Convert aniso Mag to motion_corr2

Dear all,
I have refined the anisotropic mag parameters for the data collected from a microscope using global CTF refinement. I obtained the parameters like this:
Anisotropic Mag: [[-0.00571369 -0.00932393] [-0.01013075 0.00451204]]
Anisotropic Mag Determinant: 0.99867812
I am wondering if there is a way to convert these parameters to Motioncorr2 format, so I can correct the aniso Mag during motion correction.
In Motioncorr2, three inputs are needed including magnifications along major and minor axes and the angle of the major axis relative to the image x-axis in degree.

Hi @rainfieldcn,

This isn’t a full answer, but to point you to a recent discussion about interpreting the anisomag matrix, its worthwhile to checkout this post: Help interpreting the anisotropic magnification matrix - #2 by mmclean.

After adding the identity and taking the singular-value decomposition (SVD), I believe the singular values would give you the magnifications along two orthogonal axes (major and minor). The angle relative to the image x-axis would probably be derivable from the rotation matrices (U or V) but I am not entirely sure if it would correspond to the angle relative to the x or y axes of the image.


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