OpenALPR (https://github.com/openalpr/openalpr) running in Docker image on Alpine linux.
docker run --rm -ti -v $PWD:/openalpr wallneradam/docker-openalpr-alpine -c eu test.jpg
You can use the calibrate utility as well on Linux under X:
docker run --rm -ti \
--entrypoint=openalpr-utils-calibrate \
-e DISPLAY -v /tmp:/tmp --ipc=host \
-v $PWD:/openalpr wallneradam/docker-openalpr-alpine -c eu test.jpg
The line started with "-e DISPLAY..." makes container be able to use your X session and able to show the gui.