geom3003 engineering surveying (mining) 1 the previous slide set contains: spatial information...
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GEOM3003 Engineering Surveying (Mining)
The previous Slide Set contains:• Spatial Information• Terrain Modelling• GIS, Geographic Information Systems
This Lecture Notes Slide Set contains:• Introduction to Remote Sensing
The next Silde Set contains:• Introduction to Photogrametry
Dr Gerd R Dowideit
School of Geography, Planning and ArchitectureThe University of Queensland
Copyright, 2004
2Start this PowerPoint Session as a Slide Show !
Engineering Surveying (Mining)THE UNIVERSITYOF QUEENSLAND
GEOM3003 Engineering Surveying (Mining)
Remote SensingLecture 7, Part 1
Dr Gerd R Dowideit
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GEOM3003 Engineering Surveying (Mining)
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
REMOTE SENSING includes all methods and techniques used to gain qualitative and quantitative information about distant objects without coming into direct contact with these objects.Look-Look, NO Touch
Landsat TM Near IR Band
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GEOM3003 Engineering Surveying (Mining)
Remote Sensing (RS) methods try to answer four basic questions:
HOW MUCH of WHAT is WHERE? What is the SHAPE and EXTENT of ... ? (Area, Boundaries, Lineaments, ...)Has it CHANGED?What is the MIX of Objects
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
HOW MUCH of WHAT is WHERE? WHAT: Type, Characteristic and Properties of Object. eg. Water, Vegetation, Land; Temperature, Concentration, State of Development; Subtype, Species, Use of ... ; Includes determination of generic object type, character and property as well as it’s abstract meaning.
=> DATA INTERPRETATION
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
HOW MUCH of WHAT is WHERE?HOW MUCH: determine by simple COUNTING, measuring AREA covered or percentage of total area coverage.WHERE: Relate locations and area covered to either a standard map or to the actual location on the ‘ground’ where the object occurs.NOTE: WHERE also refers to a moment in
time
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
What is the SHAPE and EXTENT of ... ? (Area, Boundaries, Lineaments)This extends the ‘WHERE’ to be a completely GEOMETRIC problem. MAP PRODUCTION methods are to be applied to the analysis of RS information. These include:
Photogrammetric Methods:Identification and Delineation of Boundaries and Lineaments (Roads, Rivers, Fault Lines)
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
Has it CHANGED?
CHANGE may occur with progress of TIME.Change may be detected through comparison of observed states at different moments in time.
=> CHANGE DETECTION
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
What is the MIX of Objects?The surface of the Earth is covered by objects like Soil, Water, Grass, Trees, Houses, Roads and so on. These are ‘GENERIC OBJECTS’. We know these well, but we also know objects like Open Forest, Residential and Industrial Estates, etc. Each of these ABSTRACT OBJECTS are made up of a typical collection of Generic Objects.
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
Remote Sensing (Look-Look, No Touch) is a much wider field than we will discuss in this lecture series. We will concentrate on that part of RS dealing with EARTH RESOURCES
Vision Medical Imaging
Sound and Radio Wave Detection
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
What makes it tick ???(1) RS requires a CARRIER of information, which can bridge distances.(2) RS requires a SENSOR which can detect changes in the carried Signal.(3) RS requires RECORDING, ANALYSIS, INTERPRETATION and REPRESENTATION of the sensed information in a purposeful way.
(1) RS requires a CARRIER of information, which can bridge distances.These Carriers of Information are FIELDS of FORCES:* Pressure Wave Fields of Sound,* Gravity Force Fields,* Magnetic Force Fields and* Electro-magnetic Force Fields.The latter are of our main interest, since they include visible and invisible LIGHT.
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
(2) RS requires a SENSOR which can detect changes in the carried Signal.Apart from our own eyes and ears, technology has provided us with a multitude of sensors operating in the detection of force fields:microphones, geophones,photographic film, video cameras and photo detectors,radio wave receivers, gravimeters and magnetometers.
What makes it tick ???(1) RS requires a CARRIER of information, which can bridge distances.(2) RS requires a SENSOR which can detect changes in the carried Signal.(3) RS requires RECORDING, ANALYSIS, INTERPRETATION and REPRESENTATION of the sensed information in a purposeful way.
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
(3) RS requires RECORDING, ANALYSIS, INTERPRETATION and REPRESENTATION of the sensed information in a purposeful way.This is a technique based topic. It is essential for the success or failure of RS in respect of it’s anticipated purpose.This topic will be dealt with in it’s main aspects (but not completely).
