closing {spatstat} | R Documentation |
Perform morphological closing of a window, a line segment pattern or a point pattern.
closing(w, r, ...) ## S3 method for class 'owin' closing(w, r, ..., polygonal=NULL) ## S3 method for class 'ppp' closing(w, r, ..., polygonal=TRUE) ## S3 method for class 'psp' closing(w, r, ..., polygonal=TRUE)
w |
A window (object of class |
r |
positive number: the radius of the closing. |
... |
extra arguments passed to |
polygonal |
Logical flag indicating whether to compute a polygonal
approximation to the erosion ( |
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.
The algorithm applies dilation
followed by
erosion
.
If r > 0
, an object of class "owin"
representing the
closed region. If r=0
, the result is identical to w
.
Adrian Baddeley Adrian.Baddeley@csiro.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
Serra, J. (1982) Image analysis and mathematical morphology. Academic Press.
opening
for the opposite operation.
dilation
, erosion
for the basic
operations.
owin
,
as.owin
for information about windows.
data(letterR) v <- closing(letterR, 0.25, dimyx=256) plot(v, main="closing") plot(letterR, add=TRUE)