I was looking at a technology which enables virtual advertisement on the perimeter ads in soccer. It's relatively an old technology for a few years back, but I'm surprised to see the quality of it. They overlay the physical perimeter ads with new ads on different camera feeds. Basically from this link. And here is a video on Youtube.
LED perimeter system with integrated virtual replacement technology - makes it possible to change the content seen by different viewing audiences around the world
How does this overlaying mechanism work? Is there any hardware involved (like the LED boards itself), or it is purely based on Computer Vision and Augmented Reality? How can it be such high-quality without glitches purely based on computer vision?!