Multi-use applications of dual-band infrared (DBIR) thermal imaging for detecting obscured structural defects
Precise dual-band infrared (DBIR) thermal imaging provides a useful diagnostic tool for wide-area detection of defects from corrosion damage in metal airframes, heat damage in composite structures and structural damage in concrete bridge decks. We use DBIR image ratios to enhance surface temperature contrast, remove surface emissivity noise and increase signal-to-clutter ratios. We clarify interpretation of hidden defect sites by distinguishing temperature differences at defect sites from emissivity differences at clutter sites. This reduces the probability of false calls associated with misinterpreted image data. For airframe inspections, we map flash-heated defects in metal structures. The surface temperature rise above ambient at corrosion-thinned sites correlates with the percentage of material loss from corrosion thinning. For flash-heated composite structures, we measure the temperature-time history which relates to the depth and extent of heat damage. In preparation for bridge deck inspections, we map the natural day and night temperature variations at known concrete slab delamination sites which heat and coot at different rates than their surroundings. The above-ambient daytime and below-ambient nightime delamination site temperature differences correlate with the volume of replaced concrete at the delamination sites.
- Research Organization:
- Lawrence Livermore National Lab., CA (United States)
- Sponsoring Organization:
- Federal Aviation Administration, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10176914
- Report Number(s):
- UCRL-JC-117416; CONF-940449-14; ON: DE94017178
- Resource Relation:
- Conference: Society of Photo-Optical Instrumentation Engineers conference on intelligent information systems,Orlando, FL (United States),4-8 Apr 1994; Other Information: PBD: May 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Dual-band infrared imaging to detect corrosion damage within airframes and concrete structures
Dual-band infrared imaging for concrete bridge deck inspection