Film-Tech Forum ARCHIVE: CCTV with IR in auditorium

This is topic CCTV with IR in auditorium in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Amanda Mundin (Member # 3386) on 10-30-2005, 05:11 AM:

Hi all
I'm planning to have CCTV in the auditorium probably mounted at the screen end pointing back towards the audience, to 'supervise' the audience as we intend to have the auditorium licensed for alcohol consumption, and assume i'll need InfraRed lighting in order to be able to get a constant visible image, I also assume that because IR is out of the visible spectrum of humans no one will see the light, does anyone envisage any problems I may have using IR lights during the show?
Thanks in advance

Posted by Kevin Baglow (Member # 721) on 10-30-2005, 05:51 AM:

You could arrange the red LED's around the walls in an artistic manner, a glow in the dark mural!!
There are also very low light video cameras to be considered. Don't forget to put up a sign advising patrons that the theatres are equipt with 'see in the dark' security cameras.

Posted by Cory Isemann (Member # 2517) on 10-31-2005, 07:30 AM:

How tough would it be to make a light arrangement like that? Could you just wire them all up or would you need ICs and resistors and the like. Also, would shooting infrared light at the patrons for two hours pose any health threats?

Posted by Frank Angel (Member # 248) on 10-31-2005, 09:46 AM:

Old video cameras that used saticon tubes which see infrared as well as it sees white light can be used to look at the seating area. They can probably be picked up for pittance on ebay, if they can be found at all. They were sometimes used in live theatre aimed at the stage so the stage manager would see what was going on when there was a black-out cue. I think there are IR lights that use brighter technology than LEDs -- halogen with IR filters perhaps?

Posted by Chris Trainor (Member # 9) on 10-31-2005, 12:29 PM:

Flooding something the size of a movie theater auditorium with IR is going to be a challenge. Most of the IR stuff out there is LED based and has a very narrow beamwidth and not a whole lotta output. They are mostly used for illuminating small areas like breezeways, entryways, etc. The big commerical stuff is gonna cost a fortune.

If you have any amount of lighting going on during the show (dimmed houselights, etc are fine) then a good high-grade B&W camera should do just fine. If it's bright enough for humans to see where they are going, then a B&W camera should be able to see as well. Color cameras won't work in any case, even with IR lighting. Just find a B&W camera with a really low lux level and you should be OK between the houselights and the screen reflection for lighting.

--Chris

Posted by Brad Allen (Member # 470) on 10-31-2005, 12:48 PM:

I have used these, and they work very well.
Hawk-I security cams

Posted by Gordon McLeod (Member # 33) on 10-31-2005, 10:54 PM:

Also it may interferre with a IR based hearing impaired system