You know when you’re watching tennis on the TV and one of the players calls a challenge, saying ‘hey! That shot was in!’
Then, an animation plays on your screen of a little virtual ball bouncing across a 3D court.
If you’ve ever wondered how they spit out this replay so fast, it’s thanks to an incredibly precise technology called Hawk-eye.
But how does this tech work exactly? And just how accurate is it?
Dr Sophie Calabretto chats to Cosmos Magazine journalist Matthew Agius to find out and how Hawk-eye is even more sophisticated at this years Australian Open.