Hello,
I’m interested in using the new FSL tool FIRST, but I’m hoping you
could help me with something. The meaning of the boundary-threshold
or z-threshold is unclear to me. While I understand that this is a
threshold for determining whether an edge voxel is inside or outside
the structure, I’m unsure how it is parameterized. In the example on
the FIRST web page, in run_first_all, the parameter is set to “3”.
Does this have units? How do I choose a rational value? Is three the
suggested value? Is it a threshold for inclusion or exclusion – does
lowering the parameter increase or decrease the volume of the region?
Why is the parameter only specified when running run_first_all, and
not just run_first? I’ve glanced through the technical report, and I
couldn’t find any information on this. Any help you can offer would be most
appreciated.
Thanks!
Allison
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