Journal of the Korean Wood Science and Technology

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

Development of Portable X-ray CT System II - CT Image Reconstruction of Wood using Density Distribution -

현장 적용이 가능한 X선 CT 시스템 개발 II- 밀도분포를 이용한 목재의 CT영상 구성 -

  • Kim, Kwang-Mo (Timber Engineering Lab., Mahjor in Environmental Materials Science, Department of Forest Science. Seoul National University) ;
  • Lee, Sang-Joon (Timber Engineering Lab., Mahjor in Environmental Materials Science, Department of Forest Science. Seoul National University) ;
  • Lee, Jun-Jae (Timber Engineering Lab., Mahjor in Environmental Materials Science, Department of Forest Science. Seoul National University)
  • 김광모 (서울학교 산림과부 환경재료과학전공 목구조연구실) ;
  • 이상준 (서울학교 산림과부 환경재료과학전공 목구조연구실) ;
  • 이전제 (서울학교 산림과부 환경재료과학전공 목구조연구실)
  • Received : 2005.10.11
  • Accepted : 2005.12.05
  • Published : 2006.01.25
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Abstract

X-ray transit materials with straight path and the its intensity is proportional to the density of materials. Therefore, X-ray has been extensively used as a nondestructive evaluation (NDE) method in various fields. This study was carried out for development of a portable X-ray CT (computed-tomography) system to detect deteriorations of wood members in buildings. Based on the results of our previous study, a procedure of CT image reconstruction was established In order to verify the applicability of developed system, CT images of three wood disks were reconstructed by newly developed procedure and compared with the prototypes. From the results of this study, it was shown that the newly developed system could be used not only to determine the shape, size, and position of defects, but also to find the density distribution in cross section of wood structure members. The density distribution may be utilized to clarify the reason of wood deterioration and to provide the preventive method on how to treat or repair wood buildings. Because it was initial stage of system development, there were some limitations concerned with measuring equipment and image reconstruction algorithm. Especially, measuring time including equipment setup time was longer and measuring accuracy was lower than we expected. Therefore, we planned some additional studies on improvement of equipment and algorithm to enhance the capability of X-ray CT system.

X선은 강한 투과성과 직진성으로 인하여 비파괴 검사법으로써 다양한 분야에서 활용되고 있다. 본 연구에서는 고건축물과 같은 목조 건축물에 사용되고 있는 구조부재의 열화를 현장에서 탐지할 수 있는 비파괴 검사법을 개발할 목적으로 X선 CT시스템의 적용가능성을 검토하였다. 먼저 이전 연구의 결과를 바탕으로 CT영상을 구성하는 체계를 확립하고, 얻어진 CT영상을 실제 부재의 단면 형태와 비교함으로써 개발된 시스템의 적용가능성을 확인하였다. 개발된 X선 CT시스템의 적용을 통해 결함의 형태와 크기, 위치뿐만 아니라 결함에서의 밀도 또한 비교적 정확하게 탐지할 수 있음이 확인되었다. 이러한 결과는 건축물에서 사용되고 있는 목재 부재에 열화가 발생하였을 경우에, 열화 발생의 원인을 파악하고 그에 따른 효과적인 대처방안을 수립하는데 있어서 유용하게 활용될 수 있을 것으로 기대된다. 그러나 현재의 시스템은 개발 초기단계로 측정에 따른 소요시간이나 측정회수, 측정 정밀도에 있어서 여러 제약을 받는다. 따라서 이러한 제약을 극복하기 위한 추가적인 연구가 요구된다.

Keywords

Acknowledgement

Supported by : 농림부

References

  1. 구양모, 신남수. 2000. X-선 과학과 응용. 도서출판 아진. 490p
  2. 김광모, 이상준, 이전제. 2006. 현장 적용이 가능한 X선 CT시스템 개발 I - X선 촬영법을 이용한 목재의 밀도 측정. 목재공학 34(1): 15-22
  3. Bhandarkar, S. M., T. D. Faust, and M. Tang. 2002. Design and prototype development of a computer vision-based lumber production planning system. Image and Vision Computing. 20: 167-189 https://doi.org/10.1016/S0262-8856(01)00087-7
  4. Bucur, V. 2003. Nondestructive Characterization and Imaging of Wood. Springer, Germany. pp. 13-74
  5. Funt, B. B. and E. C. Bryant. 1987. Detection of internal log defects by automatic interpretation of computer tomography imges, Forest Prod. J. 37(1): 56-62
  6. Jain, A. K. 2003. Fundamentals of Digital Image Processing. Prentice Hall. Korea. pp. 431-475
  7. Kim, K. M. and J. J. Lee. 2005a. CT image reconstruction of wood using ultrasound velocities I - Effects of reconstruction algorithms and wood characteristics. J. of the Korean Wood Science and Technology. 33(5): 21-28
  8. Kim, K. M. and J. J. Lee. 2005b. CT image reconstruction of wood using ultrasound velocities II - Determination of the initial model function of the SIRT method. J. of the Korean Wood Science and Technology. 33(5): 29-37
  9. Lo, T. and P. L. Inderwiesen. 1994. Fundamentals of Seismic Tomography. Society of Exploration Geophysicists. USA. pp. 9-43
  10. McMillin, C. W. 1982. Application of Automatic Image Analysis to Wood Science. Wood Sci. 14(3): 97-105
  11. Schmoldt, D. L., D. Zhu, and R. W. Conners. 1993. Nondestructive evaluation of hardwood log using automated interpretation of CT images Review of Progress in Quantitative Nondestructive Evaluation, Vol. 12. Plenum Press, New York
  12. Schmoldt, D. L., L. G. Occena, A. L. Abbott, and N. K. Gupta. 1999. Nondestructive evaluation of hardwood logs: CT scanning, machine vision and data utilization. Nondestr. Test. Eval. 15: 279-309 https://doi.org/10.1080/10589759908952876
  13. Taylor, F. W., F. G. Wagner, Jr., C. W. McMillin, I. L. Morgan, and F. F. Hopkins. 1984. Location knots by industrial tomography- A feasibility study, Forest Prod. J. 34(5): 42-46
  14. Wagner, F. G., F. W. Taylor, D. S. Ladd, C. W. McMillin, and F. L. Roder. 1989. Ultrafast CT scanning of and oak log for internal defects. Forest Prod. J. 39(11/12): 62-64