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See point cloud in rviz

asked 2014-03-19 10:28:03 -0500

davidgitz gravatar image

Hi, I'm trying to view a point cloud that I am generating with an AR Drone in rviz. I have the transform set as /ardrone_base_link --> /cam_front and using tf_echo I see:

rosrun tf tf_echo /ardrone_base_link /cam_front
At time 1395260250.630
- Translation: [0.007, 0.209, -0.001]
- Rotation: in Quaternion [-0.677, 0.034, -0.037, 0.735]
            in RPY [-1.489, -0.000, -0.101]
At time 1395260251.568
- Translation: [0.006, 0.209, -0.001]
- Rotation: in Quaternion [-0.677, 0.034, -0.037, 0.735]
            in RPY [-1.489, -0.000, -0.101]

If i do an echo on the /tf I get:

rostopic echo /tf
    transforms: 
  - 
    header: 
      seq: 0
      stamp: 
        secs: 1395260346
        nsecs: 276967023
      frame_id: /ardrone_base_link
    child_frame_id: /cam_front
    transform: 
      translation: 
        x: 0.0063893099241
        y: 0.209490348767
        z: -0.000927047945466
      rotation: 
        x: -0.676587213276
        y: 0.0340744443113
        z: -0.0371685138251
        w: 0.734634042674

And the tf_monitor:

    rosrun tf tf_monitor /ardrone_base_link /cam_front 
RESULTS: for /ardrone_base_link to /cam_front Chain is: /ardrone_base_link -> NO_PARENT -> /ardrone_base_link -> /ardrone_base_link Net delay     avg =
    0.069172: max = 0.21447

And I am publishing the point_cloud on /ardrone/point_cloud:

rostopic type /ardrone/point_cloud
sensor_msgs/PointCloud2

If I do a rostopic echo on the point_cloud I get proper data.

When I try to use rviz on the point_cloud with the above tranform I get the following errors whenever a new point_cloud message is published:

Message from [/drone_stateestimation] has a non-fully-qualified frame_id [1]. Resolved locally to [/1].  This is will likely not work in multi-robot systems.  This message will only print once

And the point_cloud never shows up. I also get message in rviz saying "Showing [0] points from [0] messages."

In my tf broadcase I am doing:

tf::StampedTransform t = tf::StampedTransform(tr,ros::Time::now(),"/ardrone_base_link","/cam_front");

I think part of the problem is the seq:0 in the rostopic echo /tf never changes, but I don't know how to fix that. There could be other problems too. Any ideas?

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answered 2014-03-19 21:28:05 -0500

Your pointcloud appears to have the frame_id "1", which is no frame_id that is available in your tf tree. You probably want it to have the frame_id "/cam_front".

You can also test if your pointcloud gets published properly by setting the fixed frame in rviz to "1" (just type it into the box).

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answered 2014-04-10 23:53:03 -0500

I seem to remember that tf has a problem with purely numeric frame names (such as "1"). Try renaming it to "frame1" or such everywhere.

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Asked: 2014-03-19 10:28:03 -0500

Seen: 1,330 times

Last updated: Apr 10 '14