What's the difference between thermal imaging and night vision goggle?

Infrared thermal imager

Infrared thermal imagers are completely different from ordinary cameras. The thermal imager can not only detect heat but also detect small heat differences (as low as 0.01 ° C) and display gray shadows or different colors. Everything we encounter in our daily life will release heat energy, even ice. The hotter something is, the more heat it emits. The heat energy emitted is called a "thermal signal". When the thermal characteristics of two objects adjacent to each other are slightly different.

NVG

NVG absorbs a small amount of visible light, amplifies it a lot, and then projects it onto the display. Cameras made from NVG technology have the same limitations as the naked eye: they can't see well without enough visible light. The imaging performance of anything that depends on reflected light is limited by the amount and intensity of reflected light. 

All these visible cameras (daylight camera, NVG camera, and infrared lighting camera) work by detecting the reflected light energy. However, the amount of reflected light they receive is not the only factor determining whether you can see with these cameras: image contrast is also important.

Thermal imagers can see them well because they can not only take images through thermal energy but also image thermal energy. They use the small thermal difference between objects to take photos. Night vision devices have the same disadvantages as daylight and low illumination cameras: they need enough light and enough contrast to create usable images. On the other hand, the thermal imager can clearly observe day and night, while creating its own contrast. There is no doubt that a thermal imager is the best 24-hour imaging choice.