1. Introduction to Remote Sensing
Dr. Hassan J. Eghbali

2. Format of the course Course outline
Lectures for first part of session, practicals second part
Course mark 70% for exam, 30% for write-up of final practical, to be handed in by the end of term (Weds Mar 23rd?)
First week familiarise ourselves with lab PCs and sources of image data on the web
Next 3 practicals 2 weeks each (expect you to spend time on this outside Monday session)
Final practical (Classification): 3 weeks, write-up
Dr. Hassan J. Eghbali

3. Course material
Books
Jensen, J. R. (2000) Remote Sensing of the Environment: An Earth Resource Perspective, 2000, Prentice Hall, New Jersey. (Excellent on RS but no image processing, around £40 from Waterstones).
Jensen, J. R. (2005, 3rd ed.) Introductory Digital Image Processing, Prentice Hall, New Jersey. (Companion to above, around £40 from Waterstones) BUT mostly available online at
Lillesand, T. M., Kiefer, R. W. and Chipman, J. W. (2004, 5th ed.) Remote Sensing and Image Interpretation, John Wiley, New York. (good all-round text-book around £35).
Mather, P. M. (1999) Computer Processing of Remotely‑sensed Images, 2nd Edition. John Wiley and Sons, Chichester.
Campbell, J. B. (1996) Introduction to Remote Sensing (2nd Ed), London:Taylor and Francis.
Dr. Hassan J. Eghbali

4. Course material Web Tutorials http://rst.gsfc.nasa.gov/Front/tofc.html
Glossary of alphabet soup acronyms!
Other resources
NASA
NASAs Visible Earth (source of data):
European Space Agency
NOAA
Remote sensing and Photogrammetry Society UK
Dr. Hassan J. Eghbali

5. Format of the course Course outline Lecture 1: Introduction to EO
Lecture 2: Introduction to image processing (image display/enhancement) - practical 1
Lecture 3: Introduction to electromagnetic spectrum
Lecture 4: Image arithmetic: ratios and spectral indices - practical 2
Lecture 5: EM spectrum and the atmosphere, plus angular info.
Lecture 6: Information extraction: spatial filtering and classification - practical 3 (assessed practical)
Lecture 7: Spatial, spectral, temporal resolution and tradeoffs
Lecture 8: Orbits, swaths and coverage
Lecture 9: Pre-processing stages and sensor scanning mechanisms
Lecture 10: Applications plus recap
Dr. Hassan J. Eghbali

6. Lecture outline
General introduction to remote sensing (RS), Earth Observation (EO)
definitions of RS
Why do we do it?
Applications and issues
Who and where?
Concepts and terms
remote sensing process, end-to-end
Dr. Hassan J. Eghbali

7. What is remote sensing? The Experts say "Remote Sensing is...”
...techniques for collecting image or other forms of data about an object from measurements made at a distance from the object, and the processing and analysis of the data (RESORS, CCRS).
”...the science (and to some extent, art) of acquiring information about the Earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information.”
Dr. Hassan J. Eghbali

8. What is remote sensing (II)?
The not so experts say "Remote Sensing is...”
Advanced colouring-in.
Seeing what can't be seen, then convincing someone that you're right.
Being as far away from your object of study as possible and getting the computer to handle the numbers.
Legitimised voyeurism
(more of the same from
Dr. Hassan J. Eghbali

9. Remote Sensing Examples
First aerial photo credited to Frenchman Felix Tournachon in Bievre Valley, 1858.
Boston from balloon (oldest preserved aerial photo), 1860, by James Wallace Black.
Dr. Hassan J. Eghbali

10. Remote Sensing Examples
Kites (still used!) Panorama of San Francisco, 1906.
Up to 9 large kites used to carry camera weighing 23kg.
Dr. Hassan J. Eghbali

11. Remote Sensing Examples
Dr. Hassan J. Eghbali

12. Remote Sensing: scales and platforms
Not always big/expensive equipment
Individual/small groups
Calibration/validation campaigns
Dr. Hassan J. Eghbali

13. Remote Sensing: scales and platforms
Both taken via kite aerial photography
Dr. Hassan J. Eghbali

14. Remote Sensing: scales and platforms
upscale
upscale
Platform depends on application
What information do we want?
How much detail?
What type of detail?
Dr. Hassan J. Eghbali

15. Remote Sensing: scales and platforms
E.g. aerial photography
From multimap.com
Most of UK
Cost? Time?
Dr. Hassan J. Eghbali

16. Remote Sensing: scales and platforms
upscale
Many types of satellite
Different orbits, instruments, applications
Dr. Hassan J. Eghbali

