Night Vision Devices

The last seminar (Visual Computing) talked about Near Infrared Red (NIR) and that arouse my curiosity on how Night vision devices works. Is it using NIR or something else. Always have I wondered how NVD are able to work in the night when the illumination was so terrible. I had the fortune of using it before during my army days but I did not bother about the mechanism behind it.

Apparently, there are 2 different way of how NVD works, namely image enhancement and thermal imaging.

Image enhancement works in a way that it amplifies the surrounding light. It collects whatever possible amount of surrounding light including the lower portion of infrared light spectrum

On the other hand, thermal imaging works with the upper portion of the infrared light spectrum, which is emitted as heat by objects.

In this case, I was more interested in thermal imaging so I Googled more of it and this was what I found.

Thermal Imaging

1. A special lens focuses the infrared light emitted by all of the objects in view.

2. The focused light is scanned by a phased array of infrared-detector elements. The detector elements create a very detailed temperature pattern called a thermogram. It only takes about one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram. This information is obtained from several thousand points in the field of view of the detector array.

3. The thermogram created by the detector elements is translated into electric impulses.

4. The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from the elements into data for the display.

5. The signal-processing unit sends the information to the display, where it appears as various colors depending on the intensity of the infrared emission. The combination of all the impulses from all of the elements creates the image.

Image courtesy of Infrared, Inc. The basic components of a thermal-imaging system

source from : http://electronics.howstuffworks.com/gadgets/other-gadgets/nightvision2.htm

It sometimes caught me how amazing technologies are. With technologies, we are able to overcome constrain our human genes ain't able to (In this case, we could actually even see in the dark. ) However, this technology is more commonly used in the military than as a aid to human society. I would hope that technology such as this would benefit the human daily life such as driving in the dark more than a tool used by the military to detect enemies.