Crash - cause 'memory not mapped'

| extern "C" {
| SEXP FiltroGaus(SEXP size1_r, SEXP size2_r, SEXP sigma_r) {

[...]
 
| The compilation go without errors but when in R i type 
| .C("FiltroGaus",3,3,2)

You missed the part in "Writing R Extension" about .C() and .Call()
arguments.  You are mixing both approaches here, which usually ends badly.

Do some more reading, and maybe study some existing (simpler) examples /
packages.  You really do not need to engage OpenCV headers and libraries
before you understand the basics better.  

Dirk

Dirk Eddelbuettel | edd at debian.org | http://dirk.eddelbuettel.com