If you don't have a TF transform tree (http://ros.org/wiki/tf), the fixed frame needs to match the frame you've set. You also need to set the timestamp in the header. msg.header.stamp = ros::Time::now(); Josh On Wed, May 19, 2010 at 7:53 AM, Sacha Aury wrote: > Thanks for your help. I now have a single node synchronizing my two > cameras (image and infos). It works with the stereo_view and I get the > disparity map, which I am configuring. My question is now about rviz, > which I've never used. It seems to need a fixed frame to display my 3D > cloud points. I tried to set a frame_id in my synchronization node > (before broadcasting it to stereo_image_proc), but it does not work, > rviz still can't get any fixed frame. > > How can I do that ? I think I am close to the result, but I can't see > it ! > > Le mardi 18 mai 2010 à 09:07 -0700, Blaise Gassend a écrit : > > Hi Sacha, > > > > stereo_image_proc doesn't care about when your message was published, it > > just cares about the timestamp in the message. So your republishing node > > needs to set the timestamp, both in the image topic and in the > > camera_info topic. > > > > Blaise > > > > On Tue, 2010-05-18 at 16:29 +0100, Sacha Aury wrote: > > > I think that having a hardware solution is a bit overkill for my > > > problem. So I tried to write a node which collected image messages from > > > my two cameras and which published both message every x seconds, > > > typically 1/2. And when I am using image_pipeline/stereo_image_proc, I > > > got messages of that kind : > > > > > > [ WARN] 1274196325.866264000: [stereo_image_proc] Low number of > > > synchronized left/right image pairs received. > > > Left images received: 831 > > > Right images received: 831 > > > Synchronized pairs: 0 > > > Possible issues: > > > * The cameras are not synchronized. > > > * The network is too slow. For each synchronized image pair, at > most 1 > > > is getting through. > > > > > > I don't know what I could do more, since the synchronisation should be > > > done by a TimeSynchronizer in the stereo_image_proc class. Could it be > > > posible to cheat on the timestamps in any way ? > > > > > > Thanks, and sorry for the double post, I made a mistake at first. > > > > > > Le lundi 17 mai 2010 à 07:53 -0700, Gary Bradski a écrit : > > > > What level do you want synchronization on? Within framerate (both > > > > frames happen randomly but within 1/30 of a second of each other) or > > > > exact frame synchronization? The first is achievable, the second > needs > > > > extra hardware. > > > > > > > > At most, ROS can get you timestamps to align to, but to get actual > > > > simultaneous frames, you'll need a triggering signal in hardware such > > > > as a wire between 2 cameras (that allow for this). Some 1394 cameras > > > > may allow triggering over the 1394 bus and then you'll only have the > > > > problem of getting both buses to trigger at the same time ... which > > > > may be approximately possible, most of the time ... on average. > > > > Depends on the driver and the 1394 port. > > > > > > > > I've seen an automotive 1394 article (not ROS related) where they > have > > > > about 10 cameras. The cameras run the cameras at very high framerates > > > > and then they do timestamp synchronization which allows fairly > > > > synchronous alignment of multiple with no extra hardware. > > > > > > > > Gary > > > > > > > > On Mon, May 17, 2010 at 5:23 AM, Sacha Aury > > > > wrote: > > > > Hi, > > > > > > > > I am trying to make a stereo camera acquisition using ROS > with > > > > the > > > > cameradc1394 driver and the stereo_proc package. I've got a > > > > separate > > > > computer to stream the image_raw from my two cameras. The > > > > stream works, > > > > but when I launch stereo_image_proc, it seems that my two > > > > cameras are > > > > not synchronized : > > > > > > > > [ WARN] 1274098675.074074000: [stereo_image_proc] Low number > > > > of > > > > synchronized left/right image pairs received. > > > > Left images received: 3079 > > > > Right images received: 3076 > > > > Synchronized pairs: 0 > > > > Possible issues: > > > > * The cameras are not synchronized. > > > > * The network is too slow. For each synchronized image > > > > pair, at most 1 > > > > is getting through. > > > > > > > > Here is my launch file : > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > type="cameradc1394" > > > > respawn="true"> > > > > > > > value="/stereo/left/"/> > > > > > > > > > > > > > > > > > > > > > > > type="cameradc1394" > > > > respawn="true"> > > > > > > > value="/stereo/right/"/> > > > > > > > > > > > > > > > > > > > > > > > > Is there any specific way to make the two cameras > > > > synchronize ? > > > > > > > > I am following that tutorial : > > > > > > > > http://www.ros.org/wiki/stereo_image_proc > > > > > > > > Thank you for any help. > > > > > > > > Sacha > > > > > > > > > > > > _______________________________________________ > > > > ros-users mailing list > > > > ros-users@code.ros.org > > > > https://code.ros.org/mailman/listinfo/ros-users > > > > > > > > _______________________________________________ > > > > ros-users mailing list > > > > ros-users@code.ros.org > > > > https://code.ros.org/mailman/listinfo/ros-users > > > > > > > > > _______________________________________________ > > > ros-users mailing list > > > ros-users@code.ros.org > > > https://code.ros.org/mailman/listinfo/ros-users > > > > > > _______________________________________________ > > ros-users mailing list > > ros-users@code.ros.org > > https://code.ros.org/mailman/listinfo/ros-users > > > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >