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Modal Parameter Extraction Using a Digital Camera

카메라를 이용한 구조물의 동특성 추출

  • 김병화 (경남대학교 토목공학과)
  • Published : 2008.12.20

Abstract

A set of modal parameters of a stay-cable have been extracted fi:on a moving picture captured by a digital camera supported by shaking hands. It is hard to identify the center of targets attached on the cable surface from the blurred cable motion image, because of the high speed motion of cable, low sampling frequency of camera, and the shaking effect of camera. This study proposes a multi-template matching algorithm to resolve such difficulties. In addition, a sensitivity-based system identification algorithm is introduced to extract the natural frequencies and damping ratios from the ambient cable vibration data. Three sets of vibration tests are conducted to examine the validity of the proposed algorithms. The results show that the proposed technique is pretty feasible for extracting modal parameters from the severely shaking motion pictures.

Keywords

References

  1. Kim, B. H. and Park, T., 2007, 'Estimation of Cable Tension Force Using System Identification Technique,' Journal of Sound and Vibration, Vol. 304, pp. 660-676 https://doi.org/10.1016/j.jsv.2007.03.012
  2. Nassif, H. H., Gindy, M. and Davis J., 2005, 'Comparison of Laser Doppler Vibrometer with Contact Sensors for Monitoring Bridge Deflection and Vibration,' NDT&E International, Vol. 38, pp. 213-218 https://doi.org/10.1016/j.ndteint.2004.06.012
  3. Wahbeh, A. M., Caffrey, J. P. and Masri, S. F., 2003, 'A Vision-based Approach for the Direct Measurement of Displacements in Vibrating Systems,' Smart Mater Struct., Vol. 12, pp. 785-794 https://doi.org/10.1088/0964-1726/12/5/016
  4. Olaszek, P., 1999, 'Investigation of Dynamic Characteristic of Bridge Structures Using a Computer Vision Method,' Measurement, Vol. 25, pp. 227-236 https://doi.org/10.1016/S0263-2241(99)00006-8
  5. Jauregui, D. V., White, K. R., Woodward, C. B. and Leitch, K. R., 2003, 'Noncontact Photogrammetric Measurement of Vertical Bridge Deflection,' Journal of Bridge Engineering, Vol. 8, No. 4, pp. 212-222 https://doi.org/10.1061/(ASCE)1084-0702(2003)8:4(212)
  6. Lee, J. J., Shinozuka, M., 2006, 'Real-time Displacement of a Flexural Bridge Using Digital Image Processing Technique,' Experimental Mechanics, Vol. 46, pp. 105-114 https://doi.org/10.1007/s11340-006-6124-2
  7. Yoneyama, S., Kitagawa, A., Iwata, S., Tani, K. and Kikuta, H., 2007, 'Bridge Deflection Measurement Using Digital Image Correlation,' Experimental Techniques, Vol. 31, No. 1, pp. 34-40 https://doi.org/10.1111/j.1747-1567.2006.00132.x
  8. Kim, K.-Y. and Kwak, M. K., 2005, 'Measurement of Large-amplitude and Low-frequency Vibrations of Structures Using the Image Processing Method,' Transactions of the Korean Society for Noise and Vibration Engineering, Vol. 15, No. 3, pp. 329-333 https://doi.org/10.5050/KSNVN.2005.15.3.329
  9. Lee, C.-B., Ahn, S.-H., Yang, S.-H., Yum, J.-W., Kang, D.-W. and Kim, K,-D., 2004, 'Vibration Measurements of Large-scale Structure Using Laser and High-speed CCD Camera,' Journal of Korean Information and Communication Society, Vol. 29, No. 8C, pp. 1104-1112
  10. Lewis, J. P. 2003, 'Fast Normalized Crosscorrelation,' Available from: www.idiom.com/˜zilla/index.html#Publications
  11. Wang, S., Guan, B., Wang, G. and Li, Q., 2007, 'Measurement of Sinusoidal Vibration from Motion Blurred Images,' Pattern Recognition Letters, Vol. 28, pp. 1029-1040 https://doi.org/10.1016/j.patrec.2006.12.019
  12. Bendat, J. S., Piersol, A. G., 1980, Engineering Applications of Correlation and Spectral Analysis, Wiley, New York, pp. 181-186
  13. Ibrahim, S. R. and Mikulick, E. C., 1977, 'A Method for the Identification of Vibration Parameters from the Free Responses,' Shock and Vibration Bulletin, Vol. 47, No. 4, pp. 183-198
  14. Juang, J.-N., 1994, Applied System Identification, Prentice-Hall, Englewood Cliffs, NJ
  15. Kim, B. H., Park, T., Stubbs, N., 2005, 'A New Method to Extract Modal Parameters Using Output-only Responses,' Journal of Sound and Vibration, Vol. 282, pp. 215-230 https://doi.org/10.1016/j.jsv.2004.02.026
  16. Rao, K. R. and Ben-Arie, J., 1994, 'Multiple Template Matching Using the Expansion Filter,' IEEE Transactions on Circuits and Systems for Video Technology, Vol. 4, No. 5, pp. 490-503 https://doi.org/10.1109/76.322996
  17. Farrar, C. R., James III, G. H., 1997, 'System Identification from Ambient Vibration Measurements on Bridge,' Journal of Sound and Vibration, Vol. 205, pp. 1-18 https://doi.org/10.1006/jsvi.1997.0977
  18. Stubbs, N., Kim, J. T., 1996, 'Damage Localization in Structures without Baseline Modal Parameters,' AIAA Journal, Vol. 34, pp. 1644-1649 https://doi.org/10.2514/3.13284