[1] [1] Lin Shangyang. Present situation of welding production and development trend of welding technology in China［J］. Ship Engineering, 2005, 27(s1): 15-24.

[2] [2] Shen Junqi. Research on seam image processing for CO2 horizontal position welding based on laser vision sensing［D］. Tianjin: Tianjin University, 2010.

[3] [3] Wang Wei, Zou Qishi, Zhu Liumei, et al. The development state and implementing method of seam tracking system with optical sensor［J］. Electric Welding Machine, 2002, 32(5): 1-8.

[4] [4] Marr D. Vision: a computational investigation into the human representation and processing of visual information［M］. New York: Henry Holt and Co., 1982.

[5] [5] Zou Yirong. Research on visual method for weld seam recognition and tracking based on multi-feature extraction and information fusion［D］. Beijing: Tsinghua University, 2012.

[6] [6] Li Yangchun. Research on computer active vision theory［J］. Journal of Xianning College, 2008, 28(6): 63-66.

[7] [7] Wu Zhangliang, Sun Changku, Yang Zhongdong. Analysis and design of structure parameters of vision measuring sensor system［J］. Opto-Electronic Engineering, 2009, 36(12): 56-61.

[8] [8] Wan Jin, Huang Yuanqing. Study on laser triangulation method measurement［J］. Journal of Sanming University, 2006, 23(4): 361-364.

[9] [9] Guo Zhipeng, Yu Zhishui, Zhang Peilei, et al. Research status of seam tracking technology based on visual sensing［J］. Light Industry Machinery, 2016, 34(5): 95-100.

[10] [10] Zou Yanbiao, Gong Guoji. Researcher on line laser detecting technology for seam tracking［J］. Applied Laser, 2015, 35(4): 500-507.

[11] [11] Zhu Jigui, Guo Lei, Liu Changjie, et al. Measurement system of flexible electronic checking fixture on robot［J］. Optics and Precision Engineering, 2011, 19(8): 1787-1793.

[12] [12] Fennander H, Kyrki V, Fellman A, et al. Visual measurement and tracking in laser hybrid welding［J］. Machine Vision & Applications, 2009, 20(2): 103-118.

[13] [13] Shi Yu, Wang Haitao, Xue Cheng, et al. Visual detection of welding groove gap with linear laser source［J］. Journal of Lanzhou University of Technology, 2009, 35(6): 29-32.

[14] [14] Liu Xiwen, Hong Bo, Dai Tiefeng. Image processing and groove recognition in weld seam tracking based on laser vision［J］. Laser & Infrared, 2011, 41(7): 804-807.

[15] [15] Zhao Sujuan. Research on laser of seam detection and automatic seam tracking system［D］. Changchun: Changchun University of Technology, 2015.

[16] [16] Zhou Lü. Research on the acquisition method of welding path for arc welding robot based on visual servoing［D］. Shanghai: Shanghai Jiao Tong University, 2007.

[17] [17] Yu J Y, Na S J. A study on vision sensors for seam tracking of height-varying weldment: Part 1 mathematical model［J］. Mechatronics, 1997, 7(7): 599-612.

[18] [18] Yu J Y, Na S J. A study on vision sensors for seam tracking of height-varying weldment: Part 2 applications［J］. Mechatronics, 1998, 8(1): 21-36.

[19] [19] Yan Wencai. Research and development of robot welding seam tracking control technology based on visual guide［D］. Wuxi: Jiangnan University, 2014.

[20] [20] Li Yongzhe. On-line detection and control system of GMAW rapid prototyping process based on structured light［D］. Harbin: Harbin Institute of Technology, 2012.

[21] [21] Wang Yanfeng, Liu Nansheng, Lin Haoliang, et al. Image taking and processing of welding pool based on structured light projection［J］. Transactions of the China Welding Institution, 2008, 29(10): 81-84.

[22] [22] Zhang Huajun, Zhang Guangjun, Cai Chunbo, et al. Laser-based visual recognition of multi-pass seam in robot arc welding［J］. Transactions of the China Welding Institution, 2009, 30(4): 105-108.

[23] [23] Li Xianxi. Multipass seam tracking based on vision sensor［D］. Nanchang: Nanchang Hangkong University, 2011.

[24] [24] Wang Zhijiang, Zhang Guangjun, Liang Zhimin, et al. Current status and development trend of tridimensional monitoring and measurement technology for weld pool surface［J］. Welding & Joining, 2007(8): 15-19.

[25] [25] Wang Zhijiang, Zhang Guangjun, Zhang Yuming, et al. 3D sensing of gas tungsten arc weld pool surface and sensing device design［J］. Chinese Journal of Mechanical Engineering, 2008, 44(10): 300-303.

[26] [26] Song H S, Zhang Y M. Measurement and analysis of three-dimensional specular gas tungsten arc weld pool surface［J］. Welding Journal, 2008, 87(4): 85s-95s.

[27] [27] Wang Z, Zhang Y M, Yang R. Analytical reconstruction of three-dimensional weld pool surface in GTAW［J］. Journal of Manufacturing Processes, 2013, 15(1): 34-40.

