THERMAL IMAGING1.pptx

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THERMAL IMAGING CAMERA 

Presented by

Pushpendra Kr. Singh

2011CRF2279

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Flow of presentation 

• What is thermal imaging

• Infrared radiation

•

Thermal imaging camera components• Image interpretation

• Types o TIC

• Specification of TIC• Application

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Thermal Imaging

• Thermal Imaging is :

 – Detection of Infrared Radiation

 – Translation of the detected energy levels into a

viewable image

• It is a way to look at the “Heat Signature” of 

an object or person

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IR Radiation

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Infrared Subdivision

As per International Commission on

Illumination Infrared is subdivided as :

 – IR-A: 0.7 µm – 1.4 µm

 – IR-B: 1.4 µm – 3 µm

 – IR-C: 3 µm – 1000 µm

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A commonly used sub-division

scheme

• Near-infrared 0.78-1.4 µm in wavelength, can’t seethrough smoke, used in fiber optic telecommunicationbecause of low attenuation losses in the SiO2 glass (silica)

medium.

• Short-wavelength infrared : 1.4-3 µm, water absorptionincreases significantly at 1,450 nm. The 1,530 to 1,560 nmrange is the dominant spectral region for long-distance

telecommunications

• Mid-wavelength infrared : 3-8 µm. Used in IR homingheads of guided missile (passive heat seeking missiles)

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Continued… 

• Long-wavelength infrared : 8 –15 µm. This is the

"thermal imaging" region, in which sensors can

obtain a completely passive picture of the outside

world based on thermal emissions only andrequiring no external light or thermal source such

as the sun, moon or infrared illuminator.

• Far infrared (FIR): 15 - 1,000 µm. Used in far

infrared laser.

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Basic Components of TIC

Lens

IR Waves

Display Screen

Electronic Signal

Signal Processor

IR Detector

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Thermograms

Thermogram of a Lion

Thermogram of a Dog

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Image Interpretation

•Hottest Objects : White or Light Shades

• Coolest Objects : Black or Darker Shades

• Display is relative to the area viewed i.e. Thermal Contrast

 – How well objects stand out from one another, related to

detector sensitivity and the variance of temperature in

objects being viewed

 – Objects that have a high temperature variation, in relation

to the surrounding background, can be seen at greater

distances.

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Image Interpretation

High Contrast

Background and victim are distinct shades  – Betterimage of the Victim

Low Contrast

Background is faded together,

victim is almost the same shade as

the background

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Types of TICs

• There are two common types of thermal-

imaging devices:

 – Uncooled 

 – Cryogenically cooled 

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Specifications of TIC

• Number of pixels

• Minimum resolvable temperature

difference (MRTD)• Field of view

• Dynamic range

•Mass and volume

• Scan rate

• Cost

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Applications of TIC

• Night vision

• Fire fighting operations

• Military and police target detection & acquisition

• Predictive maintenance (early failure warning) onmechanical & electrical equipment.

• Moisture detection in walls & roofs.

•Non-destructive testing.

• Search & rescue operation.

• Medical testing for diagnosis

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References

• http://www.flir.com

• Paper on Infrared radiation by Lynn Bryant

•

Wikipedia• www.docstop.com

• Principles of Thermal imaging by Jacob

Thompson