Multispectral Remote Sensing

Sumetted by :-Dharmendera Kumar meena

Content

1. Interoduction2. Types Of MS Remote Sensing

(a) Line detector

(b) Wishbroom (c) Pushbroom3. Application of MSS

Introduction OF MSS

• Defination :-MSS is define as the collection of reflected, emitted and backscattered energy from an object in multiple bands of electromagnetic spectral

OR• Multispectral remote sensing is

generally based on acquisition of image data of Earth's surface simultaneously in multiple wavelengths.

Types OF MS Remote Sensing

• We Use Mainly Three Types Detector in mss (a) Line detector (b) Wishkbroom (c) Pushbroom (d)(a) Line Detector :- • In Line Detector sensor detect

only one object at a time

Whiskbroom scanning

Wiskbroom OR Cross-trackIn whiskbroom a mirror of fixed size rotates along an axis and the energy received from the ground is focused on to a spectrometer or grating for dispersion into different spectral bands. After dispersion the reflected radiation is focused on an array of photovoltaic cells and energy sensed in different spectral bands is than calibrated.

The widely used cross-track scanning system employ a faced mirror that is rotated by an electric motor, with an horizontal axis of rotation aligned parallel with the flight direction.

Wiskbroom OR Cross-track

Along-track or Pushbroom scanning

Along-track or Pushbroom scanning These sensors do not use opto-mechanical device and have no moving parts. The energy coming from ground directly falls on the array of charge-coupled devices {CCD), which calibrate the received energy and change it to digital counts. This method allows sensing of energy for larger time and hence results in better signal. • GIFOV :- Ground projected instenteneous FOV• GSI :- Ground projected sample interval• FOV :- Fieeld of view• IFOV :- Instenteneous field of view• GFOV :- Ground projected field of view

Circular scanning

Circular scanning The scan motor and mirror are mounted with a

vertical axis of rotation that sweeps a circular path on the terrain. Only forward motion of the sweep is recorded to produce images. An advantage of this system is the distance between scanner and terrain is constant and all the ground resolution cells have the same dimension. Circular scanners are used for reconnaissance purposes in helicopters and low flying aircrafts. The axis of rotation is tilted to point forward and acquire images of the terrain well in advance of the aircraft position.

APPLICATION OF MSS

1. In Military :- To gather military intelligence or information about terrorist information about ground targets and activities of national security significance .

2. IN Medical :-Most medical remote sensing is designed to "see into" the body without having to be invasive (cutting it open).

3. X-Ray :- Tomographic imagery is the outcome of a CAT Scan which today is a widely used means of imaging primarily the body's soft parts

4. -Land Assessment 5. -Tostudy seasonal variation