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What topics is my nodelet listening to? (For RGBD6D playback)

asked 2011-05-20 08:24:04 -0600

Mac gravatar image

updated 2016-10-24 09:02:36 -0600

ngrennan gravatar image

Hello folks,


I'm playing around with openni_camera_unstable, hoping to get a two-pass pointcloud-generation system going (in the first pass, I record the image and depth data; in the second, I generate the registered pointclouds; limited hardware on my robot makes this handy).


If I fire up unstable's openni.launch, I get nice pointclouds exactly like I would expect. What I'd like to do is figure out what topics I need to bag in order to be able to run the point-cloud projection nodelet in a second pass. rosnode list shows /camera/points_xyzrgb_depth_rgb, which is the nodelet doing this work, but rosnode info on that node just lists a bunch of bond topics. The node actually publishing the point clouds is the manager (which I suppose makes sense, as I understand that to be the actual owning process of the various nodelets).

So: how do I figure out which topics my nodelet is subscribing to? (Alternatively, which topics do I need to accomplish what I'm after?)


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answered 2011-05-25 11:05:12 -0600

Patrick Mihelich gravatar image

To answer your specific use case: you need to bag /camera/depth_registered/image_rect_raw, /camera/rgb/image_rect_color, and /camera/rgb/camera_info.

As for the more general question, I have the same frustration. We need nodelet equivalents of rosnode info and rxgraph, but that tooling doesn't exist yet.

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Thanks for posting; I had, in fact, figured that out by source-code perusal, but failed to post the results. What's the right way to request said features? File a bug? Organize a mob, with signs and patriotic music?
Mac gravatar image Mac  ( 2011-05-26 03:38:36 -0600 )edit
At the bottom of (stack containing the nodelet package) there's a "request features" link to create a ticket in the right Trac.
Patrick Mihelich gravatar image Patrick Mihelich  ( 2011-05-26 10:49:01 -0600 )edit
If you have the bag file playing, run this to get the point cloud: ROS_NAMESPACE=camera rosrun nodelet nodelet standalone openni_camera/point_cloud_xyzrgb
JFReuter gravatar image JFReuter  ( 2011-08-31 01:14:55 -0600 )edit

answered 2011-05-20 08:45:43 -0600

I think if you do rosnode info on the nodelet manager you'll see the topics all of the nodlets running under it are subscribed to.

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Nope (at least, not what I want). I get the "external" plumbing information (the manager is publishing all of the various topics assembled by the nodelets), plus a whole bunch of bond subscriptions. What I want, so to speak, is the "internal" plumbing, showing how the nodelets are connected up.
Mac gravatar image Mac  ( 2011-05-20 09:00:20 -0600 )edit
I've use it with success for stere_image_proc which is a collection of nodelets and saw subscriptions between nodelets (other than bond). The key was that I did it on the nodelet manager rather than the nodelet.
Asomerville gravatar image Asomerville  ( 2011-05-20 09:49:12 -0600 )edit
Yeah, I did that. No luck. I see a long list of publications (none of which are inter-nodelet; the manager is publishing everything all of the nodelets produce), and a huge number of Bonds, and nothing else.
Mac gravatar image Mac  ( 2011-05-23 04:49:57 -0600 )edit

answered 2011-07-25 00:53:12 -0600

(Alternatively, which topics do I need to accomplish what I'm after?)

My answer for this post could be helpful.

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Asked: 2011-05-20 08:24:04 -0600

Seen: 2,342 times

Last updated: Jul 25 '11