Re: issues related to multiple map merging

Posted by matlabbe on
URL: http://official-rtab-map-forum.206.s1.nabble.com/issues-related-to-multiple-map-merging-tp8775p8786.html

Hi,

To remove a session from a merged map, see this post.
To remove specific nodes of the map, see this post.

2. Normally using rtabmap-reprocess to merge databases, it won't care if one database has been taken before or after the other. I would have expected this to work though:

the merging cannot be done while loading the previous database and playing the bags from the next overlapping region

A workaround would be to create a database from the bag, then use rtabmap-reprocess to combine them.

3. There are some parameters inside rtabmap to downsample laser scan before creating grid or saving them:

./rtabmap --params | grep Mem/LaserScan
Param: Mem/LaserScanDownsampleStepSize = "1"               [If > 1, downsample the laser scans when creating a signature.]
Param: Mem/LaserScanNormalK = "0"                          [If > 0 and laser scans don't have normals, normals will be computed with K search neighbors when creating a signature.]
Param: Mem/LaserScanNormalRadius = "0.0"                   [If > 0 m and laser scans don't have normals, normals will be computed with radius search neighbors when creating a signature.]
Param: Mem/LaserScanVoxelSize = "0.0"                      [If > 0 m, voxel filtering is done on laser scans when creating a signature. If the laser scan had normals, they will be removed. To recompute the normals, make sure to use "Mem/LaserScanNormalK" or "Mem/LaserScanNormalRadius" parameters.]

So to voxelize laser scans at 10 cm of a database:

rtabmap-reprocess --Mem/LaserScanVoxelSize 0.1 input.db output_lidar10cm.db

cheers,
Mathieu