transform.flip.handedness: Convert a transformation between the LPS and the RAS...

In freesurferformats: Read and Write 'FreeSurfer' Neuroimaging File Formats

Convert a transformation between the LPS and the RAS convention.

Description

Changing the convention of the coordinates that a transformation maps flips the sign of its first two axes on each side of the transformation that changes: the input side by multiplying the matrix from the right and the output side by multiplying it from the left, with a diagonal matrix that negates x and y. That matrix is its own inverse, which is why the conversion in both directions is the same operation.

Usage

## S3 method for class 'flip.handedness'
transform(tf, target)

Arguments

tf	an fs.transform instance.
target	character string, either 'ras' or 'lps'.

Value

an fs.transform instance whose matrix is expressed in the requested convention.

freesurferformats documentation built on Sept. 25, 2026, 1:07 a.m.