``region isolation'' - extract a large bright region

VFX name:

iRegionIso

IMPROMPTU Equivalent:

Region_isolation

purpose:

Crudely isolate the largest bright region in a volume.

The following operations are done: 1. threshold the volume, using a user-preset threshold; 2. apply a 3$\times$3$\times$1 erosion followed by a 3$\times$3$\times$1 dilation (i.e., these two operations constitute a 3$\times$3$\times$1 opening) to smooth the thresholded result [25,19]; 3. save the largest connected object > 25 voxels in size.

input:

An 8-bit volume.

output:

An 8-bit volume containing the isolated object. Voxels equal to 1 belong to the object; 0's belong to the background.

parameters:

Default parameters menu is

threshold = 0

comments:

1.

This operation takes a moderate amount of computation time.