Understanding Infrared Thermography Reading 3

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40.Fiber optic, infrared - A flexible fiber made of a material that transmits infrared energy, used for making noncontact temperature measurements when there is not a direct line of sight between the instrument and the target. 41.Filter, spectral - An optical element, usually transmissive, used to restrict the spectral band of energy received by an instrument's detector. 42.Focal plane array (FPA) - A linear or two-dimensional matrix of detector elements, typically used at the focal plane of an instrument. In thermography, rectangular FPAs are used in staring (nonscanning) infrared imagers. These are called infrared focal plane array imagers. 43.Focal point - The point at which the instrument optics image the infrared detector at the target plane. In a radiation thermometer, this is where the spot size is the smallest. In a scanner or imager, this is where the instantaneous field of view ([FOV) is smallest. 44.Foreground temptrature (see instrument ambient background) - Temperature of the scene behind and surrounding the instrument as viewed from the target. (See Figure A-1.) Charlie Chong/ Fion Zhang
45.Frame repetition rate - The time it takes an infrared imager to scan (update) every thermogram picture element (pixel); in frames per second. 46.Full scale - The span between the minimum value and the maximum value Ihat any instrument is capable of measuring. In a thermometer, this would be the span between the highest and lowest temperature that can be measured. 47.Graybody - An radiating object whose emissivity is a constant value less than unity ( 1.0), over a specific spectral range. 48.Hertz (Hz) – A unit of measurement of signal frequency; 1 Hz = 1 cycle per second. Image, infrared - See Thermogram. 49.Imager, infrared - An infrared instrument that collects the infrared radiant energy from a target surface and produces an image in monochrome (black and white) or color, where the gray shades or color hues correspond respectively to target exitance. 50.Image display tone - Gray shade or color hue on a thermogram. 51.Image processing, thermal - Analysis of thermal images, usually by computer; enhancing the image to prepare it for computer or visual analysis. In the case of an infrared image or thermogram, this could include temperature scaling, spot temperature measurements, thermal profiles, image manipulation, subtraction and storage. Charlie Chong/ Fion Zhang
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Infrared Thermal Testing Reading II
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Infrared Thermography ~-- ... ... .
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Infrared Thermography Charlie Chong
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See Through & Fun Thermal Camera Ex
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How to see through clothing 2 I'
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Apache IR Thermal Weaponry ■ http
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Charlie Chong/ Fion Zhang
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Greek alphabet Letter Name Sound An
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Greek letter l fl 0 I1 p u w Charli
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SGuide-IRT Content Part 1 of 2 ■
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1.1 Introduction to Principles & Th
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The infrared thermal imaging equipm
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The three modes of heat transfer ar
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The three modes of heat transfer ar
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Temperature and Temperature Scales
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Boston Tea Party - New governances
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The Mighty Fahrenheit & ⅝”, Eng
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Absolute zero is equal to - 273.16
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The Fourier conduction Law expresse
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The Fourier conduction Law ( One di
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Convective Heat Transfer Convective
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Figure 1.2: Convective heat flow T
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Newton's cooling law defines the co
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Radiative Heat Transfer Radiative h
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Figure 1.4: Infrared radiation leav
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Thermal infrared radiation impingin
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Reflections off Specular and Diffus
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Reflections off Specular and Diffus
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Radiant Energy Related to Target Su
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The Stefan-Boltzmann law: W= σƐT
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Figure 1.6: Typical blackbody distr
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1.4 Practical Infrared Measurements
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Characteristics of the Target Surfa
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Referring back to Figure 1.5, the t
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Characteristics of the Transmitting
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Figure 1.10; Transmission of 10m (3
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Figure 1.11: Transmission, absorpti
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Figure 1.12: Transmission curves of
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Chapter 1 Review Questions Q&A 1. b
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Q4. Heat can only flow in the direc
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Q10. The follow ing spectral band i
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Q16. In forced convection, the boun
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Q22. In the 8 to 14 μm spectral re
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2.1 Materials Characteristics A kno
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For an emissivity reference table t
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Errors because of point source refl
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View Angle The angle between the in
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Thermal Conductivity Thermal conduc
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Thermal Diffusivity As in emissivit
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Partial 2.1 Table 2.1: d i'ffusivit
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Partial Table 2.2 Table 2.2: Normal
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Chapter 2 Review Questions Q&A 1. c
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4. When measuring the temperature o
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10. A highly textured surface is sa
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3.1 Thermal Instrumentation Overvie
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Thermopile- Thermoelectric Seebeck
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What is a IR Thermopile? (non-conta
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IR Thermopile Quad Sensor (non-cont
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Thermocouple A thermocouple is a te
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Bourdon Gas Thermometers 5 f\G.3 0
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Liquid Crystal Thermometer A liquid
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Bimetallic Thermometers Dial Spiral
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In RTD devices; Copper, Nickel and
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Platinum Resistance Thermometer Cha
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RTD Materials Different materials u
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Operations of RTD An RTD takes a me
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Benefits of Thin Film RTD There are
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Thermistor +V r===~ Op A p V to A I
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3.2 Contacting Thermal Measuring De
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■ Thermocouple Thermocouples are
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■ Thermistors Thermistors arc als
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3.3 Optical Pyrometers Optical pyro
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Pyrometer A pyrometer is a type of
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Brightness Pyrometers -Wien’s Law
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The processing electronics unit amp
