C# Класс AForge.Imaging.Filters.OtsuThreshold

Otsu thresholding.

The class implements Otsu thresholding, which is described in N. Otsu, "A threshold selection method from gray-level histograms", IEEE Trans. Systems, Man and Cybernetics 9(1), pp. 62–66, 1979.

This implementation instead of minimizing the weighted within-class variance does maximization of between-class variance, what gives the same result. The approach is described in this presentation.

The filter accepts 8 bpp grayscale images for processing.

Sample usage:

 // create filter OtsuThreshold filter = new OtsuThreshold( ); // apply the filter filter.ApplyInPlace( image ); // check threshold value byte t = filter.ThresholdValue; // ...

Initial image:

Result image (calculated threshold is 97):

Наследование: BaseInPlacePartialFilter

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Открытые методы

Метод	Описание
CalculateThreshold ( Bitmap image, Rectangle rect ) : int	Calculate binarization threshold for the given image. The method is used to calculate binarization threshold only. The threshold later may be applied to the image using Threshold image processing filter.
CalculateThreshold ( BitmapData image, Rectangle rect ) : int	Calculate binarization threshold for the given image. The method is used to calculate binarization threshold only. The threshold later may be applied to the image using Threshold image processing filter.
CalculateThreshold ( UnmanagedImage image, Rectangle rect ) : int	Calculate binarization threshold for the given image. The method is used to calculate binarization threshold only. The threshold later may be applied to the image using Threshold image processing filter.
OtsuThreshold ( ) : System	Initializes a new instance of the OtsuThreshold class.

Защищенные методы

Метод	Описание
ProcessFilter ( UnmanagedImage image, Rectangle rect ) : void	Process the filter on the specified image.

Описание методов

CalculateThreshold() публичный Метод

Calculate binarization threshold for the given image.

The method is used to calculate binarization threshold only. The threshold later may be applied to the image using Threshold image processing filter.

Source pixel format is not supported by the routine. It should be /// 8 bpp grayscale (indexed) image.

public CalculateThreshold ( Bitmap image, Rectangle rect ) : int
image	System.Drawing.Bitmap	Image to calculate binarization threshold for.
rect	System.Drawing.Rectangle	Rectangle to calculate binarization threshold for.
Результат	int

CalculateThreshold() публичный Метод

Calculate binarization threshold for the given image.

The method is used to calculate binarization threshold only. The threshold later may be applied to the image using Threshold image processing filter.

Source pixel format is not supported by the routine. It should be /// 8 bpp grayscale (indexed) image.

public CalculateThreshold ( BitmapData image, Rectangle rect ) : int
image	System.Drawing.Imaging.BitmapData	Image to calculate binarization threshold for.
rect	System.Drawing.Rectangle	Rectangle to calculate binarization threshold for.
Результат	int

CalculateThreshold() публичный Метод

Calculate binarization threshold for the given image.

The method is used to calculate binarization threshold only. The threshold later may be applied to the image using Threshold image processing filter.

Source pixel format is not supported by the routine. It should be /// 8 bpp grayscale (indexed) image.

public CalculateThreshold ( UnmanagedImage image, Rectangle rect ) : int
image	UnmanagedImage	Image to calculate binarization threshold for.
rect	System.Drawing.Rectangle	Rectangle to calculate binarization threshold for.
Результат	int

OtsuThreshold() публичный Метод

Initializes a new instance of the OtsuThreshold class.

public OtsuThreshold ( ) : System
Результат	System

ProcessFilter() защищенный Метод

Process the filter on the specified image.

protected ProcessFilter ( UnmanagedImage image, Rectangle rect ) : void
image	UnmanagedImage	Source image data.
rect	System.Drawing.Rectangle	Image rectangle for processing by the filter.
Результат	void