Sobel Operator - Extension To Other Dimensions

Extension To Other Dimensions

The Sobel operator consist of two separable operations :

  • Smoothing perpendicular to the derivative direction with a triangle filter :
  • Simple central difference in the derivative direction :

Sobel filters for image derivatives in different dimensions with :

1D:

2D:

3D:

4D:

Thus as an example the 3D Sobel kernel in z-direction:


h_z'(:,:,-1) =
\begin{bmatrix}
+1 & +2 & +1 \\
+2 & +4 & +2 \\
+1 & +2 & +1
\end{bmatrix}
\quad
h_z'(:,:,0) =
\begin{bmatrix}
0 & 0 & 0 \\
0 & 0 & 0 \\
0 & 0 & 0
\end{bmatrix}
\quad
h_z'(:,:,1) =
\begin{bmatrix}
-1 & -2 & -1 \\
-2 & -4 & -2 \\
-1 & -2 & -1
\end{bmatrix}

Read more about this topic:  Sobel Operator

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