17. Remote Sensing Examples
Global maps of vegetation from MODIS instrument
Dr. Hassan J. Eghbali

18. Remote Sensing Examples
Global maps of sea surface temperature and land surface reflectance from MODIS instrument
Dr. Hassan J. Eghbali

19. Remote sensing applications
Environmental: climate, ecosystem, hazard mapping and monitoring, vegetation, carbon cycle, oceans, ice
Commercial: telecomms, agriculture, geology and petroleum, mapping
Military: reconnaissance, mapping, navigation (GPS)
Weather monitoring and prediction
Many, many more
Dr. Hassan J. Eghbali

20. EO process in summary..... Collection of data
Some type of remotely measured signal
Electromagnetic radiation of some form
Transformation of signal into something useful
Information extraction
Use of information to answer a question or confirm/contradict a hypothesis
Dr. Hassan J. Eghbali

21. Remote sensing process: I
Statement of problem
What information do we want?
Appropriate problem-solving approach?
In situ: field, lab, ancillary data (Meteorology? Historical? Other?)
EO data: Type? Resolution? Cost? Availability?
Pre/post processing?
Data collection
Analog: visual, expert interp.
Digital: spatial, photogrammetric, spectral etc.
Modelling: prediction & understanding
Information extraction
Data analysis
Products: images, maps, thematic maps, databases etc.
Models: parameters and predictions
Quantify: error & uncertainty analysis
Graphs and statistics
Presentation of information
Formulate hypothesis
Hypothesis testing
Dr. Hassan J. Eghbali

22. The Remote Sensing Process: II
Collection of information about an object without coming into physical contact with that object
Passive: solar reflected/emitted
Active:RADAR (backscattered); LiDAR (reflected)
Dr. Hassan J. Eghbali

23. The Remote Sensing Process: III
What are we collecting?
Electromagnetic radiation (EMR)
What is the source?
Solar radiation
passive - reflected, emitted
OR artificial source
active - RADAR, LiDAR
Dr. Hassan J. Eghbali

24. Electromagnetic radiation?
Electric field (E)
Magnetic field (M)
Perpendicular and travel at velocity, c (3x108 ms-1)
Dr. Hassan J. Eghbali

25. Energy radiated from sun (or active sensor)
Energy  1/wavelength (1/)
shorter  (higher f) == higher energy
longer  (lower f) == lower energy
from
Dr. Hassan J. Eghbali

26. Information What type of information are we trying to get at?
What information is available from RS?
Spatial, spectral, temporal, angular, polarization, etc.
Dr. Hassan J. Eghbali

27. Spectral information: vegetation
Wavelength, nm
400
600
800
1000
1200
reflectance(%)
0.0
0.1
0.2
0.3
0.4
0.5
very high leaf area
very low leaf area
sunlit soil
NIR, high reflectance
Visible green, higher than red
Visible red, low reflectance
Dr. Hassan J. Eghbali

28. Spectral information: vegetation
Dr. Hassan J. Eghbali

29. Colour Composites: spectral
‘Real Colour’ composite
Green band on green
Red band on red
Blue band on blue
Approximates “real” colour (RGB colour composite)
Landsat TM image of Swanley, 1988
Dr. Hassan J. Eghbali

30. Temporal information Change detection Rondonia 1975 Rondonia 1986
Dr. Hassan J. Eghbali

31. Always bear in mind.....
when we view an RS image, we see a 'picture’ BUT need to be aware of the 'image formation process' to:
understand and use the information content of the image and factors operating on it
spatially reference the data
Dr. Hassan J. Eghbali

32. Remote Sensing: What is it and why do we use it?
Many monitoring issues global or regional
Drawbacks of in situ measurement …..
Remote sensing can provide (not always!)
Global coverage
Range of spatial resolutions
Temporal coverage (repeat viewing)
Spectral information (wavelength)
Angular information (different view angles)
Dr. Hassan J. Eghbali

33. Why do we study/use remote sensing?
source of spatial and temporal information (land surface, oceans, atmosphere, ice)
monitor and develop understanding of environment (measurement and modelling)
information can be accurate, timely, consistent
remote access
some historical data (1960s/70s+)
move to quantitative RS e.g. data for climate
some commercial applications (growing?) e.g. weather
typically (geo)'physical' information but information widely used (surrogate - tsetse fly mapping)
derive data (raster) for input to GIS (land cover, temperature etc.)
Dr. Hassan J. Eghbali

34. Caveats! Remote sensing has many problems Can be expensive
Technically difficult
NOT direct
measure surrogate variables
e.g. reflectance (%), brightness temperature (Wm-2  oK), backscatter (dB)
RELATE to other, more direct properties.
Dr. Hassan J. Eghbali