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FreeTrack Forum > FreeTrack : English Forum > Support : Tracking System > LED selection and visble light interferance, need help... :)

RSS >  LED selection and visble light interferance, need help... :)
uzipaz #1 28/12/2010 - 13h31

Class : Apprenti
Posts : 4
Registered on : 27/11/2010

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Hello everyone,
           I am a total newbie in this business...I have a

'Logitech C120' webcam, I have tested it with freetrack and its

working great, I am getting 30 fps with almost 0 JPS... thats

great...

now the problem is that it detects almost every light source as a

marker... I have a light bulb behind my computer... and the light

strikes on the webcam, the FreeTrack software detects it as a LED

marker...

How can I deal with that???

One More thing, there is an option in the Webcam Software for 'Led

Control'... I can turn it 'Off', 'On' or set it to 'Automatic'...

So, If I turn it 'off', Do I still need to remove the IR filter in

the webcam...

Which LEDs should I use??? Standard LEDs or InfraRed LEDs????
If I disable LED Control in the webcam software, Can I use

InfraRed LEDs and at the same time prevent visable light from

interfaring with the sofware???

Is there a way So that I can use standarad LEDs and still prevent

Ordinary light from interfaring with FreeTrack software??

Please Give me neat and straightforward answers... I will greatly

Appreciate you guys for your help... Thanks :)

and my Hats of to the all people who contributed on this

software.. Thank you so much and please keep working on it.. :D
tracker #2 28/12/2010 - 21h45

Class : Apprenti
Posts : 26
Registered on : 09/10/2010

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Hi.


When you have IR leds on your webcam try to turn them on and use a pointer from some reflexive material. Could be from reflexive safety car vest?

If you are lucky, it would be possible not to remove IR filter and use only filter which blocks normal light - from old floppy disk or film. And you could be able to use this setup with just reflexive pointers. Check a post here with constructions. There is a photo.

If your webcam blocks IR light, then well, you will have to remove IR filter. Point a remote control with IR led at your webcam and you will see if there is IR filter.

I would prefer IR leds because you don't see any light from it. It's good for night gaming. It should be led with wide angle. Osram SFH485P has +-40 degree. You can buy a pack of them from seeedstudio with P&P for cheap:

http://www.seeedstudio.com/depot/original-osram-ir-led-sfh485p-10-pcs-pack-p-69.html?cPath=28

I hope you will understand this. If you will have any question, ask...
Edited by tracker on 28/12/2010 at 21h52.
uzipaz #3 29/12/2010 - 10h42

Class : Apprenti
Posts : 4
Registered on : 27/11/2010

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Thank you for the answer...

I want to make 3 point system... I am inspired by this model.... orginally by user: zaelu

http://i32.photobucket.com/albums/d36/zaelu/freetrack/sample.jpg

I have made a hat just like this...

another question is that... How much important is for the LED assembly to be accurate in length with respect to each other.....

If you take a close look at the hat in the picture... the 3 leds doesnt follow the length and dimensions of the 3 point system assembly as directed in the software... so will it concern if my 3 leds assembly is just like this?!?

Thanks again...  :)
Edited by uzipaz on 29/12/2010 at 11h41.
tracker #4 29/12/2010 - 18h48

Class : Apprenti
Posts : 26
Registered on : 09/10/2010

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You can use your model dimensions and edit them in freetrack software. Or it can be in some scale- 2:1, 1.5:1, ... It doesn't matter. However, dimmensions are a bit limited both by the software and how a webcam can recognize which led is top, left and right. You should experiment with this.

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FreeTrack Forum > FreeTrack : English Forum > Support : Tracking System > LED selection and visble light interferance, need help... :)

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