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dilation

Marking a pixel foreground if the structuring element's footprint touches any foreground pixel at all.

Dilation of A by B, written A\oplus B, sets output pixel p to foreground if at least one foreground cell of B, aligned so B's origin sits at p, lands on a foreground pixel of A -- the opposite test from erosion, growing rather than shrinking foreground regions.

See also

erosion opening and closing
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