Hello Laurent, and thank you very much for taking time for our issue.
We already noticed this issue: at first the total time of the shooting
is around 40 seconds. Then, it is 18 seconds :)
The problem is, that for the 3D modeling, we really need the best
resolution available for the webcam...
Any other idea (Another cam with high res, hardware tweaking, or such
thing...)?
Thanks!
Pierre.
On 9 juil. 08, at 18:48, Laurent Pinchart wrote:
Hi Pierre,
On Wednesday 09 July 2008, MARTIN Pierre wrote:
Hello list people :)
i have been posting about some issues i had a couple of monthes ago.
The company i'm working for was in the need of a system with 5
webcams, able to shoot simultaneously "objects" from 5 different
POVs.
The generated pictures are then used for 3D modeling.
Big problem, the "object" is a horse, so the total time of shooting
has to be around 10 seconds, not more, because holding a horse still
for more than 10 seconds require super powers, which we don't have
(Or
are too expensive, i dont know) :)
So we bought 5 quickcam 9000 pro, since the required resolution to
have a find 3D mesh is 1600x1200.
Actually, all the webcams are wired to a single USB hub, and a little
application i have coded handles a very simple queue when the user
presses the "shoot" button.
The application simply calls the uvccapture command, waits for it to
finish, stores the result, and starts uvccapture on the next camera
(/
dev/video0 / 1 / 2 / 3 / 4) and so on.
The task takes around 18 seconds it's a bit too much.
So i was wondering... Why not to use two USB hubs to wire the
cameras,
3 cameras on the first hub, two on the second, so the application
will
be able to shoot two cams at the same time, then again, then the one
remaining?
So today i coded this workflow on my application, /dev/video0 to /
dev/
video2 on the first hub, /dev/video3 and /dev/video4 on the other.
The goal was to shoot video0 / video 3 at the same time, then
video1 /
video4 at the same time, then /dev/video3.
And i was very surprised to see that the system doesn't allows me
simultaneous requests to the driver.
Is there any solution to that?
Logitech cameras don't support MJPEG compression for 1600x1200.
Streaming such
a high resolution in YUV requires a high bandwidth, and USB 2.0
doesn't
provide enough bandwidth to stream from two 1600x1200 cameras at the
same
time.
Logitech webcams are quite slow to initialise the first time you use
them, but
might be faster the second time your run your application if you don't
disconnect the cameras. Could you please try that and let me know if
it
helps ?
Best regards,
Laurent Pinchart
BEGIN:VCARD
VERSION:3.0
N:MARTIN;Pierre;;;
FN:MARTIN Pierre
EMAIL;type=INTERNET;type=HOME;type=pref:[EMAIL PROTECTED]
EMAIL;type=INTERNET;type=WORK:[EMAIL PROTECTED]
TEL;type=HOME;type=pref:+33 5 53 56 90 83
TEL;type=HOME:+33 9 52 68 90 83
TEL;type=CELL:+33 6 30 14 52 15
item1.ADR;type=HOME;type=pref:;;17 rue de Verdun;Nontron;;24300;France
item1.X-ABADR:fr
BDAY;value=date:1982-02-18
X-AIM;type=WORK;type=pref:[EMAIL PROTECTED]
X-MSN;type=HOME;type=pref:[EMAIL PROTECTED]
PHOTO;BASE64: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X-ABUID:54EA62E1-196A-47E1-A561-C67A7DED60B4\:ABPerson
END:VCARD
_______________________________________________
Linux-uvc-devel mailing list
[email protected]
https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
