Understanding Infrared Thermography Reading 7 Part 2 of 2.pdf

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A.4 Performance Parameters of Thermal-Sensing Instruments To select an instrument suitable to a particular application, the thermographer needs to understand how to determine and specify its required performance. This section provides information regarding the performance parameters of (1) point-sensing instruments and (2) scanning & imaging instruments. Charlie Chong/ Fion Zhang
A.4.1 Point-Sensing Instruments For point-sensing instruments (infrared radiation thermometers), the following performance parameters should be considered: • Temperature range: The high and low limits over which the target emperature can vary • Absolute accuracy: As related to the National Institute of Standards and Technology (NIST) standard • Repeatability: How faithfully a reading is repeated for the same target • Temperature sensitivity: The smallest target temperature change that the instrument needs to detect • Speed of response: How fast the instrument responds to a temperature change at the target surface • Target spot size and working distance: The size of the spot on the target to be measured, and its distance from the instrument (FOV/IFOV) • Output requirements: How the output signal is to be used • Spectral range: The portion of the infrared spectrum over which the instrument will operate • Sensor environment: The ambient conditions under which the instrument will operate Charlie Chong/ Fion Zhang
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Infrared Thermal Testing Reading VI
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6.1 Basic Elements An in-house prog
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6.1.4 Responsibilities This section
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IR Viewing Window - Opaque Polymer
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6.1.8 Acceptance Criteria All surve
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6.1.9 Reporting Criteria A rigid pr
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6.1.10 Qualification of Personnel P
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EPRI Licensed Material Basic Elemen
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7. TRAINING AND CERTIFICATION This
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Recommended training and certificat
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■ Level II A Level II infrared th
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The experience and education recomm
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B. Spatial Resolution • the conce
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D. Equipment Operation • Be able
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The PdM basic examination is more s
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Appendix-A The Science Of Thermogra
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Erroneous conclusions can have an e
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A.2.1 Heat and Temperature What is
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To convert changes in temperature o
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A.2.3 The Three Modes of Heat Trans
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The Fourier Conduction Law: Q/A Q =
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A.2.5 Convection Convective heat tr
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Figure A-2 Convective Heat Flow Cha
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A.2.6 Radiation Radiative heat tran
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A.2.7 Radiation Exchange at the Tar
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Charlie Chong/ Fion Zhang
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Figure A-4 Radiative Heat Flow W ε
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A.2.8 Specular and Diffuse Surfaces
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Specular or Diffuse Surfaces Diffus
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Specular and Diffuse Surfaces Confu
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Specular reflection is the mirror-l
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Reflections off Specular and Diffus
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The thermogram of the outside surfa
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Steady-state conduction Steady stat
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A.3 The Basic Physics of Infrared R
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A.3.1 Some Historical Background Th
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A.3.3 The Target Surface The chart
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Figure A-6 shows the distribution o
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Two physical laws define the radian
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According to (2), the wavelength at
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Figure A-7 Spectral Distribution of
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Figure A-8 shows that the instrumen
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If the emissivity of a gray body is
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Under certain conditions, an error
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EXAM score! Non-graybody (colored b
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Figure A-10 illustrates the spectra
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Figure A-10 Infrared Transmission o
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Figure A-11 Infrared Spectral Trans
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Figure A-11 shows transmission curv
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EXAM score! Glass is opaque λ > 5
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Figure A-12 Characteristics of IR T
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The characteristics of the window m
Page 115 and 116: IR Lenses - LWIR Len Charlie Chong/
Page 117 and 118: IR Lenses - Fresnel Len Charlie Cho
Page 119 and 120: Figure A-13 Components of an Infrar
Page 121 and 122: Infrared optics are available in tw
Page 123 and 124: All infrared detector-transducers e
Page 125 and 126: Figure A-14 Typical Infrared Radiat
Page 127 and 128: Germanium Len Charlie Chong/ Fion Z
Page 129 and 130: Thermopile Detector Charlie Chong/
Page 139 and 140: The IR Detectors Infrared detectors
Page 141 and 142: Figure A-15 Spectral Sensitivity of
Page 143 and 144: The Mercury- Cadmium-telluride (Hgc
Page 145 and 146: The Mercury- Cadmium-Telluride (HgC
Page 151 and 152: Point-sensing instruments for measu
Page 153 and 154: A.3.6.1 Line Scanning The purpose o
Page 155 and 156: A.3.6.2 Two-Dimensional Scanning Th
Page 157 and 158: Opto-mechanical Scanner A typical c
Page 159 and 160: Electronic scanning Electronic scan
Page 161 and 162: Figure A-18 Schematic of a Typical
Page 163 and 164: Applications for infrared FPAs incl
Page 165: Staring Charlie Chong/ Fion Zhang
Page 169 and 170: Temperature sensitivity is also cal
Page 171 and 172: EXAM score! thermal resolution (≠
Page 173 and 174: NETD - Noise Equivalent Temperature
Page 175 and 176: Figure A-19 Instrument Speed of Res
Page 177 and 178: Figure A-20 Fields of View of Infra
Page 179 and 180: Figure A-20 Fields of View of Infra
Page 181 and 182: The output requirements are totally
Page 183 and 184: Spectrally selective instruments em
Page 185 and 186: Figure A-21 Spectral Filtering for
Page 187 and 188: Figure A-22 shows a similar solutio
Page 189 and 190: A.4.2 Scanners and Imagers.Qualitat
Page 191 and 192: • Total field of view (TFOV): the
Page 193 and 194: Despite some manufacturers’ claim
Page 195 and 196: A.4.3.1 Temperature Sensitivity, Mi
Page 197 and 198: Figure A-23 Test Setup for MRTD Mea
Page 199 and 200: A.4.3.2 Spot Size (FOV) , Instantan
Page 201 and 202: ■ A standard 4 bar (slit) resolut
Page 203 and 204: Both MRTD and MTF are functions of
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Page 207 and 208: IFOVmeas: The slit width at which t
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Page 211 and 212: FPA Charlie Chong/ Fion Zhang http:
Page 213 and 214: FPA Charlie Chong/ Fion Zhang
Page 215 and 216: A.4.3.3 Speed of Response and Frame
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A.4.4 Thermal Imaging Software In o
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The newest field-portable instrumen
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Appendix B Measuring Emissivity, Re
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Figure B-1 Target Radiosity Charlie
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The reference emitter technique wor
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1. Apply the reference emitter (E)
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B.2.2 Reflective Emissivity Techniq
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Figure B-3 Using the Reflective Emi
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Figure B-4 Using the Transmittance
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Appendix C Quick Reference Charts A
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MTF Determination Using An Ir Image
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Measuring And Setting Effective Emi
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Classification Of Faults (Guideline
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Reading: Four Emissivity: Understan
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Figure 1 shows a typical three-phas
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Figure IR1: Corresponding infrared
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Thermal radiation and properties of
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The thermal nature of materials. Ma
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So in plain English, when the therm
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Figure 2: Stainless steel block. (a
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Observed with our thermal imager (w
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Can you see my eye glasses in the i
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How can the thermal imager’s read
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When we remove the block from the o
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In this experiment we see that the
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Charlie Chong/ Fion Zhang http://ww
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Using a narrow band filter to measu
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Emissivity, the variable’s variab
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Emissivity and electrical equipment
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In manufacturing processes, steel o
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In this case, we have another power
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Figure IR1: Corresponding infrared
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Figure 7: Measuring the loads on a
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Summary Predictive maintenance PDM
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It is much like most endeavors in l
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Good Luck Charlie Chong/ Fion Zhang
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Charlie https://www.yumpu.com/en/br
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