Anybody knows if Tbeta software can works capturing shadows and apply the system to a floor projection?
Could I modify it to do shadow tracking?
What I’m trying to do is something like this ( http://www.rmh.de/fish_pool ).
Can someone put some example of this?

Thanx in advance!
Mladen

Well, tBeta works for Front DI, so yes. Front DI relies on shadows to find blobs. Floor projection is more than just that though - check this thread out: http://nuigroup.com/forums/viewthread/2772/

You might want to use something more ‘stable’ than just relying on shadows - perhaps FTIR or DI?

hope this helps
rbedi100

Hi.

I’d say basically yes, tBeta could be used for your purpose, although floor/wall front projection requires some more relaxed tracking.
Imagine your projector/camera is mounted on the ceiling looking downwards you’ll get a lot of occlusions and overlaps.
Hence, it’s not that easy to define, what a shadow is and to keep track of it.
Sometimes there won’t be any shadows at all, so the normal background subtraction/threshold/scale/segment pipeline will not work well enough.

Also, this approach is even more difficult in terms of changing lighting conditions, even in dark locations (e.g. club locations, http://www.vertigo-systems.de/cocoonclub.html?&L=1#ul )
In addition, for floor/wall projections it is often desirable to have the actual (processed) camera image to perform some classic water/ripple interaction, using a grayscale map.

This would be a nice feature for tBeta, once source code is available (sending a processed/compressed cam image in addition to the TUIO data)

Alex

Thanx!
What camera would be best for tracking?
What about using optitrack cameras, model FLEX:V100?

Mladen

I don’t think you need that kind of elaborated cams, they’re more suited to do mocap (e.g. for games and movies).
Just use one of the usual suspects like fire-i, point grey or ps3 eye.

But they have low FPS?

for fast movement…
e.g. http://www.youtube.com/watch?v=D1EyuqKaHQE&feature=related

You can look at our website as well, most of the stuff is rendered at 60fps with camera 30fps and a latency of 1 to 2 frames (Fire-I cams).
You might need faster cams for really high-speed accurate tracking (like the mentioned mocap) or tracking of Multitouch screen.
If you really need 60fps cams, take the ps3 eye or the xbox cam or give one or use of these http://www.theimagingsource.com/de/products/oem_cameras/firewire_mono/

What do you think about wiimote?

FireWire Monochrom-OEM-Kameras are not IR cameras???

The Black And White Version of the Fire-I is very sensitive in the IR range, so perfectly suited for Multitouch or Read/Front DI configs.

Alex,
which camera do you prefer than?
FireWire Monochrom-OEM-Kamera (60 FPS, 640*480) or Firefly MV (Point Grey)?
If I use one of this camera with interactive floor, do I need to buy infrared source (such as a IR LED ring)?

Thanx,
Mladen

Whatever camera fits your budget. In Europe I’d prefer the Fire-I BW camera 30fps, rather cheap, sony ccd, for example: http://www.1394store.com/eshop/product.asp?dept_id=55&pf_id=2050
Normally you use an infrared pass filter (highpass or bandpass above 750nm) and a suitable IR source.
The hard part is not so much the HW alone but the combination of HW/SW and robustness in most lighting conditions.

Perhaps, another way to explore it´s to do a test with Retina from Alessandor Valli or Veejay ( for Linux), to do a Interactive floor traking

http://www.veejayhq.net/features/
http://www.interactivespaces.net/projects/WisdomWells/Support/Download/Retina_1.0.0.msi

Cheers