public class SobelEdgeDetector : BaseUsingCopyPartialFilter

The filter searches for objects' edges by applying Sobel operator.

Each pixel of the result image is calculated as approximated absolute gradient magnitude for corresponding pixel of the source image:

where Gx and Gy are calculate utilizing Sobel convolution kernels:

Copy 

   Gx         Gy
-1 0 +1    +1 +2 +1
-2 0 +2     0  0  0
-1 0 +1    -1 -2 -1

Using the above kernel the approximated magnitude for pixel x is calculate using the next equation:

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P1 P2 P3
P8  x P4
P7 P6 P5
|G| = |P1 + 2P2 + P3 - P7 - 2P6 - P5| +
      |P3 + 2P4 + P5 - P1 - 2P8 - P7|

The filter accepts 8 bpp grayscale images for processing.

Sample usage:

CopyC#

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

Initial image:

Result image:

System..::.Object
  AForge.Imaging.Filters..::.BaseUsingCopyPartialFilter
    AForge.Imaging.Filters..::.SobelEdgeDetector