Xenics Presentation. A 25 minute crash course in Thermography

Transcription

1 Xenics Presentation A 25 minute crash course in Thermography How to improve accuracy / repeatability on non-contact temperature measurement by selecting the right IR spectrum Copyright 2015 Guido DEUTZ

2 Outline Xenics Company Introdcution ~ 3 min Which IR Basics should you be aware of? ~ 6 min - Atmospheric Windows - Infrared Reflected Light vs. Thermal Imaging vs. Thermography Where does Thermography reliably works?~ 12 min - Spectral Intensity of ideal IR radiator - Material categories and relevant object criteria Conclusions - Benefits of non-contact temperature measurement - What you should have learned! - Infrared & Thermal Xenics / Stemmer Imaging Question & Anwers ~ 3 min ~ 1 min 2

3 Xenics Company Introduction

4 Xenics Introduction & History Independent, European supplier of IR cameras & detectors Leading supplier of line-scan and 2D InGaAs SWIR detectors Founded October 16th, 2000 as Spin-off of IMEC (institute for nanoelectronics of University of Leuven) Profitable since 2004 HQ in Leuven (East of Brussels) 4

5 Core Competences Detector technology Image enhancement ROIC design Radiometry Electronics User software Mechanics Embedded software 5

6 Mission Statement Our mission is to be a worldwide leading provider of infrared / thermal cameras and SWIR detectors. 6

7 Which IR Basics should you be aware of? Atmospheric Windows Infrared Reflected Light vs. Thermal Imaging vs. Thermography

8 Atmospheric IR Windows Overview of atmospheric transmission under typical ambient conditions. Not all radiation can travel free in space. Air transmission distortion results from absorption bands of e.g. water vapor, carbon dioxide etc. Impac Infrared Transmission curve depends on air temperature, water vapor (=> e.g. IR use on open sea) VisNIR/SWIR: 0,4 to 1,7 µm SWIR: 0,9 to 1,7 / 2,5 µm MWIR BB: 1 to 5µm MWIR: 3 to 5 µm LWIR: 8 to 14µm Xenics: Vis = Visible Light VisNIR/SWIR = Visible - SWIR SWIR = Short Wave IR MWIR = Mid Wave IR LWIR = Long Wave (IR) FIR = Far IR 8

9 SWIR vs. LWIR Imaging X-Ray UV VIS NIR SWIR MWIR LWIR X-Ray Ultra Violet Visible Near IR Short Wave Mid Wave Long Wave nm nm nm nm um um um Dr. Austin Richards Active NIR / SWIR reflectivity Passive thermal radiation 9

10 Thermal Imaging vs. Thermography Thermal Imaging Colder tire sidewall Hotter wheel rim? Thermography ~ 5 C on tire sidewall ~ 25 C on wheel rim Warmer tire shoulder Just Imaging Imaging + Temp.Measurement > 30 C on tire shoulder Non-uniformity correction (NUC) vs. black body (BB) radiators allows: See temperature distribution on the same surface! No relative temperature quantification (= No T on the same surface) No absolute temperature determination (= No T abs on surface 1, surface 2, ) NUC + LUT + sensor calibration algorithm on given BB temperature allows: See temperature distribution on the same surface! Relative temperature quantification (= T on the same surface) Absolute temperature determination via surface emissivity ( ε ) (T abs on the same surface) (T abs on surface 1 vs. T abs on surface 2, ) 10

11 Where does Thermography reliably works? Spectral Intensity of ideal IR radiator Material categories and relevant object criteria

12 Spectral Intensity of ideal IR radiator Planck s Law Radiance over wavelength Wien s Displacement Law describes that the max. spectral intensity of an emitting black body shifts towards shorter wavelengths as the temperature rises NIR: 0,9 to 1,1 µm SWIR: 0,85 to 2,5 µm MWIR: 3 to 5µm LWIR: 8 to 14µm Thermography introduction Copyright

13 Why do we need to speak about Emissivity? Apart of the idealized theory we re living in the real world and have to follow real life scenarios As a matter of fact each material has his individual ability to radiate heat which is called Emissivity and typically used with the letters ε or e - Remember school physics: White vs. Black object in the sun. Which object becomes warmer? Thermography introduction Copyright

14 Typical Emissivity of Real-Life Objects 100% IR Temp.Signal = Emitted Temp. (ε) + Reflect.Temp (ρ) + Transm.Temp. (τ) Scenario 1: τ = 0 IR Non-Transparent Scenario 2: τ 0 IR Transparent T Background Signal 100% = ε + ρ T Background Signal 100% = ε + ρ + τ ε ε ρ ρ τ T Object T Object T Behind_Object Thermography introduction T Behind_Object Copyright

