Abstract
The main sources of noise that lead to speckle phase distortion and decorrelation are identified and methods to overcome these are suggested. An automated continuous reference updating technique is shown able to avoid speckle decorrelation induced by object drift or low frequency vibrations. A second improvement using the introduction of phase shift and the addition of surface information during every image acquisition, is demonstrated to insure fringe pattern stability even in the presence of relatively high frequency noise due to thermal currents or air flow. Furthermore, phase modulation is used to reduce the speckle effect by removing the speckle phase term. The application of these techniques to the task of nondestructive detection of structural defects in aluminum plates is demonstrated in a very noisy environment.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 171-178 |
| Number of pages | 8 |
| Journal | Proceedings of SPIE - The International Society for Optical Engineering |
| Volume | 2003 |
| DOIs | |
| State | Published - Dec 10 1993 |
| Externally published | Yes |
| Event | Interferometry VI: Techniques and Analysis 1993 - San Diego, United States Duration: Jul 11 1993 → Jul 16 1993 |
Funding
This work was carried out in the course of research sponsored by the FAA Center for Aviation Systems Reliability, operated by Ames Laboratory, USDOE, for the Federal Aviation Administration under This work was carried out in the course of research sponsored by the FAA Center for Aviation Systems Reliability, operated by Ames Laboratory, USDOE, for the Federal Aviation Administration under Contract No. W-7405-ENG-82 for work by Iowa State University and Northwestern University.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Computer Science Applications
- Applied Mathematics
- Electrical and Electronic Engineering