ROS Tutorial - ROS Introduction - starting camera Node using Remote Desktop Client

Software
1

HI,

Ran the below code
rosrun image_view image_view image:=/camera/rgb/image_raw

and got the following error:

QXcbConnection: Could not connect to display Aborted

After googling, the response is to include the following line in my bash script

export DISPLAY=’:0.0’

Is this correct?

Thanks
Vineet

2

Answered my own question. It worked, but have next challenge.

husarion@husarion: echo “export DISPLAY=’:0.0’” >> ~/.bashrc

husarion@husarion:~$ source ~/.bashrc

husarion@husarion:~$ rosrun image_view image_view image:=/camera/rgb/image_raw

libEGL warning: DRI2: failed to authenticate
[ INFO] [1560552328.488488171]: Using transport “raw”
(above two lines match the tutorial).

Now no image being displayed…

Vineet

3

Hello Vineet,

I will need some more information.
Do you see image_view window with no image from camera or image_view did not appear at all?
Are you connecting to ROSbot through Remote Desktop or display + keyboard + moue setup?

Regards,
Łukasz

4

Lukasz,

I do not see the image_view window.

Remote Desktop terminal.

Thanks
Vineet

5

Hello Vineet,

The error QXcbConnection: Could not connect to display Aborted means that there is problem with access to graphical desktop. This usually happens when GUI application is started in text only mode, e.g. when connecting through SSH.

By setting the export DISPLAY=’:0.0 variable you redirected all graphical applications to default desktop, which is HDMI output in rosbot.

Please remove that line from .bashrc, restart your device and try again. If issue persist, please provide full log output and screenshot of desktop.

Regards,
Łukasz

6

Lukasz,

I just tried and it worked. Using remote desktop terminal made the difference. I was able to run the code below and run Gazebo too.

So, does Husarion have code to drive the ROSBot from Remote Desktop client similar to Cloud Four Wheel? or can that code be modified for use here?

i do this error at the end of this code: roslaunch astra_launch astra.launch

INFO] [1561089644.780410736, 145.470000000]: Unable to open camera calibration file [/home/husarion/.ros/camera_info/rgb_Astra_Orbbec.yaml]
[ WARN] [1561089644.780550176, 145.470000000]: Camera calibration file /home/husarion/.ros/camera_info/rgb_Astra_Orbbec.yaml not found.
^C[camera_base_link3-14] killing on exit
[camera_base_link2-13] killing on exit
[camera_base_link1-12] killing on exit
[camera/depth_registered_sw_metric_rect-10] killing on exit
[camera/register_depth_rgb-8] killing on exit
[camera_base_link-11] killing on exit
[camera/points_xyzrgb_sw_registered-9] killing on exit
[camera/depth_metric_rect-5] killing on exit
[camera/depth_points-7] killing on exit
[camera/depth_metric-6] killing on exit
[camera/depth_rectify_depth-4] killing on exit
[camera/rgb_rectify_color-3] killing on exit
[camera/driver-2] killing on exit
[camera/camera_nodelet_manager-1] killing on exit
shutting down processing monitor…
… shutting down processing monitor complete
done

I did go into .ros folder and there is not camera_info folder. This might be a clue that i not install something.

Notes:

Using Remmina Remote Desktop client (not run from ssh / text editor), I was able to run the view the images from astra sensor:

started master process; roscore

started camera node: roslaunch astra_launch astra.launch

to run image view node: rosrun image_view image_view image:=/camera/rgb/image_raw

Thanks
Vineet

7

Hello Vineet,

It is not mandatory to use Remote Desktop to control ROSbot, but it is introduced in first tutorial as most basic use example.
You can control ROSbot using Rviz launched on your local laptop or with Web UI.

The message you are seeing is warning regarding camera optical calibration.
The calibration file is required to fix optical distortions of the image. You can generate this file using camera_calibration tool.
Camera can work normally without the calibration file, you will be able to see camera image or perform object recognition.

Regards,
Łukasz

8

Lukasz,

Thanks again for assisting novice hobbyist (me).

It is not mandatory to use Remote Desktop to control ROSbot, but it is introduced in first tutorial as most basic use example. You can control ROSbot using Rviz launched on your local laptop or with Web UI. VG: I went to the husarion github website and will try Rviz. When using remmina on my laptop, the window is 1/4 the size. Is that normal?

The message you are seeing is warning regarding camera optical calibration.
The calibration file is required to fix optical distortions of the image. You can generate this file using camera_calibration1 tool.
Camera can work normally without the calibration file, you will be able to see camera image or perform object recognition. VG: thank again and provide link for calibration tool.

9

Lukasz,

I have this working as well.

Again, i had the lidar camera connected.

Once astra was connected, i am able to view the image on the remmina desktop client window.

Thanks
Vineet