© 2013 г. L. Shen*, D. G. Li*, F. Luo**
* Huazhong University of Science and Technology, Wuhan, PR China
** China Academy of Engineering Physics, Mianyang, PR China
E-mail: lidinggen@sina.com
Laser speckle is a kind of noise in triangulation displacement measurement. It's meaningless to restrain speckles when the imaging light spot is so weak that facular image can not be extracted from speckles. Speckles can also be viewed as a kind of information carrier of displacement of the interface. In this paper, digital correlation method was used in laser triangulation displacement measurement system to measure the displacement of rough surface with strong scattering and the experimental results were analyzed. The results show that the digital correlation method is feasible in triangulation displacement measurement system, the measuring range can reach micron grade and the experimental errors are below 2%. This method can overcome the disadvantage of traditional laser triangular displacement measurement in rough surface with strong scattering, improve the accuracy and expand the scope of application.
Key words: laser triangulation, displacement measurement, laser speckle, correlation method.
OCIS codes: 120.6160
Submitted: March 9 2013
REFERENCES
1. Zhou Zhenshu. Non contact measurement of laser optical probe // J. Optics and precision engineering in China. 1997. V. 5. № 3.
2. Nakadate S., Yatagai T., Saito H. Computer-aided speckle pattern interferometry // Appl. Opt. 1983. V. 2. № 2. P.237243.
3. Diaz F.V., Kaufmamm G.H. Impact-induced transient deformation analysis by means of digital speckle interferometry // Exp. Mech. 1999. V. 39. № 4. P. 311-316.
4. Crutis D.M., Hao Zhang, Kenneth J.V. Effects of optically shallow bottoms on upwelling radiances:Bidirectional reflectance distribution function effects // Limnol. Oceanogr. 2003. V. 48. № 1. P. 2, P. 337-345.
5. Maradudin A. Backscattering effects in the elastic scatter of polarized light from a large-amplitude random metallic grating. Scattering in Volumes and Surface. North-Itolland: Elsevier Science Publishers BV, 2000. P. 157-174.
6. Francis D., James S.W., Tatam R.P. Surface strain measurement of rotating objects using puslsed laser shearography with coherent fibre-optic imaging bundles // Measurement Science and Technology. 2008. V. 19. № 10. P.113.
7. Jin Guanchang, Meng Libo. Digital speckle correlation technique development and application // J. Experimental mechanics in China. 2006. V. 21. № 6. P. 689-702.
Полный текст
