¥Conjunction Junction: WhatÕs Your Function?
HThe program 3dcalc is a general purpose program
for performing logic and arithmetic calculations
åcommand line is of the
format
å
3dcalc -a Dset1 -b Dset2 ... -expr
(a * b...)
å some expressions can be used to select voxels with values v
meeting certain criteria:
ífind voxels where v >
th and mark them with value=1
í step (v Ð th)
íin a range of values: thmin < v < thmax
í step (v Ð thmin) * step (thmax - v)
íexact value: v = n
í 1 Ð bool(v Ð n)
åcreate masks to apply to
functional datasets
ítwo values both above
threshold:
í step(v-A)*step(w-B)