Dilatation and Erosion
In classic computer vision, operations like dilatations and erosions are used for extraction of important features from the images.
Dilatation
Here I show a dilatation operation, where it convolves the following structuring element or kernel over the original image, when at least one pixel in the structuring element coincides with a foreground pixel in the image underneath, the center pixel if transformed into foreground. Note that the end image is larger or a "dilated" version of the original image.
Original Image
Kernel
Dilatation Output
Erosion
And Here I show an erosion operation, where it convolves the following structuring element or kernel over the original image, when all pixels in the structuring element coincide with foreground pixels in the image underneath, the center pixel is transformed into foreground. Note that the end image is smaller or an "eroded" version of the original image.