Compact fiber-optic electronic laser speckle pattern shearography
US6040900A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 1, 1997 |
| Grant date | Mar 21, 2000 |
| Priority date | — |
| Expiry date | Jul 1, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/1731
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Material defects and damage are detected and evaluated by stressing the material while looking for flaw-induced anomalies. In one embodiment, a thermal stressing unit is used to provide a slight temperature difference between a localized region and surrounding areas, with the change in temperature being used to reveal the defects and damage using a fringe pattern generated through the interference between two coherent laser beams. A sensor head and a head-mounted display (HMD), interfaced to a computer, power supply, and control electronics are used to measure the derivative of out-of-plane displacement with respect to an image shearing direction so as to generate a display of the fringe pattern, preferably in three dimensions through a displacement or depth map.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.