conndef

Create connectivity array

Syntax

conn = conndef(num_dims,type)

Description

conn = conndef(num_dims,type) returns the pixel connectivity array defined by type for num_dims dimensions. Several Image Processing Toolbox™ functions use conndef to create the default connectivity input argument.

Examples

Create 2-D Connectivity Array with Minimal Connectivity

Create a 2-D connectivity array.

conn = conndef(2,'minimal')

conn = 3×3

     0     1     0
     1     1     1
     0     1     0

Create 2-D Connectivity Array with Maximal Connectivity

Create a 2-D connectivity array.

conn = conndef(2,'maximal')

conn = 3×3

     1     1     1
     1     1     1
     1     1     1

Create 3-D Connectivity Array with Minimal Connectivity

Create a 3-D connectivity array.

conndef(3,'minimal')

ans = 
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

Input Arguments

num_dims — Number of dimensions

positive integer

Number of dimensions, specified as a positive integer.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

type — Type of neighborhood connectivity

'minimal' | 'maximal'

Type of neighborhood connectivity, specified as 'minimal' or 'maximal'

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)).

Data Types: char | string

Output Arguments

conn — Pixel connectivity

3-by-3-by...-3 logical array

Pixel connectivity, returned as a 3-by-3-....-by-3 logical array. conn is symmetric about its center element. See Specifying Custom Connectivities for more information.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• conndef supports the generation of C code (requires MATLAB^® Coder™). For more information, see Code Generation for Image Processing.

• When generating code, the num_dims and type arguments must be compile-time constants.

GPU Code Generation

Generate CUDA® code for NVIDIA® GPUs using GPU Coder™.

Usage notes and limitations:

• When generating code, the num_dims and type arguments must be compile-time constants.

Version History

Introduced before R2006a