Forum

Video tracking with multiple cameras

vvvv beta question
#1

Hi,

my current project involves the tracking of the movement of several persons inside a room.
But since the room height is only about 2,5m, and I want to cover at least 3x8m it seems like I’ll need more than one camera.

Has anyone of you experience with this? I think the best solution would be, in theory, to merge the incoming video streams and do the tracking afterwards!?

I though about buying 2, or maybe even 4, sony ps3 eye cams. Do you think I’ll get performance problems because of the USB bus?

I appreciate your thoughts…

Best regards,
Claude

#2

Hello,

Already done project with 2 camera for multitouch purpose.

The things is to map the value incoming from the 2 camera
after being process by your Tracking plugin :

for 2 cam and 1 renderer :

Camera 1 :

-1 ; 0 for x
-1 ; 1 for y

Camera 2 :

0 ; 1 for x
-1 ; 1 for y

and then use the cons node to join them

#3

Sounds easy. Thanks, I’ll try that - as soon as I get the PS3 Cams working.
Currently vvvv keeps crashing when I insert a VideoIn node…

#4

seems there is a new driver out:

#5

hehe, the new driver was part of the problem…^^

after installing and uninstalling the older v2 driver the newest one now works. strange, but i don’t mind ;-)

but now i encountered a new problem:
the fiducial tracking doesn’t work reliable enough for distances > 70cm. i tried bigger markers, played with resolution, contrast and threshold, but it’s still not good enough.
any ideas?

with simple background supression tracking i can’t track individuals if their “blobs” merge once.

so the new plan could be color tracking.
freeframe color tracking seems to like some preparation,
ie fancy hats or stuff like that.

has anybody tracked people just based on the (random) color of their clothes - viewed from above, yet?

#6

I just received mY New Ps3 cam which has been bought only for Vvvv… following the previous link… I found the driver that is working with it… But it look like an extra pin is needed for framerate and other properties… With CL-Eye test (the software gave with the drivers) I’ve got 2 property page… One with With white balance,… which is the same as the VideoIn properties pin… but Framerate Pin seems not to work… And this is the most important thing about this Cam : it’s framerate up to 125 fps… and I can’t use it whith Vvvv… Any Idea???

#7

I also forgot to mentionned… that I tried both under XP and 7… may be an extra Node especially made for Ps3 cam will be a great Idea

#8

hi claude,
I did it with 2 cams from above and colortracking. Link see 1:45 and 2:21 So, its possible ;) Ive done it like this:

-Background Substraction(!) shader, this will keep colors alive for colortracking and clears image.
-There was a fixed position, where you start installation and colortracker inits immediately at color of visitor at his point.
Will work bad with dark colors colors though, because of Background shader is black.
-I had big troubles to merge both cams as they were widelenses and thus a quite distorted image. As a result people moving in the middle of/direct under my camera are a head only and at the edges people are head and body (towards center) through widelens distortions and optics.
So you have to do a remapping of your values anyway.

I would recommend first to try a tracking of each cam by colortracker seperately as Digitalslaves said. Its easier than trying to undistort widelenses. And I dont think 4 USB cams will work at one Pc only. But I dont know how it works if you have more than one moving around, how colortracker handles loosing and finding colors, could be tricky to find a smooth solution then. But might be easy either. V4 often surprises me ;)

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