This could be an automated build but it does not work (apt-get gets confused somewhere in the middle). So it is build elsewhere from https://github.com/joov/openface.git, file opencv-dlib-torch.Dockerfile
In fact an rpi is to small (1GB RAM) to compile the image. So I used a scalaway (2GB RAM) arm server (armv71, 32 bit).
Compilation works now due to https://github.com/clementfarabet/torchinstall
Image layers havce not been optimized yet...
First working version!