·Table of Contents
·Methods and Instrumentation

Ultrasonic Tomography of closely spaced defects

S. K. Rathore, N. N. Kishore and P. Munshi,
Department of Mechanical Engineering
S. K. Singhal,
Department of Aerospace Engineering
Indian Institute of Technology, Kanpur - 208 016 (India)
Email: skrathor@iitk.ac.in





Problem Definition

Results and Discussion


  1. Improvement in quality of reconstruction is achieved for all contrast levels with the curved-ray approach.
  2. Curved-ray Approach has made it possible the reconstruction at very low contrast and very high contrast when the gap is of order of the defect size or more.
  3. Two defects are separable for as low as 4mm gap for the velocity contrast in the range 2% to 15%. Below 4mm, the separation is not possible in the present case for any contrast level.
  4. Velocity contrast range giving good reconstruction shrinks as the gap between the defects reduces.


  1. Anderson A.H. and Kak A.C., Digital ray tracing in two-dimensional refractive index fields, Jr. of the Acoustical Society of America, 72(5), 1982, 1593-1606
  2. Bold G.E.J. and Birdsall T.G., A top-down philosophy for accurate numerical ray tracing, Jr. of the Acoustical Society of America, 80(2), 1986, 656-660
  3. Denis F., Basset O. and Gimenez G., Ultrasonic transmission tomography in refracting media: Reduction of refraction artifacts by curved-ray techniques, IEEE transactions on Medical Imaging, 14(1), 1995, 173-188
  4. Herman G.T., Image reconstruction from projections, Academic Press, New York, 1980
  5. Kak A.C., Computerized tomography with X-ray, Emission and Ultrasound sources, Proceedings of the IEEE, 67(9), 1979, 1245-1275
  6. Mishra D., Muralidhar K., and Munshi P., A robust MART algorithm for tomographic applications, Numerical Heat Transfer, Part B35(4), 1999, 485-506
  7. Verhoeven D., Multiplicative algebraic computed tomographic algorithms for the reconstruction of multidimensional interferometric data, Optical Engineering, 32(2), 1993, 410-419

© AIPnD , created by NDT.net |Home|    |Top|