What is each used for?
In: Physics
Thermal is for seeing heat levels, infrared is radiation and night vision is expanding low light to see better in the dark.
Infrared camera illuminate in front of them with short wave infrared radiation, which bounce back from the surface and enter the camera, making an image.
Thermal camera don’t illuminate anything. See any object emit what we call thermal radiation depending on their temperature. This is why the heating element of your oven glow reddish. Most object around us is low enough in temperature that they emit their thermal radiation in infrared. A thermal camera will detect that radiation and depending on the wavelenght they detect, it can show a gradiant of temperature.
Night Vision transform photon in electron, then multiply the number of electron and transform them back into photon. That way, even if there is very little light, you can see. But that doesn’t work in complete darkness. That said, night vision google often work at the boundary between visible light and infrared, and so they can use the same technics as an infrared camera too. So when it’s too dark for the amplifycation method to work, they just shine an infrared light and can still see.
Thermal can pick up heat sources making it useful for targeting. In the context of a vehicle it can be used for blacked out night driving, the high contrast in the viewer makes it easy (if bumpy) to drive with whereas night vision would be too blurry between the road and sky and edges of the terrain. You can easily pick out the heat of a person or animal as it stands out against the background. Some systems have “red hot” overlays where temps over a certain amount show up as red on the black and white feed, making them instantly stand out. The downside is that things that are mostly the same temperature are basically just a blur. It depends on the use and model of thermal, some are better than others when it comes to looking at low temp variations.
Night vision is image illumination. The natural image strikes a plate inside the view tube and the same image, but brighter is displayed on the eye piece. It is better for on foot navigation as it picks up more obstacles and pitfalls clearly where thermal would see them all as a cool blur, so picking out very fine details is harder. Night vision can also see IR light sources (by picking the “near infrared” spectrum not the heat itself). So, a dark corner with no natural light can be illuminated with an IR flashlight and viewed through night vision. IR lasers also mean targeting to varying degrees of precision is possible.
Modern night vision-thermal fusion devices try to combine the qualities of both. They are like night vision devices, but with the overlays from thermals, causing high or low temps to be highlighted within the viewer.
frequency. They work under the same principle – blackbody radiation. In thermal radiation, it detects only the temperature of a body, in infrared it detects every temperature and in night visio it detects the infrared/blackbody radiation coming from an object – that’s why soldiers can see from dark such as tank, its engine produces heat then its body absorbs it, then it will release blackbody and it can be detected.
Thermal vision sees light that the human eye cant see, which is emmited by warm objects. That is very useful when you are seeking a human or an animal but you dont know where they are, because their bodyheat makes them light up. Downside, it cannot see through glass and it erases any detail or features. You just see the shape.
Night vision multiplies the amount of light that is already there. That is why early nightvision devices were called starlight scopes. Modern night vision provides extremely clear picture. You can actually see thing like faces, read text etc. But camouflaged things (whether it be humans in camo or naturally camouflaged animals) are generally still camouglaged and thus hard to see under night vision. That is why hunters often have a handheld thermal unit that they use to find the animal but they take the actual shot under nightvision to see better and to be absolutely sure that it actually is the animal they are looking for.
Infrared vision. Both night vision and thermal vision devices are extremely expensive. Too expensive to be used in applications like security cameras. On the other hand, a floodlight attached to the camera would make it annoying and easy to spot. Lucky for you, camera electronics does actually pick up some wavelengths of light that the human eye cant see, namely infrared light. Only most cameras come with a filter on the lense because the infrared light would be visible on your photos and videos and it would look different that what you eye sees in real liffe. But for a security camera, you can get one without the filter and use an infrared light attached to it so that the camera can see at night without any visible light being emmited.
TL. DR.:
Thermal – sees heat
Night vision – sees regular light, only its much more sensitive than your eye
Infrared – basically a regular camera with a special light attached that you cant see but the camera can
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