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opening and closing

Erode-then-dilate to remove small bright noise; dilate-then-erode to fill small dark gaps.

Opening, A\circ B=(A\ominus B)\oplus B, removes foreground features smaller than B without changing the size of features larger than B. Closing, A\bullet B=(A\oplus B)\ominus B, fills background gaps and notches smaller than B the same way, from the opposite direction.

See also

erosion dilation
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