Abstract
Hilbert transformation and improved ellipse localization method is applied in ultrasonic transducer array tomography to detect defect of metal plate. By combining the improved ellipse localization method and time-reversal method, the new ultrasonic tomography algorithm employs smooth Hilbert envelope instead of discrete amplitude to reconstruct defect image. An ultrasonic tomography system with six transducers is built to evaluate the effectiveness of the new ultrasonic tomography algorithm. The S0 mode Lamb wave is excited on special condition, and the mode of received signal is identified by Vigner-Wille distribution. The gray value of image area is defined by envelope of the reflected S0 mode Lamb wave signal from defect boundary. Defect image can be reconstructed by summing gray value of all pixels in the image area. The experimentally reconstructed defect image shows that the new tomography algorithm based on Hilbert transformation is efficient for defect detection in metal plate.
| Original language | English |
|---|---|
| Pages (from-to) | 514-519 |
| Number of pages | 6 |
| Journal | Journal of Beijing Institute of Technology (English Edition) |
| Volume | 20 |
| Issue number | 4 |
| Publication status | Published - Dec 2011 |
Keywords
- Hilbert transformation
- Lamb wave
- Tomography
- Transducer array