If you don't have a TF transform tree (<a href="http://ros.org/wiki/tf">http://ros.org/wiki/tf</a>), the fixed frame needs to match the frame you've set. You also need to set the timestamp in the header.<br><br>msg.header.stamp = ros::Time::now();<br>
<br>Josh<br><br><div class="gmail_quote">On Wed, May 19, 2010 at 7:53 AM, Sacha Aury <span dir="ltr"><<a href="mailto:sacha@shadowrobot.com">sacha@shadowrobot.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Thanks for your help. I now have a single node synchronizing my two<br>
cameras (image and infos). It works with the stereo_view and I get the<br>
disparity map, which I am configuring. My question is now about rviz,<br>
which I've never used. It seems to need a fixed frame to display my 3D<br>
cloud points. I tried to set a frame_id in my synchronization node<br>
(before broadcasting it to stereo_image_proc), but it does not work,<br>
rviz still can't get any fixed frame.<br>
<br>
How can I do that ? I think I am close to the result, but I can't see<br>
it !<br>
<br>
Le mardi 18 mai 2010 à 09:07 -0700, Blaise Gassend a écrit :<br>
<div><div></div><div class="h5">> Hi Sacha,<br>
><br>
> stereo_image_proc doesn't care about when your message was published, it<br>
> just cares about the timestamp in the message. So your republishing node<br>
> needs to set the timestamp, both in the image topic and in the<br>
> camera_info topic.<br>
><br>
> Blaise<br>
><br>
> On Tue, 2010-05-18 at 16:29 +0100, Sacha Aury wrote:<br>
> > I think that having a hardware solution is a bit overkill for my<br>
> > problem. So I tried to write a node which collected image messages from<br>
> > my two cameras and which published both message every x seconds,<br>
> > typically 1/2. And when I am using image_pipeline/stereo_image_proc, I<br>
> > got messages of that kind :<br>
> ><br>
> > [ WARN] 1274196325.866264000: [stereo_image_proc] Low number of<br>
> > synchronized left/right image pairs received.<br>
> > Left images received: 831<br>
> > Right images received: 831<br>
> > Synchronized pairs: 0<br>
> > Possible issues:<br>
> > * The cameras are not synchronized.<br>
> > * The network is too slow. For each synchronized image pair, at most 1<br>
> > is getting through.<br>
> ><br>
> > I don't know what I could do more, since the synchronisation should be<br>
> > done by a TimeSynchronizer in the stereo_image_proc class. Could it be<br>
> > posible to cheat on the timestamps in any way ?<br>
> ><br>
> > Thanks, and sorry for the double post, I made a mistake at first.<br>
> ><br>
> > Le lundi 17 mai 2010 à 07:53 -0700, Gary Bradski a écrit :<br>
> > > What level do you want synchronization on? Within framerate (both<br>
> > > frames happen randomly but within 1/30 of a second of each other) or<br>
> > > exact frame synchronization? The first is achievable, the second needs<br>
> > > extra hardware.<br>
> > ><br>
> > > At most, ROS can get you timestamps to align to, but to get actual<br>
> > > simultaneous frames, you'll need a triggering signal in hardware such<br>
> > > as a wire between 2 cameras (that allow for this). Some 1394 cameras<br>
> > > may allow triggering over the 1394 bus and then you'll only have the<br>
> > > problem of getting both buses to trigger at the same time ... which<br>
> > > may be approximately possible, most of the time ... on average.<br>
> > > Depends on the driver and the 1394 port.<br>
> > ><br>
> > > I've seen an automotive 1394 article (not ROS related) where they have<br>
> > > about 10 cameras. The cameras run the cameras at very high framerates<br>
> > > and then they do timestamp synchronization which allows fairly<br>
> > > synchronous alignment of multiple with no extra hardware.<br>
> > ><br>
> > > Gary<br>
> > ><br>
> > > On Mon, May 17, 2010 at 5:23 AM, Sacha Aury <<a href="mailto:sacha@shadowrobot.com">sacha@shadowrobot.com</a>><br>
> > > wrote:<br>
> > > Hi,<br>
> > ><br>
> > > I am trying to make a stereo camera acquisition using ROS with<br>
> > > the<br>
> > > cameradc1394 driver and the stereo_proc package. I've got a<br>
> > > separate<br>
> > > computer to stream the image_raw from my two cameras. The<br>
> > > stream works,<br>
> > > but when I launch stereo_image_proc, it seems that my two<br>
> > > cameras are<br>
> > > not synchronized :<br>
> > ><br>
> > > [ WARN] 1274098675.074074000: [stereo_image_proc] Low number<br>
> > > of<br>
> > > synchronized left/right image pairs received.<br>
> > > Left images received: 3079<br>
> > > Right images received: 3076<br>
> > > Synchronized pairs: 0<br>
> > > Possible issues:<br>
> > > * The cameras are not synchronized.<br>
> > > * The network is too slow. For each synchronized image<br>
> > > pair, at most 1<br>
> > > is getting through.<br>
> > ><br>
> > > Here is my launch file :<br>
> > ><br>
> > > <!-- startstream.launch --><br>
> > > <launch><br>
> > > <param name="display" type="int" value="0"/><br>
> > > <param name="framerate" type="double" value="15"/><br>
> > > <param name="mode" value="MODE_320x240_YUV422"/><br>
> > ><br>
> > > <node name="camera_left" pkg="cameradc1394"<br>
> > > type="cameradc1394"<br>
> > > respawn="true"><br>
> > > <param name="prefix" type="string"<br>
> > > value="/stereo/left/"/><br>
> > > <param name="cameraindex" type="int" value="0"/><br>
> > > </node><br>
> > ><br>
> > ><br>
> > > <node name="camera_right" pkg="cameradc1394"<br>
> > > type="cameradc1394"<br>
> > > respawn="true"><br>
> > > <param name="prefix" type="string"<br>
> > > value="/stereo/right/"/><br>
> > > <param name="cameraindex" type="int" value="1"/><br>
> > > </node><br>
> > ><br>
> > > </launch><br>
> > ><br>
> > > Is there any specific way to make the two cameras<br>
> > > synchronize ?<br>
> > ><br>
> > > I am following that tutorial :<br>
> > ><br>
> > > <a href="http://www.ros.org/wiki/stereo_image_proc" target="_blank">http://www.ros.org/wiki/stereo_image_proc</a><br>
> > ><br>
> > > Thank you for any help.<br>
> > ><br>
> > > Sacha<br>
> > ><br>
> > ><br>
> > > _______________________________________________<br>
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