First of all, you must be aware of the fact that our eyes are able to see only the reflected light. And you will be shocked to know that the daylight cameras, night vision devices, and also our human eye is able to see an image based on the same fundamentals.
Hence, you can say that visible light energy hits an object, and then it bounces back, and the moment it happens, the detector receives it and then transforms it into an image. But at the same time you must keep one point in your mind that irrespective of the fact that it is an eyeball or a camera the detector must be able to receive enough light otherwise they will not be able to make any image.
Here, an important question that might have crossed your mind that during the nighttime, we do not have any sunlight to reflect any light. Hence, they are just limited to the lights that are received by the moon, start, and also the artificial light. Now let us understand the difference between thermal imaging and night vision scope.
Thermal Imaging
Well talking about the thermal imaging let us let you that it would be even better if we can address thermal imager as sensors instead of the camera. In order to get a clear idea about thermal imaging, you must understand how they work. You will be shocked to know that the thermal optics can detect heat as small as 0.01 degree Celsius, and the difference in heat are indicated with some different shades of grey and color. More about thermal optics, you can check at scopesreviews.com.
source:visiononline.org
Understanding could be a bit tricky, but you must know that everything which we encounter in our day to day lives gives off thermal energy and this is true even in the case of ice. But you can say that a hotter object emits more energy compared to the cold ones. And as the different objects absorb and radiate different thermal energy so the area which you will be viewing will be a mosaic of different temperatures.
source:visiononline.org
The thermal imaging or you can say as the thermal optics detects this temperature indifference and then at the same time, they also transform it into the image detail. It may seem to be very complex, but the real fact is that the modern thermal cameras are very easy to use and operate.
Night vision scope
You might have encountered the greenish picture in the movies, and it is only possible with the use of night-vision goggles, which is also known as the NVGs. According to agmglobalvision.com, the main thing that a night vision scope does is that it takes some small amount of light, which is visible, and then it magnifies the same and projects that on display.
source:visiononline.org
You will be amazed to know that the cameras, which are manufactured based on the same technology as that night vision scope, have the limitation like that of the naked eye. This means that if there is not enough visible light, then you will not be able to see it.
source:visiononline.org
One demerit of NVG or the lowlight camera is that they are not very useful during the twilight house. Thus, you can say that they become highly ineffective in the presence of excess light, but the thermal cameras are not at all affected by the visible light.
