of TOFD technique in ultrasonic examination of welds. Rome:15th World Conference on Non-Destructive Testing, 2000
12 M. Goto, H. Tanaka, H. Nimura, et al. Study-Code case 2235 application of TOFD to reactors. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP. 2005, 407:15~18
13余国民,常永刚,丁小军,等.超声TOFD法在无损检测领域中的应用.焊管. 2007, 30(6):39~44
14 G. Baskaran, K. Balasubramaniam and C.V. Krishnamurthy. Ultrasonic TOFD Flaw Sizing and Imaging in Thin Plates Using embedded Signal Identification Technique. Insight:Non-Destructive Testing and Condition Monitoring. 2004, 46 (9):537~542
15 H. Hatanaka, N. Ido, M. Furikoma, et al. Application of ultrasonic TOFD method for welds of LNG storage tanks. Ishikawajima-Harima Giho/IHI Engineering Review. 2002, 42(3):151~156
16 K. Maalmi, A. E. Ouaazizi, R. Benslimane, et al. Crack defect detection and localization using genetic-based inverse voting Hough transform. Proceedings-International Conference on Pattern Recognition, 2002, 16(3):257~260
17 A. Kechida, R. Drai and M. Khelil. 2D Gabor functions and FCMI algorithm for flaws detection in ultrasonic images. Transactions on Engineering, Computing and Technology. 2005, (9):1305~5313
18倪进飞,范贤振,马庆增. TOFD检测技术基本原理及其应用探讨.广东电力. 2007, 20(10):17~19
19张平.超声衍射时差检测技术在中国的应用进展.无损检测. 2008, 30(7):397~402
20刘志远,阎长海,车成武.采用衍射超声波测量焊缝缺陷的高度.焊接学报. 1998, (12):42~44
21张锐,万明习.超声衍射—回波渡越时间方法焊接裂纹原位定量无损估计.机械工程学报. 2000, 36(5):54~57
22曹明,王巍,刘桂芹.反求工程在超声衍射时差法三维建模中的应用.无损检测. 2006, 28(2):73~74
23徐书根,王威强,宋明大,等. 2.25Cr1Mo钢试块缺陷的超声TOFD检测.无损检测. 2007, 29(11):627~629
24 T. L. Chen, P. W. Que, Q. Zhang, et al. Ultrasonic nondestructive testing accurate sizing and locating technique based on time-of-flight-diffraction method. Russian Journal of Nondestructive Testing. 2005, 41(10):594~601
25 Tian-lu Chen, Pei-wen Que, Qi Zhang, et al. Ultrasonic signal identification by empirical mode decomposition and Hilbert transform. Review of Scientific Instruments. 2005, 76(8):1~6
26刚铁,徐艳,迟大钊,等.铝合金焊缝超声TOFD检测的信号特征.焊接学报. 2005, 26(8):1~4
27刚铁,徐艳,吕品.厚板铝合金焊缝超声TOFD法检测.第十一次全国焊接会议论文集. 2005:2-20
28刚铁,迟大钊,袁媛.基于合成孔径聚焦的超声TOFD检测技术及图像增强.焊接学报. 2006, 27(10):7~10
29迟大钊,刚铁,袁媛,等.面状缺陷超声TOFD法信号和图像的特征与识别.焊接学报. 2005,26(11):1~4
30吕品.基于超声TOFD法的厚板铝合金焊缝缺陷识别.哈尔滨工业大学硕士论文. 2005
31 Gang Tie, Xu Yan, Chi Da-zhao, et al. Ultrasonic TOFD testing for aluminum alloy weld of thick plate. Trans. Nonferrous Met . Soc. China. 2005, 15(2):79~82
32盛朝阳.超声TOFD检测信号采集与缺陷识别方法研究.哈尔滨工业大学硕士论文. 2005
33龚铭.无损检测中涡流焊缝识别处理机的实现与TOFD缺陷定位算法的研究.上海交通大学硕士论文. 2007
34于殿泓.图像检测与处理技术.西安电子科技大学出版社, 2006. (12):74~79
35徐海洋.基于支持向量机方法的图像分割与目标分类.华中科技大学博士学位论文. 2005:2~19
36杨晖,曲秀杰.图像分割方法综述.电脑开发与应用. 2005, 18(3):21~23
37谢建林,袁小平,王胜利,等.基于分水岭算法的金相图像分割.能源技术与管理. 2006, 2:102~103
38盛朝阳,刚铁.超声TOFD检测成像及缺陷定位系统.焊接. 2007, (8):37~40
39李衍.超声TOFD原理和方法精要.无损检测. 2006.31(6):8~13
40 W. J. Zippel, J. A. Pincheira, G. A. Washer. Crack measurement in steel plates using TOFD method. Journal of Performance of Constructed Facilities. 2000, 14(2):75~82
41 Gang Tie, Xu Yan, Chi Da-Zhao, et al. Signal characteristic of ultrasonic TOFD testing for aluminum alloy weld. Hanjie Xuebao/Transactions of the China Welding Institution. 2005, 26(8):1~4
42徐艳.厚板铝合金焊缝的超声TOFD检测方法研究.哈尔滨工业大学工学硕士学位论文. 2004:37~44
43梁宏林,腾永平,吕香慧.用超声衍射时差法对焊缝缺陷定性表征.无损检测. 2006, 28(1):14~16
44薛永盛,袁军生. TOFD检测中典型缺陷定性图谱分析.云南水力发电. 2008, 24(4):76~78
45孙秋菊,韩焱.信号相关性分析及其在超声检测中的应用.计量与测试技术. 2005, 32(12):28~29
46吴勃英.数值分析原理.科学出版社. 2003. 104~170
47 O Zahran, W Al-Nuaimy. Automatic segmentation of time-of-flight-diffraction images using time-frequency techniques - application to rail track defect detection, Insight:Non-Destructive Testing and Condition Monitoring. 2004, 46(6):338~343
48 J. P. Charlesworth, J. A. G. Temple. Engineering applications of ultrasonic time-of-flight diffraction. Second Edition. Research studies press LTD. Baldock, Herfordshire, England, 2002
49 T. Mihara, Y. Otsuka, H. Cho ,et al. Time-of-flight diffraction measurement using laser ultrasound. Experimental Mechanics. 2006, 46: 561~567
50 Elineudo P. Moura, Romeu R. Silva, Marcio H. S. Siqueira, et al. Pattern Recognition of Weld Defects in Preprocessed TOFD Signals Using Linear Classifiers. Journal of Nondestructive Evaluation. 2004, 23(4):163~172
2李光海,沈功田,李鹤年.工业管道无损检测技术.无损检测. 2006, 28(2):89~93
3王晓雷.承压类特种设备无损检测相关知识.中国劳动社会保障出版社. 2007:24~34, 124~132
4迟大钊.基于超声TOFD法的焊缝缺陷表征研究.哈尔滨工业大学博士论文. 2007:1~16
5 Ines Dukic and Predrag Dukic. Advantages and limitations of TOFD technique in casting inspection Brezice. Slovenia, 1998
6 M. Goto, Y. Yokote, H. Tanaka, et al. Ultrasonic time-of flight diffraction (TOFD) procedure for welds according to ASME Code Case 2235 in lieu of radiographic examination. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP. 1998, 375:141~149
7香勇,彭波,金宇飞,等.超声衍射时差技术的标准化.无损检测. 2009, 31(3):236~238
8 G. Zappavigna, C. Pedrenzani. Evaluation of indication detected in high-thickness welds: comparison between traditional methods. Insight, NDT & Condition Monitorning. 2006, 48(1):30~34
9伊新. TOFD检测技术基本原理及其应用.自动化工程. 2008, 12:53~55
10 British TOFD Standard BS 7706. Guide to Calibration and Setting-up of the Ultrasonic Time of Flight Diffraction (TOFD) Technique for Defect Detection, Location and Sizing of Flaws. 1993:1~37
11 F. Betti, G. Zappavigna and C. Pedrinzani. Accuracy capability of TOFD technique in ultrasonic examination of welds. Rome:15th World Conference on Non-Destructive Testing, 2000
12 M. Goto, H. Tanaka, H. Nimura, et al. Study-Code case 2235 application of TOFD to reactors. American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP. 2005, 407:15~18
13余国民,常永刚,丁小军,等.超声TOFD法在无损检测领域中的应用.焊管. 2007, 30(6):39~44
14 G. Baskaran, K. Balasubramaniam and C.V. Krishnamurthy. Ultrasonic TOFD Flaw Sizing and Imaging in Thin Plates Using embedded Signal Identification Technique. Insight:Non-Destructive Testing and Condition Monitoring. 2004, 46 (9):537~542
