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Title: Multi-use applications of dual-band infrared (DBIR) thermal imaging for detecting obscured structural defects

Abstract

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.

Authors:
;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (United States)
Sponsoring Org.:
Federal Aviation Administration, Washington, DC (United States)
OSTI Identifier:
10176914
Report Number(s):
UCRL-JC-117416; CONF-940449-14
ON: DE94017178
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
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
Subject:
47 OTHER INSTRUMENTATION; AIRCRAFT COMPONENTS; INFRARED THERMOGRAPHY; CONCRETE BLOCKS; IMAGE PROCESSING; THERMAL ANALYSIS; DEFECTS; 440500; THERMAL INSTRUMENTATION

Citation Formats

Del Grande, N K, and Durbin, P F. Multi-use applications of dual-band infrared (DBIR) thermal imaging for detecting obscured structural defects. United States: N. p., 1994. Web.
Del Grande, N K, & Durbin, P F. Multi-use applications of dual-band infrared (DBIR) thermal imaging for detecting obscured structural defects. United States.
Del Grande, N K, and Durbin, P F. Sun . "Multi-use applications of dual-band infrared (DBIR) thermal imaging for detecting obscured structural defects". United States. https://www.osti.gov/servlets/purl/10176914.
@article{osti_10176914,
title = {Multi-use applications of dual-band infrared (DBIR) thermal imaging for detecting obscured structural defects},
author = {Del Grande, N K and Durbin, P F},
abstractNote = {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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1994},
month = {5}
}

Conference:
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