What makes it tick ???(1) RS requires a CARRIER of information, which can bridge distances.(2) RS requires a SENSOR which can detect changes in the carried Signal.(3) RS requires RECORDING, ANALYSIS, INTERPRETATION and REPRESENTATION of the sensed information in a purposeful way.
Remote Sensing
An Introduction:
What is REMOTE SENSING ?
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GEOM3003 Engineering Surveying (Mining)
Source of ForceField
Reflection
Sensor System eg. Camera
Resulting RS Data Set
eg. Image
DATAACQUISITION
Remote Sensing
An Introduction: What is Remote Sensing
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GEOM3003 Engineering Surveying (Mining)
RS Data Seteg. Image
DATAPROCESSING
Interpretation (secondary) Measurements
Data Processing & Mapping (geometric)Presentation of Processing Results
Explaining deduced OBJECT INFORMATION
Remote Sensing
An Introduction: What is Remote Sensing
Model of Real World
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GEOM3003 Engineering Surveying (Mining)
Remote SensingElectromagnetic Radiation:
Fraunhofer Lines
(found empirically by observation)
Dispersion of Lightthrough a refractiveprism
Fraunhofer discovered ‘black lines’ in the spectrum of light emitted by various superheated chemical elements. These lines were as typical for each of the elements as fingerprints for humans.
Chemical Composition of objects effects emitted ER in a unique way for each element.
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Fraunhofer Lines
Dispersion of Lightthrough a refractiveprism
E = mc2
In Einstein's formula E = mc^2 E = Energy m = mass (of matter/object) c = propagation velocity of
lightWhat does that tell us ?There is a well defined relationship between MATTER, ENERGY and ELECTROMAGNETIC RADIATION (eg. light)
Remote Sensing
Electromagnetic Radiation:
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GEOM3003 Engineering Surveying (Mining)
The basic building blocks of all matter are ATOMSThe basic building blocks of Atoms are the NUCLEUS (Neutrons and Protons) and several ELECTRONS.Electrons are thought to be spinning around the Nucleus at orbits of different, but well pre-defined discrete sequential radii.
A change in the energy level contained in an atom (eg. by heating or cooling) changesthe balance of forces inside the atom will automatically adept to energy level changes by moving electrons to higher or lower orbits.
Remote Sensing
Electromagnetic Radiation:
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GEOM3003 Engineering Surveying (Mining)
The loss of energy from an atom causes electrons to drop back to lower orbits which is of interest to us.One widely accepted theory says, that atoms lose energy in form of Electromagnetic Radiation
One theory explains ER as a WAVE field,another as a field of a stream of PHOTONS, particles so small that they have no mass. Both are said to propagate at light speed.
Photon
Wave
Energy differential = 1 Planck’s Quantum E = mc^2
Remote Sensing
Electromagnetic Radiation:
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GEOM3003 Engineering Surveying (Mining)
Photon
Wave
Energy differential = 1 Planck’s Quantum E = mc^2
Some atoms may have been charged to a higher energy level; pushing electrons further than one orbital level. In turn they can drop back over more than one orbit level: more energy than one Quantum
Gerd’s interpretation:Since c is constant, all photons travel about 300,000 km/secThose with a higher energy charge will use a ‘more wiggly’ (thus, longer) wave path than those with lesser charge.
Remote Sensing
Electromagnetic Radiation:
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Photon
Wave
Energy differential = 1 Planck’s Quantum E = mc^2
Wave characteristics: = Wave length = distance between consecutive wave peaks (measured in m)f = frequency = number of wave peaks (wiggles) in the wave train propagating for 1 sec (measured in Hz) = c / fSumming up:High Energy Radiation proceeds at higher frequencies (shorter wavelength compares to low energy radiation.Radiation wave length mix depends on amount of (heat) energy contain in matter.
=>PLANCK’s LAWc = const ~ 300000 km/sec
Remote Sensing
Electromagnetic Radiation:
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PLANCK’s LAW
Wave Length
Total RadiationEnergy emitted
Radiation Energy Curve foran object (BLACK BODY)at constant temperature.
short long
peak
WIEN’s LAW
Wave Length
Total RadiationEnergy emitted
Radiation Energy Curves foran object (BLACK BODY) at various constant temperatures.
short long
300K1000K
3000k6000K
Radiation output curves for ideal (Black Body) objects
Remote Sensing
Electromagnetic Radiation:
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GEOM3003 Engineering Surveying (Mining)
The Average Temperature of Earth’s Surface rarely exceeds 300 K, an object temperature to low to provide for EMITTED RADIATION of sufficient strength to register on most of the available sensors (except in thermal IR sensors).
