Re: Hesai QT128 with Zed2i and external fused Odometry

Posted by matlabbe on Sep 22, 2023; 3:48pm
URL: http://official-rtab-map-forum.206.s1.nabble.com/Hesai-QT128-with-Zed2i-and-external-fused-Odometry-tp9512p9703.html


For the OpenCV error, don't remember in the thread, but do you use a jetson? In jetpack, they rebuilt optimized opencv version for nvidia but ros cvbridge is still using system opencv. Rtabmap looks building against nvidia opencv, then rtabmap_ros breaks on runtime as cvbridge (used in rtabmap_ros) will use opencv build from nvidia, which is not the same opencv version it has been built with. I'll suggest to rebuild to uninstall ros-foxy-cv-bridge package and rebuild it from source so it is built with nvidia opencv.

Other option is to use docker approach with "introlab3it/rtabmap_ros:humble-latest" image (support aarch64). You may want to wait for this build to get latest commit below.

For deskewing, thx for sharing your patch and a bag, I added support for Hesai lidar in this commit.

For the framerate, make sure you build colcon in Release mode. You can get also more efficient deskewing by setting slerp parameter to true.

I tested with (note in this example a fake odom TF is used, but should be better to be an IMU TF like in this ros1 example):

ros2 run tf2_ros static_transform_publisher 0 0 0 0 0 0 odom hesai
ros2 run rtabmap_util lidar_deskewing --ros-args -p fixed_frame_id:=odom -r input_cloud:=/hesai/points -p slerp:=false
ros2 bag play  rosbag2_2023_09_18-07_35_27_0.db3
ros2 topic hz /hesai/points
ros2 topic hz /hesai/points/deskewed

The lidar framerate in the bag is around 8-9 Hz, and I can get deskewed lidar at 7-8 Hz with slerp=true, and 5-6 Hz with slerp=false.

Deskewing would be more important to do if you expect to do fast rotations, otherwise you may not see any difference.

cheers,
Mathieu