Do arithmetic on 2D images, pixel-by-pixel.
Usage: imcalc options
where the options are:
-datum type = Coerce the output data to be stored as the given type,
which may be byte, short, or float.
[default = datum of first input image on command line]
-a dname = Read image 'dname' and call the voxel values 'a'
in the expression. 'a' may be any letter from 'a' to 'z'.
** If some letter name is used in the expression, but not
present in one of the image options here, then that
variable is set to 0.
-expr "expression"
Apply the expression within quotes to the input images,
one voxel at a time, to produce the output image.
("sqrt(a*b)" to compute the geometric mean, for example)
-output name = Use 'name' for the output image filename.
[default='imcalc.out']
See the output of '3dcalc -help' for details on what kinds of expressions
are possible. Note that complex-valued images cannot be processed (byte,