[28] [28] Saeed G, Lou M, Zhang Y M. Computation of 3D weld pool surface from the slope field and point tracking of laser beams［J］. Measurement Science & Technology, 2003, 15(2): 389-403.

[29] [29] Luo M, Shin Y C. Vision-based weld pool boundary extraction and width measurement during keyhole fiber laser welding［J］. Optics and Lasers in Engineering, 2015, 64(12): 59-70.

[30] [30] Yang Jianhua. Key technologies research on 3D surface measurement system based on linear structured light vision sensor［D］. Guangzhou: Guangdong University of Technology, 2013.

[31] [31] Xie Zexiao, Chen Wenzhu, Chi Shukai, et al. Industrial robot positioning system based on the guidance of the structured-light vision［J］. Acta Optica Sinica, 2016, 36(10): 1015001.

[32] [32] Zhang Guangjun. Machine vision［M］. Beijing: Science Press, 2005.

[33] [33] Qiao Dongxiao, Zheng Jun, Pan Jiluan. Dual structure laser vision sensor and its character［J］. Electric Welding Machine, 2010, 40(11): 14-16.

[34] [34] Mao Zhiwei, Zhou Shaoling, Zhao Bin, et al. Welding torch position and seam orientation deviation based on two stripes laser vision sensing［J］. Transactions of the China Welding Institution, 2015, 36(2): 35-38.

[35] [35] Xiao Z. Research on a trilines laser vision sensor for seam tracking in welding［J］. Lecture Notes in Electrical Engineering, 2011, 88: 139-144.

[36] [36] Sung K, Lee H, Choi Y S, et al. Development of a multiline laser vision sensor for joint tracking in welding［J］. Welding Journal, 2009, 88(4): 79s-85s.

[38] [38] Xu P, Xu G, Tang X, et al. A visual seam tracking system for robotic arc welding［J］. International Journal of Advanced Manufacturing Technology, 2008, 37(1/2): 70-75.

[39] [39] Xu P, Tang X, Yao S. Application of circular laser vision sensor (CLVS) on welded seam tracking［J］. Journal of Materials Processing Technology, 2008, 205(1/2/3): 404-410.

[40] [40] Will P M, Pennington K S. Grid coding: a preprocessing technique for robot and machine vision［J］. Artificial Intelligence, 1971, 2(3): 319-329.

[41] [41] Jin Ming. Study on structured light multi-view measurement［D］. Qingdao: Ocean University of China, 2008.

[42] [42] Wang Zongyi. Structured light sensor and underwater 3D inspecting system［D］. Harbin: Harbin Engineering University, 2005.

[43] [43] Boyer K L, Kak A C. Color-encoded structured light for rapid active ranging［J］. IEEE Transactions on Pattern Analysis & Machine Intelligence, 2009, 9(1): 14-28.

[44] [44] Wei Shanchun. Study of autonomous guidance of initial welding position based on vision sensing［D］. Shanghai: Shanghai Jiao Tong University, 2009.

[45] [45] Wang Kehong, Yang Jiajia, Sun Ke. The research status of visual-based three-dimensional reconstruction technology in welding［J］. Machine Building & Automation, 2013, 42(1): 1-5.

[46] [46] Li Xuerui. Research of three-dimensional reconstruction of corrugated board weld seam based on laser binocular vision for arc welding robot［D］. Guangzhou: South China University of Technology, 2014.

[47] [47] Chen Xiyin. Research on seam recognition and path planning of robot based on binocular vision［D］. Guangzhou: South China University of Technology, 2015.

[48] [48] Zhang T, Liu J, Liu S, et al. A 3D reconstruction method for pipeline inspection based on multi-vision［J］. Measurement, 2017, 98: 35-48.

[49] [49] Jia Z, Wang L, Liu W, et al. A field measurement method for large objects based on a multi-view stereo vision system［J］. Sensors & Actuators A: Physical, 2015, 234: 120-132.

[50] [50] Li Deling. Investigation on visual seam tracking system based on laser structured light［D］. Zhengzhou: Henan University of Technology, 2014.

[51] [51] Zou Yuanyuan, Zhao Mingyang, Zhang Lei, et al. Error analysis and structural analysis of structured-light visual sensor for seam tracking［J］. Chinese Journal of Scientific Instrument, 2008, 29(12): 2605-2610.

[52] [52] Wang Hanyu, Han Chong, Zhang Bichao. Key technology for designing weld seam tracking system based on the structured light method［J］. Electric Welding Machine, 2013, 43(8): 1-7.

[53] [53] Liu Nansheng, Guo Changrong, Liu Mingyou, et al. The internal layout experiment research of structural light visual sensor used in crawling arc welding robot［J］. Jiangxi Science, 2005, 23(4): 325-327.

[54] [54] Flandin G, Chaumette F, Marchand E. Eye-in-hand/eye-to-hand cooperation for visual servoing［C］. IEEE International Conference on Robotics and Automation, San Francisco, 2000, 3: 2741-2746.