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Accord.NET (logo) SobelEdgeDetector Class
Sobel edge detector.
Inheritance Hierarchy
SystemObject
  Accord.Imaging.FiltersBaseUsingCopyPartialFilter
    Accord.Imaging.FiltersSobelEdgeDetector

Namespace:  Accord.Imaging.Filters
Assembly:  Accord.Imaging (in Accord.Imaging.dll) Version: 3.4.0
Syntax
public class SobelEdgeDetector : BaseUsingCopyPartialFilter
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The SobelEdgeDetector type exposes the following members.

Constructors
  NameDescription
Public methodSobelEdgeDetector
Initializes a new instance of the SobelEdgeDetector class.
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Properties
Methods
  NameDescription
Public methodApply(Bitmap)
Apply filter to an image.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApply(BitmapData)
Apply filter to an image.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApply(UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApply(UnmanagedImage, UnmanagedImage)
Apply filter to an image in unmanaged memory.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApplyInPlace(Bitmap)
Apply filter to an image.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApplyInPlace(BitmapData)
Apply filter to an image.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApplyInPlace(UnmanagedImage)
Apply filter to an unmanaged image.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApplyInPlace(Bitmap, Rectangle)
Apply filter to an image or its part.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApplyInPlace(BitmapData, Rectangle)
Apply filter to an image or its part.
(Inherited from BaseUsingCopyPartialFilter.)
Public methodApplyInPlace(UnmanagedImage, Rectangle)
Apply filter to an unmanaged image or its part.
(Inherited from BaseUsingCopyPartialFilter.)
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 BaseUsingCopyPartialFilterProcessFilter(UnmanagedImage, UnmanagedImage, Rectangle).)
Public methodToString
Returns a string that represents the current object.
(Inherited from Object.)
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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.)
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Remarks

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:

|G| = |Gx| + |Gy] ,
where Gx and Gy are calculate utilizing Sobel convolution kernels:
   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:
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:

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

Initial image:

Result image:

See Also