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Hello everyone,

I would like to create simple octomap with use of both RealSense D435 and T265 cameras. I am using my own RealSense wrapper (do not ask why please, it is needed in this case). I can publish PointCloud from D435 camera (depth stream) and pose (odometry) from T265 as a topic.

What I am currently struggling with is publishing tf. I know, that octomap_server can incrementally build occupancy grid based on odometry received from tf. I just cannot figure out, how to setup frame_id's and so.

This is how I broadcast transform:

tf_br.sendTransform(tf::StampedTransform(transform, ros::Time::now(), "tf_t265", "map"));

The transform object is filled with the exact same data as I am using in the topic for publishing T265 pose (which is being used and it works).

This is what the part of my launchfile for octomap_server looks like:

<node pkg="octomap_server" type="octomap_server_node" name="octomap_server">
        <param name="resolution" value="0.05" />
        
        <!-- fixed map frame (set to 'map' if SLAM or localization running!) -->
        <param name="frame_id" type="string" value="tf_t265" />
        
        <!-- maximum range to integrate (speedup!) -->
        <param name="sensor_model/max_range" value="5.0" />
        
        <!-- data source to integrate (PointCloud2) -->
        <remap from="cloud_in" to="/d435/depth" />      
</node> 

I suspect, that frame_id param is the key here, but I tried to set it to map and it does not work too. I know, that maybe I am publishing the transform incorrectly, but this is why I am asking for help. There is nothing else in my code related with tf broadcasting.

If any additional info is needed, please let me know. Thank you for any help!

Have a nice day.


Originally posted by eMrazSVK on ROS Answers with karma: 41 on 2019-10-21

Post score: 2


Original comments

Comment by Jari on 2019-10-21:
I know you said don't ask but I'm genuinely curious ... (and I assume it has more to do with the t265 than the d435) ... why did you write your own RealSense wrapper :D ?

Comment by eMrazSVK on 2019-10-22:
Because I need only basic functionality from librealsense inside ROS. Furthermore I am developing application on Nvidia Jetson and D435+T265 simultaneously don't even work with RealSense wrapper. I am also maintaining a big ros package, where I have my own realsense node. If I was using realsense-ros as a module it would be difficult to maintain, because it is under heavy development and so it is updated too often. When I update core librealsense, my ROS wrapper still works. The realsense ROS wrapper is not hard to write though. + I needed to implement some features which weren't implemented (I dont know if it's still the case) in original RealSense ROS wrapper such as T265 complete camera reset (start/stop pipeline) or odometry Set (setting odometry to specific pose with service using transformation). It is much more flexible now for me as I have stable setup consisting of D435+T265. Hope I made it clear enough ;)

Comment by Jari on 2019-10-22:
That makes a lot of sense. Is any is this open source perchance? I'd like to look through it if that's the case.

Comment by eMrazSVK on 2019-10-22:
No, it's not available anywhere for now.

Comment by Dookei on 2020-04-08:
Hi @eMrazSVK I am trying to perform the same as you in octomap with T265 and D435i. Currently(contrary to you I am using the realsenselib) The pose and depth point cloud are working as expected( light modifications to the rs_d400_and_t265.launch). When I run the octomap-server, after a few secs, I get MessageFilter [target=/t265/odom/sample ]: Dropped 100.00% of messages so far. Any idea what that might be? Any help would be much appreciated.

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I'm answering my own question. The solution was to add transform between pointcloud_frame_id and map frame (this fact is clearly stated in the octomap_server docs so it seems I cannot read). It is still strangely rotated, but that would be again some wrong transform.


Originally posted by eMrazSVK with karma: 41 on 2019-10-22

This answer was ACCEPTED on the original site

Post score: 0

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