robot communication - video capture

My Linux robot uses just a cheap Logitech-clone USB webcam, and the
Video4Linux software.  I can display video from the robot on a laptop (with
an admittedly slow refresh rate) using xawtv (IIRC).

Jeff.
--
Jeff Shirley
spamzilla@mindspring.com
"Bill Gates is filthy rich, but that doesn't mean I want to be married to him."

Jeff Shirley ¼g¹D¡G


   I have read the xawtv website, it doesn't say that it can transfer
the video back through the network. So how can you do it? And what is
IIRC?

thanks
from Peter (cmk128@hotmail.com)

IIRC -- if I remember/recall correctly

Is your SBC capable of running a videolan server?  http://www.videolan.org/
That's a full-featured streaming solution.

If not, its rather easy to write a streaming video server (assuming you
don't need the greatest compression).
I wrote some code that takes a video stream, compresses each frame using
jpeg, and then sends the frames out over the network.
http://androdna.com/pubsvn/compvision/trunk/NetSend.cpp
http://androdna.com/pubsvn/compvision/trunk/NetReceive.cpp

This code uses the Qt4 GUI system, not exactly an "embedded" library,
but the basic idea is simple enough to implement.  libjpeg and a little
network code should be sufficient.

HTH (hope that helps),
Daniel

[snip]

[snip]

I was not sure I remembered the xawtv program name correctly.  Apparently I
did.

My laptop runs Linux also, so I just set the DISPLAY variable of my telnet
session to the robot to point at the laptop and start xawtv.  Voila (ah, the
joys of the X window system).

Note that this method is far too inefficient/slow to do much with, but hey, it
was easy, and it works.  Some sort of UDP-based video feed would undoubtedly
perform better.

Jeff.
--
Jeff Shirley
spamkills@mindspring.com
"Bill Gates is filthy rich, but that doesn't mean I want to be married to him."

On 5¤EB18¤E9, ¤W¤C83®C935¤C0, Jeff Shirley <spamki...@mind=

Thanks for your ideas
from Peter

How are you communicating thru 802.11g (UDP packets?)? If you had a
serial video stream could you get that over your link?  What data rate
can you support?  I have also been looking into controlling a robot
using a wireless network.

I have been considering designing a DSP based video camera system to
solve this sort of problem, but I am not sure the amature robotics
community would fork up enough dough (list price of over $500 each) to
make it worth the rather large investment.
-howy

ote:

i just put a wireless network card to my robot, then i can ping my
robot and send some data to it. In the robot, i did a little program
to receive the commands.

thanks
from Peter