激光技术, 2020, 44 (2): 226, 网络出版: 2020-04-04   

激光焊接裂纹磁光成像频域特征分析

Analysis on frequency domain characteristics of magneto-optical imaging of laser welding crack
作者单位
广东工业大学 广东省焊接工程技术研究中心,广州 510006
摘要
为了研究旋转磁场激励下激光焊接裂纹磁光成像在频域内的特征,采用对激光焊接裂纹磁光图像进行2维离散傅里叶变换的方法,进行了理论分析和实验验证,取得了旋转磁场不同励磁强度下激光焊接裂纹的频谱图数据。结合裂纹磁光图的空域特征,对所获裂纹频谱图灰度值为255的点进行统计分析。结果表明,激光焊接裂纹磁光图像的频域特征和空域特征有一定的对应关系;在一个变化周期内(885帧磁光图),对应频谱图上会出现先变小再变大、再变小再变大或相反的变化过程,最终回到初始状态。这一结果验证了旋转磁场下裂纹磁光成像规律的正确性,对激光焊接缺陷的无损检测是有帮助的。
Abstract
In order to study the characteristics of magneto-optical imaging of laser welding cracks under rotating magnetic field excitation in frequency domain, the method of 2-D discrete Fourier transform for magneto-optical image of laser welding crack was adopted. Theoretical analysis and experimental verification were carried out. Spectrum data of laser welding crack under different excitation intensities of rotating magnetic field were obtained. Combining spatial characteristics of crack magneto-optic maps, statistical analysis was carried out on the points whose gray value of crack spectrum was 255. The results show that, frequency domain characteristics of magneto-optic image of laser welding crack have a certain corresponding relationship with spatial domain characteristics. During a period of change (885 frames of magneto-optic map), the corresponding spectrum map will be a process of first decreasing, then enlarging, then decreasing, then enlarging or the opposite, and finally returning to the initial state. The results verify the correctness of magneto-optical imaging law of cracks under rotating magnetic field. It is helpful for non-destructive detection of laser welding defects.
参考文献

[1] LI X Y, WU C S, LI W S. Study on the progress of welding science and technology in China[J]. Journal of Mechanical Engineering, 2012, 48(6): 19-31(in Chinese).

[2] ZHANG Y L, ZHANG H Ch, ZHAO J X, et al. Review of non-destructive testing for remanufacturing of high end equipment[J]. Journal of Mechanical Engineering, 2013,53(7): 80-90(in Chinese).

[3] XIA N, MENG X W, HUO Q Y, et al. Monitoring and detecting of defects during fiber laser welding[J]. Laser Technology, 2017, 41(6): 788-792(in Chinese).

[4] WEI L, CHANG Y S, ZHOU H Z, et al. Internal defect detection in ferromagnetic material equipment based on low-frequency electromagnetic technique in 20# steel plate[J]. IEEE Sensors Journal, 2018, 18(16): 6540-6546.

[5] GAO X D, LAN Ch Zh, CHEN Z Q, et al. Dynamic detection and identification of magneto-optical imaging of welding defects[J]. Optics and Precision Engineering, 2017, 25(5): 1135-41(in Chinese).

[6] EOM I, YOON E, BAIK S H, et al. Retrieval of frequency spectrum from time-resolved spectroscopic data: Comparison of Fourier transform and linear prediction methods[J]. Optics Express, 2014, 22(25): 30512-30521.

[7] PANDEY S S, MANU P S, VIKAS P. Image transformation and compression using fourier transformation[J]. International Journal of Current Engineering and Technology, 2015, 26(11): 1504-1510.

[8] SUN Z, HOU P, ZHI Y N, et al. Optical image processing for synthetic-aperture imaging ladar based on two-dimensional Fourier transform[J]. Applied Optics, 2014, 53(9): 1846-1858.

[9] CHEN L, CHANG G, HE B, et al. Optical image conversion and encryption by diffraction, phase retrieval algorithm and incoherent superposition[J]. Optics and Lasers in Engineering, 2017, 88(6): 221-232.

[10] YAO S, CHEN L, CHANG G, et al. A new optical encryption system for image transformation[J]. Optics & Laser Technology, 2017, 97: 234-241.

[11] DU L L, GAO X D, ZHOU X F, et al. Study on the magneto-optical imaging law of laser welded crack under excitation of rotating magnetic field[J]. Laser Technology, 2018, 42(6): 58-62(in Chinese).

[12] MO X F, SHI J L, CHEN X G, et al. Measurement of SBS linewidth based on time-domain Fourier transform[J]. Laser Technology, 2013, 37(5): 561-564(in Chinese).

[13] LI W L, GE H L, REN Y, et al. Application of image processing technology in temperature measurement of laser pool[J]. Laser Technology, 2018, 42(5): 599-604(in Chinese).

[14] LIU S, SHAN T, TAO R, et al. Sparse discrete fractional Fourier transform and its applications[J]. IEEE Transactions on Signal Processing, 2014, 62(24): 6582-6595.

[15] LIAO J R, CHEN C M. Phase correction of discrete Fourier transform coefficients to reduce frequency estimation bias of single tone complex sinusoid[J]. Signal Processing, 2014, 94: 108-117.

[16] CALIXTO S, SOLANO C, LESSRRD R A. Real-time optical image processing and polarization holography with dyed gelatin[J]. Applied Optics, 2011, 15(18): 142-146.

[17] BELEGA D, PETRI D, DALLET D. Accuracy analysis of complex sinusoid amplitude and phase estimation by means of the interpolated discrete-time Fourier transform algorithm[J]. Digital Signal Processing, 2016, 59: 9-18.

[18] CRISTOBAL G, SCHELKENS P, THIENPONT H. Optical and digital image processing: Fundamentals and applications[M].New York,USA:Wiley-VCH,2011:169-178.

[19] MA N J, GAO X D, ZHOU X F, et al. Analysis of magneto-optical imaging characteristics of weld defects under magnetic field excitation[J]. Laser Technology, 2018, 42(4): 97-102(in Chinese).

[20] LI W, YUAN X, CHEN G, et al. High sensitivity rotating alternating current field measurement for arbitrary-angle underwater cracks[J]. NDT & E International, 2016, 79: 123-131.

杜亮亮, 高向东, 张南峰, 季玉坤. 激光焊接裂纹磁光成像频域特征分析[J]. 激光技术, 2020, 44(2): 226. DU Liangliang, GAO Xiangdong, ZHANG Nanfeng, JI Yukun. Analysis on frequency domain characteristics of magneto-optical imaging of laser welding crack[J]. Laser Technology, 2020, 44(2): 226.

本文已被 2 篇论文引用
被引统计数据来源于中国光学期刊网
引用该论文: TXT   |   EndNote

相关论文

加载中...

关于本站 Cookie 的使用提示

中国光学期刊网使用基于 cookie 的技术来更好地为您提供各项服务,点击此处了解我们的隐私策略。 如您需继续使用本网站,请您授权我们使用本地 cookie 来保存部分信息。
全站搜索
您最值得信赖的光电行业旗舰网络服务平台!