[ros-users] Firewire camera synchronization

[Thomas Moulard]

On Tue, Nov 30, 2010 at 5:12 PM, Jack O'Quin <jack.oquin at gmail.com> wrote:
> There are three possible solutions outlined in this enhancement ticket:
>
>  https://code.ros.org/trac/ros-pkg/ticket/4217
>
> Currently, stereo image processing requires identical time stamps for
> the two stereo images. Running two separate mono versions of
> camera1394_node will not ensure that.
>
> The ticket suggests modifying image_pipeline to relax that requirement
> slightly. I don't know what the status of that request is. No
> committed fix is mentioned yet. I wonder whether it will be in
> Diamondback. I don't see any image_pipeline or stereo_image_proc
> reviews for that distribution yet. So, maybe it could still be done.

Yes that what I have done locally but it can hardly considered a
solution as it leads
to unsynchronized frames. Still it would be nice to distribute a
built-in node for this
in ROS.
I was not aware of the ApproximateTime filter, I will rewrite my node
to use it and I
can submit it if you are interested.


> As ticket #4217 said, one good option would be to create a stereo
> version of the driver, which could publish both images with the same
> time stamp. This could be done in time for Diamondback, if there's a
> consensus that it's needed. I don't mind doing the work, though I'd
> need to borrow or acquire a suitable pair of stereo cameras for
> testing.

That would be great. I would definitively test and give feedback about that.


> That was not one of the future enhancements identified during the
> C-turtle API review:
>
>  http://www.ros.org/wiki/camera1394/Reviews/2010-05-27_API_Review#Conclusion
>
> Some time soon, we need to hold a review for Diamondback enhancements
> to camera1394. I'll announce that here when ready. Please participate
> if you can.

Seems the link points to an old meeting.
What is the usualy way to propose a change for the next version? Is
there a wiki page to edit?

Thanks for the quick answer,
-- 
Thomas Moulard
http://www.linkedin.com/in/moulard