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BradleyLocalThresholding Class

Adaptive thresholding using the internal image.
Inheritance Hierarchy
SystemObject
  Accord.Imaging.FiltersBaseInPlaceFilter
    Accord.Imaging.FiltersBradleyLocalThresholding

Namespace:  Accord.Imaging.Filters
Assembly:  Accord.Imaging (in Accord.Imaging.dll) Version: 3.7.0
Syntax
public class BradleyLocalThresholding : BaseInPlaceFilter
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The BradleyLocalThresholding type exposes the following members.

Constructors
  NameDescription
Public methodBradleyLocalThresholding
Initializes a new instance of the BradleyLocalThresholding class.
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Properties
  NameDescription
Public propertyFormatTranslations
Format translations dictionary.
(Overrides BaseInPlaceFilterFormatTranslations.)
Public propertyPixelBrightnessDifferenceLimit
Brightness difference limit between processing pixel and average value across neighbors.
Public propertyWindowSize
Window size to calculate average value of pixels for.
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Methods
  NameDescription
Public methodApply(Bitmap)
Apply filter to an image.
(Inherited from BaseInPlaceFilter.)
Public methodApply(BitmapData)
Apply filter to an image.
(Inherited from BaseInPlaceFilter.)
Public methodApply(UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseInPlaceFilter.)
Public methodApply(UnmanagedImage, UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseInPlaceFilter.)
Public methodApplyInPlace(Bitmap)
Apply filter to an image.
(Inherited from BaseInPlaceFilter.)
Public methodApplyInPlace(BitmapData)
Apply filter to an image.
(Inherited from BaseInPlaceFilter.)
Public methodApplyInPlace(UnmanagedImage)
Apply filter to an unmanaged image.
(Inherited from BaseInPlaceFilter.)
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 BaseInPlaceFilterProcessFilter(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 MethodToT
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 image processing routine implements local thresholding technique described by Derek Bradley and Gerhard Roth in the "Adaptive Thresholding Using the Integral Image" paper.

The brief idea of the algorithm is that every image's pixel is set to black if its brightness is t percent lower (see PixelBrightnessDifferenceLimit) than the average brightness of surrounding pixels in the window of the specified size (see WindowSize), othwerwise it is set to white.

Sample usage:

// create the filter
BradleyLocalThresholding filter = new BradleyLocalThresholding( );
// apply the filter
filter.ApplyInPlace( image );

Initial image:

Result image:

See Also