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| OCEA0059-2 | Remote Sensing of the Oceans, Introduction to satellite oceanography
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| Duration : | 15h Th, 15h Pr |
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| Number of credits : |
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| Lecturer : | Yves Cornet |
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Language(s) of instruction :
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| English language |
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Organisation and examination :
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| Teaching in the first semester, review in January |
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Course contents :
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| As this course is geared towards students with very different technical and scientific backgrounds, its goal will be to provide a common theoretical ground of general concepts used in the processing of digital images recorded by satellite sensors. We have decided to concentrate our programme on these aspects because satellite oceanography is a very broad field of study, dealing with the observation of water bodies using sensors that detect visible light, reflective infrared, thermal infrared, and microwaves (hyperfrequencies - RADAR imagers). These sensors can also be considered as amospheric sounders or imagers.
The atmospheric sounders are often used to identify the weather conditions in order to model radiative transfers through the atmosphere. Processing data from such atmospheric sensors requires advanced knowledge in atmospheric and aerosol physics. Another field of satellite oceanography aims at defining a geoid model and measuring the sea surface height above/below this reference geoid, while filtering disruptive effects (waves, tides, etc.). This is achieved by applying advanced concepts of geodesy, analysing the satellites' trajectories using their height measurements as provided by altimeters (e.g. RADAR altimeters) and their position and attitude as provided by orbital positioning systems (e.g. DORIS) and by inertial measurement units (IMU) or star trackers. In addition, the processing of data acquired using e.g. SAR systems, which provide a phase and an amplitude, calls upon complex theoretical notions of signal processing.
This is why, for the introductory course, we have chosen to only study the data produced by image sensors that detect visible light and infrared. As this course is aimed at oceanologists and limnologists, it will be illustrated by examples that are specifically related to these fields of research. In addition, as the data acquired is geolocalised, we will also explain general concepts of digital and mathematical cartography and spatial analysis, which are essential in order to analyse the data.
Whether the images are used to observe land, lakes, seas or oceans, and whether the phenomena studied are physical, biological or anthropic, it is essential that students learn the general theory of image processing, regardless of spatial and time aspects (or geographical aspects). This is what the theoretical part of the course focuses on. Most of these concepts are applied through the use of software tools during the supervised practical part of the course.
The course's general outline is as follows:
I. Introduction
1. Definition
2. Brief history
3. Satellite movements
4. Nature of the signal
5. Some satellites and sensors
II. Monogenic image processing
6. Concept of digital image
7. Monogenic image visualisation
8. Contrast enhancement
9. Geometric corrections
10. Radiometric corrections
11. Spatial image filtering
III. Polygenic image processing
12. Polygenic image visualisation - coloured composites
13. Arithmetic indices and operators
14. Polygenic transformations
15. Image classification
IV. Examples of applications (informational part of the course)
16. Nature of oceanographical satellite information
17. Classification of the shallow water seabed
18. Bathymetry
19. Ocean colour (OC)
20. Sea surface and lake surface water temperature (SSWT and LSWT)
21. Sea surface height (SSH)
22. Radar imaging (state of the sea surface)
23. Front detection
24. Analysis of temporal series and teleconnections |
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Learning outcomes of the course :
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| * Understand the data acquisition process and the nature of the information recorded by imaging sensors used to observe lakes, seas and oceans.
* Know the main types of processing used for these images
* Understand why images are processed for oceanological purposes and interpret the meaning of the processes used
* Master the features of specific software tools allowing to apply these processes
* Given the diversity of the students attending this course, the requirements in terms of theoretical knowledge are not as high as could be expected from an expert who designs original solutions, and emphasis is rather placed on practical aspects. Still, students should follow basic scientific standards (rigoyr and reliability) and our expectations will obviously be tailored to each student's background. |
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Prerequisites and co-requisites/ Recommended optional programme components :
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| The course builds upon basic skills in mathematics, statistics, spatial analysis, mathematical and numerical cartography, and physics. Students should also have an interest in computer science and programming.
Students will also be helped by the mindset they have acquired through various scientific courses (mathematics, statistics, physics, spatial analysis, etc.) and technical courses (numerical methods, programming, cartography, etc.) of former academic programmes or even secondary education.
