AutoThresholdingValue

Computes a threshold value partitioning automatically a gray level image into two classes.

Access to parameter description

For an introduction:

This algorithm computes an automatic threshold on a grayscale image; that is, separates the input image histogram in two classes of pixels from an input range

$[I_1, I_2]$ .

$C_0=[I_1,T]$ represents the first class pixels.
$C_1=[T+1,I_2]$ represents the second class pixels.

Each class can be either considered as background or foreground depending on the acquisition device and the nature of the scene.

Four methods of classification are available to determine

$C_0$ and

$C_1$ : Entropy, Factorisation, Moments, and Isodata. These methods are detailed in the AutoThresholdingBright documentation.
The computed threshold is returned in the AutoThresholdingMsr object. See also

Function Syntax

This function returns outputMeasurement.

// Function prototype
AutoThresholdingMsr::Ptr
autoThresholdingValue( std::shared_ptr< iolink::ImageView > inputGrayImage,
                       AutoThresholdingValue::RangeMode rangeMode,
                       iolink::Vector2d intensityInputRange,
                       AutoThresholdingValue::ThresholdCriterion thresholdCriterion,
                       AutoThresholdingMsr::Ptr outputMeasurement = NULL );

This function returns outputMeasurement.

// Function prototype.
auto_thresholding_value( input_gray_image,
                         range_mode = AutoThresholdingValue.RangeMode.MIN_MAX,
                         intensity_input_range = [0, 255],
                         threshold_criterion = AutoThresholdingValue.ThresholdCriterion.ENTROPY,
                         output_measurement = None )

This function returns outputMeasurement.

// Function prototype.
public static AutoThresholdingMsr
AutoThresholdingValue( IOLink.ImageView inputGrayImage,
                       AutoThresholdingValue.RangeMode rangeMode = ImageDev.AutoThresholdingValue.RangeMode.MIN_MAX,
                       double[] intensityInputRange = null,
                       AutoThresholdingValue.ThresholdCriterion thresholdCriterion = ImageDev.AutoThresholdingValue.ThresholdCriterion.ENTROPY,
                       AutoThresholdingMsr outputMeasurement = null );

Class Syntax

// Command constructor.
AutoThresholdingValue();

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

/// Gets the rangeMode parameter.
/// The way to determine the input intensity range.
AutoThresholdingValue::RangeMode rangeMode() const;
/// Sets the rangeMode parameter.
/// The way to determine the input intensity range.
void setRangeMode( const AutoThresholdingValue::RangeMode& rangeMode );

/// Gets the intensityInputRange parameter.
/// The input intensity range [a,b] inside which the threshold is searched. This parameter is ignored if the range mode is set to MIN_MAX.
iolink::Vector2d intensityInputRange() const;
/// Sets the intensityInputRange parameter.
/// The input intensity range [a,b] inside which the threshold is searched. This parameter is ignored if the range mode is set to MIN_MAX.
void setIntensityInputRange( const iolink::Vector2d& intensityInputRange );

/// Gets the thresholdCriterion parameter.
/// The criterion to compute the threshold from the histogram.
AutoThresholdingValue::ThresholdCriterion thresholdCriterion() const;
/// Sets the thresholdCriterion parameter.
/// The criterion to compute the threshold from the histogram.
void setThresholdCriterion( const AutoThresholdingValue::ThresholdCriterion& thresholdCriterion );

/// Gets the outputMeasurement parameter.
/// The output measurement containing the computed threshold.
AutoThresholdingMsr::Ptr outputMeasurement() const;


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

# Property of the inputGrayImage parameter.
AutoThresholdingValue.input_gray_image
# Property of the rangeMode parameter.
AutoThresholdingValue.range_mode
# Property of the intensityInputRange parameter.
AutoThresholdingValue.intensity_input_range
# Property of the thresholdCriterion parameter.
AutoThresholdingValue.threshold_criterion
# Property of the outputMeasurement parameter.
AutoThresholdingValue.output_measurement

// Method to launch the command.
execute()

// Command constructor.
AutoThresholdingValue()

// Property of the inputGrayImage parameter.
AutoThresholdingValue.inputGrayImage
// Property of the rangeMode parameter.
AutoThresholdingValue.rangeMode
// Property of the intensityInputRange parameter.
AutoThresholdingValue.intensityInputRange
// Property of the thresholdCriterion parameter.
AutoThresholdingValue.thresholdCriterion
// Property of the outputMeasurement parameter.
AutoThresholdingValue.outputMeasurement

// Method to launch the command.
Execute()

Parameters

Parameter Name

Description

Type

Supported Values

Default Value

inputGrayImage

The input grayscale image

Image

Grayscale

nullptr

rangeMode

The way to determine the input intensity range.

