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Can I change which topic usb_cam is publishing? [closed]

asked 2020-06-18 08:51:07 -0500

サイトダニエロ gravatar image

Can I change the topic which each node publishes? I'm using usb_cam with multiple nodes and each node will run in different devices, I need them to publish on different topics so the server can send them instructions individually.

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Closed for the following reason the question is answered, right answer was accepted by サイトダニエロ
close date 2020-08-06 12:57:58.082088

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Have you tried to remap the topics ?

Delb gravatar image Delb  ( 2020-06-18 09:15:59 -0500 )edit

oh, hello! thanks for commenting. Yes, I've tried to change the <remap from="image" to="/usb_cam/image_raw"/> to <remap from="image" to="/raspImages"/> but it just throw a error on image_view, saying that it couldn't read from that topic, so the remap worked for changing what topic a node should subscribe but I don't know how to make it change a publisher's topic.

サイトダニエロ gravatar image サイトダニエロ  ( 2020-06-18 09:55:04 -0500 )edit

Can you show the full launch file please ? There might be more remapping required.

Delb gravatar image Delb  ( 2020-06-18 10:14:23 -0500 )edit

<launch> <node name="usb_cam" pkg="usb_cam" type="usb_cam_node" output="screen" > <param name="video_device" value="/dev/video0" /> <param name="image_width" value="640" /> <param name="image_height" value="480" /> <param name="pixel_format" value="yuyv" /> <param name="camera_frame_id" value="usb_cam" /> <param name="io_method" value="mmap"/> </node> <node name="image_view" pkg="image_view" type="image_view" respawn="false" output="screen"> <remap from="image" to="/usb_cam/image_raw"/> <param name="autosize" value="true" /> </node> </launch>

from link text

I just switched the image_view remap. Which... thinking about it now, the image_view is just the visualization node, I think, it's supposed to not be able to subscribe to a different node that the node called usb_cam is publishing...but the problem remains.

サイトダニエロ gravatar image サイトダニエロ  ( 2020-06-18 10:29:07 -0500 )edit

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answered 2020-06-18 09:49:14 -0500

Remap will do what you're wanting: http://wiki.ros.org/roslaunch/XML/remap

ex.

<node pkg="nodelet" type="nodelet" args="load image_proc/crop_decimate realsense2_camera_manager"
      name="$(arg camera)_depth_image_decimator" respawn="true"  output="screen">
  <remap from="points"     to="/$(arg camera)/depth/points" /> 
</node>
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Comments

I'm gonna try here! thanks for help!

サイトダニエロ gravatar image サイトダニエロ  ( 2020-06-18 13:21:13 -0500 )edit

Ok, I tested here. It worked!! thanks a lot, I'm newbie in ROS haha.

サイトダニエロ gravatar image サイトダニエロ  ( 2020-06-18 13:24:21 -0500 )edit

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Asked: 2020-06-18 08:51:07 -0500

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Last updated: Jun 18 '20