mathematical morphology Mathematical morphology (MM) is a theory and technique for the analysis and processing of Geometry, geometrical structures, based on set theory, lattice theory, topology, and random functions. MM is most commonly applied to digital images, but it ...

, the closing of a set (

binary image A binary image is a digital image that consists of pixels that can have one of exactly two colors, usually black and white. Each pixel is stored as a single bit — i.e. either a 0 or 1. A binary image can be stored in memory as a bitmap: a p ...

) ''A'' by a

structuring element In mathematical morphology, a structuring element is a shape, used to probe or interact with a given image, with the purpose of drawing conclusions on how this shape fits or misses the shapes in the image. It is typically used in morphological oper ...

''B'' is the

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

of the

dilation wiktionary:dilation, Dilation (or dilatation) may refer to: Physiology or medicine * Cervical dilation, the widening of the cervix in childbirth, miscarriage etc. * Coronary dilation, or coronary reflex * Dilation and curettage, the opening of ...

of that set, :

A\bullet B = (A\oplus B)\ominus B, \,

where

\oplus

and

\ominus

denote the dilation and erosion, respectively. In

image processing An image or picture is a visual representation. An image can be two-dimensional, such as a drawing, painting, or photograph, or three-dimensional, such as a carving or sculpture. Images may be displayed through other media, including a pr ...

, closing is, together with

opening Opening may refer to: Types of openings * Hole * A title sequence or opening credits * Grand opening of a business or other institution * Inauguration * Keynote * Opening sentence * Opening sequence * Opening statement, a beginning statemen ...

, the basic workhorse of morphological

noise Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...

removal. Opening removes small objects, while closing removes small holes.

Example

Perform

Dilation wiktionary:dilation, Dilation (or dilatation) may refer to: Physiology or medicine * Cervical dilation, the widening of the cervix in childbirth, miscarriage etc. * Coronary dilation, or coronary reflex * Dilation and curettage, the opening of ...

(

A\oplus B

): Suppose A is the following 11 x 11 matrix and B is the following 3 x 3 matrix: 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 0 0 1 1 1 0 0 1 1 1 1 0 0 1 1 1 0 0 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 1 1 1 0 0 0 1 1 0 1 1 1 0 1 0 0 1 0 0 0 1 1 0 1 1 1 0 1 0 0 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 For each pixel in A that has a value of 1, superimpose B, with the center of B aligned with the corresponding pixel in A. Each pixel of every superimposed B is included in the dilation of A by B. The dilation of A by B is given by this 11 x 11 matrix.

A \oplus B

is given by : 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 0 0 Now, Perform

Erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

on the result: (

A\oplus B

)

\ominus B

A\oplus B

is the following 11 x 11 matrix and B is the following 3 x 3 matrix: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 0 0 Assuming that the origin B is at its center, for each pixel in

A\oplus B

superimpose the origin of B, if B is completely contained by A the pixel is retained, else deleted. Therefore the Erosion of

A\oplus B

by B is given by this 11 x 11 matrix. (

A\oplus B

)

\ominus B

is given by: 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 0 0 0 1 1 0 0 1 1 1 1 0 0 0 1 1 0 0 1 1 1 1 0 0 0 1 1 0 0 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Therefore Closing Operation fills small holes and smoothes the object by filling narrow gaps.

Properties

* It is

idempotent Idempotence (, ) is the property of certain operations in mathematics and computer science whereby they can be applied multiple times without changing the result beyond the initial application. The concept of idempotence arises in a number of pl ...

, that is,

(A\bullet B)\bullet B=A\bullet B

. * It is increasing, that is, if

A\subseteq C

, then

A\bullet B \subseteq C\bullet B

. * It is ''extensive'', i.e.,

A\subseteq A\bullet B

. * It is

translation invariant In physics and mathematics, continuous translational symmetry is the invariance of a system of equations under any translation (without rotation). Discrete translational symmetry is invariant under discrete translation. Analogously, an operato ...

Bibliography

* ''Image Analysis and Mathematical Morphology'' by Jean Serra, (1982) * ''Image Analysis and Mathematical Morphology, Volume 2: Theoretical Advances'' by Jean Serra, (1988) * ''An Introduction to Morphological Image Processing'' by Edward R. Dougherty, {{ISBN, 0-8194-0845-X (1992)

External links

Introduction to mathematical morphology
Mathematical morphology Digital geometry

Example

Properties

See also

Bibliography

External links