MSc Remote Sensing 2005/6

Title: Principles of remote sensing

Convenor: Dr. M. Disney, room 216 2nd flr Chandler House, tel. 7679 4290 x24290, ,

Times: Weds 5/10 (week 2), 10-12 and 2-5pm; Weds2-5pm (weeks 2, 3) and Thurs 11am – 1pm (weeks 3-6).

Location: Chandler House seminar room 208 (unless otherwise stated)

Course summary

This course provides a general introduction to remote sensing (RS) in lecture 1, followed by a more detailed grounding in principles and practice of RS. The course is broadly divided into two sections.

The first section (lectures 2 and 3) introduces fundamental concepts of electromagnetic radiation (EMR), EMR properties and the interactions of EMR with the Earth system which constitute the measured RS signal. These lecturesintroduce radiation laws and units; solar radiation and the blackbody concept; radiation geometry and interactions; scattering within the atmosphere and at the surface; atmospheric windows; how and why we use radiation at different parts of the EM spectrum. Note that the complementary geometric concepts of RS are covered by Prof. Dowman and Dr. Iliffe in the Geometry and Mapping components of the first term.

The second section (lectures 4 – 6) builds on the first part and introduces concepts of remote sensing instrument deign, data collection and information content. Particular emphasis is given to the various design considerations determining how electromagnetic radiation is captured and exploited by remote sensing instruments, in particular: spatial, spectral, temporal, radiometric, polarisation considerations; sensor designs and scanning mechanisms; choices of orbit; detector resolution; information collection and handling.

Examinations

Examinations will be after Christmas and prior to start of Spring term (dates and venues forthcoming from Prof. Dowman). The examination will be a combination of essay-type and problem-solving questions. Candidates will answer two questions on this part of the course from a choice of four in 1.5 hours. Past exam papers are kept in the library ( Note that the in the Principles examination paper, questions can be asked on the topics covered in the seminar programme (seminars on Thursday afternoons between 20th October and 8th Decmber, titles TBA). Confirmed speakers are as follows: 20th October Dr. Graham Thackrah, Research Systems Inc. Software; 27thOctober Prof. Shaun Quegan, director of NERC Centre for Terrestrial Carbon Dynamics; 8th December Matthias Monreal from Centre for Ecology and Hydrology Monk’s Wood (former MSc RS student). Other speakers TBA.

Course material

Teaching notes will be made available after lectures from:

Books

Jensen, John R. (2000) Remote Sensing of the Environment: an Earth Resources Perspective, Hall and Prentice, New Jersey, ISBN 0-13-489733-1, 1st ed..

Lillesand, T., Kiefer, R. And Chipman, J. (2004) Remote Sensing and Image Interpretation. John Wiley and Sons, NY, 5th ed..

Monteith, J. L and Unsworth, M. H. (1990) Principles of Environmental Physics, Edward Arnold: Routledge, Chapman and Hall, NY, 2nd ed.

Web resources

Tutorials

Other resources

NASA

European Space Agency

NOAA

Remote sensing and Photogrammetry Society UK

Journals

Remote Sensing of the Environment (via Science Direct from within UCL):

International Journal of Remote Sensing:

IEEE Transactions on Geoscience and Remote Sensing:

Detailed outline; Introduction (lecture 1)

Housekeeping

  • Course format, textbooks, library resources, computing resources, people etc.

What is remote sensing and why do we do it?

  • Definitions of remote sensing
  • Examples and applications
  • Introduction to process
  • Collection of signal
  • Interpretation into information
  • Experience of students?

Applications of where remote sensing being used

  • Give a flavour of what EO being used for
  • Atmosphere, lithosphere, geosphere, biosphere, cryosphere
  • Climate, ice, ocean, land surface
  • Commercial - mapping, policy, military, geology and petrochemical
  • Who does remote sensing?
  • Research (universities, governments, Env. Agencies)
  • Commercial organisations (BNSC, Spacemapping, ENSYS, etc. etc.)
  • Multi-body institutions and international space agencies (NASA, ESA, NASDA-Japan, Chinese NSA etc. etc.)

