ncnn deep learning framework for Raspberry Pi used for all the networks here at the repository
See for examples: https://qengineering.eu/opencv-c-examples-on-raspberry-pi.html

Installation on a Raspberry Pi 2, 3 or 4:

$ git clone https://github.com/Qengineering/ncnn_raspberry
$ cd ncnn_raspberry
$ chmod 755 install_ncnn_script
$ ./install_ncnn_script

If everthing went well libncnn.a must be stored in folder /usr/local/lib/ncnn
and in folder /usr/local/include/ncnn there must be 17 .h files stored