This document provides an introduction to remote sensing, including the electromagnetic spectrum, interaction of electromagnetic radiation with the atmosphere and Earth's surface, and spectral signatures. It discusses that remote sensing uses electromagnetic energy from the sun as the energy source. It interacts with the atmosphere through scattering and absorption before reaching Earth's surface where it can be reflected, absorbed, or transmitted by different features. The varying reflectance across the electromagnetic spectrum creates unique spectral signatures that can be used for feature identification in remote sensing images.

1. Introduction to RS,Interaction of EM Radiation
with Earth’s Surface and Atmosphere
Presented by:
Abran Idrees SS17-15
Maham Arif SS17-10
Zain Haris SS17-13
Khadeeja Mastoor SS17-14
Ameer Hamza SS17-20
Mian Shahzaib Khizer SS17-31

2. Introduction to Remote sensing
Electromagnetic Radiation
Electromagnetic Spectrum
Electromagnetic Energy interaction with Atmosphere
Electromagnetic Energy interaction with Earth Surface
Spectral Signatures Using Eradas Imagine

3. Sense of Taste Sense of Sight Sense of Touch Sense of Smell Sense of Hear

4. Remote
Far Away / Distant
Sensing
Feel / Detect
Remote Sensing
What is Remote Sensing?
Obtaining information
without contact with object
“Remote Sensing is the science and art of
obtaining information about an object, area, or
phenomenon through the analysis of data
acquired by a device that is not in direct
contact with the object, area, phenomenon
under investigation”.
(Remote Sensing and Image Interpretation ,Sixth Edition by Thomas M. Lillesand ,
Ralph W. Kiefer , Jpnathan W. Chipman)

5. Niepce takes first
picture in 1827
Beginning of photography by
Daguerre in 1839
Aerial photograph by pigeons
and balloons in 1858-1900’s
TIROS-1 Meteorological satellite
in 1960
1972 – Today
 Landsat
 Meteosat
 Seasat
 Spot
 ERS
 IRS
Today Remote sensing

6. Elements Involved In Remote Sensing

7. Elements Involved In Remote Sensing
1.Source of Energy
2.Atmosphere
3.Earth surface features and their interactions
4.Sensing system
5. Transmission, Reception,
and Processing 6.Interpretation and Analysis
7. Applications

8. EM Energy Source And Radiation Principles

9. But we only talk about EM
energy. Why?

10. The first component of remote sensing is the source of energy.
 Sun is the main source of electromagnetic energy.
 Energy from the sun travels at the speed of light c and has a wavelength λ.
 Electromagnetic waves are a combination of Electric and Magnetic waves, both being
perpendicular to each other.
1. Gravitational force 2. Acoustic wave distributions 3. Electromagnetic energy

11. There are two theories which describe the behavior of electromagnetic radiation
e.g how it is created, how it interacts with and travels in space.
1 - Wave Model Theory
2 - Particle Model Theory
Continued

12. The relationship between wavelength λ and frequency f of electromagnetic radiation is based
on the following formula , where c is the speed of the light.
where c =3× 108
𝑚𝑠−1
and λ in 𝜇𝑚, 𝑛𝑚.
Low Frequency
High Frequency
C = f . λ λ ∝
𝟏
𝒇

13. This theory tells us that electromagnetic radiation is composed of many discrete units
called photons or quanta.
OR {Inverse relation with wavelength}
Q = Energy of a quantum ,Joules(J)
h = Planck’s constant ,6.626 × 10−34
J sec
v = frequency
λ = wavelength
Q = h v Q =
𝒉𝒄
λ

14. Electromagnetic spectrum

15. Electromagnetic spectrum

16. 1 . Stefan-Boltzmann Law
The total spectral radiant flux exitance measured in watts per meter square leaving a
black body is proportional to the fourth power of its temperature.
M = Total radiant exitance from the surface of a material , watt (W𝑚−2)
𝜎 = Stefan – Boltzmann constant , 5.66797 × 10−8 𝑊𝑚−2 𝐾−4
T = Absolute temperature ( K ) of the emitting material
Continued
1 . Stefan-Boltzmann Law 2 . Wein’s Displacement Law
𝑴 = 𝝈𝑻 𝟒

17. 2 . Wein’s Displacement Law
The relationship between the true temperature of black body in Kelvin and its
dominant wavelength is describe by this law.
λ 𝑚 = wavelength of maximum spectral radiant exitance , 𝜇𝑚
A = 2898 μ𝑚𝑘 T = temperature , K
Where,
𝑀 𝑠𝑢𝑛 = 𝜎𝑇4
=(5.6697 × 10−8
)(6000)4
= 73479312 𝑊𝑚−2
λ 𝑚𝑎𝑥 =
𝐴
𝑇
=
2898
6000
= 0.483 𝜇𝑚 ( Visible energy)
𝑀 𝑒𝑎𝑟𝑡ℎ = 𝜎𝑇4 = (5.6697 × 10−8)(300)4= 459.2 𝑊𝑚−2
λ 𝑚𝑎𝑥 =
𝐴
𝑇
=
2898
300
= 9.66 𝜇𝑚(Thermal energy)
λ 𝒎 =
𝑨
𝑻

18. Blackbody
radiation
curves at
the
earth’s
temp
Blackbody
radiation
curves at
the sun’s
temp
6000

19. EM Energy’s Interaction with the Atmosphere

20. All the radiations detected by remote sensors pass through a distance which is called
path length.
The particles and gases in the atmosphere can affect the
incoming energy (EMR).
These effects are caused principally due to;
1.Atmospheric Scattering
2.Atmospheric Absorption
Continued
2 path
length
1 path
length

21. Scattering is the redirection of electromagnetic energy by suspended particles in the
atmosphere.
The type and amount of scattering that occurs depends on the size of the particles and
the wavelength of the energy. There are three types of scattering include;
a. Rayleigh Scattering
b. Mie Scattering
c. Non Selective Scattering
Continued

22. a.Rayleigh scattering
< wave length , 𝑆𝑟 ∝
1
λ
4
Gas molecule
c.Non-selective scattering
> wave length
• Water droplets or vapors
• It is due to the visible to MIR
wavelengths.
• Clouds and fog appear white due
to this type of scattering
Diameter
5-100
𝜇𝑚
Why sky is blue?
b. Mie scattering
= wave length
 smoke ,Pollen dust particles
• Mie scatter generally influences
radiation from the near UV to MIR.
• Mie scatter mostly occurs in the lower
portions of the atmosphere.

