loop closure fails in long cotton rows

[Parastou Bakhtiari]

Dear Matlabbe

I have an issue when trying to create map using rtabmap in long cotton rows.

the problem is if you look at the attached image you can see the unclear path, but the path taken by my robot was going through a row and make a turn and enter the other row and get back to the start point, but it seems like it gets lost in long rows.
I tried the same in a small area and saw that rtabmap is working fine and gives me the correct trajectory despite this one.

would you please tell me how can I solve this problem?

[matlabbe]

Can you show a picture of the environment? Which kind of odometry are you using, which sensor? Is it the same setup than in this post? http://official-rtab-map-forum.206.s1.nabble.com/RTAB-Map-launch-file-for-zed2i-tp10920p10932.html

[Parastou Bakhtiari]

Thank you for your response.

I don't have the image of the field, it's a usual cotton field with long rows of cotton (in it's first growth stage, when we can just see the small plants). I am using ZED2i camera, RTABMap rgb-d mode and ZED odometry.

this is how I launch the RTABMap:
ros2 launch rtabmap_launch rtabmap.launch.py \
   args:="--delete_db_on_start" \
   frame_id:=zed_camera_link \
   odom_topic:=/zed/zed_node/odom \
   visual_odometry:=false \
   rgb_topic:=/zed/zed_node/rgb/image_rect_color \
   depth_topic:=/zed/zed_node/depth/depth_registered \
   camera_info_topic:=/zed/zed_node/rgb/camera_info \
   wait_imu_to_init:=true \
   imu_topic:=/zed/zed_node/imu/data \
   rviz:=true \
   approx_sync:=false \
   rgbd_sync:=true \
   approx_rgbd_sync:=false \
   topic_queue_size:=2 \
   use_sim_time:=true

Is there anything else you need to know?

[matlabbe]

Hi

if there are no loop closures detected, the whole trajectory we see is then dependent only on zed2i's odometry. To debug, you would need to share a database or a rosbag of the camera data and odometry.