Introduction to Remote Sensing Dr. Hassan J. Eghbali

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

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 http://www.cla.sc.edu/geog/rslab/751/index.html 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

Course material Web Tutorials http://rst.gsfc.nasa.gov/Front/tofc.html http://mercator.upc.es/nicktutorial/TofC/table.html http://earth.esa.int/applications/data_util/SARDOCS/spaceborne/Radar_Courses/ http://www.crisp.nus.edu.sg/~research/tutorial/image.htm http://www.ccrs.nrcan.gc.ca/ccrs/learn/tutorials/fundam/fundam_e.html http://octopus.gma.org/surfing/satellites/index.html Glossary of alphabet soup acronyms! http://www.ccrs.nrcan.gc.ca/ccrs/learn/terms/glossary/glossary_e.html Other resources NASA www.nasa.gov NASAs Visible Earth (source of data): http://visibleearth.nasa.gov/ European Space Agency www.esa.int NOAA www.noaa.gov Remote sensing and Photogrammetry Society UK www.rspsoc.org Dr. Hassan J. Eghbali

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

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

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.” http://www.ccrs.nrcan.gc.ca/ccrs/learn/tutorials/fundam/chapter1/chapter1_1_e.html Dr. Hassan J. Eghbali

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 http://www.ccrs.nrcan.gc.ca/ccrs/eduref/misc) Dr. Hassan J. Eghbali

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

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

Remote Sensing Examples Dr. Hassan J. Eghbali

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

Remote Sensing: scales and platforms Both taken via kite aerial photography http://arch.ced.berkeley.edu/kap/kaptoc.html http://activetectonics.la.asu.edu/Fires_and_Floods/ Dr. Hassan J. Eghbali

Remote Sensing: scales and platforms http://www-imk.fzk.de:8080/imk2/mipas-b/mipas-b.htm upscale upscale Platform depends on application What information do we want? How much detail? What type of detail? Dr. Hassan J. Eghbali

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

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

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

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

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

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

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

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

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

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

Energy radiated from sun (or active sensor) Energy  1/wavelength (1/) shorter  (higher f) == higher energy longer  (lower f) == lower energy from http://rst.gsfc.nasa.gov/Intro/Part2_4.html Dr. Hassan J. Eghbali

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

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

Spectral information: vegetation Dr. Hassan J. Eghbali

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

Temporal information Change detection Rondonia 1975 Rondonia 1986 http://earth.jsc.nasa.gov/lores.cgi?PHOTO=STS046-078-026 http://www.yale.edu/ceo/DataArchive/brazil.html Dr. Hassan J. Eghbali

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

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

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

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