Suggestion: Manual Loop Closure via Correspondence Points

[mephisto]

Hi,

Would it be possible to add an option to manually create loop closures using correspondence points, followed by a fine alignment step in the database editor? Since I use a handheld scanner, my scans often end up at odd angles, and it's quite cumbersome to manually figure out the correct transformation between views.

I think it would be really helpful to have either:

• A gizmo to move and rotate one of the two point clouds, or
• The ability to select three or more corresponding points in each view to perform a rough alignment

This would make the process of adding manual loop closures much easier in my workflow.

Thanks!

[matlabbe]

You would want a tool like this https://www.cloudcompare.org/doc/wiki/index.php/Align. I used the 3 points picking often in CloudCompare and it works generally pretty well. We could implement something similar.

I think all needed libraries are already there (mostly VTK to render/interact/pick the point cloud), a new Qt widget could be created to implement the tool UI.

I created a feature request on the repo: https://github.com/introlab/rtabmap/issues/1562

cheers,
Mathieu