23. It is the process by which radiant energy is absorbed by atmospheric
constituents and converted into other forms of energy.
These gases tend to absorb Electromagnetic energy in specific wavelength ranges.
Water Vapors (𝑯 𝟐 𝒐)
Ozone(𝑶 𝟑)
Carbon dioxide(𝑪𝒐 𝟐)
Nitro oxide(𝑵 𝟐 𝒐)
Continued

24. The wavelength in which the atmosphere is particularly transmissive of the energy are
referred to as atmospheric windows.

25.  Sensible range
 Presence or absence of atmospheric windows through which we
wish to sense
 The source, magnitude and spectral composition of energy in the
spectral ranges.
A RS Sensor Requires…

26. Electromagnetic Energy Interaction with Earth Surface

27. Electromagnetic Energy Interaction with Earth Surface
Every feature on the earth’s surface can interact with EM energy in Three ways:
 Reflection
 Absorption
 Transmission
𝐸𝐼(λ)=𝐸 𝑅(λ)+ 𝐸𝐴(λ)+ 𝐸 𝑇(λ)
𝐸 𝑅(λ) = Energy Reflected
𝐸𝐴(λ) = Energy Absorbed
𝐸 𝑇(λ) = Energy Transmitted
𝐸𝐼(λ) = Total Energy

28. It can be described as sending back light(or other types
of energy) without absorbing or reacting with it in any
way
There is an angle of Incidence and a corresponding
angle of Reflection
Reflection can be Specular or Diffuse depending on the
surface on which the energy is incident
Specular
Diffuse
Incident Reflected

29. It can be described as converting incident
energy into other forms (internal energy)
This plays a role in what color an object
appears to be. For example, if an object
absorbs all frequencies in the visible energy
range aside from blue then only that energy
will reach the interpreter making the object
appear blue
Features that absorb all energy in the visible
spectrum appear black
Only blue reflected
All Visible Energy
Absorbed

30. This is when a surface or object does not
reflect or absorb the energy incident on it
but lets it ‘pass through’
Objects with high or maximum
transmission appear clear or transparent
An example is when water transmits some
energy to the surface below causing the
surface to heat up
Transmitting
Feature

31. Spectral Reflectance is the ratio of reflected energy to the incident energy, (both)
in terms of wavelength
It describes the energy emitted by an object and this value helps us differentiate
between the different features of earth
ρλ =
𝐸 𝑅(λ)
𝐸𝐼(λ)
=
𝐸𝑛𝑒𝑟𝑔𝑦 𝑜𝑓 𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ λ 𝑟𝑒𝑓𝑙𝑒𝑐𝑡𝑒𝑑 𝑓𝑟𝑜𝑚 𝑡ℎ𝑒 𝑜𝑏𝑗𝑒𝑐𝑡
𝐸𝑛𝑒𝑟𝑔𝑦 𝑜𝑓 𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ λ 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝑜𝑛 𝑡ℎ𝑒 𝑜𝑏𝑗𝑒𝑐𝑡
x 100
Reflected Energy
Continued

32. The reflectance values of a feature, in different ranges of wavelength, can be represented
graphically and compared. This form of representation is called a
Spectral Reflectance Curve
This can be as a Spectral Response Pattern or a Spectral Signature

33. Only NIR Band Multiple Spectrums

35. Spectral Signatures
 Green Grass  Dry Grass  Soil

36. Green Grass
 Water absorption bands
 Chlorophyll absorption bands
Dry Grass
 Some stress-low or no chlorophyll content
 Reflectance of red color along with green
Red + Green = Brown
Soil
 Coarse Soil- Low Moisture – High Reflectance
 Fine Textured Soil- More Moisture – Less Reflectance

37. Spectral Signatures
 Sand  Concrete  Asphalt

38. Sand
 More peak and valleys
 Max. reflectance in visible and NIR
Concrete and Asphalt
 Less peak and valleys
 Almost linear reflectance VS

39. Spectral Signatures
 Water  Clouds Snow

40. Water
 Reflectance in visible
 Absorption ahead
Snow
 Maximum reflectance in visible and NIR
 Absorption in MIR
Clouds
 Reflectance in MIR

41. Spectral Signatures Using ERDAS IMAGINE

42. Signature of Water

43. Signature of Vegetation

44. Signature of Sand

45. Remote Sensing and Image Interpretation sixth edition
https://profmattstrassler.com/articles-and-posts/particle-physics-basics/fields-and-
their-particles-with-math/7-particles-are-quanta/
https://global.canon/en/technology/s_labo/light/001/01.html
https://seis.bristol.ac.uk/~ggjlb/teaching/ccrs_tutorial/tutorial/chap1/c1p4_i4e.html
https://www.e-education.psu.edu/meteo300/node/682
https://imagine.gsfc.nasa.gov/science/toolbox/emspectrum1.html
https://images.search.yahoo.com/search/images;?p=remote%20sensing%20data%20pro
cessing%20softwares