public class SISThreshold : BaseInPlacePartialFilter

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:

CopyC#

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

Initial image:

Result image (calculated threshold is 127):

System..::.Object
  AForge.Imaging.Filters..::.BaseInPlacePartialFilter
    AForge.Imaging.Filters..::.SISThreshold