My Raspberry Pi digital signage service info-beamer hosted (https://info-beamer.com/hosted) has a new exciting feature. Usually when you create a video wall you have to manually specify screen sizes, relative positions. No more. I'm using AprilTags to make this all completely automated. You add the screens to your wall, tell them to display tags, snap a picture and everything is ready to play the content.Screens don't even have to be planar: They can be freely rotated as long as they are still visible on the picture you take. Here's a short videos showing how this all works:
https://www.youtube.com/watch?v=GI00HTJhSMU