Follow-Up on CCTV Blinding Gear
Ranamacar has been kind enough to come up with a detailed set of instructions on how to modify a standard-issue ball cap into the CCTV IR-blinding device referenced previously in this post.
Thanks!
posted by Concerned American | 3:37 AM
6 Comments:
what would prevent this from more fully illuminating one's countenance?
would be interesting to test the concept - say at a store or financial institution displaying images on customer viewed monitors...
"what would prevent this from more fully illuminating one's countenance?"
The fact that we're working with infrared LEDs means that they emit light that the human eye can't see.
The cameras have a feature known as "auto-gain" which opens up the aperature more in dark situations (just like your pupils dilate in a dark room) to let in more light. The IR LEDs will produce much more light than is being reflected off of your face, and since they are fairly directional (30 degree spread is normal) they will cause a "flare" on the camera. Think of it as having a kid shine a flashlight in your face at night- it knocks out your night vision for a while.
ranamacar
oh. makes sense. i see now. tested yet?
thank you.
I'm gonna bet that a license plate with strategically placed drilled holes, through which LEDs emitted might cause a similar blinding effect? Day/night?
you could buy one of the LED ballcaps that are sold at sporting goods stores and tear it apart and replace the normal LED's with infrared LED's
I have two batches of IR LEDs on order, but it will be at least two weeks before they are delivered (coming from China). I will prototype a few of my spare ball caps and test them on the cameras at work. Give me three weeks and check back on my blog
http://ranamacar.blogspot.com/
I have some other irons in the fire that I may post about while I'm waiting for my LEDs. Technology is a two-edged sword.
ranamacar
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