Info on some parameters

Posted by manuel.lo on
URL: http://official-rtab-map-forum.206.s1.nabble.com/Info-on-some-parameters-tp4568.html

Hello.
I'm newbie, so sorry for my questions.
I'm studying all RTAB-Map parameters and I need to know the meaning and the effects of these parameters (probably I will need your help again in near future :) ):

1) RTAB-Map Setting - Threshold - T_ratio: what does it mean "The loop closure hypothesis must be over T_ratio x lastHypothesisValue"? Is lastHypothesisValue a parameter?

2) RTAB-Map Settings - Memory - Laser scan filtering: what's the meaning of the 4 parameters:
- Downsampling step. If > 1, downsample the laser scans when creating a location. This feature can be used to save laser scans already downsampled.
- Voxel size. 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 Normal K or Normal Radius parameters below
- Normal K. If > 0 and laser scans don't have normals, normals will be computed with K search neighbors when creating a signature
- Normal Radius. If > 0 and laser scans don't have normals, normals will be computed with radius search when creating a signature
What's a signature? What these 4 parameters do to laser scans? How do they impact on RTAB-Map performance?

3) RTAB-Map Settings - Memory - Rehearsal/Weight Update: what's the meaning of T_similarity?
What's the meaning of "On transfer, signatures are sorted by weight->ID (i.e. the oldest of the lowest weighted signatures are transferred first). If false, the signatures are sorted by weight->Age (i.e. the oldest inserted in WM of the lowest weighted signatures are transferred first). Note that retrieval updates the age, not the ID." What is weight referred to?

4) RTAB-Map Settings - Memory: what's the meaning of "Raw descriptors kept in memory"?

If you need more clarification, I'm here.

Thanks a lot.

           Manuel