6/12/2018 About the course Thermal and Multispectral Imaging http://ekstamahlberg.se/~jorgen/thermalcourse Lecture 1: Introduction Jörgen Ahlberg F. W. Herschel 1762 Light & Radiation https://open.spotify.com/track/0kQcVlkwv2LJQ49KXnklVe Caroline & William Herschel Herschel 1800a “In this case, radiant heat will at least • 4 moons partly, if not chiefly, consist, if I may be • 8 comets permitted the expression, of invisible • 1 planet light; that is to say, of rays coming from the sun, that have such a momentum as to be unfit for vision.” F. W. Herschel, “Experiments on the refrangibility of the invisible rays of the Sun,” Philos. Trans. R. Soc. , vol. 90, pp. 284 – 292, 1800. doi: 10.1098/rstl.1800.0015 1
6/12/2018 Herschel 1800b, c F. W. Herschel, “Experiments on the Solar, and on the Terrestrial Rays that Occasion Heat; With a Comparative View of the Laws to Which Light and Heat, or Rather the Rays Which Occasion Them, are Subject, in Order to Determine Whether They are the Same, or Different. Part I,” Philos. Trans. R. Soc. London , vol. 90, pp. 293 – 326, Jan. 1800. doi: 10.1098/rstl.1800.0016 F. W. Herschel, “Experiments on the Solar, and on the Terrestrial Rays that Occasion Heat; With a Comparative View of the Laws to Which Light and Heat, or Rather the Rays Which Occasion Them, are Subject, in Order to Determine Whether They are the Same, or Different. Part II,” Philos. Trans. R. Soc. London , vol. 90, pp. 437 – 538, Jan. 1800. doi: 10.1098/rstl.1800.0020 Max Planck 1900: 2
6/12/2018 Domains and wavelengths and bands Why this particular division? Reason 1: Atmospheric transmission Reason 2: Behaviour • Reflective domain • Emissive domain Reason 3: Sensors Radiation and matter Studied object Incoming radiation • VNIR: Silicon (CCD, CMOS) Absorbed radiation • SWIR: InGaAs sensors • Absorbed • Reflected • MWIR: InSb and MCT sensors Note: • Transmitted Transmitted radiation • LWIR: MCT and bolometer sensors There are other subdivisions! For example, astronomers use: Reflected radiation • NIR 0.7-5 • MIR: 5- (25…40) • FIR: (25-40)- 3
6/12/2018 Radiation and matter Radiation and matter Studied object Studied object Incoming radiation Incoming radiation Absorbed radiation Absorbed radiation • Absorbed • Absorbed • Reflected • Reflected • Transmitted • Transmitted Transmitted radiation Transmitted radiation • Emitted • Emitted • Scattered Reflected radiation Reflected radiation • Diffracted Emitted radiation Emitted radiation What does the camera see? Thermal cameras Thermal cameras Low-end Medium Advanced Automation, monitoring, R&D SWIR High performance High resolution for Gas finder cameras for R&D R&D Defence Civilian Thermography Imaging Temperature measuring (non radiometric) (radiometric) 4
6/12/2018 Cooled vs uncooled Color mappings Visual White hot Black hot Color mappings Applications of thermal imaging Visual Rainbow Iron 5
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6/12/2018 Non-destructive testing What is multi/hyperspectral imaging? Greyscale image – one band Multi- and hyperspectral imaging Color image – three bands Multispectral image – several bands Hyperspectral image – … many contiguous bands Why multi/hyperspectral images? Applications • Defence • Mineralogy • Land-use classification • Precision farming • Food inspection • Environmental monitoring • … 7
6/12/2018 … finding the bad nuts/potatoes/apples/... Can you see the green camouflage net? … finding camouflaged objects. … finding out where your crops are fine, and where they are not. 8
6/12/2018 Topics • Radiometry: Deeper into how light interacts with matter, including radiation geometry. • Sensors and cameras: How sensors capture light, common problems, The Rest of the Course and how to build multi- and hyperspectral cameras. • Thermal image processing: Common tasks and problems, such as temperature estimation and ”hot spot” detection. • Hyperspectral image processing: The HS processing chain; atmospheric correction, unmixing, classification. • Hyperspectral detection: Anomalies, targets, changes. Artiklar • Zhao: Amanda • Ma: Gustav • Bernstein: Karl 9
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