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ICP rotation matrix - order of rotations

Posted: Thu Jan 25, 2024 7:35 pm
by DanceEng
Hi all,

I want to use Euler angle formulas to get the yaw, pitch, and roll from the transformation matrix following ICP registration.
Can someone confirm if CloudCompare derives the transform in the order of X,Y, and Z? Would also love a link to that documentation.

I assume once I confirm that the transform is calculated in that order, that I can use the formulas in the below and attached photo (from https://en.wikipedia.org/wiki/Euler_angles) to calculate yaw, pitch, and roll from the registration transformation matrix.

Image
rotation-matrix-equations.png
rotation-matrix-equations.png (210.03 KiB) Viewed 3361 times

Re: ICP rotation matrix - order of rotations

Posted: Fri Jan 26, 2024 2:59 pm
by DanceEng
Urgently need help with this :(

Re: ICP rotation matrix - order of rotations

Posted: Fri Jan 26, 2024 8:03 pm
by DanceEng
Looks like the apply transform modal has an option to display euler angles for whatever transform is entered. I trust they are correct

Re: ICP rotation matrix - order of rotations

Posted: Fri Jan 26, 2024 9:09 pm
by daniel
Mind that any rotation matrix can be converted to Euler angles. Then you just have to chose a convention that suits your needs.

And with this in mind, mind that the ICP algorithm doesn't use explicit Euler angles. It just finds a transformation that brings the 2 clouds as close as possible (depending on the parameters you've set). The 'Apply Transformation' displays the Euler angles according to the Tait-Bryan Z1Y2X3 convention.