Why wait for decisions? (Image: Gregg Porteous/Newspix/Rex Features)

JUDGING whether a batsman has been “run out” is one of the trickier tasks facing the umpires officiating in a game of cricket. Now an inexpensive computer vision system has been developed that it is claimed can do the job as well as a human official, and without the need for a time-consuming video replay.

A batsman can be dismissed by being run out if the ball knocks over his wicket before he or she has completed a run. A batsman’s run is completed by the bat touching the ground behind the “crease” – a line 1.2 metres in front of each wicket. To judge this, the two umpires have to simultaneously watch both the wicket and the batsman.

To help with this difficult task, the sport’s authorities introduced an off-field umpire with access to a video replay. Consulting this third umpire can halt play for a minute or more, which can seriously disrupt fast-paced versions of the game such as Twenty20 cricket.


“It really disrupts the flow,” says Tariq Mahmood of the National University of Computer and Emerging Sciences in Karachi, Pakistan, who has created a system called A-Eye to automate such decisions. A-Eye combines a low-cost video camera sitting at ground level with open-source software called AForge.NET that scans a video feed for moving objects.

A-Eye automatically identifies the position of the crease and the wicket, and tracks the motion of the bat. If the system detects any movement of the wicket while the bat is outside the crease, it deems the batsman to be run out.

The system looks for movement of the wicket while the bat is outside the crease

Mahmood tested the system on a series of video clips, two-thirds of which showed the batsman being run out. A-Eye proved to be 3 per cent less accurate than a human umpire. But whereas the video umpire took about a minute to decide, A-Eye produced its judgements in less than a second. The system was due to be presented at the International Conference on Information Science and Applications on Jeju Island, South Korea, this week.

Using a high-quality camera would make A-Eye more accurate and could remove the need for a human video umpire, Mahmood claims. He has convinced his local cricket council to try the system out in a tournament later this year, and plans to submit the results of the trial to the International Cricket Council.

If A-Eye is taken up, it would not be the first time computer vision has played a role in cricket matches. A system called Hawk-Eye uses four elevated cameras to reproduce the ball’s trajectory in 3D. Hawk-Eye helps umpires make “leg before wicket” (lbw) decisions – where a batsman is deemed out because their legs have blocked a ball that would otherwise have hit their wicket.

Cricket has embraced other technologies too, though they are used to augment TV coverage rather than inform umpires’ decisions. One example is Sky Sports’ Hot Spot, an infrared camera that can indicate if the ball has hit the batsman’s leg pads or bat, which is crucial in lbw decisions. Another is the “Snickometer”, which displays a plot of the sound recorded by microphones at the wicket. It can show viewers whether or not a ball made contact with the bat.

Mahmood says his system can easily be integrated with Hawk-Eye. Fraser Stewart of the MCC in London, which oversees the laws of cricket, is not so sure. He says A-Eye’s ground-level cameras could interfere with the game, and that the delay when consulting the third umpire isn’t a huge problem anyway. “A fall of the wicket is a big thing in cricket,” he says, “and if it takes 30 seconds to get it right, then people would rather that than the decision be rushed.” But he adds that A-Eye could be useful if it proves to be extremely accurate.