remonte sensing

7/28/2019 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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remonte sensing

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