Introduction to some terms and concepts

  • EM Radiation
  • Solar properties
  • Interaction with atmosphere
  • Interaction with surface
  • Resolution
  • Spatial
  • Spectral
  • Temporal
  • Angular
  • Radiometric

The remote sensing process

  • Instrument design
  • Mission
  • Information collection and processing

Detailed outline: radiation principles (lectures 2 and 3)

Introduction to EM spectrum

  • Conduction, convection, radiation (JJ29)

Wave model of EM radiation

  • Properties of EM wave (JJ30)
  • Concepts of wave velocity, wavelength, period etc. (JJ31)

Solar radiation

  • Concept of blackbody (MU25)
  • Kirchoff's Law (JJ250)
  • Radiant energy of sun/Earth (thermal emission)
  • Stefan-Boltzmann law (MU25/JJ247)
  • Wien's displacement law (MU25)
  • Planck's law (MU26)
  • Solar constant (MU36)
  • Implications of en. distribution for EO
  • Calculation of energy between given wavelengths
  • Implications for evolution of the eye, chlorophyll pigments etc. etc.

Particle model of EM radiation

  • Photon energy (JJ35)
  • Photoelectric effect (JJ36)
  • Quantum energy and unit (MU27/JJ37)
  • Atomic energy levels (JJ38)

Radiation geometry and interactions

  • Radiant flux, and radiant flux density (MU28)
  • Radiance/Irradiance, Exitance, Emittance (MU28/MU31)
  • Flux from a point source and from a plane source (MU29/MU30)
  • Cosine law for emission & absorption, Lambert's Cosine Law (MU29/MU30)

Interaction with the atmosphere

  • Refraction (index of etc.), Snell's Law (JJ39)
  • Scattering
  • Rayleigh, Mie, Non-selective (JJ41)
  • Absorption (JJ42/MU39) and atmospheric windows
  • Absorption (and scattering at the surface)
  • Examples of vegetation, soil, snow spectra
  • Spectral features and information
  • Sun/Earth geometry, direct and diffuse radiation (MU40-42)

Interaction of radiation with the surface

  • Reflectance, specular, diffuse etc.
  • BRDF
  • Hemispherical reflectance, transmittance, absorptance
  • Albedo
  • Surface spectra
  • Spectral features and information

Detailed outline: data acquisition and sensor design considerations (lectures 4-7)

Resolution: concepts (JJ12-17)

  • Spatial
  • Spectral
  • Temporal
  • Angular
  • Radiometric
  • Time-resolved signals
  • RADAR, LiDAR (sonar)

Spatial:

  • High v Med/Moderate v Low
  • E.g. IKONOS, MODIS/AVHRR, MSG
  • IFOV and pixel size
  • GRE/GRD/GSD (L&K 334)
  • Point spread function
  • What's in a pixel? (Cracknell, A. P., IJRS, 1998, 19(11), 2025-2047).
  • Mixed pixel, continuous v. Discrete, generalisation

Spectral

  • Wavelength considerations
  • Optical
  • Photography, scanning sensors, LiDAR et.
  • Microwave (active/passive)
  • RADAR
  • Thermal
  • Atmospheric sounders

Temporal/Angular

  • Orbits
  • Kepler's Laws
  • Orbital period, altitude
  • Polar, equatorial and Geostationary (L&K 397-9; JJ187-9 and 201)
  • Advantages/disadvantages of various orbits
  • Coverage of surface
  • Solar crossing time/elevation
  • Broad swath instruments
  • AVHRR/POLDER/MODIS etc.
  • v Narrow swath
  • Landsat ETM+, IKONOS, MISR etc.

Radiometric

  • Precision v accuracy
  • Digital v analogue
  • Signal to noise

Processing stages

  • Transmission
  • Storage and dissemination
  • Ground segment
  • Overview of pre-processing stages
  • Geometric, radiometric, atmospheric correction

Multi/hyperspectral scanners

  • Heritage
  • Landsat, AVHRR (NOAA), EOS/NPOESS (NASA), ESA (Envisat, Explors etc.)
  • Discrete detectors and scanning mirrors (JJ183)
  • Pushbroom/whiskbroom linear arrays (JJ184)
  • Across track scanning (L&K 331, 337)
  • Digital frame camera area arrays
  • Detector types (CCD, L&K 336)
  • Hyperspectral area arrays
  • Examples of the different systems

Photography (briefly!)

  • Historical importance (military) (JJ75)
  • Focal length, aperture (f-stop), shutter
  • Digital cameras

Time-resolved signals

  • RADAR
  • Altimetry
  • LiDAR
  • Vegetation
  • First/last pass plus waveform

Ground-based

  • Radiometry
  • Upwards-looking
  • Ground-penetrating RADAR