imextendedmax (Image Processing Toolbox)

Extended-maxima transform

Syntax

```
BW = imextendedmax(I,H)
```

Description

BW = imextendedmax(I,H) computes the extended-maxima transform, which is the regional maxima of the H-maxima transform. H is a nonnegative scalar.

Regional maxima are connected components of pixels with the same intensity value, t, whose external boundary pixels all have a value less than t.

By default, imextendedmax uses 8-connected neighborhoods for 2-D images and 26-connected neighborhoods for 3-D images. For higher dimensions, imextendedmax uses conndef(ndims(I),'maximal').

BW = imextendedmax(I,H,CONN) computes the extended-maxima transform, where CONN specifies the connectivity. CONN may have any of the following scalar values.

Value
Meaning

Two-dimensional connectivities

4
4-connected neighborhood

8
8-connected neighborhood

Three-dimensional connectivities

6
6-connected neighborhood

18
18-connected neighborhood

26
26-connected neighborhood

Value	Meaning
Two-dimensional connectivities
`4`	4-connected neighborhood
`8`	8-connected neighborhood
Three-dimensional connectivities
`6`	6-connected neighborhood
`18`	18-connected neighborhood
`26`	26-connected neighborhood

Connectivity may be defined in a more general way for any dimension by using for CONN a 3-by-3-by- ...-by-3 matrix of 0's and 1's. The 1-valued elements define neighborhood locations relative to the center element of CONN. Note that CONN must be symmetric about its center element.

Class Support

I can be of any nonsparse numeric class and any dimension. BW has the same size as I and is always logical.

Example

I = imread('bonemarr.tif');
BW = imextendedmax(I,40);
imshow(I), figure, imshow(BW)

Reference

[1] Pierre Soille, Morphological Image Analysis: Principles and Applications, Springer-Verlag, 1999, pp. 170-171.

imerode imextendedmin