This project requires OpenCV3, with contrib modules. You will build this project using cmake. You will need to know the location of your OpenCV3 installation, including the subdirectory containing the .cmake files. For example, the location of this directory when you have installed OpenCV3 using brew is /usr/local/opt/opencv3/share/OpenCV/. Here are example build instructions:
mkdir build
cd build
cmake -D OpenCV_DIR=/usr/local/opt/opencv3/share/ ..
make