How virtual ads work in stadiums?
Since &quot;green grass&quot; and &quot;viewers/whatevers behind the LED boards&quot; do nicely contrast from the boards themselves, and because the shape of these is pretty precise known beforehand, I'd probably go with &quot;pure computer vision&quot;. You could even make the image processing aware of what's displayed on the LEDs, so that recognition gets even easier.
Of course you could do something like blinking the LEDs at a specific rate and synchronize cameras to that blinking, so that it gets even easier on the processing side, but honestly, I don't think that's necessary. Might still be done to make the whole thing failsafer.