Re: Losing odometry when doing fixed point scanning

Posted by matlabbe on
URL: http://official-rtab-map-forum.206.s1.nabble.com/Losing-odometry-when-doing-fixed-point-scanning-tp4336p4344.html

Knowing accuratly the pose of each capture, for a single scan (24 photos + 24 poses), it is possible to reconstruct the point cloud without RTAB-Map (without extracting features or doing fancy registration as clouds should be already aligned). If you you want to merge two scans (moving the tripod to another place), then RTAB-Map can help to register the two scans together (features matching and motion estimation). RTAB-Map cannot do this out-of-the-box, some coding is required to merge the 24 images together (single SensorData) before sending them to RTAB-Map. I suggest to debug a single scan before going into this.

The units should be meters, however if the focal distance of the camera is wrong, even if the poses are super accurate, the result will be bad. The camera should be then recalibrated. I don't know how you rotate the camera in pitch, but if the lens move along z axis, there should be some z offset.

You can also use rtabmap-databaseViewer to debug the poses you are sending to rtabmap. Open Constraint View and browse the neighbor links, you will see the point clouds aligned two by two.

Cheers,
Mathieu