# closing.owin

0th

Percentile

##### Morphological Closing of a Window

Perform morphological closing of a window

Keywords
spatial, math
##### Usage
closing.owin(w, r, ...)
##### Arguments
w
A window (object of class "owin".
r
positive number: the radius of the closing.
...
extra arguments passed to as.mask controlling the pixel resolution
##### Details

The morphological closing (Serra, 1982) of a set $W$ by a distance $r > 0$ is the set of all points that cannot be separated from $W$ by any circle of radius $r$. That is, a point $x$ belongs to the closing $W*$ if it is impossible to draw any circle of radius $r$ that has $x$ on the inside and $W$ on the outside. The closing $W*$ contains the original set $W$.

For a small radius $r$, the closing operation has the effect of smoothing out irregularities in the boundary of $W$. For larger radii, the closing operation smooths out concave features in the boundary. For very large radii, the closed set $W*$ becomes more and more convex.

This function computes the closing of the window w as a binary pixel mask. If w is not already a mask, it is first converted to a mask by as.mask. The arguments "..." determine the pixel resolution. There is a sensible default.

The algorithm simply applies dilate.owin followed by erode.owin.

##### Value

• Another object of class "owin" representing the closed window.

##### References

Serra, J. (1982) Image analysis and mathematical morphology. Academic Press.

opening.owin for the opposite operation.

dilate.owin, erode.owin for the basic operations. owin, as.owin for information about windows.

• closing.owin
##### Examples
data(letterR)
v <- closing.owin(letterR, 0.25, dimyx=256)
plot(v, main="closing.owin")
plot(letterR, add=TRUE)
Documentation reproduced from package spatstat, version 1.15-2, License: GPL (>= 2)

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