[1] [1] Zhong Minlin, Ning Guoqing, Liu Wenjin. Research and development on laser direct manufacturing metallic components [J]. Laser Technology, 2002, 26(5): 388～391

[2] [2] Griffith Michelle L. Hofmeister, William H. Knorovsky et al.. Direct laser additive fabrication system with image feedback control [P]. USA patent 6459951, 2002

[3] [3] K. G. Watkins, Eamonn Fearon. A method of layer height control in direct laser fabrication of 304L stainless steel [C]. ICALEO 2003 Proceedings, 2003. 903～904

[4] [4] J. Mazumder, D. Dutta, N. Kikuchi et al.. Closed loop direct metal deposition: art to part [J]. Optics and Lasers in Engineering, 2000, 34(10): 397～414

[5] [5] Tan Hua, Chen Jing, Yang Haiou et al.. Real-time sensing and closed-loop control of laser rapid forming process [J]. Applied Laser, 2005, 25(2): 74～76

[6] [6] Ning Guoqing, Zhong Minlin, Yang Lin et al.. Research about close-loop control system during laser direct manufacturing metallic components [J]. Applied Laser, 2002, 22(2):172～175

[7] [7] Yang Lin. Investigation on the stable powder feeding and melt pool monitoring system and techniques for laser direct manufacturing [D]. Beijing: Tsinghua University, 2004. 39～43

[8] [8] Hu Xiaodong, Zhao Wanhua, Xu Chao et al.. The CCD based weld pool control system for directly metal forming [J]. Acta Photonica Sinica, 2003, 32(3): 375～377

[9] [9] He Jinjiang, Zhong Minlin, Liu Wenjin et al.. Observation and analysis on behaviors of powder stream concentration and molten pool in laser deposition process in controlled environment chamber [J]. Chinese J. Lasers, 2006, 33(2): 283～288

[10] [10] Rafael C. Gonzalez. Digital Image Processing [M]. 2nd Edition, New Jersey, USA: Prentice Hall, 2002. 479～494

[11] [11] He Bin, Ma Tianyu, Wang Yunjian et al.. Visual C++ Digital Image Processing [M]. 2nd Edition, Beijing: Posts & Telecommunication Press, 2004. 394～433

[12] [12] Shao Qike, Chen Guoding, Fang Yong. A study on morphological operators for weld pool image processing [J]. Mechanical Science and Technology, 2003, 22(1): 42～43,47

[13] [13] Zhang Zhiyong et al.. Jing Tong MATLAB 6.5 [M]. 1st Edition, Beijing: Beihang University Press, 2003. 283～247

[14] [14] David J. Kruglinski. Inside Visual C++ [M]. 4th Edition, Beijing: Tsinghua University Press, 1999. 64～209