Hello everybody!
I want to discuss two firewire cameras with you.
The first camera is well known in this forum…
-the unibrain fire_i Board camera B/W for about 154 $
It has a uncompressed vga resolution (640×480) and should be
pretty fast because of its relatively low resolution
and a high framerate. 
The unibrain board cameras also benefit from the fact
that you can order the lens seperate. 
(no ir coating)(better C mount lenses)

According to infos of experienced people,
you need about 60 Pixel, for safe tracking a fiducial.. 
Considering that, we can easily calculate, which resolution we need..

Example calculation:

table: 120 x 80 cm
camera resolution: 640 x 480 Px
Pixel per cm: 5 Px / cm
Size Fiducial: 60 Px / 5 Px = 12 cm

That means, the worse your resolution(640*480), the bigger your fiducial has to be(12 cm).

Now that I dont want a huge fiducial size ( i want many of them on my table)
So I´m considering buying a
Fire-i board XGAb b/w camera Price: $749.00
with a resolution of 1024 x 768 square pixels.

The price is very high for me so I want to be relatively sure that I´m
satisfied with this camera.

Here´s the website with the two cameras
http://www.1394store.com/eshop/dept.asp?dept_id=51

Sooo…
what do you think of theese two cameras compared to eachother?
I know there are camcorders out there with the same resolution,
firewire and a good nightshot mode, for less money than the unibrain XGA.
And I think thats exactly the reason why I can´t imagine that the handycams
doing better. 

So I hope I could help you with my fiducial
size calculation (got it from Patrick Kocklik)
And I also hope that you maybe can help me a bit with my decission
which camera to buy....

Why don’t you just use two unibrains?
You’d get the same resolution and a bigger surface of view even tough there’s more cpu utilization it should to the trick.
ReaTivision has built in commands for image-stiching from two cameras exactly for this purpouse.
Don’t waste 800$ on the fire-i XGA , that’s just overkill.

Suggestion:
I’d recomend to skimp a little and go for two xbox 360 vision cams.
They do 640x480@30fps and cost about 10-20$ on ebay and their really sensitive to IR light when the filter is removed , check Fairlane’s setup.
With the money you just saved invest in a better computer , in a dual camera setup you’ll need all the speed you can get.
On a P4 setup CPU utilization got close to 40% with two VGA cameras.I’d recomend getting a core2duo or a quad core based machine.

Thanks for your reply !
I didn´t knew that you can use 2 cameras with reactivision.
It´s a very good idea. But as i searched through the reactivision user forum,
I found thread if its possible to use more cameras.
“Well, this could of course be done in theory ...
reacTIVision is not prepared yet to use multiple cameras though.
Additionally it will probably be tricky to calibrate the two cameras to create a seamless image.
best,
Martin.K “

So it seems that it isn´t possible. Exept you know something I don´t.
If thats the case please share your knowledge with me!
Thank you very much !
le_wuus

I remember seeing something on the reacTIVision forums or on here about a dual camera setup.You can also use vvvv , i know that for shure has been done here.

http://vvvv.meso.net/tiki-view_forum_thread.php?comments_parentId=13133&topics_threshold=0&topics_offset=62&topics_sort_mode=replies_desc&topics_find=&forumId=7

Also why would you need such an insane resolution?Reactivision works just fine with one VGA camera and alot of fiducials , atleast from what i’ve seen.

http://nuigroup.com/forums/viewthread/272/#1381 <--- also talk to the author of this thread.

thank you very much for your interest in my problems.

The thing is I have to know how big the difference between the vga and the xga is.
And I found out that “the imaging source” have also very good industrial
firewire cameras which they do rent you for testing them 14 days WITH EQUIPMENT!
So I ´m getting a camera and 3 different types of lenses with it and then
I´ll see if the money is worth it.
And then I´ll post again…

Ok , post your results please when you get it.But i think you should try it with a decent VGA camera as well , all the reacTable tables i’ve seen use vga cameras and work like a charm.

le_wuus - 13 June 2008 04:20 AM

thank you very much for your interest in my problems.

The thing is I have to know how big the difference between the vga and the xga is.
And I found out that “the imaging source” have also very good industrial
firewire cameras which they do rent you for testing them 14 days WITH EQUIPMENT!
So I ´m getting a camera and 3 different types of lenses with it and then
I´ll see if the money is worth it.
And then I´ll post again…

any updates on this?

Hello again!
The camera arrived yeasterday so I´ll post again within the next two days.

HI !
So now you get my report on the IMAGING SOURCE XGA firewire camera:

What I can say till now is that for the format of my surface ( 100cmx80cm) it is working great.
I got 3 different lenses for evaluation. One CS-mount, and 2 C-mount lenses. (for 69.00, 183,00 and 220,00 €)
and all of them are IR sensitive.
So far the two C-mount lenses are doing a great job. The picture is very sharp even though the camera is more
than 130 cm away from the surface.
My fiducials are allowed to have the minimum size of 4-5 cm which is very small.
The cam has 30 fps and the provided software allows a huge amount of possibilitys to controll the picture.
There´s also another software where you can direcltly code to the camera ( via .NET component, ActiveX, C++ Class Library ).

What I really like about it is that you can manually controll the aperture (hope it´s the right word for it...)
like you manually controll lenses for a reflex camera.

So my résumé is that I will buy this thing. Because I´m very interestet in the tracking thing and I want to research it much more.
I think it´s a good investment for the future.

So maybe there´s a much cheaper VGA alternative out there which is good for my project.
But maybe it´s cheaper for me buying just the one expensive camera than buying
one camera after the next which don´t work.
And you can´t give a camera back when you scratched of the IR coating....

I can´t really recommend you buying this camera (because I have just experience on my setup)
but what I can really recommend is that you´re able to rent theese things (without paying for it, you just pay caution money)
for 2 weeks with many different lenses.
I think that´s a very good deal you get here.

Hello,
I would say that with that table size and camera resolution, you should be OK with a fiducial size of around 6cm
You probably should also try the new markers that come with the reacTIVision 1.4 prerelease, since they should perform better in low resolution conditions.
best,
Martin.K

le_wuus - 09 June 2008 03:23 AM

table: 120 x 80 cm
camera resolution: 640 x 480 Px
Pixel per cm: 5 Px / cm
Size Fiducial: 60 Px / 5 Px = 12 cm

That means, the worse your resolution(640*480), the bigger your fiducial has to be(12 cm).