compute mean of a set of rotations #160
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Need to make log() method handle a multi-value quaternion.
…ued quaternion object.
… a vector, v is an array.
…ase when vector part is zero.
myeatman-bdai
requested changes
Jan 22, 2025
spatialmath/pose3d.py
Outdated
| eta = tol * np.finfo(float).eps | ||
| R_mean = self[0] # initial guess | ||
| while True: | ||
| r = np.dstack((self.inv() * self).log()).mean(axis=2) |
There was a problem hiding this comment.
It's unclear to me what section of the reference paper outlines this algorithm (admittedly, I did not thoroughly read it) . Would you mind pointing it out to me?
There was a problem hiding this comment.
I've clarified that.
…for a quaternion implementation, rather than converting to/from SO(3) matrices.
|
Ok, fixed some bugs, tests pass. There is a randomised test but it is reproducible, using a seeded random number generator. I've commented out, for now, the quaternion mean. Naively applying the SO(3) algorithms for quaternions didn't work, and I need to do more reading. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
New method
mean()for each ofSO3andUnitQuaternion, computes the Karcher (rotational) mean.Relatively straightforward for
SO3butUnitQuaternionrequired a bunch of changes to allow more methods to handle multi-valuedUnitQuaternionobjects. Fixed forRPY(),Eul(),UnitQuaternion()constructor,log()andexp(). Also had to fix edge case forlog()andexp()for the unit quaternions case.Tests and doco updated.
The result is a lot of changes, but generally improved functionality for the
UnitQuaternionclass.