(Even warm nights can be pitch black)
WIEN’s LAW
Wave Length
Total RadiationEnergy emitted
Radiation Energy Curves foran object (BLACK BODY) at various constant temperatures.
short long
300K1000K
3000k6000K
The surface of the Sun’s outer atmosphere (photosphere) has a temperature of about 5800K, hot enough to provide adequate radiation energy. (Peak output in GREEN of visible light).
Most RS systems utilise reflected sun light.
Remote Sensing
Electromagnetic Radiation:
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GEOM3003 Engineering Surveying (Mining)
QUESTION: Does incident sun light interact in a similar way with matter as described is the case for emitted radiation?
ANSWER: YES!
ER (including light) is a form of energy (as is heat). Matter (atoms) can absorb as well as emit energy.
Objects under illumination by sun light will partially absorb radiation.
Absorption level varies with wave length depending on chemical composition of the object
Radiation not absorbed is mostly reflected and available for RS.
=> Spectral Signatures
Remote Sensing
Electromagnetic Radiation:
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GN238 Introduction to Remote Sensing 01/10/97 5
ER, the Physical Basis of RSExamples of Spectral Signatures
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0.4 (blue) 0.80.6 (red)0.5 (green) 0.7 (IR=>) 1.0 m
Reflectance
(of Sun Light)
0
Bare Soil (Grey/Brown)
Vegetation (green)
Water (clear)
(<= UV)
Remote Sensing
Electromagnetic Radiation:
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GN238 Introduction to Remote Sensing 01/10/97 6
ER, the Physical Basis of RSThe Electromagnetic Spectrum
(not to exact scale; see Textbook)
10^-6 10^-3 1 1000.1 10^5 10^8
-Rays
Sound
X-Ray UV
Visible
0.4 0.5 0.6 0.7 m
m
TV/RadioMicro-Wave
Thermal Infrared
Near & Mid Infrared
Wave Length
not part of ER)
Note: outsidethe visible Range,no colours orshades will be perceived.Blue Green Red
Remote Sensing
Electromagnetic Radiation:
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The General Remote Sensing Model
I
R
AT
A
Sensor
RadiationSource
I = R + A + T
SimplifiedRadiation-Balance
R = I - A - T
I = Incident ERR = ReflectedA = AbsorbedT = TransmittedS = Scattering
S
Remote Sensing
Electromagnetic Radiation:
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GN238 Introduction to Remote Sensing 01/10/97 8
ER, the Physical Basis of RSA bright Idea for RS
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0.4 (blue) 0.80.6 (red)0.5 (green) 0.7 (IR=>) 1.0m
Reflectance
(of Sun Light)
0
Bare Soil (Grey/Brown)
Vegetation (green)
(<= UV)
G R IR
Veg. SoilG med medR low highIR high+ high
Truth Table
Remote Sensing
Electromagnetic Radiation:
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A bright Idea for RS
G R IR
Truth Table
Veg. SoilG med medR low highIR high+ high
Remote Sensing
Electromagnetic Radiation:
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ImageDisplay
Remote Sensing
Electromagnetic Radiation:
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Ekati Diamond Mine,Northwest Territories
1989 1994 1999Colour codedCompsiteChange Detection:
Impact of Mine Development onthe Environment
Remote Sensing
Electromagnetic Radiation:
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Spectral Classification of a Landsat MSS scene
Remote Sensing
Electromagnetic Radiation:
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GEOM3003 Engineering Surveying (Mining)
Using Fraunhofer’s ObservationsThe variation in Radiation output from a REAL OBJECT depends on it’s chemical composition. Water has a different SPECTRAL SIGNATURE than soil or chlorophyll containing leaf matter, etc.
Wave Length
Radiation Energy Curve foran object at constant temperature.
short long
Gerd’s realobject
QUESTIONS:• Can we use these facts to measure object temperatures?• Can we use these facts to identify the chemical composition of objects and• can we use the latter to identify the object itself?
Remote Sensing
Electromagnetic Radiation: