A Computational Introduction to Digital Image Processing, 2nd Edition

286 A Computational Introduction to Digital Image Processing, Second Edition

by dilating twice:

((A B) ⊕ B) ⊕ B.

The first dilation returns the holes to their original size; the second dilation removes them.

But this will enlarge the objects in the image. To reduce them to their correct size, perform

a final erosion:

(((A B) ⊕ B) ⊕ B)  B.

The inner two operations constitute an opening; the outer two operations a closing. Thus,

this noise removal method is in fact an opening followed by a closing:

(A ◦B) •B).

This is called morphological filtering.

Suppose we take an image and apply 10% shot noise to it. This can be done in MATLAB

or Octave by:

MATLAB/Octav ...