Difference between vslam launched using isaac_ros_examples v/s isaac_ros_visual_slam

[riya.n.gujarathi]

I am running isaac ros on my x86 system with a realsense D435i stereo camera.

On the isaac_ros_visual_slam page, the vslam realsense demo is launched using the isaac_ros_examples package and this works as expected i.e. the rviz and ros2 topic outputs match with what is mentioned int he documentation.

However, on the “Tutorial for Visual SLAM Using a RealSense Camera with Integrated IMU” page, vslam is launched using the isaac_ros_visual_slam package. In this case, there are no outputs printed on any of the ros2 topics (i.e. ros2 topic echo <topic_name>) and the rviz output does not have any point cloud or images visible.

What is the difference between launching vslam from isaac_ros_examples pkg vs isaac_ros_visual_slam pkg? In both cases, my realsense D435i camera is connected to the system.

Also, in both cases, the /visual_slam/imu topic is not visible in the ros2 topic list.

[Raffaello]

Hi @riya.n.gujarathi

Welcome to the Isaac ROS forum.

@riya.n.gujarathi

What is the difference between launching vslam from isaac_ros_examples pkg vs isaac_ros_visual_slam pkg? In both cases, my realsense D435i camera is connected to the system.

There is no difference between the isaac_ros_examples pkg and the isaac_ros_visual_slam pkg.
The isaac_ros_examples package combines different examples to make it simple to run a demo, but working directly with isaac_ros_visual_slam is the same.

@riya.n.gujarathi

Also, in both cases, the /visual_slam/imu topic is not visible in the ros2 topic list.

The subscriber is visible, and you can connect to the vslam node, but remember to set enable_imu_fusion to true isaac_ros_visual_slam — isaac_ros_docs documentation

ROS Topic	Interface	Description
visual_slam/imu	sensor_msgs/Imu	Sensor data from the IMU (is only present if enable_imu_fusion is true).

Best,
Raffaello

[riya.n.gujarathi]

Hi @Raffaello,

Thanks for your reply. I still cannot resolve the /visual_slam/imu topic issue. I have set enable_imu_fusion to true. Any suggestions as to what could be going on?

[Ahung]

Hi @riya.n.gujarathi

In this demo, isaac_ros_visual_slam_realsense.launch.py remaps the subscribe topic to /camera/imu from realsense. Please check if you can find this topic.

Best,
Ahung

[riya.n.gujarathi]

Hi @Ahung,

Yes! I can see the /camera/imu topic. Also, fyi the original issue with rviz was also resolved by changing the camera firmware version in accordance with this page.