15 H. Hatanaka, N. Ido, M. Furikoma, et al. Application of ultrasonic TOFD method for welds of LNG storage tanks. Ishikawajima-Harima Giho/IHI Engineering Review. 2002, 42(3):151~156
16 K. Maalmi, A. E. Ouaazizi, R. Benslimane, et al. Crack defect detection and localization using genetic-based inverse voting Hough transform. Proceedings-International Conference on Pattern Recognition, 2002, 16(3):257~260
17 A. Kechida, R. Drai and M. Khelil. 2D Gabor functions and FCMI algorithm for flaws detection in ultrasonic images. Transactions on Engineering, Computing and Technology. 2005, (9):1305~5313
18倪进飞,范贤振,马庆增. TOFD检测技术基本原理及其应用探讨.广东电力. 2007, 20(10):17~19
19张平.超声衍射时差检测技术在中国的应用进展.无损检测. 2008, 30(7):397~402
20刘志远,阎长海,车成武.采用衍射超声波测量焊缝缺陷的高度.焊接学报. 1998, (12):42~44
21张锐,万明习.超声衍射—回波渡越时间方法焊接裂纹原位定量无损估计.机械工程学报. 2000, 36(5):54~57
22曹明,王巍,刘桂芹.反求工程在超声衍射时差法三维建模中的应用.无损检测. 2006, 28(2):73~74
23徐书根,王威强,宋明大,等. 2.25Cr1Mo钢试块缺陷的超声TOFD检测.无损检测. 2007, 29(11):627~629
24 T. L. Chen, P. W. Que, Q. Zhang, et al. Ultrasonic nondestructive testing accurate sizing and locating technique based on time-of-flight-diffraction method. Russian Journal of Nondestructive Testing. 2005, 41(10):594~601
25 Tian-lu Chen, Pei-wen Que, Qi Zhang, et al. Ultrasonic signal identification by empirical mode decomposition and Hilbert transform. Review of Scientific Instruments. 2005, 76(8):1~6
26刚铁,徐艳,迟大钊,等.铝合金焊缝超声TOFD检测的信号特征.焊接学报. 2005, 26(8):1~4
27刚铁,徐艳,吕品.厚板铝合金焊缝超声TOFD法检测.第十一次全国焊接会议论文集. 2005:2-20
28刚铁,迟大钊,袁媛.基于合成孔径聚焦的超声TOFD检测技术及图像增强.焊接学报. 2006, 27(10):7~10
29迟大钊,刚铁,袁媛,等.面状缺陷超声TOFD法信号和图像的特征与识别.焊接学报. 2005,26(11):1~4
30吕品.基于超声TOFD法的厚板铝合金焊缝缺陷识别.哈尔滨工业大学硕士论文. 2005
31 Gang Tie, Xu Yan, Chi Da-zhao, et al. Ultrasonic TOFD testing for aluminum alloy weld of thick plate. Trans. Nonferrous Met . Soc. China. 2005, 15(2):79~82
32盛朝阳.超声TOFD检测信号采集与缺陷识别方法研究.哈尔滨工业大学硕士论文. 2005
33龚铭.无损检测中涡流焊缝识别处理机的实现与TOFD缺陷定位算法的研究.上海交通大学硕士论文. 2007
34于殿泓.图像检测与处理技术.西安电子科技大学出版社, 2006. (12):74~79
35徐海洋.基于支持向量机方法的图像分割与目标分类.华中科技大学博士学位论文. 2005:2~19
36杨晖,曲秀杰.图像分割方法综述.电脑开发与应用. 2005, 18(3):21~23
37谢建林,袁小平,王胜利,等.基于分水岭算法的金相图像分割.能源技术与管理. 2006, 2:102~103
38盛朝阳,刚铁.超声TOFD检测成像及缺陷定位系统.焊接. 2007, (8):37~40
39李衍.超声TOFD原理和方法精要.无损检测. 2006.31(6):8~13
40 W. J. Zippel, J. A. Pincheira, G. A. Washer. Crack measurement in steel plates using TOFD method. Journal of Performance of Constructed Facilities. 2000, 14(2):75~82
41 Gang Tie, Xu Yan, Chi Da-Zhao, et al. Signal characteristic of ultrasonic TOFD testing for aluminum alloy weld. Hanjie Xuebao/Transactions of the China Welding Institution. 2005, 26(8):1~4
42徐艳.厚板铝合金焊缝的超声TOFD检测方法研究.哈尔滨工业大学工学硕士学位论文. 2004:37~44
43梁宏林,腾永平,吕香慧.用超声衍射时差法对焊缝缺陷定性表征.无损检测. 2006, 28(1):14~16
44薛永盛,袁军生. TOFD检测中典型缺陷定性图谱分析.云南水力发电. 2008, 24(4):76~78
45孙秋菊,韩焱.信号相关性分析及其在超声检测中的应用.计量与测试技术. 2005, 32(12):28~29
46吴勃英.数值分析原理.科学出版社. 2003. 104~170
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