Originally developed for the military use, night vision technology allows one to see in the dark. We humans have poor night-vision compared to many animal species. But now with proper equipment we can see a person standing far away on a moonless cloudy night !
Today in the 21st century we have come a long way in developing night vision technology since it’s discovery. It is used mainly for defense purposes, as the law oftens prohibits its application within scientific or civilian ranges.
Night vision technology works in two different ways, namely Image Intensification and Thermal Imaging.
- Image intensification:
This method basically involves ambient light amplication. It works by being able to detect low levels of light and then amplify it. When photons( tiny energy packets that make up light) enter an image enhancer they first hit a layer called a photo cathode which releases electrons. These electrons hit a second layer called a micro channel plate which multiplies the electrons before they hit the phosphor screen which converts them back into light because there are now so many more electrons that we get a brighter image.
But this model fails if there isn’t enough light for the thermal enhancers to see at all.
- Thermal Imaging:
This approach requires capturing the upper portion of the infrared light spectrum emitted as heat energy by objects instead of being simply reflected as light. Temperature is detected by capturing the different levels of IR radiation. Although we cannot see the light in the dark, but it can be felt as heat provided the intensity is high enough.
But thermal imaging has many disadvantages: too costly, image formed is of poor quality and we cannot see the target objects if there are transparent obstacles in our field of view.
Night vision devices:
- Scopes – Monocular device, hanheld or mounted on a weapon.
- Goggles – Binocular and worn on the head.
- Cameras – Used for capturing images/ recording videos.
- No particular skill is required.
- Compact system.
- Reduction in accident cases.