Kernels
A kernel is a structure that represents a pixel and its relationship to its neighbors.
Predefined Gradient Kernels
Prewitt Filters
Prewitt filters have the following kernels. The notations West (W), South (S), East (E), and North (N) indicate which edges of bright regions they outline.
![](kernel_prewitt.gif)
Sobel Filters
The Sobel filters are similar to the Prewitt filters, except they highlight light intensity variations along a particular axis that is assigned a stronger weight. The Sobel filters contain the kernels listed in the following table.
![](kernel_sobel.gif)
The following table lists the predefined gradient 5 x 5 kernel.
![](kernel_gradient5x5.gif)
The following table lists the predefined gradient 7 x 7 kernel.
![](kernel_gradient7x7.gif)
Predefined Laplacian Kernels
The following tables list the predefined Laplacian kernels.
Laplacian 3 x 3
![](kernel_laplacian3x3.gif)
Laplacian 5 x 5
![](kernel_laplacian5x5.gif)
Laplacian 7 x 7
![](kernel_laplacian7x7.gif)
Predefined Smoothing Kernels
The following tables list the predefined smoothing kernels.
Smoothing 3 x 3
![](kernel_smoothing3x3.gif)
Smoothing 5 x 5
![](kernel_smoothing5x5.gif)
Smoothing 7 x 7
![](kernel_smoothing7x7.gif)
Predefined Gaussian Kernels
The following tables list the predefined Gaussian kernels.
Gaussian 3 x 3
![](kernel_gaussian3x3.gif)
Gaussian 5 x 5
![](kernel_gaussian5x5.gif)
Gaussian 7 x 7
![](kernel_gaussian7x7.gif)