freesurferformats (version 1.1.0)

read.fs.transform.lta: Load transformation matrix from a FreeSurfer linear transform array (LTA) file.

Description

Load transformation matrix from a FreeSurfer linear transform array (LTA) file.

Usage

read.fs.transform.lta(filepath)

Value

an fs.transform instance. The header of an LTA file states whether the matrix operates on voxel indices (type 0, LINEAR_VOX_TO_VOX) or on RAS world coordinates (type 1, LINEAR_RAS_TO_RAS), and that is used to set space_in, space_out and voxel_base. FreeSurfer voxel indices are zero-based. The file also records both volumes it relates, so src and dst contain the file name, the dimensions, the voxel size and the voxel-to-RAS matrix of each of them. The parsed header and volume info sections are kept in the header and volumes fields.

Arguments

filepath

character string, the full path to the transform file.

See Also

Other header coordinate space: invert.fs.transform(), is.fs.transform(), mghheader.is.ras.valid(), mghheader.ras2vox(), mghheader.ras2vox.tkreg(), mghheader.scanner2tkreg(), mghheader.tkreg2scanner(), mghheader.vox2ras(), mghheader.vox2ras.tkreg(), print.fs.transform(), read.fs.transform(), read.fs.transform.dat(), read.fs.transform.fslmat(), read.fs.transform.itk(), read.fs.transform.xfm(), sm0to1(), sm1to0(), summary.fs.transform(), transform2lps(), transform2ras(), transform2voxel(), transform2world(), write.fs.transform(), write.fs.transform.dat(), write.fs.transform.fslmat(), write.fs.transform.itk(), write.fs.transform.lta(), write.fs.transform.xfm()

Examples

tf_file <- system.file("extdata", "talairach.lta",
  package = "freesurferformats", mustWork = TRUE
)
transform <- read.fs.transform.lta(tf_file)
transform$matrix