erosion(w, r, ...) ## S3 method for class 'owin': erosion(w, r, shrink.frame=TRUE, \dots, strict=FALSE, polygonal=NULL) ## S3 method for class 'ppp': erosion(w, r,\dots) ## S3 method for class 'psp': erosion(w, r,\dots)
"owin"or a line segment pattern (object of class
"psp") or a point pattern (object of class
TRUE, erode the bounding rectangle as well.
as.maskcontrolling the pixel resolution, if pixel approximation is used.
polygonal=TRUE) or a pixel grid approximation (
r > 0, an object of class
"owin"representing the eroded region (or
NULLif this region is empty). If
r=0, the result is identical to
polygonal=TRUE then a polygonal approximation
to the erosion is computed.
polygonal=FALSE then a pixel approximation
to the erosion is computed from the distance map of
"..." are passed to
to control the pixel resolution.
The erosion consists of all pixels whose distance
from the boundary of
w is strictly greater than
strict=TRUE) or is greater than or equal to
w is a window, the default (when
is to compute a polygonal approximation if
w is a rectangle or polygonal window, and to compute a
pixel approximation if
w is a window of type
shrink.frame is false, the resulting window is given the
same outer, bounding rectangle as the original window
shrink.frame is true, the original bounding rectangle
is also eroded by the same distance
To simply compute the area of the eroded window,
dilationfor the opposite operation.
w <- owin(c(0,1),c(0,1)) v <- erosion(w, 0.1) # returns rectangle [0.1, 0.9] x [0.1,0.9] v <- erosion(w, 0.6) # erosion is empty
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