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.

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