OpenCV is a free , open source toolkit for computer vision. It also has useful classes for general Machine Learning Artificial Neural Networks.
I’ve worked a fair bit with OpenCV for a project a couple years back, but never had to install it from scratch for Visual Studio C++. This page walks you through setting up dependencies for Visual Studio and creating a simple program.
Don’t forget to change the dependency file name opencv_world331.lib to match your version of OpenCV!