Compute RAS coords of center voxel.
mghheader.centervoxelRAS.from.firstvoxelRAS(header, first_voxel_RAS)numerical vector of length 3, the RAS coordinate of the center voxel. Also known as CRAS or center RAS.
Header of the mgh datastructure, as returned by read.fs.mgh. The c_r, c_a and c_s values in the header do not matter of course, they are what is computed by this function.
numerical vector of length 3, the RAS coordinate of the first voxel in the volume. The first voxel is the voxel with CRS=1,1,1 in R, or CRS=0,0,0 in C/FreeSurfer. This value is also known as P0 RAS.