Dlib library

http://dlib.net/ Dlib is a modern C++ toolkit containing machine learning algorithms and tools for creating complex software in C++ to solve real world problems. It is used in both industry and academia in a wide range of domains including robotics, embedded devices, mobile phones, and large high performance computing environments. Dlib's open source licensing allows you to use it in any application, free of charge.

git clone https://github.com/davisking/dlib, iandees gist.github As of this writing, dlib won't compile due to weirdness with the system-installed libjpeg, so the developer suggests modifying line 277 of dlib/CMakeLists.txt to look like this: if (JPEG_FOUND AND LIBJPEG_IS_GOOD AND NOT APPLE)