Welding in the World

, Volume 49, Issue 1–2, pp 14–16 | Cite as

Image Processing on High Speed Photograph of CO2 Laser Welding Plasma in the Light of Isogrey Scale Line

  • Jinhe Liu
  • Yimin Wang


In this paper the high speed photograph of CO2 laser welding plasma is analyzed in the light of isogrey scale line of photograph. It is found that the image of laser induced plasma can be divided into three regions: outer-edge region, smooth region and kernel region. In the outer-edge region the shape of isogrey scale line is non-regular and changes severely. In the smooth region the shape of the isogrey scale line is regular. In the kernel region the shape of the isogrey scale line is complex and there is the small closed isogrey scale line. The welding plasma can be seen as non-homogeneous three-dimension body composed of N layers with different thickness and different refractive index.

IIW-Thesaurus keywords

CO2 lasers Lasers Laser welding Photon beam welding Radiation welding Plasma Imaging High Speed 


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    Hutchinson I. H.: Principle of plasma diagnostic, Cambride University Press, 1987.Google Scholar
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    Liu Jinhe, Zhang Fengming, Yang Decai: Analysis on the variation of Argon and Helium plasma refractive index with temperature in CO2 laser beam welding, SPIE, Vol. 3550, 1998.Google Scholar
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    Kenneth R. Castleman: Digital Image Processing, Prentic-Hall International, Inc., 1996.Google Scholar

Copyright information

© International Institute of Welding 2005

Authors and Affiliations

  • Jinhe Liu
    • 1
  • Yimin Wang
    • 1
  1. 1.Welding Research Institute, College of Material Science and EngineeringNorthwestern Polytechnical Univ.City Xi’anChina

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