Hello OpenCV with C++, using Visual Studio 2017 and VcPkg

In this post, I will show how to do your first steps with OpenCV quickly using Visual Studio 2017 and VcPkg.

What is OpenCV?

OpenCV (Open Source Computer Vision) is an open-source and cross-platform library mainly aimed at real-time computer vision. Originally, it was developed by Intel. It is free for use under the BSD license.

What is VcPkg?

Acquiring native libraries on Windows is a critical part of the application development process, and it used to be a nightmare.  VcPkg is a VC++ Packaging Tool that helps to get C and C++ libraries on Windows.

Getting started with VcPkg

If you want to use VcPkg (I strongly recommend it if you are planning to develop software for Windows using C++), you will need:

1. Clone VcPkg GitHub repository;
2. Run the VcPkg bootstrapping process

   .bootstrap-vcpkg.bat

3. Make all installed packages available to all VS projects.

   .vcpkg integrate install

Done! Now you can get OpenCV in a very easy way.

.vcpkg install opencv

Hello, OpenCV

We are ready to create our application using OpenCV. There is no need to any configuration – we just need #include it.

#include <opencv2/opencv.hpp>
#include <iostream>

int main()
{
	cv::namedWindow("raw", cv::WINDOW_AUTOSIZE);
	cv::namedWindow("gray", cv::WINDOW_AUTOSIZE);
	cv::namedWindow("canny", cv::WINDOW_AUTOSIZE);

	cv::VideoCapture cap;
	cap.open(0);

	if (!cap.isOpened())
	{
		std::cerr << "Couldn't open capture." << std::endl;
		return -1;
	}
	
	cv::UMat bgr_frame, gray, canny;

	for (;;) 
	{
		cap >> bgr_frame;
		if (bgr_frame.empty()) break;

		cv::imshow("raw", bgr_frame);

		cv::cvtColor(bgr_frame, gray, cv::COLOR_BGR2GRAY);
		cv::imshow("gray", gray);

		cv::Canny(gray, canny, 10, 100, 3, true);
		cv::imshow("canny", canny);

		char c = cv::waitKey(10);
		if (c == 27) break;
	}

	cap.release();
	return 0;
}

This code starts the camera, capturing images, applying filters on it and displaying the results in three different windows.

That’s all folks.