Restoration and Enhancement of X-Ray Images of Molten Pool during Laser Deep Penetration Welding

Abstract:

Owing to a strong capability of penetration, the radiography can be used to observe and analyze the formation of a molten pool inside weldments during laser deep penetration welding. The shape of a molten pool and the thermal transmit of laser through keyhole can be monitored and analyzed in real-time. During a high-power fiber laser bead on plate welding of Type 304 stainless steel, a high-speed radiography camera was employed to capture the molten pool images. These captured X-ray images were degraded by the disturbance and noises from the welding process and radiography devices. This paper proposes an efficient arithmetic to restore and enhance the X-ray images of molten pools. The point spread function (PSF) of X-ray image degeneration was obtained through blind deconvolution, And the PSF was applied as a parameter to implement the constrained least squares filtering of X-ray image of a molten pool. Also, the X-ray image was enhanced by contrast stretching transformation. Experimental results showed that the proposed arithmetic of image restoration and enhancement could improve the quality of X-ray images efficiently and protrude the contour feature of a molten pool.

• Periodical: Applied Mechanics and Materials (Volumes 201-202)
• Pages: 356-359
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.201-202.356
• Online since: October 2012
• Authors: Jun Bin Xiang, Xiang Dong Gao
• Keywords: Image Restoration, Laser Deep Penetration Welding, X-Ray Images of Molten Pool

References

[1] X.D. Gao, D.Y. You and S.J. Katayama: Transactions of the China Welding Institution, Vol. 5 (2011) No.32, pp.1-4 (in Chinese).

[2] A. Matsunawa, N. Seto and J. Kim: Trans. JWRI, Vol. 30 (2001), pp.14-16.

[3] M.Y. Cao, N.L. Sun and D.Y. Yu: Opto-Electronic Engineering, Vol. 30 (2003), pp.1-4 (in Chinese).