Author Topic: 3d finger tracking setup  (Read 14474 times)

Offline wizzed

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on: July 06, 2009, 05:15:50 PM
Hi,

would it be sufficient for simple 3d tracking of (up to 4) fingers to put one led-array in the middle and 2 wiimotes placed aside (with some distance)?

Also i can't yet see how many leds would approximately be needed.

Thanks,
wizzed



Offline cloudflint

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Reply #1 on: July 06, 2009, 05:24:11 PM
hi,

For my array I have 130 leds spaced as close together as possible, this gives me an effective range of about 2 meters.

when you say 2 wiimotes places aside do you mean like one pointing from in front and one pointing from the side to give full 3d? Each wiimote can track 4 points so if you only wanted two axes one wiimote would be enough.



Offline wizzed

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Reply #2 on: July 06, 2009, 05:41:55 PM
Thanks for the quick answer.
130 leds for 2 meters is not as efficient as i hoped :|

I thought about a simplified setup which i can put into my workspace.
I also want 3 axes, so i thought 2 arbitrarily placed wiimotes and a software-side calibration process would be the easiest.

Here is a schema to clarify what i mean:


edit: changed schema slightly to avoid misunderstandings
« Last Edit: July 06, 2009, 08:09:45 PM by wizzed »



Offline cloudflint

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Reply #3 on: July 07, 2009, 02:51:48 PM
i just tried the set-up in your diagram.

I found that if I had the wiimotes pointing parallel to the array, I got nothing back

Turning the wiimotes in slightly meant that I was able to pick up the point on both wiimotes imultaneously but in a very small area, probably a few inches left and right. it also limited my distance since I had to hold my finger at the correct distance so that both wiimotes could see the marker.

The problem seems to be that leds shine their light pretty much in a straight line so the light that is reflected from the markers seems to be getting reflected back in a fairly specific direction depending on the angle the markers where held at.

So I would say that to do this you would probably have to use markers which where able to disperse the infra-red light so that it is reflected back over a wider area, or just use multiple arrays.



Offline wizzed

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Reply #4 on: July 07, 2009, 03:02:47 PM
I guess the problem is mainly with the reflective material, but higher dispersion would also lead to a lower intensity.

I found and ordered an ir illuminator with 80 illumination angle and will simply test it with that.
Worst case scenario is i have to order one more.

Thanks for trying out :)



Offline wizzed

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Reply #5 on: July 07, 2009, 04:53:56 PM
Turning the wiimotes in slightly meant that I was able to pick up the point on both wiimotes imultaneously but in a very small area, probably a few inches left and right.
Ah, misunderstanding here by the way: i intend to have them positioned so that angle between their viewing directions is >=45 and <=90
I want to use the wiimotes relative position (aquired through calibration) for the 3d finger tracking.



Offline cloudflint

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Reply #6 on: July 07, 2009, 05:02:16 PM
ah I  see, I managed to get a set-up like you describe using two arrays and cameras mounted 90 degrees from each other. This gave full 3d tracking.



Offline bridleman4

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Reply #7 on: December 11, 2009, 03:08:39 PM
Hey guys,

I've constructed a setup sort of like what you're talking about above.  I have two Wiimotes pointed inwards at angles and gloves with IR LEDs on the fingertips pointing in two directions.  It allows both 3D finger tracking and gesture recognition.  I posted a Youtube video about it, it's here: http://www.youtube.com/watch?v=7gc87ZGSP6A .

Nick Bridle
Rice University



Offline Jiazzz

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Reply #8 on: December 01, 2010, 10:07:53 AM
Can this setup be used to "easily" create a finger tracking interface with Windows 7 and/or Ubuntu?

I've got a 36" LCD screen and I want to make the gestures approx. 45cm (18 inches) in front of the screen, like there's an area in the air functioning as the touchscreen. So I don't want it to respond if my hands aren't "on" that area.

Can this technique be used together with Microsoft's own touchscreen interface?