running error

[Abduoit]

Hi after running with webcam I get the this error ?

[ERROR] [1516809186.355774485]: Client [/ar_track_alvar] wants topic /usb_cam/image_raw to have datatype/md5sum [sensor_msgs/CameraInfo/c9a58c1b0b154e0e6da7578cb991d214], but our version has [sensor_msgs/Image/060021388200f6f0f447d0fcd9c64743]. Dropping connection.
[ERROR] [1516809187.558273192]: Client [/ar_track_alvar] wants topic /usb_cam/camera_info to have datatype/md5sum [sensor_msgs/Image/060021388200f6f0f447d0fcd9c64743], but our version has [sensor_msgs/CameraInfo/c9a58c1b0b154e0e6da7578cb991d214]. Dropping connection.

[atomoclast]

Hello,

Have you tried to look through these two links:

http://wiki.ros.org/image_view/Troubleshooting

Can you use rqt_image_view to visualize your webcam stream first?

This may also be relevant:

https://answers.ros.org/question/11618/error-client-wants-topic-a-to-have-b-but-our-version-has-c-dropping-connection/

Are you advertising the right message type?

[Abduoit]

Yes I can run rqt_image_view and check my webcam

I even tried to change the [sensor_msgs/CameraInfo/c9a58c1b0b154e0e6da7578cb991d214], [sensor_msgs/Image/060021388200f6f0f447d0fcd9c64743]

but the issue still there ?

[varunagrawal]

I encountered this issue and I have also submitted a PR #2 to solve this. @atomoclast can you please review the PR?

[atomoclast]

I just noticed what the error was.

My apologies guys!

Thanks for the fix @varunagrawal .

@Abduoit, just refetch and pull master and I think you'll be good to go!

[Abduoit]

Ok @atomoclast

I did the following steps and I don't know if that what I suppose to do

abdulrahman@abdu:~/catkin_ws/src/ar_tag_toolbox$ git reset --hard 
HEAD is now at 1b406e9 Merge pull request #2 from varunagrawal/usb_cam-fix
abdulrahman@abdu:~/catkin_ws/src/ar_tag_toolbox$ git pull
Already up-to-date.

Now, I don't see the error, BUT the markers are not detected, I open rviz and I see the base link and optical frame are not moving.

What should I do ??

even when I run rostopic ech /tf all dimensions are zeros

[atomoclast]

Can you run rqt_graph and post the results so I can see?

What nodes are running? What's the output of rostopic list?

Sorry for all the issues. I may need to check this out and try it on my computer again! I was working on this around the time my (now old) laptop died, so I wonder if there was a commit I didn't push on there...

[Abduoit]

Ok @atomoclast thanks for your effort

I will show you all the info, by the way (I am using ros indigo)

first I run these two

roslaunch ar_tag_toolbox usb_cam.launch cam_id:=0

roslaunch ar_tag_toolbox ar_track_usb_cam.launch marker_size:=5

everything looks fine, but the marker are not detected,

abdulrahman@abdu:~$ rostopic list 
/ar_pose_marker
/ar_track_alvar/enable_detection
/ar_track_alvar/parameter_descriptions
/ar_track_alvar/parameter_updates
/image_view/output
/image_view/parameter_descriptions
/image_view/parameter_updates
/joint_states
/rosout
/rosout_agg
/tf
/tf_static
/usb_cam/camera_info
/usb_cam/image_raw
/usb_cam/image_raw/compressed
/usb_cam/image_raw/compressed/parameter_descriptions
/usb_cam/image_raw/compressed/parameter_updates
/usb_cam/image_raw/compressedDepth
/usb_cam/image_raw/compressedDepth/parameter_descriptions
/usb_cam/image_raw/compressedDepth/parameter_updates
/usb_cam/image_raw/theora
/usb_cam/image_raw/theora/parameter_descriptions
/usb_cam/image_raw/theora/parameter_updates
/visualization_marker
abdulrahman@abdu:~$ rosnode list
/ar_track_alvar
/image_view
/rosout
/state_publisher
/usb_cam

and this is the rqt_graph

I tried MarkerData_0.png and the three tags that you are using in your tutorial, but nothing detected in rviz, even when I run rostopic echo /ar_pose_marker

Thanks

[atomoclast]

@Abduoit

I have been able to replicate your issue. I'm seeing the same thing....I wonder if this is an issue with ar_track_alvar myself now. I'm making sure the TFs look good and that it's getting good data, and it seems to not be recognizing anything.

I myself may look through ar_track_alvar to see where it broke.

My tutorial video used a Kinect, so let me do some digging. I do belive I also got this working with a Bebop drone, so not sure what happened. I don't have more time today to keep playing with it, but I'll keep you posted.

I do urge you to look into it though. I'm not sure if there's an issue with the TF publish rate or the frame names or what.

Since you said you are on indigo, you can try this package: http://wiki.ros.org/apriltags_ros

I'll keep you posted. This is rather frustrating, honestly.

[j5207]

the same. Nothing detected on rviz with webcam stream. Any suggestion?