DRS or Decision Review System is a technological advance in cricket that guides the umpires in better decision-making. This system comprises of electronic review systems that comprise of replays, ultra edge or snickometer, hotspot detection and ball tracking technology.
Replays
Even though third umpires have been using the replay technology since 1992 to review instances of run outs, it was in 2008 when replays officially became a part of the DRS. Video replays in slow motion helps in checking many things. Firstly, if the bowler has landed a legal delivery and the position of the batter in cases of stumpings and run outs. Furthermore, it helps in seeing the gap between bat/glove and ball in case there is a referral for caught out or caught behind. Additionally, it is also used to check the position of the fielders in instances when they are eerily close to the boundary line.
Snickometer
A snickometer or ultra edge is an audio-based advancement. It is used to check if the ball has edged the bat or any other part of the body in cases of appeals for leg before wicket or caught out. The detection of the edge is viewed on screen where a spike can be observed if the ball edges the bat or any other part of the body. If there is no contact established then a flat line is seen.
Hawk-Eye
The hawk eye is a ball tracking technology that predicts the trajectory of the ball in referrals for leg before wicket. If the initial slow motion video replay has confirmed that the bowler bowled a legal delivery and that the ball has not touched the batter’s bat or glove, then the hawk-eye is employed. It is used to check if the ball would have gone on to hit the stumps it the batter’s legs or any other part of the body would have hindered the ball’s path towards the stumps. A total of 6 cameras with a speed of 340 frame per seconds is used in the hawk-eye.
Hotspot
The hotspot technology is an infrared imaging system that requires heavy equipment installation. It utilizes two cameras which are placed on opposite sides of the ground. The heat generated by the friction of the ball with the batter’s bat or any other part of the body is detected as a white spot. It helps in improving the efficacy of decisions of the umpires when an appeal is made for caught behind or leg before wicket.
Number of reviews
There are two types of reviews: Umpire review and Player or Team review. An umpire review is when the umpires want a better clarification on a proceeding in which they have their doubts. Umpire reviews do not count as player reviews.
Player reviews, irrespective of any format must be taken within 15 seconds after the umpire’s decision. In ODI and T20 cricket, a team has one review. If their review is successful, they retain their review. In Test cricket, a team has two reviews per innings. Unused reviews of first innings are not carried forward to the second innings. If the decision of the review says “Umpire’s call” the team will retain its review.
