• Prince Shrivastava

Dynamics of Hawk-Eye ?

Blog edited by Shashank Raj and authored by Prince Shrivastava

Sports are no longer just about physical activity. In the present times the involvement of technology in sports has been an important factor, especially at International levels.

Similar has been a case for CRICKET. Now, everyone knows about cricket, right?

Source: WCC

It looks like this but with real humans and sports field.

It is the sport played with a bat, a ball, stumps and eleven players. Also being the game who gave us legends such as Sir Don Bradman, Sachin Tendulkar, etc.

In case you don’t know much and want to know the basic, here is a recommendation:

International cricket has various types of technology in use nowadays. For now, we will focus on: Hawk-eye in relation to the LBW dismissal.

For those who don’t know about the LBW, here is something for you, to again…save time.

LBW (Click to get an insight).

In a nutshell, it is a form of dismissal including the ball striking the batsman's body (except the hands in contact with the bat) when it would otherwise have continued on to hit the batsman's wicket. It has its own conditions to be fulfilled, which have been covered in the recommended link above.

Fun Fact: leg before wicket is the third-most common form of dismissal in cricket.

Need for such trajectory tech and what before that?

One interesting thing about LBW is that the other forms of dismissals have conclusive eye evidence that whatsoever happened is witnessed by the umpires and have recorded footage as a proof... But for the LBW dismissal, it is something that actually never happened on the ground! Think about it, the ball actually never hit the stumps, it is based on a hypothetical trajectory that where the ball *would* have gone if it had not been in contact with the batsman’s body. So why bring such a controversial dismissal in the first place? LBW first came into existence in the late eighteenth century to stop the batsmen from using their body as barrier for the ball to stop hitting the stumps. It has gone through a lot of amends since then. LBW did face a lot of questions in its early stage though. In the early times, there wasn’t any tech to show us the trajectory, it was completely based on umpire’s decision that whether the ball would hit the stumps or not. So there actually wasn’t any proof to cross check the umpire’s decisions, except opinions.

Back to the Present:

In present, LBW decisions can be checked with trajectory tech used by ICC (International Cricket Council) known as Hawk-eye. It is also used in other sports such as Football, Tennis, Volleyball, etc.

It is used to track the trajectory of the ball and show us the*most likely* path as a moving image. The onscreen representation of the trajectory results is called Shot Spot. The system was originally implemented in 2001 for television purposes & has been used for Decision Review System (then, Umpire’s Decision Review System) since 2009 in cricket.

Working of Hawk-eye:

All Hawk-Eye systems are based on the principles of triangulation using visual images (the process of determining a point in 3D space given its projections onto two, or more images) and timing data provided by a number of video cameras located at different locations and angles around the ground. In each frame sent from each camera, the system identifies the group of pixels which corresponds to the image of the ball. It then calculates for each frame the position of the ball by comparing its position on at least two of the physically separate cameras at the same instant in time. A succession of frames builds up a record of the path along which the ball has travelled. It "predicts" the future path of the ball.

The technology was first used by Channel 4 during a Test match between England and Pakistan on Lord's Cricket Ground, on 21 May 2001.

It is also used to show delivery patterns of a bowler's behavior such as line and length, or swing/turn, batsmen’s wagon wheel, etc.

There are a lot of other forms of tech used as well like the hotspot, ultraedge, etc. Let me know if you want to know about them too.

To not get this article too long, we will discuss the limitations and controversies related in the next article and if you have any queries or suggestions do ping me up in the box below. Have a knowledgeable & productive time till then!

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