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mmero
Erode an image by a structuring element.

Synopsis

function y = mmero ( f , b )

Input

f Image Gray-scale (uint8 or uint16) or binary image
b Structuring Element

Default: 3x3 elementary cross

Output

y Image

Description

mmero performs the erosion of the image f by the structuring element b. Erosion is a neighbourhood operator that compairs locally b with f, according to an inclusion rule. Since erosion is a fundamental operator to the construction of all other morphological operators, it is also called an elementary operator of Mathematical Morphology. When f is a gray-scale image , b may be a flat or non-flat structuring element.

Examples

Numerical examples
f=mmbinary([ 1 1 1 0 0 1 1; 1 0 1 1 1 0 0; 0 0 0 0 1 0 0])

Warning: converting image from double to int32
f =
     1     1     1     0     0     1     1
     1     0     1     1     1     0     0
     0     0     0     0     1     0     0

b=mmbinary([1 1 0]);

Warning: converting image from double to int32

mmero(f,b)

ans =
     1     1     1     0     0     0     1
     1     0     0     1     1     0     0
     0     0     0     0     0     0     0

f=uint8([0 1 2 50 4 5; 2 3 4 0 0 0; 12 255 14 15 16 17])

f =
    0    1    2   50    4    5
    2    3    4    0    0    0
   12  255   14   15   16   17

mmero(f,b)

ans =
    0    0    1    2    4    4
    2    2    3    0    0    0
   12   12   14   14   15   16

f=mmbinary(mmreadgray('blob.tif'));

bimg=mmbinary(mmreadgray('blob1.tif'));

b=mmimg2se(bimg);

g=mmero(f,b);

mmshow(f);

mmshow(g);

mmshow(g,mmgradm(f));
f g
g,mmgradm(f)
Gray-scale image:
f=mmreadgray('pcb_gray.tif');

b=mmsedisk(3);

mmshow(f);

mmshow(mmero(f,b));
f mmero(f,b)

Equation

Flat structuring element:
Non-flat structuring element:
Where

See also

mmfreedom Control automatic data type conversion.
mmdil Dilate an image by a structuring element.
mmimg2se Create a structuring element from a pair of images.
mmsebox Create a box structuring element.
mmsecross Diamond structuring element and elementary 3x3 cross.
mmcero Erode an image conditionally.
mmdist Distance transform.
mmsesum N-1 iterative Minkowski additions
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