How to remove a TF from a ROS bag? [closed]

asked 2013-03-03 22:13:08 -0600

867 ●27 ●36 ●48

updated 2013-03-03 22:49:13 -0600

I have a bag that contains a large TF tree where one TF (base_link->virtual_cam) was calculated based on several TFs and parameters. I would like to replay this bag without this generated TF in order to interactively re-generate it as a play the bag.

Hence the question, how do I remove this TF from the bag? Alternatively, can I play the bag without outputting this TF?

Specs: Ubuntu 12.04, Fuerte

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Closed for the following reason the question is answered, right answer was accepted by Miquel Massot
close date 2015-06-25 02:51:13.094676

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answered 2013-03-03 22:34:31 -0600

Procópio

flag of United Kingdom of Great Britain and Northern Ireland

4402 ●23 ●64 ●67 https://www.linkedin.c...

updated 2019-01-30 06:58:18 -0600

You can use the rosbag filter command to generate a new bag file filtering out the topics you do not want. For example, I used this command

rosbag filter input.bag output.bag 'topic == "/camera/image_raw/compressed" or topic == "/scan" or topic == "/timetag" or  topic == "/tf" and m.transforms[0].header.frame_id != "/odom" and m.transforms[0].child_frame_id != "/odom"'

here I want to keep the topics /camera/image_raw/compressed , /scan and /timetag and also the /tf EXCEPT the ones that had /odom either as a frame_id or as a child_frame_id, effectively removing only some /tf messages instead of all of them.

in your case you can use adapt the above example to fit your needs:

rosbag filter input.bag output.bag 'topic == "ALL THE TOPICS YOU WANT TO KEEP" or topic == "/tf" and m.transforms[0].header.frame_id != "/base_link" and m.transforms[0].child_frame_id != "/virtual_cam"'

EDIT: as pointed by @Ben_S, this is a more concise form, with the same results (from this answer):

rosbag filter input.bag output.bag 'topic != "/tf" or topic == "/tf" and m.transforms[0].header.frame_id != "/base_link" and m.transforms[0].child_frame_id != "/virtual_cam"'

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1

This tool seems really useful (it could have its own page with many examples), but I don't see how to remove a particular TF. All TFs were published to /tf.

Benoit Larochelle ( 2013-03-03 22:39:24 -0600 )edit

check my first example code, there you have to play with the last two conditions to fit your case, meaning you remove tf messages where your frame_id is base_link and the child_frame_id is virtual_cam.

Procópio ( 2013-03-03 22:54:23 -0600 )edit

I think that this alone should work, but I did not try it: rosbag filter input.bag output.bag 'm.transforms[0].child_frame_id != "/virtual_cam"'. I'm working with a recording of 30+ GB in several bags, so the other solution was more practical. I would mark this as correct if I could choose two. :-)

Benoit Larochelle ( 2013-03-04 00:59:48 -0600 )edit

2

You'll need the more complex commands given in the answer as the condition will be evaluated for every message, not only tf. So accessing m.transforms will give you an assertion.

dornhege ( 2013-03-04 01:04:48 -0600 )edit

This will only work if you are sure that only one transformation is sent in every message (i.e. there is only one element in m.transforms).

hitzg ( 2014-01-08 05:18:03 -0600 )edit

I know that what it looks like, due to the [0] index, but actually I tested it with many transformations in each message and it works. Have you tried it?

Procópio ( 2014-01-08 23:48:51 -0600 )edit

1

This should work for up to five transforms being broadcast in a single message, and it can be extended:

https://gist.github.com/ayrton04/6629...

Tom Moore ( 2015-05-14 20:11:30 -0600 )edit

1

@Procópio there's a typo in the edited solution. It's 'topic != "tf" or ...' but it should be 'topic != "/tf" or ...'

littlelordy2 ( 2019-01-30 06:08:02 -0600 )edit

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answered 2013-03-04 23:55:06 -0600

Miquel Massot

1471 ●7 ●17 ●33 http://srv.uib.es/

updated 2014-01-08 10:49:52 -0600

You could try a script we did to do exactly the same. It is located in our public repo srv_tools, which is not fully documented yet on ROS. The script you look for is this one.

