RegionalExtrema2d

Computes the regional maxima or minima of a two-dimensional grayscale image and marks them in a binary image.

Access to parameter description

For an introduction:

section Mathematical Morphology
section Geodesic Transformations

This algorithm computes the regional (or relative) maxima or minima of a grayscale image

$I$ and creates a binary image

$O$ containing these extrema.

A regional maximum (resp. minimum)

$C$ is a set of connected pixels such that:

Pixels belonging to $C$ have the same intensity $I_C$ .
Pixels connected to $C$ , but not belonging to $C$ (neighbors), have an intensity strictly lower (resp. greater) than $I_C$ .

<b> Figure 1.</b> One-dimensional example of a regional maxima detection

Figure 1. One-dimensional example of a regional maxima detection

<b> Figure 2.</b> One-dimensional example of a regional minima detection

Figure 2. One-dimensional example of a regional minima detection

This algorithm uses a recursive method combined with a geodesic propagation.
To avoid getting too many regions in the output image, the input should be smoothed first with a low-pass filter or with the numerical reconstruction algorithm.

Figure 3. Original image (left) and regional maxima in red (right)

Reference:
P. Soille, Morphological Image Analysis. Principles and Applications, Second Edition, Springer-Verlag, Berlin, pp.201-203, 2003.

See also

Function Syntax

This function returns outputBinaryImage.

// Function prototype
std::shared_ptr< iolink::ImageView >
regionalExtrema2d( std::shared_ptr< iolink::ImageView > inputImage,
                   RegionalExtrema2d::ExtremaType extremaType,
                   RegionalExtrema2d::Neighborhood neighborhood,
                   std::shared_ptr< iolink::ImageView > outputBinaryImage = nullptr );

This function returns outputBinaryImage.

// Function prototype.
regional_extrema_2d(input_image: idt.ImageType,
                    extrema_type: RegionalExtrema2d.ExtremaType = RegionalExtrema2d.ExtremaType.MAXIMA,
                    neighborhood: RegionalExtrema2d.Neighborhood = RegionalExtrema2d.Neighborhood.CONNECTIVITY_8,
                    output_binary_image: idt.ImageType = None) -> idt.ImageType

This function returns outputBinaryImage.

// Function prototype.
public static IOLink.ImageView
RegionalExtrema2d( IOLink.ImageView inputImage,
                   RegionalExtrema2d.ExtremaType extremaType = ImageDev.RegionalExtrema2d.ExtremaType.MAXIMA,
                   RegionalExtrema2d.Neighborhood neighborhood = ImageDev.RegionalExtrema2d.Neighborhood.CONNECTIVITY_8,
                   IOLink.ImageView outputBinaryImage = null );

Class Syntax

// Command constructor.
RegionalExtrema2d();

/// Gets the inputImage parameter.
/// The input grayscale image.
std::shared_ptr< iolink::ImageView > inputImage() const;
/// Sets the inputImage parameter.
/// The input grayscale image.
void setInputImage( std::shared_ptr< iolink::ImageView > inputImage );

/// Gets the extremaType parameter.
/// The type of extrema to detect.
RegionalExtrema2d::ExtremaType extremaType() const;
/// Sets the extremaType parameter.
/// The type of extrema to detect.
void setExtremaType( const RegionalExtrema2d::ExtremaType& extremaType );

/// Gets the neighborhood parameter.
/// The 2D neighborhood configuration used for geodesic propagation.
RegionalExtrema2d::Neighborhood neighborhood() const;
/// Sets the neighborhood parameter.
/// The 2D neighborhood configuration used for geodesic propagation.
void setNeighborhood( const RegionalExtrema2d::Neighborhood& neighborhood );

/// Gets the outputBinaryImage parameter.
/// The output binary image. Its dimensions are forced to the same values as the input.
std::shared_ptr< iolink::ImageView > outputBinaryImage() const;
/// Sets the outputBinaryImage parameter.
/// The output binary image. Its dimensions are forced to the same values as the input.
void setOutputBinaryImage( std::shared_ptr< iolink::ImageView > outputBinaryImage );


// Method to launch the command.
void execute();

