Documentation

imextendedmax

Extended-maxima transform

Syntax

  • BW = imextendedmax(I,H) example
  • BW = imextendedmax(I,H,conn)

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. H is a nonnegative scalar. 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(numel(size(I)),'maximal').

This function supports code generation (see Tips).

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

Examples

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Perform Extended-Maxima transform

Read image into workspace.

I = imread('glass.png');

Calculate the extended-maxima transform.

BW = imextendedmax(I,80);

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

imshowpair(I,BW,'montage')

Input Arguments

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I — Input imagereal, nonsparse numeric array of any dimension

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

Example: I = imread(‘glass.png'); BW = imextendedmax(I,80);

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

H — H-maxima transformreal, nonnegative scalar

H-maxima transform, specified as a real, nonnegative scalar.

Example: BW = imextendedmax(I,80);

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

conn — Connectivity8 (default) | 4 | 6 | 18 | 26 | 3-by-3-by- ...-by-3 matrix of zeroes and ones

Connectivity, specified as a one of the scalar values in the following table. 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(numel(size(I)),'maximal'). Connectivity can be defined in a more general way for any dimension by using for conn 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 around its center element.

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

Example: BW = imextendedmax(I,80,4);

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

Output Arguments

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BW — Transformed imagelogical array

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

More About

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Tips

  • This function supports the generation of C code using MATLAB® Coder™. Note that if you choose the generic MATLAB Host Computer target platform, the function generates code that uses a precompiled, platform-specific shared library. Use of a shared library preserves performance optimizations but limits the target platforms for which code can be generated. For more information, see Understanding Code Generation with Image Processing Toolbox.

    When generating code, the optional third input argument, conn, must be a compile-time constant.

References

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

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