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Infrared Detector An infrared detec
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Figure 3.2: Response Curves of Vari
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The mercury cadmium telluride (HgCd
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Infrared Optics - Lenses, Mirrors a
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Field of View (FOV) A field of view
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What is IFOV? A measure of the spat
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Instantaneous Field of View (IFOV)
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3.5 Scanning and Imaging When probl
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Line Scanning When the measurement
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Two-dimensional Scanning - Thermal
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Figure 3.5: Optomechanlcally scanne
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Pyroelectric Vidicon Thermal Imager
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Figure 3.6: Typical uncooled infrar
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IRFPA Charlie Chong/ Fion Zhang htt
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3.6 Performance Parameters of Infra
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Performance parameters of qualitati
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Temperature Range Temperature range
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Temperature Sensitivity Temperature
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Speed of Response Speed of response
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Figure 3.7: Instrument speed to res
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Figure 3.8: Instrument field-of-vie
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D ≡ αd D = spot size (approximat
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Output Requirements Output requirem
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Spectral Range Spectral range denot
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Spectrall y selective instrumems us
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Figure 3.9: Spectral response of an
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3.7 Performance Characteristics of
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The total field of view for a line
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Instantaneous Field of View IFOV In
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Recalling! Temperature sensitivity
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IFOV - MTF The 0.35 MTF refers to:
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Fig. 2a. Slit Response Function. Ca
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Minimum Resolvable Temperature Diff
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EXAM score! D=σ∙d IFOV ratio = d
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Charlie Chong/ Fion Zhang
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Answer: D= σ•d, IFOV ration= 1/
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Break Time - Kenya Coffee Picker Ch
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Portable Handheld Devices Charlie C
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Temperature sensitivity and readabi
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Hand Held Infrared Module Charlie C
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Note that the laser beam docs not r
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Emissivity set controls, located in
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IR Sensor Module Charlie Chong/ Fio
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IR Sensor Module Charlie Chong/ Fio
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Two-color Pyrometers or Ratio Pyrom
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Phenomena which are non-dynamic in
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Some ratio thermometers use more th
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Infrared Radiometric Microscopes Ch
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Line Scanners Line scanners are div
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Special Purpose Devices Special pur
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FLIR- Forward Looking Infrared Char
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Typically, the total field of view
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Pyroelectric devices have no direct
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Figure 3.12: Infrared focal plane a
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Infrared focal plane array imager C
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Infrared focal plane array imager C
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On-board capabilities include isoth
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ccc Electron Microscope Image of mi
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Platinum Silicide IrFPA 19 t«lU 98
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Quantitative IR Image Charlie Chong
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Quantitative Thermal Measurements S
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In addition to the spot measurement
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Stored images can be retrieved, dis
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Calibration Accessories Infrared ra
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Online printers and plotters are re
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Q1. The thermal resolution of an in
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Q7. The 3 to 5 μm spectral region
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Q13. A line scanner can be used to
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Q19. For which of the following app
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Q25. Two-color (ratio) pyrometers m
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Chapter 4 Operating Equipment and U
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■ Emissivity Differences ∆τ Em
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Causes of Real Temperature Changes
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Mass Transport Differences (Fluid F
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Figure 4.1: An indication of water
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Thermal Capacitance Differences ∆
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■ Induced Heating Differences (by
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Induced Heating Differences Charlie
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■ Energy Conversion Differences E
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Figure 4.3: Catalytic reformer vess
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Infrared Thermogram Energy Conversi
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Infrared Thermogram Energy Conversi
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■ Combination of Heat Transfer Me
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Infrared Thermogram of a running mo
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■ Spectral Considerations in Prod
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Infrared Thermogram Charlie Chong/
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Infrared Thermogram ..... " I Charl
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Figure 4.5: Spectral selectivity fo
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Figure 4.7: temperature thermogram
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Figure 4.8 shows the transmission s
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Figure 4.9: Measuring temperature o
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IR Filter Charlie Chong/ Fion Zhang
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Figure 4.10: Line scanner for conti
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Preparation of Equipment for Operat
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If the instrument is out of cal ibr
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The batteries mentioned on the miss
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Comments: ■ ■ ■ Thermal resol
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Figure 4.11 : Test configuration fo
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3. Reduce the ΔT until the image i
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■ Imaging Spatial Resolution Imag
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A sample setup is illustrated in Fi
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5. If the modulation transfer funct
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Figure 4.13: Test configuration for
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4. Open slit until V meas = V max .
