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UDRS comes under sharp focus

S. Dinakar

Chennai: The use of technology in arriving at a verdict has come under sharp focus in the World Cup. The ICC's 2.5 metre-barrier for leg-before decisions under the review system enabled Ian Bell survive at a crucial juncture of the nerve-wracking India-England encounter in Bangalore.

The Hawk-eye, Snick-o-meter and Hot Spot are the critical elements that a third umpire relies upon before making up his mind. How do the decision-enhancing systems work?

“The Hawk-eye is basically a ball tracking system. The technology uses four to eight high speed cameras. These cameras capture the ball frame to frame from the point of release to the point of impact,” said Director of Sports Mechanics, S. Ramakrishnan, popularly called Ramki.

Ramakrishnan, also the former video analyst of the Indian cricket team, added, “These cameras are placed at long-on, long-off and the straight-field, and on the two sides of the wicket. The side cameras capture the point of release, trajectory and height. The straight cameras pick the line.”

He, then, revealed, “How the cameras are calibrated is extremely important. It plays a crucial role and any flaw could give the wrong picture.”

How does the Hawk Eye determine the path of the ball after the point of impact? Ramakrishnan said, “Virtual data is extrapolated from the actual data gathered from frame-by-frame tracking of the ball by the high-speed cameras.”

Principles of triangulation

He added, “The Hawk Eye uses the principles of triangulation. This is a process of determining the location of a point by measuring angles to it from known points. The data is processed and visualised in the 3-D format. The margin of error is only 3.4 mm or less than half a centimetre.”

Then, how is the height of the ball on different surfaces determined by Hawk-eye? Ramakrishnan answered, “Pitch to pitch variation is provided for from the data normalised from over 400 matches played over different venues in different surfaces. This information is fed through a processor using a complex algorithm to predict the future path of the ball.”

Now we come to the heart of the matter. Why do inaccuracies creep in beyond the 2.5 metre mark? This was the reason that allowed Bell to stay at the wicket even when Hawk-eye showed the ball clearly hitting the stumps.

Over to Ramakrishnan: “There is more data to extrapolate and evidence from past data has shown that the chances of an error increase if the point of impact is more that 2.5 metres. In most systems, there may be a point from where the information may not be completely accurate.”

Tracking of audio waves

He then turned his attention to Snick-o-meter that helps in determining the edges.

“It is a technology where the audio waves are tracked. But then, the Snicko has to be seen along with a video, synchronised with a particular frame. On its own, it is not of great value.”

However, the vital component of the Umpire Decision Review System (UDRS), a technology that gives it the cutting edge, was missing in the India-England game.

The Hot Spot technology provides conclusive evidence on the ball's contact, or not, with any part of the bat, pads, gloves, or the body.

What, then, is Hot Spot? “It uses infrared technology. There are two infrared cameras on opposite ends of the ground. It's like an x-ray filter, shows the point of impact in a very decisive manner. And the point of impact becomes bright because of the friction caused by a collision, such as the ball hitting the bat, pad or the glove,” said Ramakrishnan.

But then, the cost of hiring the Hot Spot technology is a major deterrent. “It costs around $ 10,000 to lease the Hot Spot package for a day. And buying the infrared cameras is an expensive proposition.”

Cricket, though, is now an ultra-rich sport, so is its ruling body. If the ICC wants the UDRS to deliver, it should ensure that all its essential components — the Hawk-eye, the Snick-o-meter and the Hot-Spot are in use.

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