On Sat, 24 Sep 2005, Kenn Sebesta wrote:
I'm using a TouCam II Pro under gentoo and everything's working okay, except
I'm having problems grabbing all the images coming through the pipe.
I'm using Matlab to control a Ball and Plate project
(www.engr.uky.edu/~kdsebe01/HowToBandP.html) and need the data from the
camera as quickly and as reliably as possible. I'm switching to linux because
I don't at all like Windows's habit of seizing control whenever it feels like
it, which inevitably leads to a fallen ball. My problem is finding the best
way to capture all the data.
Right now I'm using vgrabbj, and telling it to capture once every 20ms. The
thing is, I have no idea if it means a thing to tell it to capture that
quickly. I could very well tell it 1ms, it doesn't seem to bat an eye, except
for the fact that in the end it doesn't work at that speed.
I've tried vidcat and streamer, with disappointing results, although it's
possible I'm just misusing them. Ideally, I'd like to capture a new image
_only_ when there's a new image, and capture all the new images, indicating
if/when for some reason or another an image goes missing. Is there anything
like this in the linux world?
Even better, is there any sort of Matlab module
that will let me import the image directly into Matlab, instead of saving it
to the hard drive and then reading it into Matlab?
Lastly, just a question about the driver and Linux. Are the images buffered
anywhere, or do they come directly into the /dev/video object? About how long
(in ms) is there between the time the image is taken and the driver makes it
available for use? Can the driver be integrated into real-time environments?
Give a try to qastrocam, I use it to acquire astro images, I've tried it
at 30 fps, no problem. It also generates a file with a timestamp of each
image that might help you detect a missed image. The rate is fairly
stable and so is the delay between effective image acquisition and time
stamping (on my hardware I have measured it at 0.03s, but I cannot
guarantee it will be identical on another system.
There is a debian package in this repository:
deb http://3demi.net/debian debs/./
while home page is there:
http://3demi.net/astro/qastrocam/doc/
-- François Meyer
http://dulle.free.fr/alidade/galerie.php?maxim=12 _______________________________________________
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