install opencv on raspberry Pi 3 and create Mat vector in opencv in linux

Have you installed the OpenCV development packages from the repository (usually suffixed with -dev )? Without knowing the specific components of OpenCV you are using, version or programming language, I am assuming you want to use the most common header files. You may need to include others depending on your requirements but the following is a basic guide.

From the terminal install the header files with:

$ sudo apt-get install libcv-dev libhighgui-dev

The current version in the repositories is 2.4. If using C++, the header files are included as an example:

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>

In your code use the namespace using namespace cv; or prefix OpenCV objects with cv:: as in cv::Mat image; or cv::Point point;.

Again in C++ don't forget to add the following, usually at the end of your compile statement:

`pkg-config --cflags --libs opencv`

For example:

$ g++ test_opencv.cpp -o test_opencv `pkg-config --cflags --libs opencv`