occupancy grid from t265

[David_dmj]

Hi,
I am trying to use RTAB-MAP for indoor autonomous navigation. I am fairly new to robotics. The only camera I can use right now is a Realsense t265. I used yaml_to_camera_info.py to publish the calibration info, and then started rtabmap with:
 
'roslaunch rtabmap_ros rtabmap.launch    args:="-d --udebug --Rtabmap/ImagesAlreadyRectified false"    stereo:=true    left_image_topic:=/camera/fisheye1/image_raw    right_image_topic:=/camera/fisheye2/image_raw    left_camera_info_topic:=/camera/fisheye1/camera_info_calib    right_camera_info_topic:=/camera/fisheye2/camera_info_calib    visual_odometry:=false    odom_frame_id:=camera_odom_frame'


The output I get is:


I don't know if it is working properly, it seems a little messy to me.
How can I get an occupancy grid from here?
I checked the topic '/rtabmap/proj_map' and it is not publishing data while the application is running. Any help would be much appreciated.

[matlabbe]

You may launch rtabmap.launch with rviz:=true. In rviz, add a Map display and subscribe to /rtabmap/grid_map

The t265 camera is fisheye stereo, very noisy points are expected (may appear cleaner outside).

You may need to add "--Grid/MapFrameProjection true" so that occupancy grid is generated in right frame.

Param: Grid/MapFrameProjection = "false"                   [Projection in map frame. On a 3D terrain and a fixed local camera transform (the cloud is created relative to ground), you may want to disable this to do the projection in robot frame instead.]

cheers,
Mathieu

[David_dmj]

Thanks Mathieu for the response.
I have tried your suggestion and I get a grid map in rviz but honestly it doesn't depict the environment very well. I guess it has to do with the t265 not being the best sensor for that application. I realized I might be able to use a kinect v2 from an xbox one. I suppose it should work much better.
How can I combine the odometry from the t265 with the kinect for a best result in my application. All I want is to generate a 2d occupancy grid for a cherokey robot to navigate indoor environments without a previous map.

Thanks,
David.

[matlabbe]

Hi David,

It could be similar to T265+D400 camera example here: https://github.com/IntelRealSense/realsense-ros/blob/ros1-legacy/realsense2_camera/launch/rs_rtabmap.launch

You need to publish a static transform between T265 and the kinect. Use frame of T265 as base frame and its odom sample topic as odometry. Use RGB+Depth topics from the other camera.

cheers,
Mathieu