``Homotopic_Thickening'' - conditional homotopic thickening

VFX name:

iHomotopicThick

IMPROMPTU Equivalent:

Homotopic_Thickening

purpose:

Thicken a binary-valued volume conditioned (set intersection) on another binary-valued volume [25,21]. Thickening means to add layers to objects in the volume without changing the connectivity (homotopy) of objects in the volume; it is the opposite of thinning. Conditioning the thickening on another volume restricts the extent of the thickening. The function thickens the input volume until it reaches a stable configuration (i.e., no further voxels can be added without changing the connectivity or going outside the extent of the conditioning volume). The function can be done in 3-D or 2-D.

Using it in conjunction with erosion, you can separate loosely connected objects without changing the shape of objects [21].

input:

Two different 8-bit binary-valued volumes.

output:

An 8-bit binary-valued volume.

parameters:

Default parameters menu is

connectivity = 3-D
num_passes = to_completion
cond_volume = 1

The option ``connectivity'' toggles between ``3-D'' and ``2-D'' and specifies how the operation is done.

comments:

1.

To separate connected objects: (1) copy input volume 0 to slot 1; (2) erode volume 0 a few times to break regions apart (you must determine empirically how many erosions are necessary); (3) do a conditional homotopic thickening on volume 0, conditioned on volume 1. The result will have the objects separated, without their shapes changing.

2.

The operation ``object separation'' in the ``integrated'' category performs the object separation function described above.

3.

This is a moderately slow operation.