ROS2: Unable to send images using ros2 topics

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1

Hi.

I am trying to send video from my webcam (approximately at 30 fps) to another device in the same network. Both devices are connected via husarnet.

I followed all the instructions available here - Using Husarnet & ROS 2 | Husarnet

I am also able to view the /chatter topic as given in the above tutorial. I am using FastDDS with the default configuration xml created by husarnet.

I ran the following commands-

PC1-
ros2 run image_tools cam2image

PC2-
ros2 run image_tools showimage

After going through the documentation of FastDDS available here - 15.3. Large Data Rates — Fast DDS 2.12.0 documentation, it seems we need to do some changes in the xml file.

Could you help in creating the new xml file?

PS- If I do not use husarnet and follow the above process by setting the same domain ID for both the PCs connected to the same network, I am able to clearly view the video on PC2.

Looking forward to your reply.

2

Hi @amit , please take a look at this example showing you how to use Husarnet in a ROS 2 system where robot is sending compressed camera images to the laptop: GitHub - husarion/rosbot-telepresence: Real-Time Internet Control and Video Streaming with ROSbot 2R / 2 PRO.

Please review all branches, because each of them presents how to achieve the same goal over Husarnet VPN, but with different setups.

Best,
Dominik

3

Hi @dominik ,

Thank you for your reply. I did test what was mentioned in the above GitHub repo. With that I am able to send compressed images. However, I am not able to send the raw images even when both the computers are on the same WiFi network.

To test the issue, I uninstalled husarnet, and sent the same image by connecting to the same router and setting the ROS_DOMAIN_ID parameter. It works flawlessly.

Could you guide where I am going wrong in using husarnet?

To give you context, I want to transfer the video and depth stream coming from a realsense depth camera. I had tried this in ROS1 using husarnet, and it worked flawlessly.

4

Hi @amit , have you tried tips from Useful tips section?

Especially this one:

sudo sysctl -w net.ipv6.ip6frag_time=3 # 3s
sudo sysctl -w net.ipv6.ip6frag_high_thresh=134217728 # (128 MB)

Best,
Dominik

5

Yes. After running this, I was able to view images received on compressed image topic. However raw images and depth stream are still not working.

Also, ifstat -i hnet0 command shows KB/s of out as 10,000+ .

6

@dominik Please let me know if you have any other resource for solving this.

7

@amit , have you tried reducing the size of the raw image? Also what htop shows where you are sending large raw images?

8

Yes. Reducing the image size and using compressed image works. However raw image or depth topic doesn’t.

htop shows this-

Screenshot from 2023-11-24 18-16-40
Screenshot from 2023-11-24 18-16-401107×836 194 KB

As mentioned before-

To test the issue, I uninstalled husarnet, and sent the same image by connecting to the same router and setting the ROS_DOMAIN_ID parameter. It works flawlessly.

How can this work with husarnet installed? Do I have to make any changes to XML?

9

@dominik Any update regarding this?

10

Hi @amit , maybe try with Husarnet and ROS 2 Router? Please take a look at one of our latest blog posts: ROS 2 Router for Remote Robotics and Topic Filtering | Husarnet