A lockdown hair censor for video conferencing

Here in London, we've been in coronavirus lockdown tier ∞+n for a little while now, and I haven't had a decent haircut in quite some time, but I still need to appear on video calls. So I made a hair censor.

The code uses OpenCV, which makes it very simple -- it finds faces using a Haar cascade and then blurs squares in an area around the face. I used v4l2loopback and an OBS plugin to have it show up as a camera under Linux, which meant I could then pipe it into Zoom, Teams, Skype and so on (for some reason I am using all of these).