Contouring by electronic speckle pattern interferometry
Abstract
Application of electronic speckle pattern interferometry (ESPI) to contouring of surfaces of arbitrary curvature is discussed. A modification of two-wavelength holographic contouring with advantages in scope, simplicity, and practicability is presented. Contouring of irregular surfaces via holographic reconstruction of a 'master' wavefront and comparison of test components with a 'master' component shape, or where feasible direct comparison of two similar object surfaces, is described. Surfaces with deep recesses or other irregular features can be contoured conveniently, and video recording plus electronic processing make for a real-time operation, with photographic processing eliminated in some circumstances. The holographic illumination contouring technique (using a 'master' wavefront) is recommended for optical contouring and inspection of such shapes as turbine blades.
- Publication:
-
The Engineering Uses of Coherent Optics
- Pub Date:
- 1976
- Bibcode:
- 1976euco.proc..171D
- Keywords:
-
- Contours;
- Holographic Interferometry;
- Photographic Recording;
- Speckle Patterns;
- Surface Geometry;
- Wave Front Reconstruction;
- Displacement Measurement;
- Laser Applications;
- Nondestructive Tests;
- Photoelastic Analysis;
- Photographic Processing;
- Real Time Operation;
- Turbine Blades;
- Two-Wavelength Lasers;
- Instrumentation and Photography