¥Intra-session
registration:
² 3dvolreg -base 4 -heptic -clipit -zpad 4 \
² -prefix
fred1_epi_vr \
² -dfile
fred1_vr_dfile \
²
fred1_epi+orig
²-base 4 Þ Selects sub-brick #4
of dataset fred1_epi+orig as base image J(x)
²-heptic Þ Use 7th order
polynomial interpolation (my personal favorite)
²-clipit Þ Clip off negative
voxels to zero
åNegative voxels are artifacts of high-order interpolation
methods
²-zpad 4 Þ Pad each target image, I(x), with layers of zero voxels 4 deep on each face prior to shift/rotation, then strip them off
afterwards
åZero padding is particularly desireable for -Fourier interpolation
åIs also good for polynomial methods, since if there are
large rotations, some data may get ÔlostÕ when
no zero padding if used (due to 4-way shift algorithm used for fast rotation)
²-prefix fred1_epi_vr Þ Save output dataset
into a new dataset with the given prefix
name (e.g., fred1_epi_vr+orig)
²-dfile fred1_vr_dfile Þ Save estimated movement parameters into a 1D (i.e., text) file with the given name
åCan be plotted with command
² 1dplot -volreg -dx 5
-xlabel Time Ôfred1_vr_dfile[1..6]Õ