Daylight TV cameras, image intensified (I²) night vision devices, and the human eye all see the same thing: reflected visible light.
Unfortunately, we need visual contrast to discern an object from its surroundings and at night there is very little visual contrast to work with. Conventional night vision scopes are great for situational awareness, but they can’t see in total darkness. Conventional night vision scopes also struggle to penetrate foliage or make a picture at great distances.
The examples below demonstrate how Image
Intensified Night Vision and Thermal Night vision differ.
Active Infrared
This image is an example of amplified, intensified or active infrared light through a night vision goggle or scope. Relying on reflected visible light, this image may show some detail, but will certainly miss the camouflaged figure in the trees.
Thermal Infrared
This image is an example of thermal infrared. Notice immediately that the FLIR camera detects heat signatures, and does not amplify any light. In fact, this requires no light at all. The figure’s heat signature is clearly distinguishable within the trees and described as “white hot”.
Visible Light Camera / Human Vision
Without the thermal infrared technology, essentially you’ll be left in the dark. As mentioned above, night vision goggles are limited in their capability to see objects in low light. Most visible cameras are even worse, they won’t show much of anything in the dark.
Thermal Infrared
With the thermal infrared you can see in total darkness regardless of lighting conditions. Capture sharp crisp images anywhere with the proper distance for your lens. The only resistance you may experience would be with water or heavy moisture. Thermal infrared cannot see through glass or water.
Thermal Energy in Day-to-Day Life
Everything we encounter in day-to-day life gives off thermal energy, even ice. The hotter something is, the more thermal energy it emits. This emitted thermal energy is called a heat signature. When two objects next to one another have even subtly different heat signatures, they show up clearly to a thermal imager regardless of lighting conditions.
Thermal imaging cameras will vary in price depending on the features of the camera. The camera’s resolution and lens options will often dictate the price. The higher the camera’s resolution, the better image clarity and detail you will see on images and video.
Good afternoon,
So far, I am impressed wtih the Thermal Imaging products–especially since we live in a high crime area…and if I see great results would definitely promote the Thermal Imaging Cameras. However, just out of curiousity, the details you provided specifry that these products clearly pick up objects which are heated (obviously any living creature; as well as some machinery). Would these thermal imaging products/cameras help for example when looking for a missing person or pet…what if in worst case scenario they are laying on/in the ground having suffered a fatal injury or fatally hurt by a fall or shot by an uncaring individual? Since these cameras detect body heat and usually the human body or pets won’t have any more body heat–how can these thermal cameras work in those unfortunate cases? Thanks
You bring up some very interesting points, and your concerns are very valid. These thermal imaging cameras are very sensitive to temperature changes. They way the technology works is the sensor detects the difference between the ambient temperature of the scene and the subjects in that scene down to less than 1°F. Although a deceased body is no longer the same temperature as a living person or animal, it still retains some heat. The amount of heat retained by the body depends on the length of time that goes by and weather conditions. Additionally, the process of decomposition gives off heat. Regardless, there will still be a marked difference between the subject and the surrounding scene. These cameras are excellent, if not essential, tools for search and rescue efforts.