``3D_conn_comp'' -- three-dim. connected components analysis

purpose:

This is a package of 3-D topological operations geared toward locating, labeling, and deleting connected sets of 1's [28]. A connected set of 1's is referred to as a connected component and the general set of operations packaged here is referred to as connected component analysis [24]. The specific operations possible here are

1. Delete overly small components.
2. Save a specified maximum number of components.
3. Save component labels. The labels help to distinguish various objects.

The function ``2D_conn_comp'' performs the analogous operations on 2-D x-y planes of a volume.

input:

An 8-bit binary-valued volume.

output:

An 8-bit volume, possibly grayscale-valued.

parameters:

Default parameters menu is

min component size = 10
max no. of components = 254
connectivity = 6
save labels = no
input from vol # = 0
copy output to vol # = 0

The ``min component size = '' restricts the minimum size in voxels of saved components; all components smaller than this number are deleted (set to 0).

The ``max no. of components = '' option determines how many components to save. If this parameter is set to 5, for example, only the 5 largest components are saved -- all others are deleted. If you only want to save the largest connected component, set this parameter to 1.

The option ``connectivity = '' sets the connectivity requirement of connected components. The options are ``6'' (for 6-connected) and ``26'' (for 26-connected) [28,23].

The ``save labels = '' option toggles between ``yes'' and ``no''. When the option is set to ``no'', only actions involving deleting components are done (per the settings of the parameters ``min component size = '' and ``max no. of components = ''). If the option is set to ``yes'', each different component will be assigned a unique number between 2 and 255; i.e., the component labeled 2 will have all of its voxels set to 2, etc.

comments:

 

1. A medium-speed function, taking about 2 minutes in a typical 100x100x100 volume. 26-connectivity takes roughly twice as long as 6-connectivity.
2. Only a maximum of 254 components can be saved safely within the volume!