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FreeTrack Forum > FreeTrack : English Forum > Support : Tracking System > Problems tracking my 3 led settup.

RSS >  Problems tracking my 3 led settup.
Phantoms #1 01/01/2008 - 19h25

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I've built a cap 3 point setup using IR LEDs from Radio Shack. They are RS model 276-0143 and spec as 5mm High Output IR LEDs, 1.2 Foward Voltage, 100mA Foward Current, 45° viewing angle. I sanded the domes flat to increase the viewing angle, and built the system with the recommended 24ohm resistor for a 6v setup (four AAAs).

My webcam is a Phillips model of which I have removed the IR filter and set it to manual control, redeuced exposure, turned off white balance, etc. 30 fps 640x480 video. Also added two strips of exposed film over the lens.

As the video below shows, the webcam software has no problems tracking the LEDs, but in FreeTrack the tracking jumps around occasionally even when my head is held still. This is nearly impossible to use in any game.


http://home.comcast.net/~phantoms/temp/VideoFT.mpg
Kestrel #2 02/01/2008 - 03h03

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The tracking points in your video are too big and aren't being tracked properly, correct tracking only occurs when the tracking crosses are always centered on the tracking points. It seems your webcam is out of focus, producing large blurry blobs, while being a little out of focus can make the tracking points appear smoother and produce better tracking, being too out of focus creates tracking problems.
francoistarlier #3 03/01/2008 - 00h35

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You look like Sam Fisher ... :D

-__-' ok that wasn't funny, nevermind ...
Phantoms #4 04/01/2008 - 02h01

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Sorry it took a while to respond. I tried to reply yesterday but I've been fighting connection problems with my ISP  :( .

Kestrel, you are the man.

My webcam has a screw-in piece of plastic that holds the lens. When I removed the IR filter, I had screwed that back in until it was snug. After you're comment I disassembled it to check that.

While it was apart on my desk, I screwed this housing in and out to check if it affected focus, and it does. I adjusted it until the webcam was in sharp focus and then took the video below before reassembling it.

http://home.comcast.net/~phantoms/temp/VideoFT2.mpg
Edited by Phantoms on 04/01/2008 at 02h05.

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