spatstat (version 1.15-4)

dilate.owin: Dilate a Window

Description

Perform morphological dilation of a window

Usage

dilation.owin(w, r, ..., polygonal=TRUE, tight=TRUE)
 dilate.owin(w, r, ..., polygonal=TRUE, tight=TRUE)

Arguments

w

A window (object of class "owin".

r

positive number: the radius of dilation.

...

extra arguments to as.mask controlling the pixel resolution, if the pixel approximation is used.

polygonal

Logical flag indicating whether to compute a polygonal approximation to the erosion (polygonal=TRUE) or a pixel grid approximation (polygonal=FALSE).

tight

Logical flag indicating whether the bounding frame of the window should be taken as the smallest rectangle enclosing the dilated region (tight=TRUE), or should be the dilation of the bounding frame of w (tight=F

Value

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

Details

The morphological dilation of a set $W$ by a distance $r > 0$ is the set consisting of all points lying at most $r$ units away from $W$. Effectively, dilation adds a margin of width $r$ onto the set $W$.

The functions dilate.owin and dilation.owin are identical, and compute the dilation of the window w.

If polygonal=TRUE and w is a rectangle or a polygonal window, then a polygonal approximation to the dilation is computed.

Otherwise, the window w is first approximated by a binary pixel image, and the arguments "..." are passed to as.mask to determine the pixel resolution. There is a sensible default.

See Also

erode.owin for the opposite operation. owin, as.owin

Examples

w <- owin(c(0,1),c(0,1))
  v <- dilate.owin(w, 0.1)