Binary Morphology

Question 1

How does erosion work?

Answer 1

If the center of the structuring element is over an object pixel, and any other element is over a background pixel,

we set the center pixel to become background

Question 2

How does dilation work?

Answer 2

If the center of the structuring element is over the background, and any of the other elements are over an object pixel,

then the center pixel is set as an object pixel

Question 3

Erosion makes an object smaller and Dilation makes an object …

Answer 3

Larger

Question 4

What is Opening?

Answer 4

Eroding and then Dilating

This gets rid of sticky out bits and enlarges holes

Question 5

What is Closing?

Answer 5

Dilating and then Eroding

Will fill in holes and fill out sticky out bits

Question 6

Why is opening useful?

Answer 6

Separates distinct objects in a thresholded image

Question 7

Why is closing useful?

Answer 7

Identifies a single object, even when it may look like two distinct objects in the source image.