THERMAL VISIONTHERMAL VISION

Presented by ~~ Presented by ~~ AMARJIT BISWASAMARJIT BISWASECEECE

INTRODUCTIONINTRODUCTION

Also known as Infrared thermography, thermal imaging, thermographic imaging.

Infrared radiation is emitted by all objects near room temperature.

Thermography makes it possible to "see" one's environment with or without visible illumination using the Infrared radiation.

When viewed by thermographic camera, warm objects stand out well against cooler backgrounds.

Difference between infrared film Difference between infrared film and thermographyand thermography

IR film is sensitive to infrared (IR) IR film is sensitive to infrared (IR) radiation in the 250°C to 500°C rangeradiation in the 250°C to 500°C rangeWhile the range of thermography is While the range of thermography is approximately -50°C to over 2,000°C. approximately -50°C to over 2,000°C. For an IR film to show something, it must For an IR film to show something, it must be over 250°C or be reflecting infrared be over 250°C or be reflecting infrared radiation from something that is at least radiation from something that is at least that hot. that hot. Night vision infrared devices image in the Night vision infrared devices image in the near-infrared, just beyond the visual near-infrared, just beyond the visual spectrum, and can see emitted or reflected spectrum, and can see emitted or reflected near-infrared in complete visual darkness. near-infrared in complete visual darkness.

PRINCIPLE OF OPERATIONPRINCIPLE OF OPERATION Thermal imaging displays the amount of infrared energy emitted, transmitted, and reflected by an object.

Incident Energy = Emitted Energy + Transmitted Energy + Reflected Energy.

Reflected Energy is the amount of energy that reflects off the surface of the object from a remote thermal source.

The thermographic camera employ a series of mathematical algorithms to 'see' the electromagnetic radiation with its emissivity setting.

The ability of objects to emit or absorb radiation is called emissivity.

PASSIVE v/s ACTIVE PASSIVE v/s ACTIVE THERMAL SCOPETHERMAL SCOPE

In passive thermography, the features of interest are naturally at a higher or lower temperature than the background.

o Used in surveillance.

o Medical diagnosis (thermology).

Active thermography on the other hand, an energy source is required to produce a thermal contrast between the feature of interest and the background.

o Used for objects with erratic temperatures

LIMITATIONS OF THERMAL OPTICSLIMITATIONS OF THERMAL OPTICS

Due to the low volume of thermal cameras, cameras often have a high price range (often US$6,000 or more). Images can be difficult to interpret accurately when based upon objects with erratic temperatures.

Cold blooded animals such

as Reptiles and Snakes

can not be seen.

APPLICATIONAPPLICATION

USING THERMAL OPTICS WILD-LIFE OBSERVERS CAN WORK AT

NIGHT TO STUDY ANIMAL BEHAVIOUR.

THERMAL OPTICS CAN ALSO BE USED TO DETECT FAULT IN

MACHINES.

APPLICATION contd.APPLICATION contd.

MILITARY PERSONNEL USE THERMAL SCOPED WEAPONS FOR NIGHT WARFARE.

AIRCRAFTS WITH THERMAL SCOPE

PROVIDE BATTLEFIELD

SUPPORT.

FUTURE SCOPEFUTURE SCOPE

Thermographic cameras can be fine tuned to detect human diseases such as CANCER.

Tumor affected areas are designated as red or orange hot markings.

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