MIN_MAX	The histogram is computed between the minimum and the maximum of the image.
OTHER	The histogram is computed between user-defined bounds [a,b].

Enumeration

MIN_MAX

intensityInputRange

The input intensity range [a,b] inside which the threshold is searched. This parameter is ignored if the range mode is set to MIN_MAX.

Vector2d

Any value

{0.f, 255.f}

thresholdCriterion

The criterion to compute the threshold from the histogram.

ENTROPY	The measurement of dispersion used in the algorithm is the entropy of the intensity distribution.
FACTORISATION	The measurement of dispersion used in the algorithm is the variance of the intensity distribution (also known as the Otsu method).
MOMENTS	The measurement of dispersion used in the algorithm is the moments of the intensity distribution.
ISODATA	The measurement of dispersion used in the algorithm is the isodata of the intensity distribution.

Enumeration

ENTROPY

outputMeasurement

The output measurement containing the computed threshold.

AutoThresholdingMsr

nullptr

Object Examples

std::shared_ptr< iolink::ImageView > polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

AutoThresholdingValue autoThresholdingValueAlgo;
autoThresholdingValueAlgo.setInputGrayImage( polystyrene );
autoThresholdingValueAlgo.setRangeMode( AutoThresholdingValue::RangeMode::MIN_MAX );
autoThresholdingValueAlgo.setIntensityInputRange( {0, 255} );
autoThresholdingValueAlgo.setThresholdCriterion( AutoThresholdingValue::ThresholdCriterion::ENTROPY );
autoThresholdingValueAlgo.execute();

std::cout << "threshold: " << autoThresholdingValueAlgo.outputMeasurement()->threshold( 0 ) ;

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

auto_thresholding_value_algo = imagedev.AutoThresholdingValue()
auto_thresholding_value_algo.input_gray_image = polystyrene
auto_thresholding_value_algo.range_mode = imagedev.AutoThresholdingValue.MIN_MAX
auto_thresholding_value_algo.intensity_input_range = [0, 255]
auto_thresholding_value_algo.threshold_criterion = imagedev.AutoThresholdingValue.ENTROPY
auto_thresholding_value_algo.execute()

print( "threshold: ", str( auto_thresholding_value_algo.output_measurement.threshold( 0 ) ) )

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

AutoThresholdingValue autoThresholdingValueAlgo = new AutoThresholdingValue
{
    inputGrayImage = polystyrene,
    rangeMode = AutoThresholdingValue.RangeMode.MIN_MAX,
    intensityInputRange = new double[]{0, 255},
    thresholdCriterion = AutoThresholdingValue.ThresholdCriterion.ENTROPY
};
autoThresholdingValueAlgo.Execute();

Console.WriteLine( "threshold: " + autoThresholdingValueAlgo.outputMeasurement.threshold( 0 ) );

Function Examples

std::shared_ptr< iolink::ImageView > polystyrene = ioformat::readImage( std::string( IMAGEDEVDATA_IMAGES_FOLDER ) + "polystyrene.tif" );

auto result = autoThresholdingValue( polystyrene, AutoThresholdingValue::RangeMode::MIN_MAX, {0, 255}, AutoThresholdingValue::ThresholdCriterion::ENTROPY );

std::cout << "threshold: " << result->threshold( 0 ) ;

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

result = imagedev.auto_thresholding_value( polystyrene, imagedev.AutoThresholdingValue.MIN_MAX, [0, 255], imagedev.AutoThresholdingValue.ENTROPY )

print( "threshold: ", str( result.threshold( 0 ) )  )

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

AutoThresholdingMsr result = Processing.AutoThresholdingValue( polystyrene, AutoThresholdingValue.RangeMode.MIN_MAX, new double[]{0, 255}, AutoThresholdingValue.ThresholdCriterion.ENTROPY );

Console.WriteLine(  "threshold: " + result.threshold( 0 )  );

AutoThresholdingValue

- Function Syntax

+ Class Syntax

Parameters

Object Examples

Function Examples

Function Syntax

Class Syntax