conndef (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Create connectivity array

Syntax

```
CONN = conndef(NUM_DIMS,TYPE)
```

Description

CONN = conndef(NUM_DIMS,TYPE) returns the connectivity array defined by TYPE for NUM_DIMS dimensions. TYPE can have either of the values listed in this table.

Value
Description

'minimal'
Defines a neighborhood whose neighbors are touching the central element on an (N-1)-dimensional surface, for the N-dimensional case.

'maximal'
Defines a neighborhood including neighbors that touch the central element in any way; it is ones(repmat(3,1,NUM_DIMS)).

Value	Description
`'minimal'`	Defines a neighborhood whose neighbors are touching the central element on an (`N`-1)-dimensional surface, for the `N`-dimensional case.
`'maximal'`	Defines a neighborhood including neighbors that touch the central element in any way; it is `ones(repmat(3,1,NUM_DIMS))`.

Several Image Processing Toolbox functions use conndef to create the default connectivity input argument.

Examples

The minimal connectivity array for two dimensions includes the neighbors touching the central element along a line.

conn1 = conndef(2,'minimal')

conn1 =
     0     1     0
     1     1     1
     0     1     0

The minimal connectivity array for three dimensions includes all the neighbors touching the central element along a face.

conndef(3,'minimal')

ans(:,:,1) =
     0     0     0
     0     1     0
     0     0     0

ans(:,:,2) =
     0     1     0
     1     1     1
     0     1     0

ans(:,:,3) =
     0     0     0
     0     1     0
     0     0     0

The maximal connectivity array for two dimensions includes all the neighbors touching the central element in any way.

conn2 = conndef(2,'maximal')

conn2 =
     1     1     1
     1     1     1
     1     1     1

colorbar conv2