Presented by
Nikhil Mohan Narsapur

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HAWK EYE
What is Hawk Eye?
 Hawk-Eye is a used to track the path of the ball.
 In some sports, like tennis, it is now part of the adjudication process.
 It is also used in some instances to predict the future path of a ball in cricket.
History
 Developed by engineers at Roke Manor Research Limited of Romsey Hampshire in the UK, in 2001.
 A UK patent was submitted but withdrawn by Dr Paul Hawkins and David Sherry.
 Later was given to Hawk-Eye Innovations Ltd., as a joint venture with television production company Sunset+Vine.
General Overview
 Applicable to ball games.
 Our discussion will mostly contain applications which specific to the game of cricket.
Various Issues
1. Dimensions of ground can vary greatly.
2. More cameras to get the coverage of the entire field.
3. Fielders and spectators might obstruct the camera’s view of the ball
4. The ball might get confused with other similar objects.
5. To help in judging LBW calls.
6. To determine the points at which the ball makes contact with the pitch.
Flow Chart
Step-by-step details of the HAWKEYE system
1 The cameras
2 Preparation before starting to process
3 Core Image Processing Job
The cameras
Preparation before starting to process
 A predetermined model is loaded.
 The statistics generator might also aid in storing data such as the average velocity of the ball.
 This data is crucial as it can help the ball detection algorithm to predict the rough location of the ball in an image given the position in the previous image.
Core Image Processing Job
This part of the system can be further divided into 4 major parts
(1) Identifying pixels representing the ball in each image.
(2) Applying some geometric algorithm on the set of images at each instant.
(3) Coming up with the 3D position of the ball in space.
(4) Putting frames at various times together
Identifying pixels
 An algorithm is used to find the pixels corresponding to the ball in the image obtained.
 A blob detection scheme can be used to detect a round object in the image.
 We have as output the x and y co-ordinates of the ball in each image.
Geometric Algorithm
 The data of x and y co-ordinates from each camera is obtained by the Geometric Algorithm which is at work inside the HAWKEYE system.
 Knowing the exact positions of the cameras in space and the x and y co-ordinates of the ball one can determine accurately the position of the ball in 3D.
The ball is actually at the position shown by the red circle, at some height above ground.
The view in the cameras will look something like the one shown below. The view below shows the picture as seen by Camera 2 in the figure above.
Depth
 Let us assume that the radial angle, as seen from the wickets marked in the figure, between Camera 1 and Camera 2 is θ and the radius of the field is r. Then, the depth of the ball as seen from Camera 2 is as follows:
Putting frames at various times together
The two parts to this computation are:
(a) Tracking the ball at various instants.
(b) Predicting the flight or trajectory of the ball.
(a) Tracking the ball at various instants:
 The images are taken by cameras at times t0, t1,…..,tn during the play of a single ball.
 Computation done at each time instant, ti ,0≤i≤n we will get n points, say (xi,yi,zi) for 0≤i≤n.
 Plot the n points.
(b) Predicting the flight or trajectory of the ball:
 There is a standard technique, used commonly i.e. Computer Aided Geometric Design
 The more points we can get on the curve and the higher degree of polynomial basis we choose to use, we will end up with better approximations to the original curve.
 It goes through some points which are of special interest. These include the ball hitting the pitch, the stumps, and the batsman among others.
The Triangulation Process
 Triangulation can also refer to the accurate surveying of systems of very large triangles, called triangulation networks.
 how a point could be located from the angles subtended from three known points, but measured at the new unknown point rather than the previously fixed points, a problem called resectioning.
Applications of Hawk Eye
 Mainly used in ball games with predetermined area.
 Strategy formulation and studies.
 Gathering statistics
LBW Decisions
As mentioned previously, the HAWKEYE can accurately capture the trajectory of the ball and also predict the future direction of the ball using mathematical calculations.
Wagon Wheels
The trajectories which the ball has taken after being hit by the batsman are recorded in the system. This is used to generate a graphic showing 1s, 2s, 3s, 4s, and 6s all in different colours for a batsman.
Pitch Maps
As shown above, the Pitch Map graphic uses information about the position where the ball bounced on the pitch. The image above clearly shows the pitch being divided into various “zones” which the experts consider in their analysis.
 DeSpin
 RailCam
 Beehives
Tennis
 Hawk Eye was first used in the year 2004.
 In tennis Hawk Eye generates the impact of the ball whether the ball is ‘IN’ or ‘OUT’.
Snooker
This technology is useful in cases where the path of the cue ball can be tracked.
It is now being widely used in the computer games too. ‘Brain Lara 2005’ uses this in its special feature.
Conclusion
 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.
 Very fast and accurate(99.99%).
 Has a great future
 Hawk Eye is currently developing a system for Football.