# Property of the inputImage parameter.
RegionalExtrema2d.input_image
# Property of the extremaType parameter.
RegionalExtrema2d.extrema_type
# Property of the neighborhood parameter.
RegionalExtrema2d.neighborhood
# Property of the outputBinaryImage parameter.
RegionalExtrema2d.output_binary_image

// Method to launch the command.
execute()

// Command constructor.
RegionalExtrema2d()

// Property of the inputImage parameter.
RegionalExtrema2d.inputImage
// Property of the extremaType parameter.
RegionalExtrema2d.extremaType
// Property of the neighborhood parameter.
RegionalExtrema2d.neighborhood
// Property of the outputBinaryImage parameter.
RegionalExtrema2d.outputBinaryImage

// Method to launch the command.
Execute()

Parameters

Parameter Name

Description

Type

Supported Values

Default Value

inputImage

The input grayscale image.

Image

Grayscale

nullptr

extremaType

The type of extrema to detect.

MAXIMA	The regional maxima are extracted from the input image.
MINIMA	The regional minima are extracted from the input image.

Enumeration

MAXIMA

neighborhood

The 2D neighborhood configuration used for geodesic propagation.

CONNECTIVITY_4	The neighborhood configuration is a cross.
CONNECTIVITY_8	The neighborhood configuration is a square.

Enumeration

CONNECTIVITY_8

outputBinaryImage

The output binary image. Its dimensions are forced to the same values as the input.

Image

nullptr

Object Examples

auto polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

RegionalExtrema2d regionalExtrema2dAlgo;
regionalExtrema2dAlgo.setInputImage( polystyrene );
regionalExtrema2dAlgo.setExtremaType( RegionalExtrema2d::ExtremaType::MAXIMA );
regionalExtrema2dAlgo.setNeighborhood( RegionalExtrema2d::Neighborhood::CONNECTIVITY_8 );
regionalExtrema2dAlgo.execute();

std::cout << "outputBinaryImage:" << regionalExtrema2dAlgo.outputBinaryImage()->toString();

polystyrene = ioformat.read_image(imagedev_data.get_image_path("polystyrene.tif"))

regional_extrema_2d_algo = imagedev.RegionalExtrema2d()
regional_extrema_2d_algo.input_image = polystyrene
regional_extrema_2d_algo.extrema_type = imagedev.RegionalExtrema2d.MAXIMA
regional_extrema_2d_algo.neighborhood = imagedev.RegionalExtrema2d.CONNECTIVITY_8
regional_extrema_2d_algo.execute()

print("output_binary_image:", str(regional_extrema_2d_algo.output_binary_image))

ImageView polystyrene = ViewIO.ReadImage( @"Data/images/polystyrene.tif" );

RegionalExtrema2d regionalExtrema2dAlgo = new RegionalExtrema2d
{
    inputImage = polystyrene,
    extremaType = RegionalExtrema2d.ExtremaType.MAXIMA,
    neighborhood = RegionalExtrema2d.Neighborhood.CONNECTIVITY_8
};
regionalExtrema2dAlgo.Execute();

Console.WriteLine( "outputBinaryImage:" + regionalExtrema2dAlgo.outputBinaryImage.ToString() );

Function Examples

auto polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

auto result = regionalExtrema2d( polystyrene, RegionalExtrema2d::ExtremaType::MAXIMA, RegionalExtrema2d::Neighborhood::CONNECTIVITY_8 );

std::cout << "outputBinaryImage:" << result->toString();

polystyrene = ioformat.read_image(imagedev_data.get_image_path("polystyrene.tif"))

result = imagedev.regional_extrema_2d(polystyrene, imagedev.RegionalExtrema2d.MAXIMA, imagedev.RegionalExtrema2d.CONNECTIVITY_8)

print("output_binary_image:", str(result))

ImageView polystyrene = ViewIO.ReadImage( @"Data/images/polystyrene.tif" );

IOLink.ImageView result = Processing.RegionalExtrema2d( polystyrene, RegionalExtrema2d.ExtremaType.MAXIMA, RegionalExtrema2d.Neighborhood.CONNECTIVITY_8 );

Console.WriteLine( "outputBinaryImage:" + result.ToString() );

RegionalExtrema2d

- Function Syntax

+ Class Syntax

Parameters

Object Examples

Function Examples

Function Syntax

Class Syntax