Computes the set covariance function of a window.
A window (object of class
Optional. Another window.
Optional arguments passed to
The set covariance function of a region W in the plane is the function C(v) defined for each vector v as the area of the intersection between W and W+v, where W+v is the set obtained by shifting (translating) W by v.
We may interpret C(v) as the area of the set of all points x in W such that x+v also lies in W.
This command computes a discretised approximation to
the set covariance function of any
plane region W represented as a window object (of class
owin.object). The return value is
a pixel image (object of class
"im") whose greyscale values
are values of the set covariance function.
The set covariance is computed using the Fast Fourier Transform,
W is a rectangle, when an exact formula is used.
If the argument
V is present, then
computes the set cross-covariance function C(x)
defined for each vector x
as the area of the intersection between W and V+x.
A pixel image (an object of class
"im") representing the
set covariance function of
or the cross-covariance of
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