Secrets behind Hawk-Eye

So, did anyone watch this years Australian Open? There were some pretty awesome matches. And this:



What a hero.

Anyway, they have that cool system where a player can challenge the call of the line judge. I thought I would take a look at how it works, because that seemed exciting. What is happening to me...

Basically, there are four stages to this system of computerised line calling. There are multiple cameras set up around the court. Some smart image processing is used to identify the centre of the ball in each frame. The lines of the court are also tracked to make up for any camera movement. All this information is then fed into a part of the system that triangulates (what a cool word) the information from all the cameras to create a 3D position of the ball. The triangulation process is repeated for every frame, generating that cool 3D image of the balls trajectory. This is used to calculate exactly where the ball bounced on the court. It is surprisingly accurate. The players and fans then get to admire this spectacle of technological genius, although I think they are less concerned with how cool it is and more about whether the challenge is won or lost. But hey, we know it is cool.