Nevertheless, the variety of backgrounds among the students who generally enrol in this course will certainly require that the teaching be adapted and that many refreshers be provided in these fields. In addition, students are given the opportunity at the beginning of each class to ask questions about the content from the previous class. It is therefore up to students to act professionally and go through their notes every week in order to identify potential points of confusion. |
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Planned learning activities and teaching methods :
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| The theoretical part of the course is given as lectures. We also offer students an exercise book, featuring numerical examples illustrating the various methods studied during the lectures. Their goal is to help students understand the theoretical concepts that we have identified over the years as being the most difficult. Examples of solutions are provided. The exercises can be done using the calculation or programming tools that are known to the students (Excel, programming languages learned in IT class, scientific calculators, etc.).
The practical part of the course consists in assignments that are mostly completed using Idrisi. It illustrates almost all the methods presented during the theoretical part of the course. Classes alternate between practical work and theoretical lectures. Students are also given standard exercises and datasets similar to those used in the practical assignments, along with the solutions, so that they can autonomously assess their ability to use the software before the exam.
Students are free to use the university's Idrisi license as well as other software applications through the ULg's VPN. For information on how to access these applications, students can visit the following web page: http://www.gitan.ulg.ac.be/cms, which also features the timetable of the computer room (B5a/4/18). Students can also use other rooms (B5a/2/35), and may contact the Geomatics unit if they wish to practise or advance in their practical assignments. |
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Mode of delivery (face-to-face ; distance-learning) :
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| The course consists mostly in face-to-face classes, but students can install open software on their laptops and use the ULg's licenses in order to progress as their own rhythm outside of class and the academic environment. Attendance is mandatory. Classes are held in room B5a/4/18 or B5a/2/35. |
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Recommended or required readings :
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| MATHER P.M., 1999. Computer Processing of Remotely-Sensed Images. 2nd edition. Wiley, Chichester, 292 p.
RUSSELL G. CONGALTON & KASS GREEN, 2008. Assessing the Accuracy of Remotely Sensed Data: Principles and Practices. CRC Pres, Second Edition.
Platform of Earth Observation (BELSO) : http://eo.belspo.be/ (viewed on 14/8/2014)
Landsat 7 handbook : http://landsathandbook.gsfc.nasa.gov/ (viewed on 14/8/2014)
Landsat 8 documentation: http://landsat.usgs.gov/landsat8.php (viewed on 14/8/2014)
Landsat Science : http://landsat.gsfc.nasa.gov/?page_id=11 (viewed on 14/8/2014)
NOAA documentation: http://www.ncdc.noaa.gov/oa/pod-guide/ncdc/docs/intro.htm (viewed on 14/8/2014) |
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Assessment methods and criteria :
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| An ongoing non-certifying self-evaluation is carried out during demonstrations and exercise sessions, through close interaction between students and teachers. In addition, students have a book featuring numerical exercises with solutions on the one hand, in order to assess their own theoretical knowledge, and exam-type questions with solutions on the other hand, in order to test their skill in using the Idrisi software application to solve a problem that is new but similar to those seen during practical classes.
The certifying evaluation will consist in an oral exam on the course's theoretical content and a problem to solve, similar to those given during practical classes. Each part of the evaluation is worth 50% of the final mark.
This standard evaluation procedure may however be modified in agreement with the students, who will be notified of any change.
The assessment criteria are as follows: Clarity, coherence, logic, rigorousness, precision, completeness, brevity, relevance, cross-cutting nature (within the course and between courses), quality of mathematical (mathematical meaning of the different coefficients of the equation, e.g.), physics (dimensions and units, order of magnitude - scaling, e.g.) and geographical (mono and multivariate spatial and temporal interaction and meaning - type - of the variables e.g.) interpretations. Furthermore, answers will also be evaluated based on the quality and the originality of the graphic illustration since graphic expression is the scientist's specificity. It further allows demonstrating a good understanding of the phenomenon. Finally, enriching an answer with a rich personal scientific culture will also be considered a factor of excellence in the assessment. |
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Work placement(s) :
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| xxx |
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Organizational remarks :
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| Classes are held on Monday morning during the first term. Theoretical lectures alternate with supervised practical work classes. Attendance to the practical classes is mandatory. |
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Contacts :
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| Yves CORNET, Professor
Geomatics unit, 17 (B5a), Allée du 6 Août, 4000 Liège
Phone #: +32 4 366 53 71
E-mail: ycornet@ulg.ac.be
Web: http://139.165.44.35/cms/index.php |
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| Items online : |
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| Course notes |
| Course materials can be downloaded on the ULg's eCampus platform. |
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