Connectivity

In image processing, connectivity is the way in which voxels in 3-dimensional images relate to their neighbors and are labeled as separate components. You should note that a set of voxels in an image that are connected to each other is often called a connected component. Finding all of the connected components in an image and marking each of them with a distinctive label is referred to as connected component labeling.

Connectivity is selectable in Dragonfly for creating multi-ROIs and for processing islands, as shown in the following illustration and explained below.

6-connected versus 26-connected

6-connected… Propagation is done by strictly using the 6 faces adjacent to the current seed and will result in the maximum number of labeled objects.

18-connected… Propagation is done using the 6 faces and 12 edges adjacent to the current seed. Will result in fewer connected components than 6-connected. You should note that this option is currently not available in Dragonfly.

26-connected… Propagation is done in all directions, using the 6 faces, 12 edges, and 8 corners adjacent to the current seed. Will result in the fewest connected components, but computation times may increase.