Investigation of Displacement Limitations for Laser Speckle Photography.
Abstract
A double exposure procedure, similar to that used with holographic interferometry, is used with laser speckle photography. A photographic image made using this technique has each speckle recorded twice; once before and once after displacement of the subject. The distance between corresponding speckle pairs on the photographic plate is directly proportional to the local in-plane displacement. Data may be extracted from these specklegrams by illuminating a local area of the image with a small diameter laser beam and observing Young's fringes which modulate the resulting diffraction halo. These fringes are perpendicular to the displacement vector and have a spacing inversely proportional to the displacement magnitude.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1974
- Accession Number
- ADA062153
Entities
People
- Mark R. Lenci
Organizations
- Flight Dynamics Laboratory