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Thanks, the script is short and simple! Just the way I like it! ;-)

Benoit Larochelle ( 2013-03-05 00:06:15 -0600 )edit

Works like a charm! The direct link does not work anymore, here's one to the file on github: remove_tf

hitzg ( 2014-01-08 05:19:56 -0600 )edit

404 on the link for "this one" : remove_tf.py

benabruzzo ( 2015-03-19 15:48:25 -0600 )edit

A quick search finds what I think is the content here: http://docs.ros.org/hydro/api/bag_too...

tfoote ( 2015-03-19 16:20:28 -0600 )edit

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1

answered 2013-03-03 22:59:44 -0600

Ben_S

2500 ●14 ●29 ●53

I dont know of any solution to completely remove only one TF from a bag, but if the transform you want to remove is to a leaf of the tree, you could try remapping it to an unused frame.

Have a look at tf_remap and the description of the node. You could leave all frames unchanged except for the one you want to have removed. But i think this will only work for leafs of the tree. (Or you would have to remap the whole branch of the tree and redefine it while playing back the bag)

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1

you can remove only one specific tf creating a condition in the rosbag filter (check my code example). there I kept all the tf except the ones that had /odom either as the frame_id or the child_frame_id. of course your remap alternative also should do the job.

Procópio ( 2013-03-03 23:04:04 -0600 )edit

2

Yes, you wrote your comment just while i was typing this answer. In the meantime i also found this answer http://answers.ros.org/question/12285/gmapping-simulation/?answer=18124#post-id-18124 where brian gave the same solution. :) A use case that i also stumbled across some weeks ago.

Ben_S ( 2013-03-03 23:16:12 -0600 )edit

I tried rosrun tf tf_remap _mappings:='[{old: /ptz, new: /ptz_original}]' and rosrun tf tf_remap _mappings:='[{old: /map/odom/base_link/omnicam/ptz, new: /map/odom/base_link/omnicam/ptz_original}]' but both have no effect. I get no errors, but I get only the old frames, not the new ones.

Benoit Larochelle ( 2013-03-03 23:39:10 -0600 )edit

1

Using your first commandline works for me: rosrun tf tf_remap _mappings:='[{old: /imu_link, new: /imu_link_old}]' Applying the following mappings to incoming tf frame ids {'/imu_link': '/imu_link_old'} Remember to play the bag with rosbag play x.bag /tf:=/tf_old

Ben_S ( 2013-03-03 23:51:01 -0600 )edit

Yes, you're right! I had not read the part about remapping the tf topic, and was I wondering what kind of black magic would make this work. Now it makes sense. Also to confirm, I have to use the short TF names and not the fully qualified names.

Benoit Larochelle ( 2013-03-04 00:34:17 -0600 )edit

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answered 2013-03-03 22:19:18 -0600

davinci

2563 ●35 ●45 ●60

You could record it again and record only the topics you need. rosbag record -O subset /turtle1/command_velocity /turtle1/pose http://www.ros.org/wiki/rosbag/Tutorials/Recording%20and%20playing%20back%20data

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I don't see how to remove a particular TF. All TFs were published to /tf.

Benoit Larochelle ( 2013-03-03 22:23:05 -0600 )edit

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How to remove a TF from a ROS bag? [closed]

Closed for the following reason the question is answered, right answer was accepted by Miquel Massot
close date 2015-06-25 02:51:13.094676

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How to remove a TF from a ROS bag? [closed] edit

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How to remove a TF from a ROS bag? [closed]

Closed for the following reason the question is answered, right answer was accepted by Miquel Massot
close date 2015-06-25 02:51:13.094676