unu heq: Perform histogram equalization. If this seems to be doing nothing,
try increasing the number of histograms bins by an order of magnitude or two
(or more). Or, use "unu gamma" to warp the values in the direction you know
they need to go. Either of these might work because extremely tall and narrow
peaks in the equalization histogram will produce poor results.
Usage: unu heq -b <bins> [-s [<bins>]] [-a <amount>] [-m <filename>] \
[-i <nin>] [-o <nout>]
-b <bins> = # bins to use in histogram that is created in order to
calculate the mapping that achieves the equalization. (int)
-s [<bins>] = # bins in value histogram to ignore in calculating the
mapping. Bins are ignored when they get more hits than other
bins, and when the values that fall in them are constant. This
is an effective way to prevent large regions of background
value from distorting the equalization mapping.
(optional int); default: "0"
-a <amount> = extent to which the histogram equalizing mapping should be
applied; 0.0: no change, 1.0: full equalization (float);
default: "1.0"
-m <filename> = The value mapping used to achieve histogram equalization is
represented by a univariate regular map. By giving a filename
here, that map can be saved out and applied to other nrrds
with "unu rmap" (string)
-i <nin> = input nrrd
-o <nout> = output nrrd (string); default: "-"
