SelectComponents

SelectComponents[{image,lmat},crit]

selects components of image indicated by the label matrix lmat that satisfy crit, replacing other parts with black.

SelectComponents[image,crit]

selects connected components of image.

SelectComponents[…,"prop",n]

computes the property "prop" and selects the first n in sorted order.

SelectComponents[…,"prop",n,p]

sorts computed properties using the ordering function p.

Details and Options

  • SelectComponents can be used to select image components with specific desired characteristics. Selection may be performed on components' location, shapes, and intensity properties.
  • Component selection is also used to filter undesired image parts, including small, large, border touching, or specifically shaped components.
  • SelectComponents works with 2D or 3D images and label matrices.
  • A label matrix lmat is an array of non-negative integers, in which each integer represents a component, and 0 represents the background.
  • If the label matrix lmat is not given, it is computed using the connectivity of nonzero pixels in image.
  • SelectComponents selects components based on the given criteria crit. Components that are not selected are replaced with 0 (black) in both image and lmat.
  • Possible forms of crit include:
  • Largecomponents bigger than a globally determined threshold
    Smallcomponents smaller than a globally determined threshold
    fcomponents that satisfy f
  • When a pure function f is used, component properties can be accessed using #prop1, #prop2, …. A component is selected if f returns True.
  • For the complete list of possible properties, see the reference page for ComponentMeasurements.
  • SelectComponents[{image,lmat},…] returns a modified version of {image,lmat} where unselected components are replaced with 0.
  • SelectComponents[lmat,…] can also be used to select components from a label matrix lmat.
  • SelectComponents[…,"prop",n] computes "prop" for all components and returns the first n, sorted using Sort.
  • SelectComponents[…,{"prop1","prop2",…},n] computes and sorts multiple properties.
  • SelectComponents[…,"prop",-n] returns the last n components.
  • SelectComponents takes a CornerNeighbors option. The default setting is CornerNeighbors->True.

Examples

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Basic Examples  (3)

Select the outermost components in an image:

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Select three smallest components:

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Select 3D image components:

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Scope  (7)

Options  (1)

Applications  (5)

See Also

ComponentMeasurements  DeleteSmallComponents  DeleteBorderComponents  Select  MorphologicalComponents

Introduced in 2010
(8.0)
| Updated in 2016
(11.0)