Dilation is a morphological operation used to enhance the features of an image. Dilation as a function requires two inputs, an image to be dilated, and a two dimensional structuring element. Dilation has many applications, but is most commonly used to exaggerate features in an image that would otherwise be missed.
Dilation for binary images is defined as follows:
Let Kx denote the translation of K so that its origin is at x.
Then the dilation of X by K is simply the set of all points x such that the intersection of Kx with X is non-empty.
Dilation is frequently used to enhance the structure of an image, by either exaggerating features in the foreground, or conversely, obscuring features in the background.