How to get zed2i topics to remap to work with stereo_image_proc

Software ROS1
1

Apologies, I am somewhat new to ros. I’m having issues trying to pass the zed2i topics to work with stereo_image_proc (http://wiki.ros.org/stereo_image_proc)

The latter subscribes to 4 topics:

  • stereo/left/image_raw
  • stereo/left/camera_info
  • stereo/right/image_raw
  • stereo/right/camera_info

I am unsure how to remap the zed published topics to the desired topics.

I attempted to edit the zed_camera.launch.xml file to include:

<remap from="zed2i/zed_node/left_raw/image_raw" to="stereo/left/image_raw"  />
<remap from="zed2i/zed_node/left_raw/camera_info" to="stereo/left/camera_info"  />   
<remap from="zed2i/zed_node/right_raw/image_raw" to="stereo/right/image_raw"  />   
<remap from="zed2i/zed_node/right_raw/camera_info" to="stereo/right/camera_info"  />

above the zed_node entry, however, running the zed2i wrapper still didn’t map the topics.

What am i doing wrong?

2

Hi @bc524
probably you are only missing the / at the very beginning of all the topic names.

Can I ask you why you are trying to get the depth map by using stereo_image_proc?
The depth map and the point cloud provided by the ZED SDK are better than the best result that you can obtain by using stereo_image_proc.
Furthermore, they are generated at high frequency by using the GPU and CUDA, thing that is not possible (as far as I know) with stereo_image_proc.

3

Thank you for replying. I will try adding the / when i get access to the device again.

I’m trying to use it with a velo2cam calibration (GitHub - beltransen/velo2cam_calibration: Automatic Extrinsic Calibration Method for LiDAR and Camera Sensor Setups. ROS Package.). One step of the calibration requires a filtered_cloud that is generated from the disparity map of the stereo camera.

I tried to do the calibration in gazebo and used the stereo_image_proc to generate the disparity map. So, going with what I knew, I attempted the same with the Zed2i camera.

Is there something similar with the zed2i camera?

4

The ZED ROS Wrapper provides also the disparity map:
https://www.stereolabs.com/docs/ros/zed-node/#published-topics

Topic zed2i/zed_node/disparity/disparity_image

5

alright, I’ll give a try later. Thanks for now.

6

hi again,

I am still having trouble getting the disparity data from the zed camera to work with the calibration package.

I believe the package calls on the disparity here:

Screenshot from 2022-10-25 13-53-30
Screenshot from 2022-10-25 13-53-30926×477 62.7 KB

(the above is from velo2cam_calibration/stereo_pattern.launch at master · beltransen/velo2cam_calibration · GitHub, which is meant to handle the stereo camera calibration)

How exactly do I rework it to use the zed camera’s disparity image?

I’m trying to use the example for nodelets, adding the “include zed wrapper nodelet” but I am unsure what to change the stereo_image_proc to.

7

This is the node that generates the disparity map. You do not need it if you use the disparity map generated by the ZED SDK.

What is the node that subscribes to the disparity topic?

9

Hi again,

I’ve managed to get the topic to properly transfer to the node. It was an issue with the way the calibrator code looked for topics.

Thanks

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