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Hawk Eye Technology - An Understanding


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A detailed understanding about the technology and its implementations in various sports along with its limitations in Cricket. Comment your queries and mail me if you want to discuss upon this with me at

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Hawk Eye Technology - An Understanding

  1. 1. Hawk Eye Technology
  2. 2. Once there was a Hockey coach who used to tell his team to start every match by imagining they were 0-3 down, “A goal for your weaknesses, another for your opponent’s strengths and a third for umpiring errors.”
  3. 3. Humans are fallible, deciding who has won a tennis game or a sprint race can come down to a millimeter -accurate decision. So when an Olympic gold medal is on the line, it’s no wonder we turn to electronics to help us.
  4. 4. It was developed by the engineers of Roke Manor Research Limited in 2001. This technology was created by Dr. Paul Hawkins
  5. 5. Hawk Eye basically consist of two significant parts: Tracking System Video Replay System
  6. 6. Schematic Layout:
  7. 7. Principle: Its works basically on the Principle of Triangulation.
  8. 8. 𝑙 = 𝑑 tan 𝛼 + 𝑑 tan 𝛽 𝑑 = 𝑙 𝑑 tan 𝛼 + 𝑑 tan 𝛽 Principle of Triangulation:
  9. 9. Hawk Eye uses high range algorithms to predict the trajectory of the ball and for that it generally takes two inputs: Video produced by 6 different cameras Speed of the ball
  10. 10. The 6 cameras are placed as shown:
  11. 11. Hawk Eye’s Core Image Processing Job is done in 3 steps: Identifying pixels representing the ball in each image. Applying some geometric algorithm on the set of images at each instant. Coming up with the 3D position of the ball in space. 𝐷𝑒𝑝𝑡ℎ = 𝑟 − (𝑟 cos( θ )+ 𝑥 sin( θ ))
  12. 12. Hawk Eye is used in the following:- Tennis Cricket Badminton Snooker Baseball Rugby Volley ball Military and Defense Services
  13. 13. In Tennis: • It is majorly used for making Line calls i.e judges whether the impact of the ball is IN or OUT. • To locate the player moving areas.
  14. 14. In Cricket: Apart like Tennis, here in Cricket the Hawk Eye is used for many other purposes like: LBW Decisions Wagon Wheels Pitch Maps De Spin Rail Cam Beehives
  15. 15. LBW Decision: For an umpire to give an LBW decision, he checks for the following : Whether the ball did not pitch outside leg stump. If the batsman offered a shot, the ball hit him in line with the stumps. Whether the ball did not hit the bat first. The ball would have gone on to hit the stumps.
  16. 16. Wagon Wheels:
  17. 17. Pitch Maps:
  18. 18. De Spin:
  19. 19. Rail Cam:
  20. 20. Beehives:
  21. 21. In Snooker:
  22. 22. In Automobile and Military Power:
  23. 23. BEYOND THE LINE CALL: How Hawk-Eye can improve performance Hawk Eye is not just used to make line calls, there is much more than line calls for Hawk Eye. It is used as a data source to analyze the game. Tennis Australia (TA) is amassing richer data sources than ever. At this year’s Australian Open, Hawk-Eye based insights as a tool for pre-match opposition analysis will be greater utilized than ever before by Tennis Australia’s High- Performance unit. Hawk-Eye has been deployed on multiple courts at the Australian Open and AO series events (Brisbane and Sydney for example) since 2007, and as such we have tracking data for some 250 tennis players. Thanks partially to funding from an Australian Institute of Sport (AIS) grant, an app (like the ones on your favorite smart-phone) has been constructed using open source technologies with Hawk- eye data at its core. Coaches can log-in from anywhere in the world, and interactivity sort and visualize data, tapping into their unique expertise without the need to consult the performance analysis team every time they want to delve deeper into the data.
  24. 24. Limitations in Cricket:
  25. 25. LBW Decision: For an umpire to give an LBW decision, he checks for the following : Whether the ball did not pitch outside leg stump. If the batsman offered a shot, the ball hit him in line with the stumps. Whether the ball did not hit the bat first. The ball would have gone on to hit the stumps.
  26. 26. Side view of the trajectory of ball during LBW:
  27. 27. Another Limitation with Impact: • Law 5 states that a cricket ball must have a circumference not less than 22.4 cms and not greater than 22.9 cms. I will now draw out what the margin of error should look like if Hawkeye were to create a graphic that actually demonstrated what their technology can do, according to their own specifications. For the purpose of this argument, let's assume that the diameter of our chosen cricket ball is 22.5cms. Assuming Pi to be the ratio 22/7, the diameter of our cricket ball is 7.16 cms. Let's consider the margins of error reported by Hawkeye in various conditions in sequence. In each image the light gray band is the margin of error.
  28. 28. 1. Pitching Point, Interception Point accuracy between 2.6 - 5mm. Let's say that the pitching point accuracy is 3mm. It appears as in figure(a) 2. Predicted impact in the plane of the stumps - between 0 and 15mm, average 5mm, for normal LBWs. Let's assume 5mm. It appears as in figure(b) 3. Predicted impact in the plane of the stumps, less than 25mm for "extreme" LBW's. "Extreme" LBW's are typically ones where the batsman is well forward and is playing a fairly full ball but get's hit on the pad. Let's be generous as assume that the error in such instances is 15mm. It appears as in figure(c).
  29. 29. Conclusion We have looked at various aspects of the HAWKEYE technology. Initially, we outlined the main problems which one could encounter while trying to implement such a system for a sport like cricket. Then, we looked into the details of each step of the process which finally gives us the wonderful looking graphics that we see on TV during cricket analysis shows. We have thus seen that the HAWKEYE is a great innovation, which puts technology to good use in the field of sports. The technology is used widely these days, in sports such as Tennis and Cricket. The accuracy which can be achieved with the use of the system is making the authorities think seriously about reducing the human error component involved in important decisions. As the system runs in real time, there is no extra time required to see the visualizations and graphics. The system is also a great tool which can be used by players, statisticians, tacticians, coaches to analyze previous games and come up with strategies for subsequent ones.
  30. 30. References • Conway, Richard “Goal –line technology edges closer,” BBC Sport. Retrieved 18 May 2012. • Video Processor Systems for Ball Tracking in Ball Games. International Patent • IEEE Spectrum:Hawk Eye in the Crosshairs at Wimbledon Again. Retrieved on 15-08-2010 • • • • •