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SauvolaThreshold Class
Sauvola Threshold.
Inheritance Hierarchy
SystemObject
  Accord.Imaging.FiltersBaseFilter
    Accord.Imaging.FiltersSauvolaThreshold

Namespace:  Accord.Imaging.Filters
Assembly:  Accord.Imaging (in Accord.Imaging.dll) Version: 3.8.0
Syntax
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public class SauvolaThreshold : BaseFilter
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The SauvolaThreshold type exposes the following members.

Constructors
  NameDescription
Public methodSauvolaThreshold
Initializes a new instance of the SauvolaThreshold class.
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Properties
  NameDescription
Public propertyFormatTranslations
Format translations dictionary.
(Overrides BaseFilterFormatTranslations.)
Public propertyK
Gets or sets the user-defined parameter k. Default is 0.5.
Public propertyR
Gets or sets the dynamic range of the standard deviation, R. Default is 128.
Public propertyRadius
Gets or sets the filter convolution radius. Default is 15.
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Methods
  NameDescription
Public methodApply(Bitmap)
Apply filter to an image.
(Inherited from BaseFilter.)
Public methodApply(BitmapData)
Apply filter to an image.
(Inherited from BaseFilter.)
Public methodApply(UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseFilter.)
Public methodApply(UnmanagedImage, UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseFilter.)
Public methodEquals
Determines whether the specified object is equal to the current object.
(Inherited from Object.)
Protected methodFinalize
Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.
(Inherited from Object.)
Public methodGetHashCode
Serves as the default hash function.
(Inherited from Object.)
Public methodGetType
Gets the Type of the current instance.
(Inherited from Object.)
Protected methodMemberwiseClone
Creates a shallow copy of the current Object.
(Inherited from Object.)
Protected methodProcessFilter
Process the filter on the specified image.
(Overrides BaseFilterProcessFilter(UnmanagedImage, UnmanagedImage).)
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
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Extension Methods
  NameDescription
Public Extension MethodHasMethod
Checks whether an object implements a method with the given name.
(Defined by ExtensionMethods.)
Public Extension MethodIsEqual
Compares two objects for equality, performing an elementwise comparison if the elements are vectors or matrices.
(Defined by Matrix.)
Public Extension MethodTo(Type)Overloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
Public Extension MethodToTOverloaded.
Converts an object into another type, irrespective of whether the conversion can be done at compile time or not. This can be used to convert generic types to numeric types during runtime.
(Defined by ExtensionMethods.)
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Remarks

The Sauvola filter is a variation of the NiblackThreshold thresholding filter.

This filter implementation has been contributed by Diego Catalano.

References:

  • Sauvola, Jaakko, and Matti Pietikäinen. "Adaptive document image binarization." Pattern Recognition 33.2 (2000): 225-236.

Examples
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Bitmap image = ... // Lena's picture

// Create a new Sauvola threshold:
var sauvola = new SauvolaThreshold();

// Compute the filter
Bitmap result = sauvola.Apply(image);

// Show on the screen
ImageBox.Show(result);

The resulting image is shown below:

See Also