C++ VS code Ubuntu : cannot open source file "opencv2/opencv.hpp"

I am new to C++ and VS Code. I am trying to use OpenCV in VS Code, and I’m running on Ubuntu.

I followed This tutorial to install and use OpenCV in Ubuntu, and it works. The problem is, when I try to use OpenCV in other projects in VS code, I have the following error when compiling :
cannot open source file "opencv2/opencv.hpp"

Now I suspect that in the tutorial it work because of the command line

g++ test.cpp -o testoutput -std=c++11 `pkg-config --cflags --libs opencv`

Since if I open the tutorial project in VS code and try to compile it normally, I have the same error as my own project.

For information here is my c_cpp_properties.json for my own project (the tutorial project does not have one):

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**",
                "/usr/local/include/opencv4/opencv2/"
            ],
            "defines": [],
            "compilerPath": "/usr/bin/gcc",
            "cStandard": "c17",
            "cppStandard": "gnu++17",
            "intelliSenseMode": "linux-gcc-x64"
        }
    ],
    "version": 4
}

And here is my code for my project :

#include <iostream> 
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;  

int main(){
    cout << "It's ok" << endl;
}

Is it possible to be able to use the ‘compile and run’ functionnality of VS code, and having my project running wit hopenCV ?

When I use the said command line

g++ test.cpp -o testoutput -std=c++11 `pkg-config --cflags --libs opencv`

on my own project, it works, but I would like for it to work by simple compilation