INFRARED IMAGING

By

Sonawane Swapnil R

Sub.: CV

Department of Electronics & Telecommunication

VIIT, Pune

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OUTLINE

Infrared light

Emissivity

Infrared Thermography

Principle

Image format

Image camera

Advantages

Disadvantages

Applications

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INFRARED LIGHT

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Sir William Herschel

EMISSIVITY

a = absorption

t = transmission

r = reflection

For a blackbody, absorptivity=emissivity=1

Practically, absorptivity + transmissivity + reflectivity = 14

PLANCK’S LAW

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INFRARED THERMOGRAPHY

Detect the infrared energy emitted from object and

produce images of that radiation, called

thermograms.

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PRINCIPLE

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IMAGE FORMAT

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INFRARED CAMERA

Infrared cameras operate in wavelengths as long as

14,000 nm (14 µm)

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INFRARED CAMERAS...

Two types having:

Cooled Infrared detectors

Uncooled Infrared detectors

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Cooled Detector Uncooled detector

1. Use sensors with

operating range from 4K

to just below room

temperature

Use a sensor operating at

ambient temperature

2. Cooling is necessary for

operation of

semiconductor materials

used

Cooling is not necessary.

3. Use sensors that work by

catching IR radiations

Use sensors that work by

change of resistance,

voltage or current when

heated by infrared

radiation

4. Require cryogenic

coolers for cooling

Do not require such

bulky, expensive

cryogenic coolers

5. They are expensive both

to produce &run

They are smaller & less

costly

6. Materials used: indium

arsenide, lead sulfide

Materials used:

amorphous silicon,

vanadium oxide

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ADVANTAGES

It shows a visual picture so temperatures over a large area can be

compared

It is capable of catching moving targets in real time

It is able to find deteriorating, i.e., higher temperature components

prior to their failure

It can be used to measure or observe in areas inaccessible or

hazardous for other methods

It is a non-destructive test method

It can be used to find defects in shafts, pipes, and other metal or

plastic parts

It can be used to detect objects in dark areas

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DISADVANTAGES

High price range

Images can be difficult to interpret accurately when based upon

certain objects

Accurate temperature measurements are hindered by differing

emissivities and reflections from other surfaces

Only able to directly detect surface temperatures

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APPLICATIONS

Preventive maintenance applications in building systems

Moisture inspection

Medical imaging

Night vision

Military

Conditional monitoring

Veterinary thermal imaging

Research

Process control

Nondestructive testing

Chemical imaging

Volcanology 14

REFERENCES

Roglski A. Chrzanowski K. 2002, “Infrared devices

& Techniques” contributed paper: Opto-electronics

review

www.wikepedia.org

www.howstuffworks.com

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THANK YOU

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