FreeTrack Forum

Hi!  So it seems that, if I want to use IR LEDs, I must remove the IR filter from my webcam and replace it with a visible light filter taken from a floppy disk.  I still like to use my webcam from time to time for video conferencing and online classes, so I kind of would prefer not to ruin it forever.  :P

Have I any options apart from just buying a second webcam?  :\

Thanks!  

Hello sillysilly


In Freetrack, all is about contrast.
You need to acheive a high contrast image on your webcam for freetrack to work (that's the whole screen black and only the marker dots white, nothing else).

This is obtained by using bright markers, relative to the general lighting of your room. The main problem is , if your markers are too bright , you'll have to deal with unwanted reflections on your screen (which is annoying)

Working in IR mode , using VL filters and removing the webcam IR filter helps reach this goal, by allowing to have those bright markers without the screen reflection problems (the reflections are still here , but since they're in IR range , we don't bother as we can't see them   ).


You can try to get the same result without removing the IR filter :
- by using bright red leds and a light VL filter
- by using 880nm IR LEDS, high powered, and a light VL filter (SFH485P at 50 to 75mA are fine).


!!!! WARNING :

If you try this setup with IR leds, you MUST use 880nm LEDS :
- they are far more easier to track by an unmodded webcam (880nm is near the edge of the IR band, so stock webcams are able to see it as a kind of red).
- some stock webcam even can't perceive 940nm IR leds, due to strong IR filter.

cya