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■ Learning the Startup Procedure
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■ Setting the Correct Effective E
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Figure 4.14: Test configuration for
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■ Measuring and Reporting Tempera
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■ Recognizing and Avoiding Reflec
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■ Measuring the Appropriate Backg
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■ Temperature Differences Between
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■ Liquid and Compressed Gases Som
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Dewar Flask for LN Loosely fitting
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■ Electrical Safety Failure to re
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Table 4.1: Electric shock current t
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4.4 Record Keeping Keeping thorough
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Easily accessible and easily unders
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Q1. Apparent but not real temperatu
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Q5. The higher the temperature of a
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Q9. Differential thermography can b
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5.1 Overview of Applications Becaus
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Electrical Applications Electrical
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High electrical resistance is the m
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Excessive heating due to a defectiv
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Inductive currents flowing with in
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Moisture in Airframes The detection
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Process Control and Product Monitor
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The differences produced by this co
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Night Vision, Seareh, Surveillance,
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Thermogram of helicopter taken at n
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Aircraft Under IR Trap Charlie Chon
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Instruments used for these applicat
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8 to 12 μm spectral region over wh
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Animal Studies Body heat allows inf
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Injured equine foreleg (left) appea
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Work energy is expended by friction
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5.4 Fluid Flow Investigations For s
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Figure 1.7: Thermographs of valve (
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■ Building Insulation and Other F
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Figures 5.8 and 5.9 illustrate thes
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Figure 5.9: Example of air exfiltra
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Example of air exfiltration Charlie
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■ Refractory Systems Industrial s
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Refractory Thermogram Charlie Chong
Page 443 and 444: ■ Subsurface Discontinuity Detect
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Page 447 and 448: The equipment necessary to perform
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Page 451 and 452: Typical failure modes of the materi
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Page 457 and 458: Figure 5.14: Conceptual sketch of t
Page 459 and 460: In this case. however, the heat pul
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Page 465 and 466: When there has been adequate solar
Page 467 and 468: Liquid Level Detection Thermal capa
Page 469 and 470: Unstimulated and Stimulated Approac
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Page 473 and 474: 1. A major area of infrared nondest
Page 475 and 476: 5. The diagnostics involved in dete
Page 477 and 478: 9. Thermography has been successful
Page 479 and 480: Appendix A Glossary The following a
Page 481 and 482: Ambient temperature - Temperature o
Page 483 and 484: Figure A-1 Apparent ambient tempera
Page 485 and 486: 13.Blackbody, blackbody radiator -
Page 487 and 488: Alas! Heat Capacity Volumetric = C
Page 489 and 490: 27.Detector, infrared - A transduce
Page 491 and 492: Thermal Effusivity In Thermodynamic
Page 493: Alas! Exitance = Rodiosity for my A
Page 497 and 498: Thermal Inertia Thermal inertia is
Page 499 and 500: Instantaneous field of View (lFOV)
Page 501 and 502: Laser pyrometer - Laser pyrometer -
Page 503 and 504: Figure 3.2: Response Curves of Vari
Page 505 and 506: Compare: Minimum resolvable tempera
Page 507 and 508: 86.Radiation rererenee source - A b
Page 509 and 510: 101. Sector - For a line scanner, a
Page 511 and 512: 113. Subtense, angular - The angula
Page 513 and 514: 121. Thermal wave imaging - A term
Page 515 and 516: 125. Thermogram - A thermal map or
Page 517 and 518: Appendix B Cost Benefit Determinati
Page 519 and 520: Although the calculations are quite
Page 521 and 522: 96 ASNT Level Ill Study Guide: Infr
Page 523 and 524: Appendix C, Commonly Used Infrared
Page 525 and 526: Appendix C, Commonly Used Infrared
Page 527 and 528: Peach - 我爱桃子 Charlie Cho
Page 529 and 530: Good Luck Charlie Chong/ Fion Zhang
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