Multi camera mapping and 6dof laser scan

[andre-nguyen]

Hi Mathieu

Two questions:

1. Assuming I provide the correct transforms, is it possible to run rtabmap with a camera + laser scanner while still conserving 6dof mapping?

2. I noticed that there are callbacks for the purpose of processing two depth images at a time. How exactly can I use those in my launch file? I can't seem to find an example launch file with two depth cameras.

Thanks!

[matlabbe]

Hi,

1. Yes

2. There is an example here: https://github.com/introlab/rtabmap_ros/blob/master/launch/demo/demo_two_kinects.launch

cheers

[andre-nguyen]

Wow! sorry about that, it seems I was temporarily blind.

About the laser scan, should I simply change it to a point cloud and put it in the scan_cloud topic? Should I also transform the cloud into the odometry frame or can I leave it in the laser frame and put it as a child of the base_link frame?

I'm asking because of this comment "" in the stereo_mapping.launch file.

[matlabbe]

Hi,

You can convert the laser scan in a point cloud in same frame as the laser scan message. However, you can still do 6dof even if you are using the laser scan input. The stereo_mapping.launch file just assumes that if you are using a laser scanner, you want a map in 3DoF, but you can just comment these lines to disable 3DoF constraints:

      <!-- when 2D scan is set -->
      <param if="$(arg subscribe_scan)" name="Optimizer/Slam2D"        type="string" value="true">
      <param if="$(arg subscribe_scan)" name="Icp/CorrespondenceRatio" type="string" value="0.25"/>
      <param if="$(arg subscribe_scan)" name="Reg/Strategy"            type="string" value="1"/> 
      <param if="$(arg subscribe_scan)" name="Reg/Force3DoF"           type="string" value="true"/>

      <!-- when 3D scan is set -->
      <param if="$(arg subscribe_scan_cloud)" name="Reg/Strategy"      type="string" value="1"/>

cheers