How to run image_view from launch file? [closed]
How to I write a launch file to run the image_view window?
I have a launch file setting up a simple webcam and publishing its output to /camera/image/compressed
, like:
<launch>
<node name="camera" 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="camera" />
<param name="io_method" value="mmap"/>
</node>
<node name="camera_raw_to_plain" pkg="topic_tools" type="relay" output="screen" args="/camera/image_raw/compressed /camera/image/compressed" />
</launch>
And if I run:
rosrun image_view image_view image:=/camera/image _image_transport:=compressed _autosize:=true
then I get an image_view window showing my webcam video. However, if I try to run iamge_view from the launch file like:
<launch>
<node name="camera" 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="camera" />
<param name="io_method" value="mmap"/>
</node>
<node name="camera_raw_to_plain" pkg="topic_tools" type="relay" output="screen" args="/camera/image_raw/compressed /camera/image/compressed" />
<node name="image_view" pkg="image_view" type="image_view" respawn="false" output="screen">
<param name="image" value="/camera/image" />
<param name="autosize" value="true" />
<param name="image_transport" value="compressed" />
</node>
</launch>
then the image_view window never appears.
What am I doing wrong?
image
is not a parameter, but a topic name. On the command line,a:=b
remaps,_a:=b
sets parametera
to valueb
.So changing the
param name="image"
toremap from="image" to="/camera/image"
should work.Related questions: #q209035, #q266318, #q200460 and #q41756.
Q&As #q200460 and #q41756 are essentially duplicates I believe.
Thank you. That fixed it.
Good to hear.
Seeing as the other Q&As are essentially duplicates, I'm closing this.