How Does Thermal Imaging Work?

How Does Thermal Imaging Work
Alfred Mendoza

The thermal imaging camera has become an indispensable tool for a variety of civilian and professional purposes. It helps you see in the dark and locate hidden or distant objects. It’s handy, safe, fast, efficient, and accurate.

But, how does thermal imaging work? To understand its technology, here’s a simplified process.

Thermal imaging detects and measures infrared wavelengths emitted as heat from objects and converts these into an image. This non-contact technology can detect temperature differences of everything within view.

The hotter an object is, the shorter the light wavelength, and the more infrared radiation or infrared energy is emitted. 

The image is featured in various palettes representing the temperature range of the different parts of an object.

Warmer temperatures appear in shades of orange, red, or yellow, while colder temperatures are in hues of purple, blue, or green.

Some thermal cameras use grayscale color for more clarity of an image.




How Does It Work?


Objects emit infrared light, which is beyond the visible light electromagnetic spectrum but can be detected by a thermal camera. This infrared radiation is invisible to the naked eye.

Thermal cameras are equipped with special lens and minute measuring sensors known as microbolometers. Each sensor records temperature and assigns a pixel for each color.  

Detectors will send the temperature information for image processing using complex algorithms. Then, the detector elements will produce a detailed temperature pattern known as thermography. 

The signal-processing unit sends the translated infrared data to the display screen. After which, the circuit board creates an image of varying colors depending on the heat intensity of the infrared light.

When Do You Use Thermal Imaging?


The use of thermal imagers is nearly limitless. It’s been used extensively in law enforcement, particularly for safer and stealth operations like locating suspects who are at large. [1]

The thermal camera is also used for rescue operations, surveillance, security, process monitoring, and threat detection. 

As a handy gear, thermal imaging devices are used for hunting elusive animals, such as deers and elks. 

Furthermore, a thermal imaging camera is an essential tool for preventative maintenance used by electricians, mechanics, plumbers, construction technicians, engineers, and firefighters.

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Unlike thermal imaging cameras, night vision devices require visible or ambient light to detect objects. NV devices provide more realistic images like a television camera than thermal imagers.

Thermal cameras are more effective in detecting and producing images of targets that are camouflaged and obscured by dust, smoke, or fog. You’ll find a more in-depth discussion on night vision vs thermal imaging here

Yes. Some ways to hide from thermal imaging cameras include: standing behind glasses, covering up with a thick woolen blanket for insulation, blending in warm products or objects like thick walls or stones, and wearing an insulated jacket, pants, and hat, and covering your face with something cool.

Thermal imaging cameras can detect heat or infrared radiation from objects as far as your eye can see. However, the distance at which it can detect IR depends on the object’s size and contrast. It also depends on the resolution and field of view of your thermal camera.

No. Walls are thick and insulated enough, thereby blocking the infrared radiation or infrared energy from what’s behind them. But if the wall causes enough temperature difference, then the thermal imager might sense the object.

Concluding How Thermal Imaging Works

The thermal imaging system is one of the most outstanding multi-purpose innovations. Thermal cameras work differently than ordinary cameras. They use a unique lens that can detect wavelengths of light beyond the visible light spectrum. 

An object, living thing, or product emits infrared radiation or heat, which a thermal camera can detect. This information is converted into an image displayed on the screen that’s visible to the naked eye. 

People use thermal cameras in all sorts of mechanical and industrial maintenance operations. They are helpful in any law enforcement application, rescue scenarios like when someone is lost in the woods or trapped in building rubles, and many more.



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