Click or drag to resize
Accord.NET (logo) SISThreshold Class
Threshold using Simple Image Statistics (SIS).
Inheritance Hierarchy
SystemObject
  Accord.Imaging.FiltersBaseInPlacePartialFilter
    Accord.Imaging.FiltersSISThreshold

Namespace:  Accord.Imaging.Filters
Assembly:  Accord.Imaging (in Accord.Imaging.dll) Version: 3.4.0
Syntax
public class SISThreshold : BaseInPlacePartialFilter
Request Example View Source

The SISThreshold type exposes the following members.

Constructors
  NameDescription
Public methodSISThreshold
Initializes a new instance of the SISThreshold class.
Top
Properties
Methods
  NameDescription
Public methodApply(Bitmap)
Apply filter to an image.
(Inherited from BaseInPlacePartialFilter.)
Public methodApply(BitmapData)
Apply filter to an image.
(Inherited from BaseInPlacePartialFilter.)
Public methodApply(UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseInPlacePartialFilter.)
Public methodApply(UnmanagedImage, UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseInPlacePartialFilter.)
Public methodApplyInPlace(Bitmap)
Apply filter to an image.
(Inherited from BaseInPlacePartialFilter.)
Public methodApplyInPlace(BitmapData)
Apply filter to an image.
(Inherited from BaseInPlacePartialFilter.)
Public methodApplyInPlace(UnmanagedImage)
Apply filter to an unmanaged image.
(Inherited from BaseInPlacePartialFilter.)
Public methodApplyInPlace(Bitmap, Rectangle)
Apply filter to an image or its part.
(Inherited from BaseInPlacePartialFilter.)
Public methodApplyInPlace(BitmapData, Rectangle)
Apply filter to an image or its part.
(Inherited from BaseInPlacePartialFilter.)
Public methodApplyInPlace(UnmanagedImage, Rectangle)
Apply filter to an unmanaged image or its part.
(Inherited from BaseInPlacePartialFilter.)
Public methodCalculateThreshold(Bitmap, Rectangle)
Calculate binarization threshold for the given image.
Public methodCalculateThreshold(BitmapData, Rectangle)
Calculate binarization threshold for the given image.
Public methodStatic memberCalculateThreshold(UnmanagedImage, Rectangle)
Calculate binarization threshold for the given image.
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 BaseInPlacePartialFilterProcessFilter(UnmanagedImage, Rectangle).)
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
Top
Extension Methods
  NameDescription
Public Extension MethodHasMethod
Checks whether an object implements a method with the given name.
(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.)
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 Matrix.)
Top
Remarks

The filter performs image thresholding calculating threshold automatically using simple image statistics method. For each pixel:

  • two gradients are calculated - ex = |I(x + 1, y) - I(x - 1, y)| and |I(x, y + 1) - I(x, y - 1)|;
  • weight is calculated as maximum of two gradients;
  • sum of weights is updated (weightTotal += weight);
  • sum of weighted pixel values is updated (total += weight * I(x, y)).
The result threshold is calculated as sum of weighted pixel values divided by sum of weight.

The filter accepts 8 bpp grayscale images for processing.

Sample usage:

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

Initial image:

Result image (calculated threshold is 127):

See Also