I am making a big multitouch table use DI recently ,because one camera is not enough capture the whole surface,so must use 8 camera(I account) .
but the touchlib not supports multi-camera work at one time.
if some one have better method,please tell me,thanks!

MY MY ... your table must be huge then ... like 5ft X5ft!!!

Kidding how big is ur thing?

I have a few suggestions,

*use 1 extreme wide angle lens on a camera, or
*find some 3rd party software that combines multiple camera inputs into one tiled video feed.
*check out unibrain or point grey IEEE 1394, cameres, as i do believe theres a way to daisy chain them, into one image, with much smaller footprint on cpu/memory resources.

depending on your aspect ratio of the table you could go for stitching feeds from mulktiple cams… but the BIG question here is that u’ll need shit loads of processing power to process feed from 8 cams in real time… for sure one pc cant handle it (to add to that i am not sure if a single pc can connect to 8 cams at a time… well it shud i guess)… even if u’re using 640 X 480 res (.3 MP).... u’re talking bout processing 2.4 MP feed at atleast 20-25 fps (for smoother feedback) in realtime…

i have been using a octa-core (quad core dual processor 2.0 ghz) with 4 gig of ram… and tried processing feeds from 2 sony handycams (1394 connectivity 720X576 res ... comes to .45 MP) (this was not for multitouch but chroma and 3d vision) and was just bout able to get a output at 30 fps post processing ... the processing involved here was probably a little more that what is required for blob detection. but my point here is that 8 cams could be a problem to process…

i would reccommend what WILL said.... try a wide angle lens on a firewire cam that gives you a good res feed at a very hi FPS. but that depends on the aspect ratio of your surface.

another suggestion would be to have cams connected to different pc’s and you can listen to touch events through network but then u’ll need a seperate engine runnin on the main comp that maps the X,Y co-ordiantes from comp no. 1 - 8 to a local co-ordinate system (for eg: if your output res is 1024X768 , then the 0,0 from the second comp will be equal to 129,0 on the local co-ordinate to which your app should respond) ... i am suggestin just a logic here if someone can work on the programming part at your end....

I have had personal experience working on A very large Multitouch display system, it was about 10ft15ft. We used Acrylic sheets, with silicon rubber on them, with camera, projector, and mirror setup.  The screens response was very good as well, So multi cameras might not be worth the extra trouble.

JoshuaAM - 02 January 2008 07:37 PM

I have had personal experience working on A very large Multitouch display system, it was about 10ft15ft. We used Acrylic sheets, with silicon rubber on them, with camera, projector, and mirror setup.  The screens response was very good as well, So multi cameras might not be worth the extra trouble.

if you don’t mind...I’d like to hear exactly how it was laid out...or a diagram if you have one handy. Thanks

Yes, me too. like mirror placements and such.

Here is a video link of the screen inaction, this screen was setup built for HP by a company I used to work for called Obscura Digital. I will post more detail on the setup soon.

http://www.obscuradigital.com

navigate to work
then under featured work select HP
Click watch Video.

Wow, thats just nice! Looking forward to the detailed setup.

I don’t want to get too off subject here, but Joshua it would be great to have more info on the HP setup. I can’t get the HP page to load, but I’ve seen the video of it in action many times. I think a few of us speculated it was DI a while back when it was released; interesting to know if was FTIR with only 1 camera.