pixellate(x, ...)"ppp"),
    a window (object of class "owin"),
    a line segment pattern (object of class "psp"),
    or some other suitable data."im").pixellate converts a geometrical object x into
  a pixel image, by measuring the amount of x that is
  inside each pixel.
  
  If x is a point pattern, pixellate(x) counts the
  number of points of x falling in each pixel.
  If x is a window, pixellate(x) measures the area
  of intersection of each pixel with the window.  The function pixellate is generic, with methods for
  point patterns (pixellate.ppp),
  windows (pixellate.owin),
  and 
  line segment patterns (pixellate.psp),
  See the separate documentation for these methods.
  The related function as.im
  also converts x into a pixel image,
  but typically measures only the presence or absence of
  x inside each pixel.
pixellate.ppp,
  pixellate.owin,
  pixellate.psp,
  as.im