Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
권호 표지

CT Image Reconstruction of Wood Using Ultrasound Velocities I - Effects of Reconstruction Algorithms and Wood Characteristics -

  • Kim, Kwang-Mo (Major in Environmental Materials Science, College of Agriculture & Life Sciences, Seoul National University) ;
  • Lee, Jun-Jae (Major in Environmental Materials Science, College of Agriculture & Life Sciences, Seoul National University)
  • Received : 2005.07.14
  • Accepted : 2005.09.06
  • Published : 2005.09.25
Download PDF
⟨ Previous Next ⟩

Abstract

For the proper conservation of wooden cultural properties, non-destructive evaluation (NDE) method, which can be used to quantitatively evaluate the internal state of wood members, are needed. In this study, an ultrasonic CT system composed of portable devices was attempted, and the capacity of this system was verified by reconstructing the CT images for two phantoms and two artificially defected specimens. Results from this study showed that the sizes of detected defects were enlarged and the shapes were distorted on the CT images. Also, the positions were shifted somewhat toward the surface of specimen, which is regarded due to the anisotropic property of wood. Compared to the filtered back-projection method, SIRT (simultaneous iterative reconstruction technique) method was determined to be more efficient as the algorithm of image reconstruction for wood. A new ultrasonic CT system is thought to be used as a NDE method for wood. However wood characteristics and wave diffraction within wood made it difficult to accurately evaluate the size, shape and position of defects. To improve the quality of CT image of wood, more research including the relationship between wood and ultrasound is needed, and wood properties should be taken into consideration on the image reconstruction algorithm.

Keywords

References

  1. Bae, M. S. 2003. Evaluation of deterioration for wooden structural members by nondestructive testing. Master dissertation, Seoul National Univ., Seoul, Korea
  2. Bethge, K. and C. Mattheck. 1998. Instruments for detection and evaluation of decay and wood quality in standing trees. Proc. of the 11th International symposium on nondestructive testing of wood. Madison, WI. pp. 105-115
  3. Bucur, V. 1988. Wood structural anisotropy estimated by acoustic invariants. lAWA Bulletin 9(1); 67-74
  4. Bucur, V. 2003. Nondestructive Characterization and Imaging of Wood. Springer, Germany. 354p
  5. Emerson, R. N., D. G. Pollock, D. I. McLean, K. J. Fridly, R. J. Ross, and R. F. Pellerin. 1998. Nondestructive testing of large bridge timbers. Proc. of the 11th International symposium on nondestructive testing of wood. Madison, WI. pp.175-184
  6. Gerhards, C. C. 1980. Effect of cross grain on stress waves in lumber. Res. Pap. FPL-RP-368. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 8p
  7. Helms, D. and P. Niemz. 1993. New applications of the drill resistance method for quality evaluation of wood and wood products. Proc. of the 9th International symposium on nondestructive testing of wood. Madison, WI. pp. 95 - 102
  8. Jain, A. K. 2003. Fundamentals of Digital Image Processing. Prentice Hall. Korea. 569p
  9. Kim, G. C., M. S. Bae, and J. J. Lee. 2003. Difference of deterioration according to exposed condition of column in wooden traditional building. J. of the Korean Wood Science and Technology 31(2): 58-68
  10. Lee, J. J., K. M. Kim, and M. S. Bae. 2003. Investigation of transmission process for ultrasonic wave in wood. J. of the Korean Wood Science and Technology 31(2): 31-37
  11. Lee, J. J. and M. S. Bae. 2004. Determination of ratio of wood deterioration using NDT technique. J. of the Korean Wood Science and Technology 32(3): 33-41
  12. Lemaster, R. L., J. M. Biernacki, and F. C. Beall. 1993. The feasibility of using acousto-ultrasonics to detect decay in utility poles. Proc. of the 9th International symposium on nondestructive testing of wood. Madison, WI. pp. 84-91
  13. Lo, T. and P. L. Inderwiessen. 1994. Fundamentals of Seismic Tomography. Society of Exploration Geophysicists. Geophysical Monograph Series Number 6. USA. 179p
  14. Park, C. Y. 2003. Reliability Analysis of Deteriorated Post Member. Master dissertation, Seoul National Univ., Seoul, Korea
  15. Phillips, W. S. and M. C. Fehler. 1991. Traveltime tomography: A comparison of popular methods. Geophysics 56(10): 1639-1649 https://doi.org/10.1190/1.1442974
  16. Rinn, F. 1993. Catalog of relative density profiles of trees, poles, and timber derived from resistograph micro-drillings. Proc. of the 9th International symposium on nondestructive testing of wood. Madison, WI. pp. 61-67
  17. Ross, R. J. 1999. Using sound to evaluate standing timber. International Forestry Review 1(1): 43-44
  18. Ross, R. J. and M. O. Hunt. 2000. Stress wave timing nondestructive evaluation tools for inspecting historic structures - A guide for use and interpretation. Gen. Tech. Rep. FPL-GTR-119. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 15p
  19. Smith, S. M. and R. D. Graham. 1983. Relationship between early decay and radial compression strength of Douglas-fir. Forest Products Journal 33(6): 49-52
  20. Titta, M., F. C. Beall, and J. M. Biernacki. 1998. Acousto-ultrasonic assessment of internal decay in glulam beams. Wood and Fiber Science 30(3): 259-272
  21. Wilcox, W. W. 1983. Sensitivity of the 'pick test' for field detection of early wood decay. Forest Products Journal 33(2): 29 - 30