This document provides an overview of the fundamentals of remote sensing. It discusses that remote sensing involves acquiring information about the Earth's surface without direct contact through sensing and recording reflected or emitted energy. It describes how remote sensing can be done via satellites, which capture satellite images, and aircrafts, which capture aerial photographs. The document outlines different types of satellite images like true color composite and false color composite images. It also discusses key concepts in remote sensing like spatial resolution, radiometric resolution, spectral resolution, and components of a remote sensing system. Finally, it provides an overview of the electromagnetic spectrum and how the atmosphere can impact the quantity and quality of electromagnetic radiation captured by satellites.

1. Fundamentals of remote sensing
By
Ashok Peddi

2. Remote sensing is the science of acquiring information about the Earth's
surface without actually being in contact with it. This is done by sensing and
recording reflected or emitted energy and processing, analysing, and applying
that information.
Remote Sensing can be done by two different ways
1)Satellites –satellite Images 2)Aircrafts-Arial Photographs
Satellite image
Aerial photography

3. Examples
Aerial photography Satellite image

4. To analyze(Visual Interpretation) the satellite imagery we use
different combination of bands where it will produce two
variety of(composite) images
1)True Color Composite(RGB)
2)False Color Composite other( than RGB)
True color False Color

5. Quickbird
PAN – 61 cm

6. IKONO
S
MSS/
XS – 4
m
Bagdad
, Iraque

7. What is a satellite
image?
Satellite imagery consists of photographs
of Earth or other planets made by means
of artificial satellites which also gives an
opportunity to process the image and
conclude with analysis depending on your
requirement.

8. Description of a Satellite Image Urban area
River
Urban area
Vegetation 3500 m
The different Bands
Blue Green Red

9. Spatial resolution
23
40
Landsat TM 30 m 10
SPOT XS 10 m 70
NOAA/AVHRR 1100 m
120
IKONOS 4m
The value retained in each pixel is designated by digital number and it
translates the solar energy reflected by the earth surface (covered by the
pixel).

10. Radiometric Resolution

11. Urban area
River
Urban area
3500 m
Blue Green Red

12. Blue Gree Red Spectral Resolution
TM 1 nTM 2 TM 3
Near Infrared Middle Infrared Middle Infrared
TM 4 TM 5 TM
7
432
743

13. Components of a remote sensing system
A – Energy source of illumination F – Transmissions, reception and processing
B – Interaction with the atmosphere G – Interpretation and analysis
C – Interaction with the target
E – Recording of energy by the sensor

14. v = frequency
(number of cycles per second
passing a fixed point)
Wavelength is measured in meters (m) or some factor of meters such as nanometres
(nm, 10-9 m), micrometers (μm, 10-6 m) or centimeters (cm, 10-2 m).
Frequency is normally measured in hertz (Hz), equivalent to one cycle per second, and
various multiples of hertz.

15. Quantity of radiant energy is expressed in energy units.
Quality of radiant energy is characterised by frequency
(u) or wavelength (l).
c=lu
c - velocity of light (3x108m/s)
Wavelength and frequency are inversely related to each
other:
• the shorter the wavelength, the higher the
frequency;
• the longer the wavelength, the lower the frequency.

17. Electromagnetic spectrum
The electromagnetic spectrum is the range of all
possible frequencies of electromagnetic
radiation.* The "electromagnetic spectrum" of an
object has a different meaning, and is instead the
characteristic distribution of electromagnetic
radiation emitted or absorbed by that particular
object.
*The energy in remote sensing is in the form of
electromagnetic radiation.Electro magnetic Radiation is
a particular form of energy emitted and absorbed by
charged particles

19. The visible portion of the spectrum is a
very small part of the whole spectrum:
•blue - 0.4 a 0.5 mm
•green - 0.5 a 0.6 mm
•red - 0.6 a 0.7 mm.
1 mm = 10-6 m
The wavelengths smaller than 0.4
mm entails:
• gamma rays
• x rays
• ultraviolet radiation

20. The part of the electromagnetic spectrum with
wavelengths larger than 0.7 mm entails:
• infrared (0.7-10 mm),
• microwaves (1mm-1m)
• radio waves.
Infrared goes from 0.7 mm to 10 mm and can
be divided in three areas:
• Near infrared (0.7-1.0 mm),
• medium infrared (1.3-3.0 mm)
• thermal infrared (> 3 mm).

21. Interaction of electromagnetic radiation
with atmosphere
The atmosphere has a strong effect on the quantity
and quality of the electromagnetic radiation captured
by the satellite.
The atmosphere effect varies with:
• radiation path (airplane, satellite)
• wavelength
• atmospheric conditions (particles, gases, …)
• ...

22. Before radiation used for remote sensing reaches the
Earth's surface it has to travel through some distance of
the Earth's atmosphere.
Particles and gases in the atmosphere can affect the
incoming light and radiation. These effects are caused
by the mechanisms of:
• scattering
• absorption.
What is the effect of atmosphere in the satellite
images?
• Atmosphere reduces contrast
• Atmosphere may blur the images
• Atmospheres may reduce the quantity of
radiation

23. I hope that was useful 
@ashokped
Thank you!