remonte sensing
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NAME : SABALE VISHWAJEET ANANDARAO
ROLL NO: 122103
COURSE : MECHANICAL
BATCH : M5
GUIDE : B.S.KAMBLE
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Remote Sensing
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Remote means away from or at a
distance, sensing means detecting a property or
characteristics. Thus the term Remote Sensingrefers examination, measurement and analysis
of an object without being in contact with
it. Remote Sensing is the science and art
of acquiring information about the earth
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.
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DefinitionRemote Sensing is broadly defined as
collecting and interpretation information about a
target without being in physical contact with the
object .Air crafts and satellites are the common platformsfor remote sensing observation.
Remote Sensing is the acquiring of data about
an object without touching it.Such a definition is short, simple, general and memorable.
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Principles of Remote SThe basic principles of Remote Sensing may be listed
as below:1.Electromagnetic energy has been classified by wavelength and
arranged to form the electromagnetic spectrum.
2.As electromagnetic energy interacts with the atmosphere and the
surface of the Earth, the most important concept to remember is the
conservation of energy (i.e., the total energy is constant).3.As electromagnetic waves travel, they encounter objects
(discontinuities in velocity) that reflect some energy like a mirror and
transmit some energy after changing the travel path.
4.The distance (d) an electromagnetic wave travels in a certain time (t)depends on the velocity of the material (v) through which the wave is
traveling; d = vt.
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5.The velocity (c), frequency (f), and wavelength (l)
of an electromagnetic wave are related by the
equation: c = fl.6.The analogy of a rock dropped into a pond can be
drawn as an example to define wave front.
7.It is quite appropriate to look at the amplitude ofan electromagnetic wave and think of it as a
measure of the energy in that wave.
8.Electromagnetic waves lose energy (amplitude) as
they travel because of several phenomena.
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A.Remote sensing on sevenfundamentals1. Energy Source or Illumination2. Radiation and the Atmosphere
3. Interaction with the Target4. Recording of Energy by theSensor5. Transmission, Reception, andProcessing6. Interpretation and Analysis7. Application
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1.Energy Source or IlluminationThe first requirement for remote sensing is to have an energy source
which illuminates or provides electromagnetic energy to the targetof interest.
This energy is in the form of electromagnetic radiation.
Wavelengthand Frequency are the two important parameters
for remote sensing
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2. Radiation and the Atmosphere(B)As the energy travels from its source to the target, it will come in
contact with and interact with the atmosphere it passes through. This
interaction may take place a second time as the energy travels from
the target to the sensor.
Particles and gases in the atmosphere can affect the incoming light
and radiation
These effects are caused by the mechanisms ofscatteringandabsorption
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3. Interaction with the Target (C)Once the energy makes its way to the target through the
atmosphere, it interacts with the target depending on the properties
of both the target and the radiation. Radiation that is not absorbed or scattered in the atmosphere can
reach and interact with
the Earths surface. There are three (3) forms of interaction that can
take place when energy is incident (I) upon the surface. These are:
Absorption(A),Transmission(T),Reflection(R)
There are two types of reflection that can take place
i. Specular reflection is when the surface is smooth
ii. Diffuse reflection is when surface is rough
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4. Recording of Energy by the Sensor (D)After the energy has been scattered by, or emitted from the target,
we require a sensor to collect and record the electromagnetic
radiation.
Platforms for remote sensors may be situated on the ground, onan aircraft or balloon etc
or on a spacecraft or satellite outside of the Earth's atmosphere.
Satellites are used as sensors.
These geostationary satellites, at altitudes of approximately36,000 kilometre , revolve at speeds which match the rotation
of the Earth so they seem stationary.
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5. Transmission, Reception, and Processing (E)The energy recorded by the sensor has to be transmitted, often in
electronic form, to a receiving and processing station where the dataare processed into an image
Data obtained during airborne remote sensing missions can be
retrieved once the aircraftlands.
It can then be processed and delivered to the end user.
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6. Interpretation and Analysis (F)The processed image is interpreted, visually and/or digitally or
electronically, to extract
information about the target which was illuminated
When remote sensing data are available in digital format, digital
processing and analysis may be performed using a computer. Digital processing may be used to enhance data as a prelude to
visual interpretation
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7. Application (G)The final element of the remote sensing process is achieved when
We apply the information we have been able to extract from theimagery about the target in order to better understand it, reveal some
new information, or assist in solving a particular problem
_ crop type classification
_ crop condition assessment_ crop yield estimation
_ mapping of soil characteristics
_ mapping of soil management practices
Radar is one of the finest application of remote sensing
aradar is essentially a ranging or distance measuring device. It
consists fundamentally of a transmitter, a receiver, an antenna, and
an electronics system to process and record the data.
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Remote sensors
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The instruments used to measure the electromagnetic radiation
reflected/emitted by the target under study are usually referred
to as remote sensors. There are two classes of Remote Sensor:1. Passive remote sensor.
2. Active remote sensor
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Passive remote sensor:Sensors which sense natural radiations, either emitted orreflected from the earth, are called passive sensors
Remote sensing systems which measure energy that isnaturally available are called passivesensors. Passive sensors
can only be used to detect energy when the naturally occurringenergy is available.
Active remote sensor:Sensors which carry electromagnetic radiation of a specificwavelength or band of wavelengths to illuminate the earths surface
are called active sensors .
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It is relatively Inexpensive. The cost of software and
data (which often represents a one-off cost) is less
expensive than sending teams of surveyors out into
the field. Current (within reason). One particular
problem that the developing world faces is that data
is old or out of date. Satellite imagery can be
acquired for free from the last decade andcontemporary data can be acquired fairly
inexpensivelyProvides data about large areas
Advantages
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ConclusionRemote Sensing is the gathering of
information concerning the earths surface
that do not involve contact with the surface or
object under study. The techniques include-
aerial photograph, multi-spectral and
infrared imagery and radar. With the help of
remote sensing, we can able to get accurateinformation about the earths surface
including its components like- forest,
landscape, water resources, oceans etc.
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