安装人脸识别开源库（face_recognition）
pip3 install face_recognition
注意：pip3 尝试编译 dlib 依赖时很可能会报错，参考：https://www.learnopencv.com/install-dlib-on-ubuntu/ 安装dlib库。
git clone https://github.com/davisking/dlib.git cd dlib apt-get update apt-get install build-essential cmake pkg-config apt-get install libx11-dev libatlas-base-dev apt-get install libgtk-3-dev libboost-python-dev apt-get install python-dev python-pip python3-dev python3-pip pip3 install -U pip numpy mkdir build cd build cmake .. cmake --build . --config Release make install ldconfig cd .. pkg-config --libs --cflags dlib-1