Database viewer options

[senia]

Hi,
I wanted to ask how the option: "ICP: Refine all neighbour links" in DB viewer works and what does it do, as it significantly improve my results.
In addition, I don't understand what the error represent.

Thanks.

[matlabbe]

Hi,

The error is computed between the actual transformation of the link and the resulting transformation after graph optimization. For example, if there are no loop closures, the error should be null (the link transformation is identical after graph optimization).

In some cases when there is a lot of geometry in the environment, refining the constraints using ICP may give more precise results. The option "ICP: Refine all neighbor links" does ICP (Iterative-Closest-Point) using the laser scans or the point cloud created from the depth image. Parameters for ICP are under ICP panel in the (GUI) Parameters view.

cheers,
Mathieu

[senia]

Thank you for the answer, in this case, as the kinect has a pretty precise 3D point cloud,
so why does RTAB-MAP(when using kinect) uses visual-color based features(which requires light for example) and not this("ICP: Refine all neighbor links") depth features?
And if this feature is available basically through the database-viewer, why isn't an option to do this ICP depth based in the real time processing.
Thanks.

[matlabbe]

Hi,

You can read this page to know why ICP is not used by default.

In version 0.10, ICP with can be done through database viewer as you did, or with the "Post-processing" tool in the main window.

In the next version (0.11), we will have an option to choose between visual and/or geometry motion estimation approaches (so that it is done in real-time):
1- Visual
2- Geometry (ICP)
3- Visual + Geometry (ICP)


cheers