# imextendedmax

Extended-maxima transform

## Description

example

BW = imextendedmax(I,H) returns the extended-maxima transform for I, which is the regional maxima of the H-maxima transform. Regional maxima are connected components of pixels with a constant intensity value, and whose external boundary pixels all have a lower value.

BW = imextendedmax(I,H,conn) computes the extended-maxima transform, where conn specifies the pixel connectivity.

## Examples

collapse all

Read image into workspace.

Calculate the extended-maxima transform.

BW = imextendedmax(I,80);

Display original image and transformed image side-by-side.

imshowpair(I,BW,'montage')

## Input Arguments

collapse all

Input image, specified as a numeric array of any dimension.

Example: I = imread('glass.png');

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

H-maxima transform, specified as a nonnegative scalar.

Example: BW = imextendedmax(I,80);

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

Pixel connectivity, specified as one of the values in this table. The default connectivity is 8 for 2-D images, and 26 for 3-D images.

Value

Meaning

Two-Dimensional Connectivities

4

Pixels are connected if their edges touch. The neighborhood of a pixel are the adjacent pixels in the horizontal or vertical direction.

Current pixel is shown in gray.

8

Pixels are connected if their edges or corners touch. The neighborhood of a pixel are the adjacent pixels in the horizontal, vertical, or diagonal direction.

Current pixel is shown in gray.

Three-Dimensional Connectivities

6

Pixels are connected if their faces touch. The neighborhood of a pixel are the adjacent pixels in:

• One of these directions: in, out, left, right, up, and down

Current pixel is shown in gray.

18

Pixels are connected if their faces or edges touch. The neighborhood of a pixel are the adjacent pixels in:

• One of these directions: in, out, left, right, up, and down

• A combination of two directions, such as right-down or in-up

Current pixel is center of cube.

26

Pixels are connected if their faces, edges, or corners touch. The neighborhood of a pixel are the adjacent pixels in:

• One of these directions: in, out, left, right, up, and down

• A combination of two directions, such as right-down or in-up

• A combination of three directions, such as in-right-up or in-left-down

Current pixel is center of cube.

For higher dimensions, imextendedmax uses the default value conndef(ndims(I),'maximal').

Connectivity can also be defined in a more general way for any dimension by specifying a 3-by-3-by- ... -by-3 matrix of 0s and 1s. The 1-valued elements define neighborhood locations relative to the center element of conn. Note that conn must be symmetric about its center element. See Specifying Custom Connectivities for more information.

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

## Output Arguments

collapse all

Transformed image, returned as a logical array the same size as I.

## References

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

## Version History

Introduced before R2006a