#include "opencv2/text/erfilter.hpp"

hello guys, please i need help.
- ubuntu 18.10
gcc -o projet projet.cpp `pkg-config opencv --cflags --libs`
Package opencv was not found in the pkg-config search path.
Perhaps you should add the directory containing `opencv.pc'
to the PKG_CONFIG_PATH environment variable
No package 'opencv' found
In file included from projet.cpp:2:0:
opencv2/text.hpp:42:10: fatal error: opencv2/text/erfilter.hpp: No such file or directory
#include "opencv2/text/erfilter.hpp"