15 Which type of material group exist and what are their typical emissivity's? So called Non-Metals ρ vs. ε Typ. Materials: Plastics Fluids Rubber Painted parts Paper Asphalt Ceramics Wood Textiles Glass Food Coated metals NIR/SWIR: 0,85 to 2,5 µm MWIR: 3 to 5µm LWIR: 8 to 14µm Thermography introduction Copyright

16 Which typical material group exist and what are their typical emissivity's? So called Metals ρ vs. ε Typ. Materials: Ferrous Metals Iron Steel Non-Ferrous Met. Aluminium Copper Lead Nickel Zinc NIR/SWIR: 0,85 to 2,5 µm MWIR: 3 to 5µm LWIR: 8 to 14µm Thermography introduction Copyright

17 Which typical material group exist and what are their typical emissivity's? IR transparent Materials: Glass (Soda-Lime) ρ vs. ε vs. τ Attention: Other sorts of glass (e.g. brown, green,..) may have a slightly different e-curve! NIR/SWIR: 0,85 to 2,5 µm MWIR: 3 to 5µm LWIR: 8 to 14µm Thermography introduction Copyright

18 Which typical material group exist and what are their typical emissivity's? IR transparent Materials: Thin HDPE films (e.g. PE, PP) τ ε Attention: Do not measure the background signal by too broad selected IR spectrum 3,43µm Thermography introduction Copyright

19 Temperature reading errors caused by 10% wrong emissivity settings Recommendation: Select the measurement wavelength to be as short as possible to increase accuracy and repeatability to improve reading as good as possible! Reading error caused by ± 10% wrong ε-setting. E.g. T Object = C T 8 14µm = ± 80 C T 4,5 5,5µm = ± 55 C T 2,0 2,8µm = ± 30 C T 1,4 1,8µm = ± 20 C T 0,7 1,1µm = ± 12 C Thermography introduction Copyright

20 And in practice?

21 A practical example for a house man living in Belgium at our booth! The Xenics 100 C iron OR How to determine emissivity? Black HighTemp Paint Up to 650 C Silver HighTemp Paint Up to 800 C Aluminum Foil Foil Thermography introduction 5mm thick Glass Copyright

22 A practical example for a house man living in Belgium at our booth! The Xenics 100 C iron OR How to determine emissivity? Black HighTemp Paint Up to 650 C 100 C e = 100% Silver HighTemp Paint Up to 800 C 50 C e = 50% 30 C e = 30% Aluminum Foil Thermography introduction 5mm thick Glass 90 C E = 90 C Copyright

23 Conclusions Benefits of non-contact temperature measurement What you need to be aware of! Infrared & Thermal Xenics / Stemmer Imaging

24 Conclusion: Benefits of non-contact temperature meas. Thermal IR as non-contact thermometry method allows to: - Measure temperatures on moving objects e.g. passing car tire and brakes - Temperature measurement on objects at long distances e.g. rotary kilns in cement industry - Act w/o reading interference as contactthermometry e.g. thermocouples on ICs, PCBs, - Maintenance-friendly sensor as thermocouples will worn-out resp. destroyed in high temperature applications or in aggressive environments Thermography introduction Copyright

25 Conclusion 1: What you should have learned! Material categories - IR Non-Transparent Non-Metals Metals - IR (Semi-) Transparent Glass Thin plastic foils Relevant object (material) criteria - Average emissivity at used wavelength and applicable reading error NIR/SWIR MWIR LWIR Thermography introduction Copyright

26 Conclusion 2: What you hopefully learned? What did you hopefully learned today? - Some guys in Belgium have very strange irons - To look at an iron by an infrared device can be a cool thing to do - To handle Emissivity and measure temperatures by IR is easy as long as I use my brain: Non-Metals are easy to measure in LWIR due to a good overall emissivity Metals are okay in NIR/SWIR/MWIR if you take care of background reflections IR transparent materials e.g. glass or plastics have sometimes weird e-curves. Fist look up for those information before selecting the spectral wavelength. Thermography introduction Copyright

27 Infrared & Thermal Xenics MWIR Onca-Series Xenics offers - Industrial reliable un-cooled & cooled SWIR / MWIR / LWIR Cameras SWIR Bobcat-Series LWIR Gobi-Series - Optional or on-board camera calibration for Xenis Thermography cameras 100% = ε + ρ + τ - Analytic Software End-User Pakages and Windows/Linux SDKs (C# and LabVIEW) Xeneth - Dedicated technical support incl. application teams via established sales channel partners 27

28 Reference literature used Reference and to Infrared-Thermometer Handbook (LTI) Full Basics of Physical principles Properties of real objects Emissivity of various materials Determining emissivity of an object Choosing the spectral response Thermography introduction Copyright

29 Thank you for your attention Hope to see you again & Enjoy Thermography!