IR interference from fluorescent lights

[Kelosh]

I am using IR motion capture cameras fo virtual reality application. The lighting in the lab has been switched to fluorescent shop lights would to know if there is a potential for functional interference to the IR signal.

 

[MikeHalloran]

I don't think you can get much IR from a fluorescent lamp.

To check, scan the area with a digital camera's electronic viewfinder; IR shows up nice and bright. To check that, use it to look at your TV remote.



Mike Halloran
Pembroke Pines, FL, USA

 

[DRWeig]

You can also get an IR-cut filter for your camera lens.

Best to you,

Goober Dave

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[DRWeig]

Ooops, sorry. I didn't read your original post thoroughly. You need the proper infrared for your work... My bad .

There are filters, sheeting, and films to block infrared that are either made for fluorescent lamps (slip-on tubes), or for fixtures (stick on the fixture diffuser), or just rolls of film to custom-make something. 3M is one maker, I'm sure you can find others with the Google machine. That's only if you really experience a problem, which you probably won't.

I agree with Mike, though. Fluorescence emits UV that must be controlled, usually by just the phosphor. Any IR emitted is parasitic and not the result of fluorescence. Perhaps the tiny amount comes from the heat at the small electrodes.

Best to you,

Goober Dave

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[Kelosh]

What about end of life on the lights? I heard from a trades electrician something about IR emission increases towards the end of life on the light and that it disrupted some equipment in another lab due to the phosphor depleting. Would it still be considered to small of an emmission to cause concern?

 

[IRstuff]

What "infrared" are you talking about, i.e., wavelength? Infrared covers 800 nm to 25 um.

Fluorescent lights have very little NIR content:

http://www.gelighting.com/na/business_lighting/spectral_power_distribution_curves/pop_curves.htm?3&7

Mocap uses highly reflective targets with dark backgrounds. I suggest you consult with someone who's done this before.

TTFN
faq731-376

 

[Kelosh]

"Fluorescent lights have very little NIR content" is what I am finding to be true, so it is not likely to to effect our tracking cameras. I have been using Mocap for the last 7 years and have had environment issues before and have been researching any potential problems with the new lighting system. I am feeling much more confident now that there won't be any issues. This is my first time using this forum. Thanks to all for your input.

 

[VEBill]

Typical IR motion capture cameras will display what they see (converted to a visible B&W image) on a local monitor. So if they're getting interference, you should see it on the monitor. Right?

 

[Kelosh]

I am using the Mocap cameras to define my positions within a virtual environment. The Mocap software allows us to mask out interferences as well as vibrations through a filter, however we have anomolies that pop up from time to time for each camera. We can find what is causing the anomolie buy moving a tracked object within the environment within the view of the cameras showing the anomolie to be an object (like an earing) most of the time. Then again we have had anomolies that we can't define that go away over time, only to return. We have decided to try scanning the area with a digital camera's electronic viewfinder to see if IR shows up nice and bright as suggested by Mike Halloran earlier in this thread.