| Having Night Vision gives you the ability to see in a | | | | disappointed. To get better light amplification an Image |
| dark environment. Seeing in the dark is made possible | | | | Intensifier Tube is often used. These devices amplify |
| by a combination of two approaches, namely: having | | | | the available light by a factor of ten thousand times, or |
| sufficient spectral range, and intensity range. | | | | more. This makes the images that would be normally |
| Spectral Range: Human vision is limited to a small | | | | unseen at night, able to be resolved. Unfortunately, |
| portion of the electromagnetic spectrum called the | | | | these devices require some light to amplify (even if it is |
| Visible light Spectrum. By improving spectral range, a | | | | only moonlight or star light), and are totally useless in a |
| viewer can take advantage of non-visible sources of | | | | zero light condition (total darkness). |
| electromagnetic radiation such as infrared (IR), or | | | | Active systems utilize an Infrared (IR) Illuminator to |
| ultraviolet radiation (UV). For Security applications, IR | | | | swamp the viewable area with light. Under these |
| radiation is normally used. | | | | conditions there is so much light that an IR sensitive |
| Intensity Range: Enough intensity range is simply the | | | | Video Camera can be utilized without having to |
| ability to see with very small quantities of light. Even | | | | purchase any type of Image Intensifier. |
| though the human visual system can detect single | | | | Other types of Night Vision Devices (NVD) include: |
| photons (under ideal conditions), this is far from | | | | Night Vision Goggles (or NVG), and Thermal Imaging. |
| adequate for good night time viewing. | | | | NVG utilize two eye pieces. They can be configured |
| Through the use of Technology (Electronics), the | | | | with one Image Intensifier Tube, where the same |
| process of 'Seeing in the dark' (Night Vision) can be | | | | image is sent to both eyes, or a separate intensifier |
| loosely grouped into two subsets: Passive and Active | | | | tube for each eye. |
| systems. | | | | Thermal imaging cameras are excellent for night vision |
| Passive systems rely purely on the sensitivity of the | | | | use. They display thermal radiation, and do not require |
| Vision system to resolve a given screen (or Video | | | | a source of light. They produce an image in the dark |
| image). By utilizing only a Video Camera (CCD Sensor) | | | | that can seen through fog, rain and smoke giving them |
| in a dark environment: the viewer will normally be very | | | | great advantage over other detection methods. |