What is the Difference Between Night Vision Devices and Thermal Imaging?

[Dorothy]

The biggest difference between night vision devices and thermal imagers lies in their working principles: thermal imagers convert invisible infrared energy emitted by objects into visible thermal images, while night vision devices rely on an image enhancement system to actively receive light sources. They require external light sources to illuminate the object and reflect back to the night vision device for multiple receptions before an image can be formed. The effects are different. If you have used a regular night vision device, you will notice that the observation experience is completely different from that of a standard infrared thermal imager. This is because typical night vision devices observe the target directly through the lens, resulting in a circular field of view with a green-tinted image, similar to what you see through a telescope lens. If the clarity is sufficient, it may be possible to identify who the target is or even discern facial features. In contrast, infrared night vision thermal imagers display images on an internal LCD screen rather than directly observing the target, so the field of view is square. The imaging of an infrared night vision thermal imager is based on temperature distribution. Higher temperatures appear brighter, while lower temperatures appear darker. The primary purpose is to locate the target and determine its category, such as distinguishing between humans and animals. The impact of lighting conditions differs: second-generation night vision devices are more affected by environmental factors due to their imaging principles, especially lighting conditions. When the light dims, the observation distance shortens. In complete darkness, an auxiliary infrared light source is required, but its maximum range is limited to about 100 meters.