Isaac ROS Apriltag for dual USB cameras

Robotics & Edge Computing Robotics - Isaac Isaac ROS
1

Hi,
The Isaac ROS Apriltag can works well for single USB camera. Tutorial for AprilTag Detection with a USB Camera — isaac_ros_docs documentation
To improve system stability and accuracy, I’d like to use dual USB cameras. Can the Isaac ROS Apriltag support it?
For example, one ros2 launch use /dev/video0, another ros2 launch use /dev/video1.

3

Hi @ztm

Thank you for your post.

You can copy and modify following launch script and yaml for the new video node(e.g. video2):
$(ros2 pkg prefix isaac_ros_apriltag --share)/launch/isaac_ros_apriltag_usb_cam.launch.py
$(ros2 pkg prefix isaac_ros_apriltag --share)/config/usb_cam_params.yaml

Please let me know if I helped you.

Best,
Ahung

4

Hi Ahung,
Thanks for the reply.
I think only copy and modify the launch and yaml is not enough. I also tried but failed.
There will exist confict on some nodes or topics between the two launch, while using the same nodes or topics.

image
image1806×614 49.6 KB

5

Hi @ztm

Which setup are you using? Your rqt graph looks a bit different. Do you create /image_raw/image_topics? If you already made some changes, please roll them back
and try again.

6

Hi Ahung,
I ran the launch.
ros2 launch isaac_ros_apriltag isaac_ros_apriltag_usb_cam.launch.py camera_width:=1280 camera_height:=720

I don’t remember if I made minor changes. But never mind, I just post the rqt graph to show the very possible problem: There will exist confict on some nodes or topics between the two launch, while using the same nodes or topics, like the /rectify, /apriltag.

Thanks.

7

I’m having the same issue with running multiple cameras.

I tried modifying these files and I was able to get a launch script working for both cameras, but when I ran the two scripts concurrently, I found that the nodes talked over each other, like @ztm said.