Dual-Band Infrared Imaging Applications: Locating Buried Minefields, Mapping Sea Ice and Inspecting Aging Aircraft

Grande, N.K. Del; Durbin, Philip F.; Perkins, D.E.

doi:10.1007/978-1-4615-2848-7_60

Cited by 7 publications

(6 citation statements)

References 2 publications

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“…sea ice thicknesses varying from 5 to 50 cm. 7,8 In 1989, LLNL began a DARPA funded program under the name of TEMPS (Temperature Evaluated Mine Position Survey). 46 The TEMPS method used two, selectively filtered, thermal infrared images to locate buried mine sites.…”

Section: Background and Technical Approachmentioning

confidence: 99%

“…It is expected that separation of buried mine sites from surface object clutter, particularly for metal objects, will require use of both temperature-difference and emissivity-difference (or emissivity-ratio) signatures, based on the previously reported analyses of the Byron CA test site. 7. SIGNATURES OF SURFACE OBJECT SITES 7.1 Emissivity-ratio signatures A photog:aph of the Area 3 site with sod, covered by surface-objects, is shown in Figure 4.…”

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confidence: 99%

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<title>Dual-band infrared capabilities for imaging buried-object sites</title>

et al. 1993

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We discuss dual-band infrared (DBIR) capabilities for imaging buried object sites. We identify physical features affecting thermal contrast needed to distinguish buried object sites from undisturbed sites or surface clutter. Apart from atmospheric transmission and system performance, these features include: object size, shape, and burial depth; ambient soil, disturbed soil and object site thermal diffusivity differences; surfe temperature, emissivity, plant-cover, slope, albedo and roughness variations; weather conditions and measurement times. We use ground instrumentation to measure the time-varying temperature differences between buried object sites and undisturbed soil sites. We compare near surface soil temperature differences with radiometric infrared (IR) surface temperature differences recorded at 4.7 0.4 .tm and at 10.6 1.0 jim. By producing selective DBIR image ratio maps, we distinguish temperature-difference patterns from surface emissivity effects. We discuss temperature differences between buried object sites, filled hole sites (without buried objects), cleared (undisturbed) soil sites, and grass-covered sites (with and without different types of surface clutter). We compare temperature, emissivity-ratio, visible and near-JR reflectance signatures of surface objects, leafy plants and sod. We discuss the physical aspects of environmental, surface and buried target features affecting interpretation of buried targets, surface objects and natural backgrounds.

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confidence: 99%

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<title>Dual-band infrared capabilities for imaging buried-object sites</title>

et al. 1993

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“…9,10 This paper discusses the analysis of DBIR images to identify hidden defects within flash-heated test specimens and aircraft structures. Previous successful applications of DBIR imaging (from aircraft, helicopter, tower and raised platforms) detected underground and obscured object sites with 0.2 °C or more surface temperature differences from: S geothermal aquifers under 6 to 60 meters of dry soil .…”

Section: Introductionmentioning

confidence: 99%

<title>Dynamic thermal tomography for nondestructive inspection of aging aircraft</title>

et al. 1993

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We apply dual-band infrared (DBIR) imaging as a dynamic thermal tomography tool for wide area inspection of a Boeing 737 aircraft (owned by the FAA/AANC at the Sandia hangar in Albuquerque, NM) and several Boeing KC-135 aircraft panels (used for the round robin experiment conducted at Tinker AFB, OK). Our analyses are discussed in this report. After flash-heating the aircraft skin, we record synchronized DBIR images every 40 ms, from onset to 8 seconds after the heat flash. We analyze selective DBIR image ratios which enhance surface temperature contrast and remove surface-emissivity clutter (from dirt, dents, tape, markings, ink, sealants, uneven paint, paint stripper, exposed metal and roughness variations). The Boeing 737 and KC-135 aircraft fuselage panels have varying percent thickness losses from corrosion. We established the correlation of percent thickness loss with surface temperature rise (above ambient) for a partially corroded F-18 wing box structure (with a 2.9 mm uncorroded thickness) and several aluminum plates (with 1.0, 1.1, 2.3 and 3.9 mm thicknesses) which had 6 to 60 % thickness losses at milled flat-bottom hole sites. Based on this correlation, lap splice temperatures rise 1 °C per 24 5 % material loss at 0.4 s after the heat flash. We tabulate and map corrosion-related percent thickness loss effects (related to the corresponding surface temperature rise at 0.4 s after the heat flash) for the riveted (and bonded) Boeing 737, and the riveted (but unbonded) Boeing KC-135. We map the fuselage composite thermal inertia, (kpc)"2, based on the (inverse) slope of the surface temperature versus inverse square root of time. Composite thermal inertia maps characterize shallow skin defects within the lap splice at early times (<0.3 s) and deeper skin defects within the lap splice at late times (>0.4 s). Late time composite thermal inertia maps depict where corrosion-related thickness losses occur (e.g., on the inside of the Boeing 737 lap splice, beneath the galley and the latrine). Lap splice sites on a typical Boeing KC-135 panel with low composite thermal inertia values had high skin-thickness losses from corrosion. 0-8194-1250-3/93/$6.00 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/20/2015 Terms of Use: http://spiedl.org/terms SPIE Vol. 2001 Nondestructive Inspection of Aging Aircraft (1993) / 67 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/20/2015 Terms of Use: http://spiedl.org/terms

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“…• geothermal aquifers under 6 to 60 meters of dry soil 1,2 • cemetery walls, trenches and a building foundation under 80 cm of asphalt and debris 3 • buried mines, rocks and objects under 1 to 20 em of disturbed sand, soil, or sod 3-8 • sea ice thicknesses varying from 5 to 50 cm. 9,10 This paper discusses the analysis of DBIR images to identify hidden defects within flash-heated test specimens and aircraft structures.We are developing a wide-area, non-contact, non-destructive inspection (NDI) tool to depict hidden defects within: w • adhesively-bonded aluminum lap joints with disbond (no-adhesive) sites replicating the skin of a Boeing 737 aircraft 9,11,12 • an aged Boeing 737 aircraft (see AppendixA, Figs. A-1 and A-2) at Sandia National Laboratories in Albuquerque, NM ,t…”

Section: Introductionmentioning

confidence: 99%