|
If you came to this site, you probably want to know how to set up a low cost night vision system. First what you have to know is that night vision isn't worth crap if other people can see you. In that case, you could just about install a sensor into the room that you "want to see" and if the sensor "senses" somthing, it lites a lamp. The true night vision must be set up as an individual stand alone system and the purpetrators must NOT see the emitted light. To achieve this efect, you must emit IR (infra red) light. You cannot buy lightbulbs that would emit such a light (or at least I haven't heared of it) instead, you buy IR emitting diodes - not recieving but emitting (such are used in your TV remote for instance) or you can buy a field of these diodes to achieve greater lighting of the room. If you predict, that only some parts of the room have to be lighted (for instance entry points such as doors and windows), you can use some sort of lens to focus the IR light onto that spot. NOTE: Your system will depend on the quantity of your photones in a n×n field or to say otherwise it is dependant on the energy with wich you emit and on the density of your light stream. OK. Now that we have this covered, you have to have some sort of sensor to see in this IR light. NOTE: Our eyes do not see IR, because it's wavelegth is too long (or too short... hm I never seem to get it right :). Anyhow you don't see it. But a perfectly normal camera does. Use any kind of camera (preferrably some sort that can be plugged onto computer and then on to the VCR) that can be set to B/W (black and white). Because B/W can sense only the shadings of any color and the intensity of it (Only Y of the YUV composite signalling methode) you get only the information you want. The low quantities of IR light that the camera is able to sense can be seen in some gentle shades. To increase the effect, simply amplify the whole picture on your computer. This way you have real time amplification at all times. But our eyes are still not used looking at B/W (Black) pictures, especially if you want to se some details. For this reason, again at your computer change your B/W picture to color and discard Red and Blue, so that you get pure Green picture. That should do the trick, since our eyes are most sensitive fo green color. There you have it. A bit of tuning afterwards
increases the effect and you can read some guy's license plate numbers in full darkness (joke).
You might also want to try your luck with UV (ultra violet) light (try using the lightbulbs used for checking money, 'cos the emitted light has to be "invisible" for our eyes so disco UV lights are out of the question. The problem you'll encounter will probably be that the camera won't change enough light into electricity (if any even) or that you won't get any results due to the fact that UV light doesn't reflect enought from distant objects or if the person is wearing black, there'll also be some "problems" since UV is just a light with very short wavelength. Ok. I wrote enough. For any additional questions, e-mail me. I check my mails almost daily.
Written by: Simon Novak - a.k.a. Geco
|
|
|
 |
|
