Infra-red Thermography

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Infra-red Thermography

• Alex Gibson

CEE398Kuc University of Illinois at
Urbana-Champaign March 2002
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Outline

• Basic Physical Principles
• Applications
• Equipment
• References

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Theoretical Basis

• Thermal Imaging Measurement and mapping of
  infrared energy emitted by the target

Infrared Energy f(T,E) Blackbody spectral
emittance given by
(Planck's Equation)
NEAR IR - 0.7 to 1.3 µ (refl.) MID IR
- 1.3 3 µ (refl.) THERMAL IR
-3.0 to 30 µ (emitt.)
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Emissivity
Emissivity (Actual/Blackbody) (i.e.
blackbody E1.0)
Nomimal Values

Material T (C) E-Emissivity
Cement 0-200 .96
Asphalt 38 .93
Aluminum (U/O) 38 0.03/0.11
Concrete 0-1093 .94
Steel (U/O) 38 0.08/0.8
Rubber, Hard 23 .94
Rubber, Soft 24 .86
Sand 20 .76
Snow, Granular -8 .89
Plowed Field 20 .38
Water 38 .67
Wood low .80-.90
Material E (8-14m)
Steel galvanized 0.28
Steel polished 0.07
Steel oxidized 0.79
Steel oxidized strongly 0.88
Steel rolled freshly 0.24
Steel rough surface 0.96
Steel rusty, red 0.69
Steel sheet, nickel plated 0.11
Steel sheet, rolled 0.56
E f(t,?,material,surface condition) -gt a
specific surface can be calibrated
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General Applications

• Semiconductors
• Medical
• Law Enforcement
• Military

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Civil Engineering Applications

• Delaminations (Bridge decks)
• Leaks in buried pipelines
• Heat Loss analysis
• Ultrasound lock-in-Thermography
• (Vibrasound, ThermosoniX)
• Predictive Maintanance

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Bridge Deck Investigation
Simmultaneous visual and IR imaging of surface
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Pipeline investigation
1) Aqueduct
2) Oil Pipeline
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Active test
ThermosoniX movie Aluminium bar
http//www.indigosystems.com/movie_tsx2.html
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Cameras (Indigo)
Video Frame Rate
High Frame Rate
Detector Types
Range Detector
Near 0.9 1.7 µ Indium Gallium Arsenide (InGaAs)
Mid 2.0 5.0 µ Indium Antimonide (InSb)
Long 8.0 9.2 µ Gallium Arsenide (GaAs)
Source indigo
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Cameras (Rayerthon)
Radiometric PalmIR 500D
Detector BST focal plane array (320 x 240)
Sensitivity gt0.1c
Spectral Response 7 to 14 microns
Video Update Rate 60 Hz NTSC, 50 Hz PAL
Standard Lens 50mm, ƒ/1.0
Field of View 18 x 13.5
Focus Range 18 to infinity
PalmIR 225
Detector Uncooled ferroelectric (160 x 120)
Spectral Response 7 to 14 microns
Frame Rate 30 Hz NTSC, 25 Hz PAL
Standard Lens 37mm, ƒ/1.0
Field of View 12 x 9
Focus Range 5 feet minimum to infinity
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References

• Cameras/Equipment
• www.indigosystems.com
• www.rayerthoninfrared.com
• www.stressphotonics.com
• Engineering Firms
• www.infrasense.com
• www.entech-ndt.com
• General Interest
• www.snellinfrared.com
• www.x20.org