How Thermal Vision Works

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Using a thermal scope for rifle crosshairs could be fascinating, especially under ideal conditions. However, it’s important for every user of thermal vision equipment to know how these devices work. Through this post, you get complete information on how thermal vision works, and everything else you need to know.

The Invention of Thermal Vision

Hungarian physicist Kálmán Tihanyi receives credit as the inventor of what we now call thermal vision. Tihanyi invented the world’s first infrared (IR) sensitive camera in 1929. Further tweaks to Tihanyi’s original design made it easier to render images just as we know it today. In the late 1940s, it used to take one hour to develop a single thermographic image.

Today, smart sensors, high-resolution imagery, and other features have eclipsed the first breakthroughs in thermal vision technology.

Principles of Thermal Vision Work

Thermal vision works with a special lens that captures IR light from all objects in its scope. It’s worth noting that all objects give off some form of heat. Thermal imaging devices amplify the heat signature through scans powered by IR detectors.

These signatures are represented in a temperature pattern referred to as a thermogram. To make it easy, here’s a breakdown of how thermal vision operates:

  • A special lens focuses IR light from all objects in an environment
  • IR light is scanned through a phase of IR-detector elements, creating a thermogram
  • Thermogram is translated into electrical impulses
  • The electrical signals are relayed to a processing unit for transformation into display material
  • The processing unit sends information to the display with colors appearing based on their IR intensity.
  • All combined electrical impulses are seen as a thermal image through a screen

A hotter object will give off more IR light than relatively colder items in the environment. For example, a burning vehicle will give off more IR light to a dead pigeon. However, the dead pigeon will still appear in a thermal image, but with much less visibility.

Types of Thermal Vision Devices

Thermal vision devices have an impressive scan rate over other imaging devices and can detect small changes in temperature. Currently, there are two types of thermal imaging devices available to the public:

Cryo-cooled thermal vision devices

These thermal vision devices have their entire systems sealed inside a cooling container, hence the cryogenic name. Inside the container, all elements are always cooled below the freezing point (32°F). With such cooling support, the cryogenic thermal vision device supports better image rendering quality.

An immense resolution feed along with higher sensitivity is the main reason why these devices are prized equipment. In most cases, thermal vision devices are rated by their ability to notice small differences in temperature. The cryogenic thermal vision device can tell temperature differences just above the freezing point (32.1°F).

Also, the cryo-cooled thermal imager can spot such differences from hundreds of meters away. What this difference means is that you can tell if someone is armed from about 300m – 350m out. Such a vision could make a difference for hunting and surveillance personnel.

Apart from being ideal for night hunting, cryo-cooled thermal vision equipment can work in total darkness. Unlike night vision, you don’t need to have ambient light to detect movement in pitch-black areas.

Cryogenically cooled thermal vision gear is usually more fragile and pricier on the market. These devices are costly due to the immense work put into their storage conditions for a clearer image. However, most of these thermal vision devices may not survive rugged use and are suitable for professionals only.

Uncooled thermal vision devices

Thermal vision devices that run in an uncooled container are ideal for conventional use. These devices can work with surrounding temperatures based on their components.

Uncooled thermal vision devices usually have high-powered detectors that analyze essential visual metrics to standard views.  With this feature, it becomes easy to assess the voltage, current, and resistance heating in comparison with regular sight.

These thermal imagers are less expensive and can work in rugged applications due to their overall design. Anyone from hunters to curious homesteaders can use these devices to great effect.


When you need to make sense of objects in dark environments, you need a thermal scope. For rifle users, knowing how thermal vision works helps in targeting and improves visibility under a moonless night.

If you plan to use a thermal imaging device for hunting, it’s better to settle with an uncooled option. Cryogenically cooled thermal vision devices are more sophisticated but have a higher price tag. But if you’ve got a big budget to work with, the choice rests entirely in your hands.

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