++ In binary mode ... You are in "binary" mode---all non-zero voxels are treated like one giant ROI.
-bmask MASK: Report on the overlap of all non-zero voxels in MASK dataset
with various atlas regions. NOTE: The mask itself is not binary,
the masking operation results in a binary mask.
-omask ORDERED_MASK:Report on the overlap of each ROI formed by an integral
value in ORDERED_MASK. For example, if ORDERED_MASK has
ROIs with values 1, 2, and 3, then you'll get three
reports, one for each ROI value. Note that -omask and
-bmask are mutually exclusive.