C# Class Accord.Imaging.Filters.SISThreshold

Threshold using Simple Image Statistics (SIS).

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):

Inheritance: BaseInPlacePartialFilter
Show file Open project: accord-net/framework Class Usage Examples

Public Methods

Method Description
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.
SISThreshold ( ) : System

Initializes a new instance of the SISThreshold class.

Protected Methods

Method Description
ProcessFilter ( UnmanagedImage image, Rectangle rect ) : void

Process the filter on the specified image.

Method Details

CalculateThreshold() public method

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.
return int

CalculateThreshold() public method

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.
return int

CalculateThreshold() public static method

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

ProcessFilter() protected method

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.
return void

SISThreshold() public method

Initializes a new instance of the SISThreshold class.
public SISThreshold ( ) : System
return System