Inspired by this post, from the code here
I wanted to be able to use opencv inside a docker container
Running:
Have docker installed
now make build
This was only tested on Kubuntu, but should work on other OS's
sudo xhost +
and run it with a make run
2 windows will appear, tweak the sliders until you only see your 'pen'
Hit the s key, this will safe the numpy array, the next window will read from this file
If you want to debug, just do a make shell