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Thermal Remote Sensing


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thermal remote sensing

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Thermal Remote Sensing

  1. 1. ROHIT KUMAR CUJ/I/2013/IGIO/026 SEMESTER-5th
  2. 2. Contents: • Introduction • Thermal IR And Atmospheric Window • Fundamental Radiation Laws • Atmospheric Effects • Thermal Data Acquisition • Applications • Advantages & Disadvantages
  4. 4. REMOTE SENSING • Remote sensing is an art and science of acquiring info about an object of interest without coming in physical contact with it.
  5. 5. THERMAL REMOTE SENSING • Thermal remote sensing is the branch of remote sensing that deals with the acquisition, processing and interpretation of data acquired primarily in the thermal infrared (TIR) region of the electromagnetic (EM) spectrum. In thermal remote sensing we measure the radiations 'emitted' from the surface of the target, as opposed to optical remote sensing where we measure the radiations 'reflected' by the target under consideration.
  6. 6.  Thermal remote sensing is based on the measuring of EM radiation in the infrared region of spectrum.  Most commonly used intervals are 3- 5 micro-meter and 8-14 micro-meter.
  7. 7. Thermal IR and atmospheric window: Landsat 7 Band 7 Landsat 7 Band 6
  8. 8. Thermal Infrared Spectrum:  Thermal IR: 3 – 14 μm  Near IR: 0.7-1.3 μm  Mid IR: 1.3 – 3.0 μm
  9. 9. Fundamental Radiation Laws: The following laws are obeyed in this phenomenon: Planck’ Radiation (Blackbody Law) Wein’s Displacement Law Stefan-Boltzman Law
  10. 10. Atmospheric Effects: • The atmospheric intervention between the thermal sensor and the ground can modify the apparent level of radiations coming from ground depending on degree of atmospheric absorption, scattering and emission. • Atmospheric absorption & scattering make the signal appear colder and atmospheric emission make the object to be detected as warmer. • There are some factors on which both of these effects depend upon given by:
  11. 11.  Atmospheric path length  Meteorological conditions  Site  Altitude  Local weather condition
  12. 12. Thermal Image Acquisition: • Many multispectral (MSS) systems sense radiations in the thermal infrared as well as the visible and reflected infrared portions of the spectrum.
  13. 13. Thermal Sensors: • Thermal sensors use photo detectors sensitive to the direct contact of photons on their surface, to detect emitted thermal radiation. • The detectors are cooled to temperatures close to absolute zero in order to limit their own thermal emissions. • Thermal sensors essentially measure the surface temperature and thermal properties of targets.
  14. 14. THERMAL SENSORS:  TIROS (Television IR Operational Satellite), launched in 1960  GOES (Geostationary Operational Environmental Satellite), TIR at 8km spatial resolution, full-disk of Earth, day and night  HCMM (Heat Capacity Mapping Mission), launched in 1978- 600m spatial resolution, 10.5 – 12.6 micron range  CZCS (Coastal Zone Color Scanner) on Nimbus 7, launched in 1978, for SST (sea surface temperature).  AVHRR (Advanced Very High Resolution Radiometer), 1.1 and 4 km TIR bands  TIMS (Thermal Infrared Multispectral Scanner), Airborne, 6 bands  ATLAS (Airborne Terrestrial Applications Sensor), 15 bands  Landsat 4,5,7; Band 6- 10.4 – 12.5 m, 120 m (4,5), 60 m (7).  ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) on Terra, 5 bands 8.125-11.65 micron range (14 total).
  15. 15. Applications:  Surface temperature detection  Camouflage detection  Forest fire detection and fire risk mapping  Evapotranspiration and drought monitoring  Estimating air temperature  Oil spill monitoring  Water quality monitoring  Volcanic activity monitoring  Urban heat island analysis  Military purpuses
  16. 16. Thermal Remote Sensing Of Forest Fires: Detection of active fires provides an indicator of seasonal, regional and inter annual variability in fire frequency and shifts in geographic location and timing of fire events.
  17. 17. NASA's Ikhana Unmanned Research Aircraft Recorded Image of Fire Near Lake in Southern California: • The 3-D processed image is a colorized mosaic of images draped over terrain, looking east. • Active fire is seen in yellow, while hot, previously burned areas are in shades of dark red and purple. • Unburned areas are shown in green hues.
  18. 18. Volcanism in Thermal Remote Sensing: Active volcanoes exhibit many difficulties in being studied by in situ techniques. For example, during eruptions, high altitude areas are very hard to be accessed because of volcanic hazards. We use thermal remote sensing techniques in mapping and monitoring the evolution of volcanic activity.
  19. 19. Aster Image: • Size: 7.5 x 7.5 km • Orientation: North at top • Image Data: ASTER bands.
  20. 20. Most Active Volcanoes: • True Color Image Thermal Image
  21. 21. Thermal remote sensing in Military:
  22. 22. Due to their ability to detect man sized targets at extremely long distances, in total darkness and in extreme weather conditions thermal imaging cameras are extremely suited for boarder surveillance. Generally, cooled cameras are used in border security applications as they provide range performance than un-cooled detector. If the terrain is e.g. mountainous and does not permit seeing over a distance of 20 kilometers, un-cooled thermal imaging cameras can be used for border security as well. Thermal imaging cameras can be integrated with radar systems.
  23. 23. Advantages & Disadvantages: Advantages We can detect true temperature of objects. Feature cannot be detected by optical RS may be detected with Thermal IR. Disadvantages  It is pretty difficult to maintain the sensors at required temperatures.  Image interpretation of thermal image is difficult.
  24. 24. References: “Remote Sensing of the Environment ” , John. R Jensen, Edition 6th. “Remote Sensing and Image Interpretation ” , Thomas M. Lillisand, Ralph W. Kiefer, Jonathan W. Chipman, Edition 6th.  sensing/thermal/thermalirinfo.html  