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entry variable: $sfmid -- statmask sigmoid threshold
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default: 0.0

This entry is only visible if overlaymaskflag is
ticked (to left of "mskn:" or "mskup:").

This entry defines the soft threshold for masking
the value (e.g., coef) at a pixel using the stat
mask (same units as $sfthresh).

The units of this mask threshold ($sfmid) will
*not* in general be the same as the units of the
amplitude thresh ($fmid).

See $fmid help for more details.
