{{{
# transform file register.lta
# created by nmrclass on Fri Feb 10 18:37:21 2017

type      = 0 # LINEAR_VOX_TO_VOX
nxforms   = 1
mean      = 0.0000 0.0000 0.0000
sigma     = 10000.0000
1 4 4
3.431372642517090e+00 -2.051215618848801e-01 -4.745870828628540e-03 2.7534584045
41016e+01 
4.565358161926270e-03 1.446578502655029e-01 -3.996454238891602e+00 1.58296142578
1250e+02 
-2.051111757755280e-01 -3.428324222564697e+00 -1.683440804481506e-01 2.647823486
328125e+02 
0.000000000000000e+00 0.000000000000000e+00 0.000000000000000e+00 1.000000000000
000e+00 
src volume info
valid = 1  # volume info valid
filename = /home/nmrclass/tutorial_data/buckner_data/tutorial_subjs/multimodal/f
mri/fbirn-101/template.nii
volume = 64 64 35
voxelsize = 3.437500000000000e+00 3.437499761581421e+00 4.000000000000000e+00
xras   = -9.972996711730957e-01 -7.120382040739059e-02 1.798351481556892e-02
yras   = 6.254287064075470e-02 -9.518167972564697e-01 -3.002218902111053e-01
zras   = 3.849399834871292e-02 -2.982859909534454e-01 9.537000060081482e-01
cras   = 1.612358093261719e+00 1.616348266601562e+00 4.727973937988281e+00
dst volume info
valid = 1  # volume info valid
filename = /home/nmrclass/tutorial_data/buckner_data/tutorial_subjs/fbirn-anat-1
01.v4/mri/orig.mgz
volume = 256 256 256
voxelsize = 1.000000000000000e+00 1.000000000000000e+00 1.000000000000000e+00
xras   = -1.000000000000000e+00 0.000000000000000e+00 0.000000000000000e+00
yras   = 0.000000000000000e+00 0.000000000000000e+00 -1.000000000000000e+00
zras   = 0.000000000000000e+00 1.000000000000000e+00 0.000000000000000e+00
cras   = 0.000000000000000e+00 0.000000000000000e+00 0.000000000000000e+00
subject fbirn-anat-101.v4
fscale 0.100000
}}}

The matrix (starting with 3.4375 ...) is the registration matrix. xras is the direction cosines for the column direction (in scanner RAS coordinates). yras and zras are the direction cosines for the row and slice directions. cras is the center of the volume in RAS coordinates. The first set of parameters is for the source volume. The second set is for the target volume.