OpenCV (Open Source Computer Vision) is a library for computer vision created in 2000, and is currently maintained by Itseez. OpenCV is written in C++, but it also has bindings for Python and other programming languages. OpenCV supports many operating systems and GPUs. There is not enough space in this chapter to cover all the features of OpenCV. Even a single book is probably not enough—for Pythonistas, I recommend OpenCV Computer Vision with Python by Joseph Howse.
Some of the third-party patented algorithms in the OpenCV 2.x.x package, such as SIFT and SURF (refer to the relevant recipes in this chapter), have been moved to a special GitHub repository. You still can use them, but you need to explicitly include them in the installation process.
The OpenCV build process has many options. If you are unsure which options are the best for you, read the OpenCV documentation or use the appropriate package manager for your operating system. In general, you should not use too...