How Does Thermal Imaging Work

July 3, 2020

 

What Is Thermal Imaging?

Infrared waves have common uses including remote control, heat lamps, earth imaging. They are also commonly used by hunters to locate games and also by the military and law enforcement ( for example to find people hiding in the dark and running through trees or even to detect marijuana grow operations).

Now, let's dispel some common myths about thermal imaging.

• Thermal imaging can not see people through the walls. You can only detect things in its line of sight that gives off heat.
• It can not be used to detect if a suspect is carrying the gun somewhere on their body.
• It can be used to see people in the dark and detect other heat sources well.

If you live in a place with animals you can potentially use thermal imaging to hunt. What is more, a great variety of scopes on the market allow you to easily find animals that otherwise are difficult to spot without a traditional scope. Thermal imaging can also be beneficial for home defense and perhaps give you the advantage to see your enemies before they see you.
There is a great variety of different types of thermal imaging devices that are available to consumers including monoculars, binoculars, thermal imaging cameras, and even devices that you can connect to your phone and turn that to your thermal imaging device.
In order to hide from thermal imaging, you need to conceal your body heat. Let's remember an old movie Predator with Schwarzenneger where the creatures used thermal imaging to find people. In one scene Arnold covers his body with mud making these creatures unable to sense his heat.
The best way to consume yourself from thermal imaging is to cover yourself with something that reflects your body heat back at you. With mylar, for example, that is a relatively cheap and highly reflective material.

How Does Thermal Imaging Work?

A thermal imaging camera features a unique lens that allows infrared energy to pass through it. Then the focus light hits a sensor that scans the information and draws from several thousand points in the field of view. Through this process, an intricate temperature pattern known as a thermogram is created which only requires one-thirtieth of a second to develop. The thermogram then transforms into electric impulses which are directed to a signal processing unit that translates the information into data for the visual. The created image displays various colors that correlate to the amount of infrared energy emitted. It is a combination of elements that generate the image that hunter professionals rely on. The hotter an object is, the more infrared radiation it generates.

How Is It Different Than Night Vision?

Night vision goggles and scopes make images from visible light just like our eyes. Such images provide excellent situational awareness at night. Unfortunately, magnifying the amount of light in an image is only one part of the solution to true night vision. The critical element night vision doesn't address is visible image contrast. That's what you really need to be able to see at night when the target is brighter than its surroundings, it has good visual contrast and is easy to see. When the target doesn't have a good optical difference you can't distinguish it from surrounding. As we already know, thermal cameras see the heat, not light. So, the more heat an object gives the more thermal contrast it generates, and the easier it is to see.
Everything on earth gives off the heat: people, animals, car engines, etc. Atmospheric conditions like smoke or fog reflect light making night vision make night vision goggles and scopes even less effective but thermal cameras see through these obscure clearly. Night vision devices need to have the right amount of light to work well. If light levels are too low like in rural areas and when looking into deep shadows they won't be able to see anything. If there's too much light like from the street light, security lights, or car headlights they become oversaturated. Thermal cameras have none of these limitations. That's why airborne law enforcement units and special operations forces around the world choose thermal imaging devices.