Image recognition in R

Angel Lopez writes:

I have some images of bugs (insects) with many bugs in each image.
I want to count the number of bugs and to have an estimate of the area 
of each one.

See also the book
    A. Lawson & D. Denison
    Spatial cluster modelling
    Chapman & Hall
where chapters 4-6 describe different statistical strategies for recognising
objects in an image. The authors of these three chapters 
each have some code, but it's probably not wrapped up in an R package yet.
And also 
  A.J. Baddeley and M.N.M. van Lieshout.
  Stochastic geometry models in high-level vision.
  In K.V. Mardia (ed.) Statistics and Images, volume 1,
  Abingdon: Carfax, 1993. pp. 233--258.