Emgu CV Library Documentation
Sobel Method (xorder, yorder, apertureSize)
NamespacesEmgu.CVImage<(Of <(TColor, TDepth>)>)Sobel(Int32, Int32, Int32)

www.emgu.com/wiki
Calculates the image derivative by convolving the image with the appropriate kernel The Sobel operators combine Gaussian smoothing and differentiation so the result is more or less robust to the noise. Most often, the function is called with (xorder=1, yorder=0, aperture_size=3) or (xorder=0, yorder=1, aperture_size=3) to calculate first x- or y- image derivative.
Declaration Syntax
C#Visual BasicVisual C++
public Image<TColor, float> Sobel(
	int xorder,
	int yorder,
	int apertureSize
)
Public Function Sobel ( _
	xorder As Integer, _
	yorder As Integer, _
	apertureSize As Integer _
) As Image(Of TColor, Single)
public:
Image<TColor, float>^ Sobel(
	int xorder, 
	int yorder, 
	int apertureSize
)
Parameters
xorder (Int32)
Order of the derivative x
yorder (Int32)
Order of the derivative y
apertureSize (Int32)
Size of the extended Sobel kernel, must be 1, 3, 5 or 7. In all cases except 1, aperture_size xaperture_size separable kernel will be used to calculate the derivative.
Return Value
The result of the sobel edge detector

Assembly: Emgu.CV (Module: Emgu.CV) Version: 1.5.0.0 (1.5.0.0)