Hi,
I created a flirt schedule to perform eddy current correction on a phantom. Thus, I need to correct for y shift but NOT for x (and z) shift. Though, even if I select 3 DoF:
setoption paramsubset 3 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
(corresponding to yshift, xyshear and yscale)
in the affine matrix xshift is still different from zero.
Does anyone knows how to disentangle x and y shift?
Many thanks,
Silvia
PS
the schedule is the following:
# 8mm scale
setscale 8
setoption smoothing 8
setoption paramsubset 3 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
clear U
clear UA
setrow UA 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1
optimise 12 UA:1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 rel 4
# 4mm scale
setscale 4
setoption smoothing 4
setoption paramsubset 3 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
clear UB
clear UL
clear UM
# remeasure costs at this scale
clear U
measurecost 12 UA 0 0 0 0 0 0 rel
sort U
copy U UL
# optimise best 3 candidates
clear U
optimise 12 UL:1-3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 rel 4
copy U UM
# select best 4 optimised solutions and try perturbations of these
clear U
copy UM:1-4 U
optimise 12 UM:1-3 0.0 0.0 0.0 0.0 0.05 0.0 0.0 rel 4
optimise 12 UM:1-3 0.0 0.0 0.0 0.0 -0.05 0.0 0.0 rel 4
optimise 12 UM:1-3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.05 0.0 abs 4
optimise 12 UM:1-3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.05 0.0 abs 4
optimise 12 UM:1-3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.05 0.0 0.0 abs 4
optimise 12 UM:1-3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 -0.05 0.0 0.0 abs 4
sort U
clear UB
copy U UB
# 2mm scale
setscale 2
setoption smoothing 2
setoption paramsubset 3 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
clear U
clear UC
clear UD
clear UE
clear UF
# remeasure costs at this scale
measurecost 12 UB 0 0 0 0 0 0 rel
sort U
copy U UC
clear U
optimise 12 UC:1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 rel 4
copy U UD
setoption boundguess 1
if MAXDOF > 7
clear U
if MAXDOF > 7
optimise 9 UD:1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 rel 1
copy U UE
if MAXDOF > 9
clear U
if MAXDOF > 9
optimise 12 UE:1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 rel 2
sort U
copy U UF
# 1mm scale
setscale 1
setoption smoothing 1
setoption boundguess 1
setoption paramsubset 3 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0
clear U
optimise 12 UF:1-2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 rel 1
sort U
|