Infra red Thermography Alex Gibson by Q7L7iYA7

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									Infra-red Thermography




Alex Gibson

CEE398Kuc
University of Illinois at Urbana-Champaign
March 2002
Outline

   Basic Physical Principles
   Applications
   Equipment
   References
Theoretical Basis
Thermal Imaging: Measurement and mapping of infrared energy emitted by the target


                                    Infrared Energy= f(T,E)

                                    “Blackbody” spectral emittance given by:

                                             2hc 2
                                    Wb  5 ( hc / kT )        (Planck's Equation)
                                          (e             1)




NEAR IR -   0.7 to 1.3 μ (refl.)
MID IR -    1.3 – 3    μ (refl.)
THERMAL IR -3.0 to 30+ μ (emitt.)
  Emissivity
Nomimal Values                            Emissivity = (Actual/Blackbody)

Material         T (C)    E-Emissivity    (i.e. “blackbody”; E=1.0)
Cement           0-200    .96
Asphalt          38       .93                         Material           E (8-14m)
Aluminum (U/O)   38       0.03/0.11        Steel: galvanized               0.28
Concrete         0-1093   .94              Steel: polished                 0.07
Steel (U/O)      38       0.08/0.8         Steel: oxidized                 0.79
Rubber, Hard     23       .94              Steel: oxidized strongly        0.88
Rubber, Soft     24       .86              Steel: rolled freshly           0.24
Sand             20       .76              Steel: rough surface            0.96
Snow, Granular   -8       .89              Steel: rusty, red               0.69
Plowed Field     20       .38              Steel: sheet, nickel plated     0.11
Water            38       .67              Steel: sheet, rolled            0.56
Wood             low      .80-.90




E = f(t,λ,material,surface condition) -> a specific surface can be calibrated
General Applications



-   Semiconductors
-   Medical
-   Law Enforcement
-   Military
Civil Engineering Applications

               -Delaminations (Bridge decks)

               - Leaks in buried pipelines

               - Heat Loss analysis

               -Ultrasound lock-in-Thermography
                  (Vibrasound, ThermosoniX)

               - Predictive Maintanance
Bridge Deck Investigation

           Simmultaneous visual and IR
           imaging of surface
Pipeline investigation

1) Aqueduct        2) Oil Pipeline
Active test




          ThermosoniX movie: Aluminium bar
          http://www.indigosystems.com/movie_tsx2.html
 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
 Cameras (Rayerthon)
Radiometric PalmIR 500D
                                Detector     BST focal plane array
                                                  (320 x 240)
                              Sensitivity    >0.1°c
                     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
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

								
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